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Sample records for atomic layer deposition

  1. Atomic layer deposition of nanoporous biomaterials

    Directory of Open Access Journals (Sweden)

    Roger J Narayan

    2010-03-01

    Full Text Available Due to its chemical stability, uniform pore size, and high pore density, nanoporous alumina is being investigated for use in biosensing, drug delivery, hemodialysis, and other medical applications. In recent work, we have examined the use of atomic layer deposition for coating the surfaces of nanoporous alumina membranes. Zinc oxide coatings were deposited on nanoporous alumina membranes using atomic layer deposition. The zinc oxide-coated nanoporous alumina membranes demonstrated antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria. These results suggest that atomic layer deposition is an attractive technique for modifying the surfaces of nanoporous alumina membranes and other nanostructured biomaterials.

  2. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-30

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  3. Spatial atomic layer deposition: a route towards further industrialization of atomic layer deposition

    NARCIS (Netherlands)

    Poodt, P.W.G.; Cameron, D.C.; Dickey, E.; George, S.M.; Kuznetsov, V.; Parsons, G.N.; Roozeboom, F.; Sundaram, G.; Vermeer, A.

    2012-01-01

    Atomic layer deposition (ALD) is a technique capable of producing ultrathin conformal films with atomic level control over thickness. A major drawback of ALD is its low deposition rate, making ALD less attractive for applications that require high throughput processing. An approach to overcome this

  4. Atomic layer deposition of nanoporous biomaterials.

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, R. J.; Adiga, S. P.; Pellin, M. J.; Curtiss, L. A.; Stafslien, S.; Chisholm, B.; Monteiro-Riviere, N. A.; Brigmon, R. L.; Elam, J. W.; Univ. of North Carolina; North Carolina State Univ.; Eastman Kodak Co.; North Dakota State Univ.; SRL

    2010-03-01

    Due to its chemical stability, uniform pore size, and high pore density, nanoporous alumina is being investigated for use in biosensing, drug delivery, hemodialysis, and other medical applications. In recent work, we have examined the use of atomic layer deposition for coating the surfaces of nanoporous alumina membranes. Zinc oxide coatings were deposited on nanoporous alumina membranes using atomic layer deposition. The zinc oxide-coated nanoporous alumina membranes demonstrated antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria. These results suggest that atomic layer deposition is an attractive technique for modifying the surfaces of nanoporous alumina membranes and other nanostructured biomaterials. Nanoporous alumina, also known as anodic aluminum oxide (AAO), is a nanomaterial that exhibits several unusual properties, including high pore densities, straight pores, small pore sizes, and uniform pore sizes. In 1953, Keller et al. showed that anodizing aluminum in acid electrolytes results in a thick layer of nearly cylindrical pores, which are arranged in a close-packed hexagonal cell structure. More recently, Matsuda & Fukuda demonstrated preparation of highly ordered platinum and gold nanohole arrays using a replication process. In this study, a negative structure of nanoporous alumina was initially fabricated and a positive structure of a nanoporous metal was subsequently fabricated. Over the past fifteen years, nanoporous alumina membranes have been used as templates for growth of a variety of nanostructured materials, including nanotubes, nanowires, nanorods, and nanoporous membranes.

  5. Texture of atomic layer deposited ruthenium

    OpenAIRE

    Musschoot, J.; Xie, Q; Deduytsche, D.; De Keyser, K; Longrie, D.; Haemers, J.; Van den Berghe, S.; Van Meirhaeghe, R. L.; D'Haen, Jan; Detavernier, C

    2010-01-01

    Ruthenium films were grown by plasma enhanced atomic layer deposition (ALD) on Si(1 0 0) and ALD TiN. X-ray diffraction (XRD) showed that the as-deposited films on Si(1 0 0) were polycrystalline, on TiN they were (0 0 2) oriented. After annealing at 800 degrees C for 60 s, all Ru films were strongly (0 0 2) textured and very smooth. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) demonstrated that the lateral grain size of the annealed films was several 100 ...

  6. Bioactive surfaces with atomic layer deposition

    OpenAIRE

    Kvalvik, Julie Nitsche

    2015-01-01

    The overall goal of this work has been to make bioactive surfaces with atomic layer deposition (ALD). To do this, a new ALD system with titanium tetraisopropoxide (TTIP) and lysine as precursors was developed with emphasis on studying the effects of pulsing times and deposition temperatures. TTIP was chosen as titanium is regarded to be biocompatible and lysine was chosen as poly-L-lysine is a part of the extra-cellular matrix (ECM) and hence affects cell adhesion. The effect of a water pulse...

  7. Atomic-layer deposition of silicon nitride

    CERN Document Server

    Yokoyama, S; Ooba, K

    1999-01-01

    Atomic-layer deposition (ALD) of silicon nitride has been investigated by means of plasma ALD in which a NH sub 3 plasma is used, catalytic ALD in which NH sub 3 is dissociated by thermal catalytic reaction on a W filament, and temperature-controlled ALD in which only a thermal reaction on the substrate is employed. The NH sub 3 and the silicon source gases (SiH sub 2 Cl sub 2 or SiCl sub 4) were alternately supplied. For all these methods, the film thickness per cycle was saturated at a certain value for a wide range of deposition conditions. In the catalytic ALD, the selective deposition of silicon nitride on hydrogen-terminated Si was achieved, but, it was limited to only a thin (2SiO (evaporative).

  8. Hybrid inorganic–organic superlattice structures with atomic layer deposition/molecular layer deposition

    OpenAIRE

    Tynell, Tommi; Yamauchi, Hisao; Karppinen, Maarit

    2014-01-01

    A combination of the atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques is successfully employed to fabricate thin films incorporating superlattice structures that consist of single layers of organic molecules between thicker layers of ZnO. Diethyl zinc and water are used as precursors for the deposition of ZnO by ALD, while three different organic precursors are investigated for the MLD part: hydroquinone, 4-aminophenol and 4,4′-oxydianiline. The successful superla...

  9. USE OF ATOMIC LAYER DEPOSITION OF FUNCTIONALIZATION OF NANOPOROUS BIOMATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.; Narayan, R.; Adiga, S.; Pellin, M.; Curtiss, L.; Stafslien, S.; Chisholm, B.; Monteiro-Riviere, N.; Elam, J.

    2010-02-08

    Due to its chemical stability, uniform pore size, and high pore density, nanoporous alumina is being investigated for use in biosensing, drug delivery, hemodialysis, and other medical applications. In recent work, we have examined the use of atomic layer deposition for coating the surfaces of nanoporous alumina membranes. Zinc oxide coatings were deposited on nanoporous alumina membranes using atomic layer deposition. The zinc oxide-coated nanoporous alumina membranes demonstrated antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria. These results suggest that atomic layer deposition is an attractive technique for modifying the surfaces of nanoporous alumina membranes and other nanostructured biomaterials.

  10. Atomic layer deposition of high-k oxides on graphene

    OpenAIRE

    Alles, Harry; Aarik, Jaan; Kozlova, Jekaterina; Niilisk, Ahti; Rammula, Raul; Sammelselg, Väino

    2011-01-01

    Comment: Graphene - Synthesis, Characterization, Properties and Applications, Jian Ru Gong (Ed.), ISBN: 978-953-307-292-0, InTech, Available from: http://www.intechopen.com/articles/show/title/atomic-layer-deposition-of-high-k-oxides-on-graphene

  11. A Review of Atomic Layer Deposition for Nanoscale Devices

    Directory of Open Access Journals (Sweden)

    Edy Riyanto

    2012-12-01

    Full Text Available Atomic layer deposition (ALD is a thin film growth technique that utilizes alternating, self-saturation chemical reactions between gaseous precursors to achieve a deposited nanoscale layers. It has recently become a subject of great interest for ultrathin film deposition in many various applications such as microelectronics, photovoltaic, dynamic random access memory (DRAM, and microelectromechanic system (MEMS. By using ALD, the conformability and extreme uniformity of layers can be achieved in low temperature process. It facilitates to be deposited onto the surface in many variety substrates that have low melting temperature. Eventually it has advantages on the contribution to the wider nanodevices.

  12. Hybrid inorganic–organic superlattice structures with atomic layer deposition/molecular layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tynell, Tommi; Yamauchi, Hisao; Karppinen, Maarit, E-mail: maarit.karppinen@aalto.fi [Department of Chemistry, Aalto University, FI-00076 Aalto (Finland)

    2014-01-15

    A combination of the atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques is successfully employed to fabricate thin films incorporating superlattice structures that consist of single layers of organic molecules between thicker layers of ZnO. Diethyl zinc and water are used as precursors for the deposition of ZnO by ALD, while three different organic precursors are investigated for the MLD part: hydroquinone, 4-aminophenol and 4,4′-oxydianiline. The successful superlattice formation with all the organic precursors is verified through x-ray reflectivity studies. The effects of the interspersed organic layers/superlattice structure on the electrical and thermoelectric properties of ZnO are investigated through resistivity and Seebeck coefficient measurements at room temperature. The results suggest an increase in carrier concentration for small concentrations of organic layers, while higher concentrations seem to lead to rather large reductions in carrier concentration.

  13. Hybrid inorganic–organic superlattice structures with atomic layer deposition/molecular layer deposition

    International Nuclear Information System (INIS)

    A combination of the atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques is successfully employed to fabricate thin films incorporating superlattice structures that consist of single layers of organic molecules between thicker layers of ZnO. Diethyl zinc and water are used as precursors for the deposition of ZnO by ALD, while three different organic precursors are investigated for the MLD part: hydroquinone, 4-aminophenol and 4,4′-oxydianiline. The successful superlattice formation with all the organic precursors is verified through x-ray reflectivity studies. The effects of the interspersed organic layers/superlattice structure on the electrical and thermoelectric properties of ZnO are investigated through resistivity and Seebeck coefficient measurements at room temperature. The results suggest an increase in carrier concentration for small concentrations of organic layers, while higher concentrations seem to lead to rather large reductions in carrier concentration

  14. Atomic Layer Deposited Catalysts for Fuel Cell Applications

    DEFF Research Database (Denmark)

    Johansson, Anne-Charlotte Elisabeth Birgitta

    techniques. Atomic layer deposition (ALD), on the other hand, is a highly suitable and still relatively unexplored approach for the synthesis of noble metal catalysts. It is a vapor phase growth method, primarily used to deposit thin lms. ALD is based on self-limiting chemical reactions of alternately...

  15. An Introduction to Atomic Layer Deposition with Thermal Applications

    Science.gov (United States)

    Dwivedi, Vivek H.

    2015-01-01

    Atomic Layer Deposition (ALD) is a cost effective nano-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign temperature and pressure environment. Through the introduction of paired precursor gases thin films can be deposited on a myriad of substrates ranging from glass, polymers, aerogels, and metals to high aspect ratio geometries. This talk will focus on the utilization of ALD for engineering applications.

  16. Properties of Ultra-Thin Hafnium Oxide and Interfacial Layer Deposited by Atomic Layer Deposition

    Institute of Scientific and Technical Information of China (English)

    Taeho Lee; Young-Bae Kim; Kyung-Il Hong; Duck-Kyun Choi; Jinho Ahn

    2004-01-01

    Ultra-thin hafnium-oxide gate dielectric films deposited by atomic layer deposition technique using HfCl4 and H2O precursor on a hydrogen-terminated Si substrate were investigated. X-ray photoelectron spectroscopy indicates that the interface layer is Hf-silicate rather than phase separated Hf-silicide and silicon oxide structure. The Hf-silicate interfacial layer partially changes into SiOx after high temperature annealing, resulting in a complex HfO2-silicate-SiOx dielectric structure. Electrical measurements confirms that HfO2 on Si is stable up to 700 ℃ for 30 s under N2 ambient.

  17. Atomic and molecular layer deposition for surface modification

    International Nuclear Information System (INIS)

    Atomic and molecular layer deposition (ALD and MLD, respectively) techniques are based on repeated cycles of gas–solid surface reactions. A partial monolayer of atoms or molecules is deposited to the surface during a single deposition cycle, enabling tailored film composition in principle down to molecular resolution on ideal surfaces. Typically ALD/MLD has been used for applications where uniform and pinhole free thin film is a necessity even on 3D surfaces. However, thin – even non-uniform – atomic and molecular deposited layers can also be used to tailor the surface characteristics of different non-ideal substrates. For example, print quality of inkjet printing on polymer films and penetration of water into porous nonwovens can be adjusted with low-temperature deposited metal oxide. In addition, adhesion of extrusion coated biopolymer to inorganic oxides can be improved with a hybrid layer based on lactic acid. - Graphical abstract: Print quality of a polylactide film surface modified with atomic layer deposition prior to inkjet printing (360 dpi) with an aqueous ink. Number of printed dots illustrated as a function of 0, 5, 15 and 25 deposition cycles of trimethylaluminum and water. - Highlights: • ALD/MLD can be used to adjust surface characteristics of films and fiber materials. • Hydrophobicity after few deposition cycles of Al2O3 due to e.g. complex formation. • Same effect on cellulosic fabrics observed with low temperature deposited TiO2. • Different film growth and oxidation potential with different precursors. • Hybrid layer on inorganic layer can be used to improve adhesion of polymer melt

  18. Atomic and molecular layer deposition for surface modification

    Energy Technology Data Exchange (ETDEWEB)

    Vähä-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland); Sievänen, Jenni; Salo, Erkki; Heikkilä, Pirjo; Kenttä, Eija [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland); Johansson, Leena-Sisko, E-mail: leena-sisko.johansson@aalto.fi [Aalto University, School of Chemical Technology, Department of Forest Products Technology, PO Box 16100, FI‐00076 AALTO (Finland); Koskinen, Jorma T.; Harlin, Ali [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland)

    2014-06-01

    Atomic and molecular layer deposition (ALD and MLD, respectively) techniques are based on repeated cycles of gas–solid surface reactions. A partial monolayer of atoms or molecules is deposited to the surface during a single deposition cycle, enabling tailored film composition in principle down to molecular resolution on ideal surfaces. Typically ALD/MLD has been used for applications where uniform and pinhole free thin film is a necessity even on 3D surfaces. However, thin – even non-uniform – atomic and molecular deposited layers can also be used to tailor the surface characteristics of different non-ideal substrates. For example, print quality of inkjet printing on polymer films and penetration of water into porous nonwovens can be adjusted with low-temperature deposited metal oxide. In addition, adhesion of extrusion coated biopolymer to inorganic oxides can be improved with a hybrid layer based on lactic acid. - Graphical abstract: Print quality of a polylactide film surface modified with atomic layer deposition prior to inkjet printing (360 dpi) with an aqueous ink. Number of printed dots illustrated as a function of 0, 5, 15 and 25 deposition cycles of trimethylaluminum and water. - Highlights: • ALD/MLD can be used to adjust surface characteristics of films and fiber materials. • Hydrophobicity after few deposition cycles of Al{sub 2}O{sub 3} due to e.g. complex formation. • Same effect on cellulosic fabrics observed with low temperature deposited TiO{sub 2}. • Different film growth and oxidation potential with different precursors. • Hybrid layer on inorganic layer can be used to improve adhesion of polymer melt.

  19. Nanostructure templating using low temperature atomic layer deposition

    Science.gov (United States)

    Grubbs, Robert K.; Bogart, Gregory R.; Rogers, John A.

    2011-12-20

    Methods are described for making nanostructures that are mechanically, chemically and thermally stable at desired elevated temperatures, from nanostructure templates having a stability temperature that is less than the desired elevated temperature. The methods comprise depositing by atomic layer deposition (ALD) structural layers that are stable at the desired elevated temperatures, onto a template employing a graded temperature deposition scheme. At least one structural layer is deposited at an initial temperature that is less than or equal to the stability temperature of the template, and subsequent depositions made at incrementally increased deposition temperatures until the desired elevated temperature stability is achieved. Nanostructure templates include three dimensional (3D) polymeric templates having features on the order of 100 nm fabricated by proximity field nanopatterning (PnP) methods.

  20. Plasma enhanced atomic layer deposition of ultrathin oxides on graphene

    Science.gov (United States)

    Trimble, Christie J.; Zaniewski, Anna M.; Kaur, Manpuneet; Nemanich, Robert J.

    2015-03-01

    Graphene, a single atomic layer of sp2 bonded carbon atoms, possesses extreme material properties that point toward a plethora of potential electronic applications. Many of these possibilities require the combination of graphene with dielectric materials such as metal oxides. Simultaneously, there is interest in new physical properties that emerge when traditionally three dimensional materials are constrained to ultrathin layers. For both of these objectives, we explore deposition of ultrathin oxide layers on graphene. In this project, we perform plasma enhanced atomic layer deposition (PEALD) of aluminum oxide on graphene that has been grown by chemical vapor deposition atop copper foil and achieve oxide layers that are <1.5 nm. Because exposure to oxygen plasma can cause the graphene to deteriorate, we explore techniques to mitigate this effect and optimize the PEALD process. Following deposition, the graphene and oxide films are transferred to arbitrary substrates for further analysis. We use x-ray photoelectron spectroscopy, Raman spectroscopy, and atomic force microscopy to assess the quality of the resulting films. This work is supported by the National Science Foundation under Grant # DMR-1206935.

  1. Creating large area molecular electronic junctions using atomic layer deposition

    International Nuclear Information System (INIS)

    We demonstrate a technique for creating large area, electrically stable molecular junctions. We use atomic layer deposition to create nanometer thick passivating layers of aluminum oxide on top of self-assembled organic monolayers with hydrophilic terminal groups. This layer acts as a protective barrier and allows simple vapor deposition of the top electrode without short circuits or molecular damage. This method allows nonshorting molecular junctions of up to 9 mm2 to be easily and reliably fabricated. The effect of passivation on molecular monolayers is studied with Auger and x-ray spectroscopy, while electronic transport measurements confirm molecular tunneling as the transport mechanism for these devices

  2. Carbon nanotube forests growth using catalysts from atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bingan; Zhang, Can; Esconjauregui, Santiago; Xie, Rongsi; Zhong, Guofang; Robertson, John [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Bhardwaj, Sunil [Istituto Officina dei Materiali-CNR Laboratorio TASC, s.s. 14, km 163.4, I-34012 Trieste (Italy); Sincrotone Trieste S.C.p.A., s.s. 14, km 163.4, I-34149 Trieste (Italy); Cepek, Cinzia [Istituto Officina dei Materiali-CNR Laboratorio TASC, s.s. 14, km 163.4, I-34012 Trieste (Italy)

    2014-04-14

    We have grown carbon nanotubes using Fe and Ni catalyst films deposited by atomic layer deposition. Both metals lead to catalytically active nanoparticles for growing vertically aligned nanotube forests or carbon fibres, depending on the growth conditions and whether the substrate is alumina or silica. The resulting nanotubes have narrow diameter and wall number distributions that are as narrow as those grown from sputtered catalysts. The state of the catalyst is studied by in-situ and ex-situ X-ray photoemission spectroscopy. We demonstrate multi-directional nanotube growth on a porous alumina foam coated with Fe prepared by atomic layer deposition. This deposition technique can be useful for nanotube applications in microelectronics, filter technology, and energy storage.

  3. Atomic layer deposited aluminum oxide barrier coatings for packaging materials

    Energy Technology Data Exchange (ETDEWEB)

    Hirvikorpi, Terhi, E-mail: terhi.hirvikorpi@vtt.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Vaehae-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Mustonen, Tuomas, E-mail: tuomas.mustonen@vtt.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Iiskola, Eero, E-mail: eero.iiskola@kcl.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Karppinen, Maarit, E-mail: maarit.karppinen@tkk.f [Laboratory of Inorganic Chemistry, Department of Chemistry, Helsinki University of Technology, P.O. Box 6100, FI-02015 TKK (Finland)

    2010-03-01

    Thin aluminum oxide coatings have been deposited at a low temperature of 80 {sup o}C on various uncoated papers, polymer-coated papers and boards and plain polymer films using the atomic layer deposition (ALD) technique. The work demonstrates that such ALD-grown Al{sub 2}O{sub 3} coatings efficiently enhance the gas-diffusion barrier performance of the studied porous and non-porous materials towards oxygen, water vapor and aromas.

  4. Cost-Effective Systems for Atomic Layer Deposition

    Science.gov (United States)

    Lubitz, Michael; Medina, Phillip A., IV; Antic, Aleks; Rosin, Joseph T.; Fahlman, Bradley D.

    2014-01-01

    Herein, we describe the design and testing of two different home-built atomic layer deposition (ALD) systems for the growth of thin films with sub-monolayer control over film thickness. The first reactor is a horizontally aligned hot-walled reactor with a vacuum purging system. The second reactor is a vertically aligned cold-walled reactor with a…

  5. Silicon protected with atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Seger, Brian; Tilley, David S.; Pedersen, Thomas;

    2013-01-01

    The semiconducting materials used for photoelectrochemical (PEC) water splitting must withstand the corrosive nature of the aqueous electrolyte over long time scales in order to be a viable option for large scale solar energy conversion. Here we demonstrate that atomic layer deposited titanium...

  6. Atomic layer deposition of alternative glass microchannel plates

    International Nuclear Information System (INIS)

    The technique of atomic layer deposition (ALD) has enabled the development of alternative glass microchannel plates (MCPs) with independently tunable resistive and emissive layers, resulting in excellent thickness uniformity across the large area (20 × 20 cm), high aspect ratio (60:1 L/d) glass substrates. Furthermore, the use of ALD to deposit functional layers allows the optimal substrate material to be selected, such as borosilicate glass, which has many benefits compared to the lead-oxide glass used in conventional MCPs, including increased stability and lifetime, low background noise, mechanical robustness, and larger area (at present up to 400 cm2). Resistively stable, high gain MCPs are demonstrated due to the deposition of uniform ALD resistive and emissive layers on alternative glass microcapillary substrates. The MCP performance characteristics reported include increased stability and lifetime, low background noise (0.04 events cm−2 s−1), and low gain variation (±5%)

  7. Passivation effects of atomic-layer-deposited aluminum oxide

    Directory of Open Access Journals (Sweden)

    Kotipalli R.

    2013-09-01

    Full Text Available Atomic-layer-deposited (ALD aluminum oxide (Al2O3 has recently demonstrated an excellent surface passivation for both n- and p-type c-Si solar cells thanks to the presence of high negative fixed charges (Qf ~ 1012−1013 cm-2 in combination with a low density of interface states (Dit. This paper investigates the passivation quality of thin (15 nm Al2O3 films deposited by two different techniques: plasma-enhanced atomic layer deposition (PE-ALD and Thermal atomic layer deposition (T-ALD. Other dielectric materials taken into account for comparison include: thermally-grown silicon dioxide (SiO2 (20 nm, SiO2 (20 nm deposited by plasma-enhanced chemical vapour deposition (PECVD and hydrogenated amorphous silicon nitride (a-SiNx:H (20 nm also deposited by PECVD. With the above-mentioned dielectric layers, Metal Insulator Semiconductor (MIS capacitors were fabricated for Qf and Dit extraction through Capacitance-Voltage-Conductance (C-V-G measurements. In addition, lifetime measurements were carried out to evaluate the effective surface recombination velocity (SRV. The influence of extracted C-V-G parameters (Qf,Dit on the injection dependent lifetime measurements τ(Δn, and the dominant passivation mechanism involved have been discussed. Furthermore we have also studied the influence of the SiO2 interfacial layer thickness between the Al2O3 and silicon surface on the field-effect passivation mechanism. It is shown that the field effect passivation in accumulation mode is more predominant when compared to surface defect passivation.

  8. Graphene oxide monolayers as atomically thin seeding layers for atomic layer deposition of metal oxides

    Science.gov (United States)

    Nourbakhsh, Amirhasan; Adelmann, Christoph; Song, Yi; Lee, Chang Seung; Asselberghs, Inge; Huyghebaert, Cedric; Brizzi, Simone; Tallarida, Massimo; Schmeißer, Dieter; van Elshocht, Sven; Heyns, Marc; Kong, Jing; Palacios, Tomás; de Gendt, Stefan

    2015-06-01

    Graphene oxide (GO) was explored as an atomically-thin transferable seed layer for the atomic layer deposition (ALD) of dielectric materials on any substrate of choice. This approach does not require specific chemical groups on the target surface to initiate ALD. This establishes GO as a unique interface which enables the growth of dielectric materials on a wide range of substrate materials and opens up numerous prospects for applications. In this work, a mild oxygen plasma treatment was used to oxidize graphene monolayers with well-controlled and tunable density of epoxide functional groups. This was confirmed by synchrotron-radiation photoelectron spectroscopy. In addition, density functional theory calculations were carried out on representative epoxidized graphene monolayer models to correlate the capacitive properties of GO with its electronic structure. Capacitance-voltage measurements showed that the capacitive behavior of Al2O3/GO depends on the oxidation level of GO. Finally, GO was successfully used as an ALD seed layer for the deposition of Al2O3 on chemically inert single layer graphene, resulting in high performance top-gated field-effect transistors.Graphene oxide (GO) was explored as an atomically-thin transferable seed layer for the atomic layer deposition (ALD) of dielectric materials on any substrate of choice. This approach does not require specific chemical groups on the target surface to initiate ALD. This establishes GO as a unique interface which enables the growth of dielectric materials on a wide range of substrate materials and opens up numerous prospects for applications. In this work, a mild oxygen plasma treatment was used to oxidize graphene monolayers with well-controlled and tunable density of epoxide functional groups. This was confirmed by synchrotron-radiation photoelectron spectroscopy. In addition, density functional theory calculations were carried out on representative epoxidized graphene monolayer models to correlate the

  9. Plasma enhanced atomic layer deposition of silicon nitride using neopentasilane

    International Nuclear Information System (INIS)

    Progress in transistor scaling has increased the demands on the material properties of silicon nitride (SiNx) thin films used in device fabrication and at the same time placed stringent restrictions on the deposition conditions employed. Recently, low temperature plasma enhanced atomic layer deposition has emerged as a viable technique for depositing these films with a thermal budget compatible with semiconductor processing at sub-32 nm technology nodes. For these depositions, it is desirable to use precursors that are free from carbon and halogens that can incorporate into the film. Beyond this, it is necessary to develop processing schemes that minimize the wet etch rate of the film as it will be subjected to wet chemical processing in subsequent fabrication steps. In this work, the authors introduce low temperature deposition of SiNx using neopentasilane [NPS, (SiH3)4Si] in a plasma enhanced atomic layer deposition process with a direct N2 plasma. The growth with NPS is compared to a more common precursor, trisilylamine [TSA, (SiH3)3 N] at identical process conditions. The wet etch rates of the films deposited with NPS are characterized at different plasma conditions and the impact of ion energy is discussed

  10. Plasma enhanced atomic layer deposition of silicon nitride using neopentasilane

    Energy Technology Data Exchange (ETDEWEB)

    Weeks, Stephen, E-mail: Stephen.Weeks@intermolecular.com; Nowling, Greg; Fuchigami, Nobi; Bowes, Michael; Littau, Karl [Intermolecular, 3011 North 1st Street, San Jose, California 95134 (United States)

    2016-01-15

    Progress in transistor scaling has increased the demands on the material properties of silicon nitride (SiN{sub x}) thin films used in device fabrication and at the same time placed stringent restrictions on the deposition conditions employed. Recently, low temperature plasma enhanced atomic layer deposition has emerged as a viable technique for depositing these films with a thermal budget compatible with semiconductor processing at sub-32 nm technology nodes. For these depositions, it is desirable to use precursors that are free from carbon and halogens that can incorporate into the film. Beyond this, it is necessary to develop processing schemes that minimize the wet etch rate of the film as it will be subjected to wet chemical processing in subsequent fabrication steps. In this work, the authors introduce low temperature deposition of SiN{sub x} using neopentasilane [NPS, (SiH{sub 3}){sub 4}Si] in a plasma enhanced atomic layer deposition process with a direct N{sub 2} plasma. The growth with NPS is compared to a more common precursor, trisilylamine [TSA, (SiH{sub 3}){sub 3 }N] at identical process conditions. The wet etch rates of the films deposited with NPS are characterized at different plasma conditions and the impact of ion energy is discussed.

  11. Atomic layer deposition in porous structures: 3D photonic crystals

    International Nuclear Information System (INIS)

    This paper reports recent results from studies of atomic layer deposition for the infiltration of three-dimensional photonic crystals. Infiltration of ZnS:Mn and TiO2 are reported for SiO2-based opal templates. It has been demonstrated that high filling fractions can be achieved and that the infiltrated material can be of high crystalline quality as assessed by photoluminescence measurements. The highly conformal and uniform coatings obtained in these studies are shown to contribute significantly to the photonic band gap properties. These investigations show the advantages of atomic layer deposition (ALD) as a flexible and practical pathway for attaining high performance photonic crystal structures and optical microcavities

  12. Blistering during the atomic layer deposition of iridium

    International Nuclear Information System (INIS)

    The authors report on the formation of blisters during the atomic layer deposition of iridium using iridium acetylacetonate and oxygen precursors. Films deposited on fused silica substrates led to sparsely distributed large blisters while in the case of silicon with native oxide additional small blisters with a high density was observed. It is found that the formation of blisters is favored by a higher deposition temperature and a larger layer thickness. Postdeposition annealing did not have a significant effect on the formation of blisters. Finally, changing purge duration during the film growth allowed us to avoid blistering and evidenced that impurities released from the film in gas phase were responsible for the formation of blisters

  13. Blistering during the atomic layer deposition of iridium

    Energy Technology Data Exchange (ETDEWEB)

    Genevée, Pascal, E-mail: pascal-genevee@chimie-paristech.fr, E-mail: a.szeghalmi@uni-jena.de; Ahiavi, Ernest; Janunts, Norik; Pertsch, Thomas; Kley, Ernst-Bernhard; Szeghalmi, Adriana, E-mail: pascal-genevee@chimie-paristech.fr, E-mail: a.szeghalmi@uni-jena.de [Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Oliva, Maria [Fraunhofer IOF, Albert-Einstein-Strasse 7, 07743 Jena (Germany)

    2016-01-15

    The authors report on the formation of blisters during the atomic layer deposition of iridium using iridium acetylacetonate and oxygen precursors. Films deposited on fused silica substrates led to sparsely distributed large blisters while in the case of silicon with native oxide additional small blisters with a high density was observed. It is found that the formation of blisters is favored by a higher deposition temperature and a larger layer thickness. Postdeposition annealing did not have a significant effect on the formation of blisters. Finally, changing purge duration during the film growth allowed us to avoid blistering and evidenced that impurities released from the film in gas phase were responsible for the formation of blisters.

  14. Holmium and titanium oxide nanolaminates by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kukli, Kaupo, E-mail: kaupo.kukli@helsinki.fi [University of Helsinki, Department of Chemistry, University of Helsinki FI-00014 Helsinki (Finland); University of Tartu, Institute of Physics, Department of Materials Science, EE-50411 Tartu (Estonia); Lu, Jun [Linköping University, Department of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, SE-58183 (Sweden); Link, Joosep [National Institute of Chemical Physics and Biophysics, EE-12618 Tallinn (Estonia); Kemell, Marianna; Puukilainen, Esa; Heikkilä, Mikko [University of Helsinki, Department of Chemistry, University of Helsinki FI-00014 Helsinki (Finland); Hoxha, Roland; Tamm, Aile [University of Tartu, Institute of Physics, Department of Materials Science, EE-50411 Tartu (Estonia); Hultman, Lars [Linköping University, Department of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, SE-58183 (Sweden); Stern, Raivo [National Institute of Chemical Physics and Biophysics, EE-12618 Tallinn (Estonia); Ritala, Mikko; Leskelä, Markku [University of Helsinki, Department of Chemistry, University of Helsinki FI-00014 Helsinki (Finland)

    2014-08-28

    Nanolaminate (nanomultilayer) thin films of TiO{sub 2} and Ho{sub 2}O{sub 3} were grown on Si(001) substrates by atomic layer deposition at 300 °C from alkoxide and β-diketonate based metal precursors and ozone. Individual layer thicknesses were 2 nm for TiO{sub 2} and 4.5 nm for Ho{sub 2}O{sub 3}. As-deposited films were smooth and X-ray amorphous. After annealing at 800 °C and higher temperatures the nanolaminate structure was destroyed by solid-state reaction to form Ho{sub 2}Ti{sub 2}O{sub 7}. The films demonstrated diamagnetic or paramagnetic behaviour in the as-deposited state. After annealing, the films possessed net magnetic moment, allowing one to record saturation magnetization and weak coercivity. - Highlights: • Ho{sub 2}O{sub 3}–TiO{sub 2} nanolaminates were grown by atomic layer deposition. • Ho{sub 2}O{sub 3}–TiO{sub 2} nanolaminates were crystallized at 700–800 deg. • Ternary Ho{sub 2}Ti{sub 2}O{sub 7} was formed upon annealing. • Annealed Ho{sub 2}O{sub 3}–TiO{sub 2} demonstrated soft magnetization hysteresis at room temperature.

  15. Holmium and titanium oxide nanolaminates by atomic layer deposition

    International Nuclear Information System (INIS)

    Nanolaminate (nanomultilayer) thin films of TiO2 and Ho2O3 were grown on Si(001) substrates by atomic layer deposition at 300 °C from alkoxide and β-diketonate based metal precursors and ozone. Individual layer thicknesses were 2 nm for TiO2 and 4.5 nm for Ho2O3. As-deposited films were smooth and X-ray amorphous. After annealing at 800 °C and higher temperatures the nanolaminate structure was destroyed by solid-state reaction to form Ho2Ti2O7. The films demonstrated diamagnetic or paramagnetic behaviour in the as-deposited state. After annealing, the films possessed net magnetic moment, allowing one to record saturation magnetization and weak coercivity. - Highlights: • Ho2O3–TiO2 nanolaminates were grown by atomic layer deposition. • Ho2O3–TiO2 nanolaminates were crystallized at 700–800 deg. • Ternary Ho2Ti2O7 was formed upon annealing. • Annealed Ho2O3–TiO2 demonstrated soft magnetization hysteresis at room temperature

  16. Characterization of hafnium oxide resistive memory layers deposited on copper by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, B.D.; Bishop, S.M. [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States); Leedy, K.D. [Air Force Research Laboratory, 2241 Avionics Circle, Wright Patterson Air Force Base, Dayton, OH 45433 (United States); Cady, N.C., E-mail: ncady@albany.edu [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States)

    2014-07-01

    Hafnium oxide-based resistive memory devices have been fabricated on copper bottom electrodes. The HfO{sub x} active layers in these devices were deposited by atomic layer deposition (ALD) at 250 °C with tetrakis(dimethylamido)hafnium(IV) as the metal precursor and an O{sub 2} plasma as the reactant. Depth profiles of the HfO{sub x} by X-ray photoelectron spectroscopy and secondary ion mass spectroscopy revealed a copper concentration on the order of five atomic percent throughout the HfO{sub x} film. In addition to the Cu doped HfO{sub x}, a thin layer (20 nm) of Cu{sub x}O is present at the surface. This surface layer is believed to have formed during the ALD process, and greatly complicates the analysis of the switching mechanism. The resistive memory structures fabricated from the ALD HfO{sub x} exhibited non-polar resistive switching, independent of the top metal electrode (Ni, Pt, Al, Au). Resistive switching current voltage (I–V) curves were analyzed using Schottky emission and ionic hopping models to gain insight into the physical mechanisms underpinning the device behavior. During the forming process it was determined that, at voltages in excess of 2.5 V, an ionic hopping model is in good agreement with the I–V data. The extracted ion hopping distance ∼ 4 Å was within the range of interatomic spacing of HfO{sub 2} during the forming process consistent with ionic motion of Cu{sup 2+} ions. Lastly the on state I–V data was dominated at larger voltages by Schottky emission with an estimated barrier height of ∼ 0.5 eV and a refractive index of 2.59. The consequence of the Schottky emission analysis indicates the on state resistance to be a product of a Pt/Cu{sub 2}O/Cu filament(s)/Cu{sub 2}O/Cu structure. - Highlights: • HfO{sub 2} was grown via atomic layer deposition at 250 and 100 °C on Cu substrates. • A Cu{sub 2}O surface layer and Cu doping were observed in post-deposition of HfO{sub 2}. • Resistive memory devices were fabricated and

  17. Atomic layer deposition and characterization of biocompatible hydroxyapatite thin films

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) was used to produce hydroxyapatite from Ca(thd)2 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) and (CH3O)3PO onto Si(100) and Corning (0211). Film crystallinity, stoichiometry, possible impurities and surface morphology were determined. The as-deposited films contained significant amounts of carbonate impurities however, annealing at moist N2 flow reduced the carbonate content even at 400 oC. The as-deposited Ca-P-O films were amorphous but rapid thermal annealing promoted the formation of the hydroxyapatite phase. Mouse MC 3T3-E1 cells were used for the cell culture experiments. According to the bioactivity studies cell proliferation was enhanced on as-deposited ALD-grown Ca-P-O films and greatly enhanced on films annealed at 500 oC in comparison with reference cells on borosilicate glass or cell culture polystyrene.

  18. Monocrystalline zinc oxide films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wachnicki, L., E-mail: lwachn@ifpan.edu.p [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland); Krajewski, T.; Luka, G. [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland); Witkowski, B. [Cardinal Stefan Wyszynski University, College of Science, Department of Mathematics and Natural Sciences, Warszawa (Poland); Kowalski, B.; Kopalko, K.; Domagala, J.Z. [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland); Guziewicz, M. [Institute of Electron Technology (ITE), al. Lotnikow 32/46, Warsaw 02-668 (Poland); Godlewski, M. [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland); Cardinal Stefan Wyszynski University, College of Science, Department of Mathematics and Natural Sciences, Warszawa (Poland); Guziewicz, E. [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland)

    2010-06-01

    In the present work we report on the monocrystalline growth of (00.1) ZnO films on GaN template by the Atomic Layer Deposition technique. The ZnO films were obtained at temperature of 300 {sup o}C using dietylzinc (DEZn) as a zinc precursor and deionized water as an oxygen precursor. High resolution X-ray diffraction analysis proves that ZnO layers are monocrystalline with rocking curve FWHM of the 00.2 peak equals to 0.07{sup o}. Low temperature photoluminescence shows a sharp and bright excitonic line with FWHM of 13 meV.

  19. Atomic Layer Deposition of Zirconium Oxide on Carbon Nanoparticles

    International Nuclear Information System (INIS)

    In this report we describe preparation of structures containing carbon nanoparticles for potential applications in nonvolatile memories. The carbon nanoparticles were synthesized from 5-methylresorcinol and formaldehyde via base catalysed polycondensation reaction, and were distributed over substrates by dip-coating the substrates into an organic solution. Before deposition of nanoparticles the substrates were covered with 2 nm thick Al2O3 layer grown by atomic layer deposition (ALD) from Al(CH3)3 and O3. After deposition of nanoparticles the samples were coated with ZrO2 films grown from C5H5Zr[N(CH3)2]3 and H2O. Both dielectrics were grown in two-temperature ALD processes starting deposition of Al2O3 at 25 °C and ZrO2 at 200 °C, thereafter completing both processes at a substrate temperature of 300 °C. Deposition of ZrO2 changed the structure of C-nanoparticles, which still remained in a Si/Al2O3/C/ZrO2 structure as a separate layer. Electrical characterization of nanostructures containing Al2O3 as tunnel oxide, C-nanoparticles as charge traps and ZrO2 as control oxide showed hysteretic flat-band voltage shift of about 1V

  20. Silicon protected with atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Seger, Brian; Tilley, S. David; Pedersen, Thomas;

    2013-01-01

    atomic layer deposited TiO2 increased the donor density from an as-deposited value of 1.3 × 1019 cm -3 to 2.2 × 1020 cm-3 following the annealing step. Using an Fe(ii)/Fe(iii) redox couple it was shown that the lower dopant density only allows electron transfer through TiO2 under conditions of weak band......The present work demonstrates that tuning the donor density of protective TiO2 layers on a photocathode has dramatic consequences for electronic conduction through TiO2 with implications for the stabilization of oxidation-sensitive catalysts on the surface. Vacuum annealing at 400 °C for 1 hour of...

  1. Holmium titanium oxide thin films grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Thin solid holmium titanium oxide films were grown by atomic layer deposition at 300 °C on silicon substrates. The precursors used were Ho(thd)3, Ti(OCH(CH3)2)4 and O3. The composition of the films was varied via changing the holmium–titanium ratio by variation of relative amounts of the sequential deposition cycles of constituent oxides, i.e. Ho2O3 and TiO2. The constituent oxides alone were crystallized in as-deposited states. After mixing the Ho2O3 or TiO2 layers the films were amorphous but were crystallized after annealing at 800–1000 °C, mostly transforming into the Ho2Ti2O7 phase. The stoichiometric ratio of 1:1 between Ti and Ho contents was achieved by application of at least twice as many Ho2O3 deposition cycles as TiO2 cycles. Magnetometry revealed that saturation magnetization could be observed in the films containing lower amounts of holmium compared to titanium. - Highlights: • Holmium-doped TiO2 and holmium titanates were deposited by ALD. • Crystallization temperature increased with the Ho:Ti ratio. • Holmium titanate films possessed pyrochlore phase. • The films could demonstrate saturative magnetization

  2. Nanoscale Structuring of Surfaces by Using Atomic Layer Deposition.

    Science.gov (United States)

    Sobel, Nicolas; Hess, Christian

    2015-12-01

    Controlled structuring of surfaces is interesting for a wide variety of areas, including microelectronic device fabrication, optical devices, bio(sensing), (electro-, photo)catalysis, batteries, solar cells, fuel cells, and sorption. A unique feature of atomic layer deposition (ALD) is the possibility to form conformal uniform coatings on arbitrarily shaped materials with controlled atomic-scale thickness. In this Minireview, we discuss the potential of ALD for the nanoscale structuring of surfaces, highlighting its versatile application to structuring both planar substrates and powder materials. Recent progress in the application of ALD to porous substrates has even made the nanoscale structuring of high-surface-area materials now feasible, thereby enabling novel applications, such as those in the fields of catalysis and alternative energy. PMID:26538495

  3. Atomic layer deposition of superparamagnetic and ferrimagnetic magnetite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yijun; Liu, Ming, E-mail: mingliu@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn, E-mail: zye@sfu.ca; Ren, Wei, E-mail: mingliu@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn, E-mail: zye@sfu.ca [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Yuepeng; Chen, Xing [Energy Systems Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Ye, Zuo-Guang, E-mail: mingliu@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn, E-mail: zye@sfu.ca [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi' an Jiaotong University, Xi' an 710049 (China); Department of Chemistry and 4D LABS, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada)

    2015-05-07

    One of the key challenges in realizing superparamagnetism in magnetic thin films lies in finding a low-energy growth way to create sufficiently small grains and magnetic domains which allow the magnetization to randomly and rapidly reverse. In this work, well-defined superparamagnetic and ferrimagnetic Fe{sub 3}O{sub 4} thin films are successfully prepared using atomic layer deposition technique by finely controlling the growth condition and post-annealing process. As-grown Fe{sub 3}O{sub 4} thin films exhibit a conformal surface and poly-crystalline nature with an average grain size of 7 nm, resulting in a superparamagnetic behavior with a blocking temperature of 210 K. After post-annealing in H{sub 2}/Ar at 400 °C, the as-grown α−Fe{sub 2}O{sub 3} sample is reduced to Fe{sub 3}O{sub 4} phase, exhibiting a ferrimagnetic ordering and distinct magnetic shape anisotropy. Atomic layer deposition of magnetite thin films with well-controlled morphology and magnetic properties provides great opportunities for integrating with other order parameters to realize magnetic nano-devices with potential applications in spintronics, electronics, and bio-applications.

  4. Atomic layer deposition of superparamagnetic and ferrimagnetic magnetite thin films

    International Nuclear Information System (INIS)

    One of the key challenges in realizing superparamagnetism in magnetic thin films lies in finding a low-energy growth way to create sufficiently small grains and magnetic domains which allow the magnetization to randomly and rapidly reverse. In this work, well-defined superparamagnetic and ferrimagnetic Fe3O4 thin films are successfully prepared using atomic layer deposition technique by finely controlling the growth condition and post-annealing process. As-grown Fe3O4 thin films exhibit a conformal surface and poly-crystalline nature with an average grain size of 7 nm, resulting in a superparamagnetic behavior with a blocking temperature of 210 K. After post-annealing in H2/Ar at 400 °C, the as-grown α−Fe2O3 sample is reduced to Fe3O4 phase, exhibiting a ferrimagnetic ordering and distinct magnetic shape anisotropy. Atomic layer deposition of magnetite thin films with well-controlled morphology and magnetic properties provides great opportunities for integrating with other order parameters to realize magnetic nano-devices with potential applications in spintronics, electronics, and bio-applications

  5. Atomic Layer Deposition of Bismuth Vanadates for Solar Energy Materials.

    Science.gov (United States)

    Stefik, Morgan

    2016-07-01

    The fabrication of porous nanocomposites is key to the advancement of energy conversion and storage devices that interface with electrolytes. Bismuth vanadate, BiVO4 , is a promising oxide for solar water splitting where the controlled fabrication of BiVO4 layers within porous, conducting scaffolds has remained a challenge. Here, the atomic layer deposition of bismuth vanadates is reported from BiPh3 , vanadium(V) oxytriisopropoxide, and water. The resulting films have tunable stoichiometry and may be crystallized to form the photoactive scheelite structure of BiVO4 . A selective etching process was used with vanadium-rich depositions to enable the synthesis of phase-pure BiVO4 after spinodal decomposition. BiVO4 thin films were measured for photoelectrochemical performance under AM 1.5 illumination. The average photocurrents were 1.17 mA cm(-2) at 1.23 V versus the reversible hydrogen electrode using a hole-scavenging sulfite electrolyte. The capability to deposit conformal bismuth vanadates will enable a new generation of nanocomposite architectures for solar water splitting. PMID:27246652

  6. Nanoengineering and interfacial engineering of photovoltaics by atomic layer deposition

    Science.gov (United States)

    Bakke, Jonathan R.; Pickrahn, Katie L.; Brennan, Thomas P.; Bent, Stacey F.

    2011-09-01

    Investment into photovoltaic (PV) research has accelerated over the past decade as concerns over energy security and carbon emissions have increased. The types of PV technology in which the research community is actively engaged are expanding as well. This review focuses on the burgeoning field of atomic layer deposition (ALD) for photovoltaics. ALD is a self-limiting thin film deposition technique that has demonstrated usefulness in virtually every sector of PV technology including silicon, thin film, tandem, organic, dye-sensitized, and next generation solar cells. Further, the specific applications are not limited. ALD films have been deposited on planar and nanostructured substrates and on inorganic and organic devices, and vary in thickness from a couple of angstroms to over 100 nm. The uses encompass absorber materials, buffer layers, passivating films, anti-recombination shells, and electrode modifiers. Within the last few years, the interest in ALD as a PV manufacturing technique has increased and the functions of ALD have expanded. ALD applications have yielded fundamental understanding of how devices operate and have led to increased efficiencies or to unique architectures for some technologies. This review also highlights new developments in high throughput ALD, which is necessary for commercialization. As the demands placed on materials for the next generation of PV become increasingly stringent, ALD will evolve into an even more important method for research and fabrication of solar cell devices.

  7. Reducing interface recombination for Cu(In,Ga)Se2 by atomic layer deposited buffer layers

    International Nuclear Information System (INIS)

    Partial CuInGaSe2 (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnOx buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystalline II–VI systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide

  8. Synthesis of platinum nanoparticle electrocatalysts by atomic layer deposition

    Science.gov (United States)

    Lubers, Alia Marie

    Demand for energy continues to increase, and without alternatives to fossil fuel combustion the effects on our environment will become increasingly severe. Fuel cells offer a promising improvement on current methods of energy generation; they are able to convert hydrogen fuel into electricity with a theoretical efficiency of up to 83% and interface smoothly with renewable hydrogen production. Fuel cells can replace internal combustion engines in vehicles and are used in stationary applications to power homes and businesses. The efficiency of a fuel cell is maximized by its catalyst, which is often composed of platinum nanoparticles supported on carbon. Economical production of fuel cell catalysts will promote adoption of this technology. Atomic layer deposition (ALD) is a possible method for producing catalysts at a large scale when employed in a fluidized bed. ALD relies on sequential dosing of gas-phase precursors to grow a material layer by layer. We have synthesized platinum nanoparticles on a carbon particle support (Pt/C) by ALD for use in proton exchange membrane fuel cells (PEMFCs) and electrochemical hydrogen pumps. Platinum nanoparticles with different characteristics were deposited by changing two chemistries: the carbon substrate through functionalization; and the deposition process by use of either oxygen or hydrogen as ligand removing reactants. The metal depositing reactant was trimethyl(methylcyclopentadienyl)platinum(IV). Functionalizing the carbon substrate increased nucleation during deposition resulting in smaller and more dispersed nanoparticles. Use of hydrogen produced smaller nanoparticles than oxygen, due to a gentler hydrogenation reaction compared to using oxygen's destructive combustion reaction. Synthesized Pt/C materials were used as catalysts in an electrochemical hydrogen pump, a device used to separate hydrogen fuel from contaminants. Catalysts deposited by ALD on functionalized carbon using a hydrogen chemistry were the most

  9. Atomic layer deposition of TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Tallarida, Massimo; Dessmann, Nils; Staedter, Matthias; Friedrich, Daniel; Michling, Marcel; Schmeisser, Dieter [BTU-Cottbus, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany)

    2011-07-01

    We present a study of the initial growth of TiO{sub 2} on Si(111) by atomic layer deposition (ALD). The Si substrate was etched with NH{sub 4}F before ALD to remove the native oxide film and to produce a Si-H termination. In-situ experiments by means of photoemission and X-ray absorption spectroscopy were conducted with synchrotron radiation on Ti-oxide films produced using Ti-tetra-iso-propoxide (TTIP) and water as precursors. O 1s, Ti 2p, C 1s, and S i2p core level, and O 1s and Ti 2p absorption edges show the transition of the Ti-oxide properties during the first layers. The growth starts with a very small growth rate (0.03 nm/cycle) due to the growth inhibition of the Si-H termination and proceeds with higher growth rate (0.1 nm/cycle) after 1.5 nm Ti-oxide has been deposited.

  10. CMUTs with High-K Atomic Layer Deposition Dielectric Material Insulation Layer

    OpenAIRE

    Xu, Toby; Tekes, Coskun; Degertekin, F. Levent

    2014-01-01

    Use of high-κ dielectric, atomic layer deposition (ALD) materials as an insulation layer material for capacitive micromachined ultrasonic transducers (CMUTs) is investigated. The effect of insulation layer material and thickness on CMUT performance is evaluated using a simple parallel plate model. The model shows that both high dielectric constant and the electrical breakdown strength are important for the dielectric material, and significant performance improvement can be achieved, especiall...

  11. Oxygen-free atomic layer deposition of indium sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

    2016-07-05

    A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

  12. Highly reflective polymeric substrates functionalized utilizing atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zuzuarregui, Ana, E-mail: a.zuzuarregui@nanogune.eu; Gregorczyk, Keith E. [CIC Nanogune Consolider, de Tolosa Hiribidea 76, 20018 San Sebastián (Spain); Coto, Borja; Ruiz de Gopegui, Unai; Barriga, Javier [IK4-Tekniker, Iñaki Goenaga 5, 20600 Eibar (Spain); Rodríguez, Jorge [Torresol Energy (SENER Group), Avda. de Zugazarte 61, 48930 Las Arenas (Spain); Knez, Mato [CIC Nanogune Consolider, de Tolosa Hiribidea 76, 20018 San Sebastián (Spain); IKERBASQUE Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao (Spain)

    2015-08-10

    Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur.

  13. Highly reflective polymeric substrates functionalized utilizing atomic layer deposition

    International Nuclear Information System (INIS)

    Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur

  14. Oxygen-free atomic layer deposition of indium sulfide

    Science.gov (United States)

    Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

    2016-07-05

    A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

  15. Nanoscale engineering materials by supercritical fluid and atomic layer deposition

    Science.gov (United States)

    Peng, Qing

    With the development of material science and technology, modification of substrates, which have random geometry and high aspect ratio three dimensional (3D) complex structures, with desired functional, reactive and stable coatings becomes important and challenging. The ability to fabricate mono- or multi-layers of functional materials with precisely controlled dimensions, finely tuned composition and molecular structures, attracts significant interests in materials science and is the key to construct such devices and structures at nano- and micro-scale with desired properties. In this study, supercritical carbon dioxide (scCO2) has been studied as an alternative route for modifying substrates due to the unique gas-like (low viscosity, high diffusivity and zero surface tension) and liquid-like properties (high density). (1) The reaction kinetics of metal oxides thin film deposition from pyrolysis of metal organics in scCO2 was studied in detail. This method was demonstrated as a powerful technique to coat oxides, including Al2O3, Ga2O3 and others, into 3D high aspect ratio complex structure of carbon nanotubes (CNTs) forest. (2) The low temperature scCO 2 based hydrogenolysis process was developed as a useful way to functionalize aligned CNTs forest with dense Nickel nanoparticles. On the second part of this work, atomic layer deposition (ALD)/molecular layer deposition (MLD), as a vapor phase, stepwise and self-limiting vacuum based deposition process, was demonstrated as a powerful way to form highly conformal and uniform film onto substrates, even into highly complex 3D complex structures. In this study, (4) Metal oxide ALD is applied onto 3D electrospun polymer microfiber mats template to illustrate an effective and robust strategy to fabricate long and uniform metal oxide microtubes with precisely controllable wall thickness. Designer tubes of various sizes and different materials were demonstrated by using this method. (5) By further extending this technique

  16. Gyroidal mesoporous multifunctional nanocomposites via atomic layer deposition

    Science.gov (United States)

    Werner, Jörg G.; Scherer, Maik R. J.; Steiner, Ullrich; Wiesner, Ulrich

    2014-07-01

    We demonstrate the preparation of rationally designed, multifunctional, monolithic and periodically ordered mesoporous core-shell nanocomposites with tunable structural characteristics. Three-dimensionally (3D) co-continuous gyroidal mesoporous polymer monoliths are fabricated from a solution-based triblock terpolymer-resol co-assembly and used as the functional templates for the fabrication of free-standing core-shell carbon-titania composites using atomic layer deposition (ALD). The deposition depth into the torturous gyroidal nanonetwork is investigated as a function of ALD conditions and the resulting composites are submitted to different thermal treatments. Results suggest that ALD can homogenously coat mesoporous templates with well defined pore sizes below 50 nm and thicknesses above 10 μm. Structural tunability like titania shell thickness and pore size control is demonstrated. The ordered nanocomposites exhibit triple functionality; a 3D continuous conductive carbon core that is coated with a crystalline titania shell that in turn is in contact with a 3D continuous mesopore network in a compact monolithic architecture. This materials design is of interest for applications including energy conversion and storage. Gyroidal mesoporous titania monoliths can be obtained through simultaneous titania crystallization and template removal in air.We demonstrate the preparation of rationally designed, multifunctional, monolithic and periodically ordered mesoporous core-shell nanocomposites with tunable structural characteristics. Three-dimensionally (3D) co-continuous gyroidal mesoporous polymer monoliths are fabricated from a solution-based triblock terpolymer-resol co-assembly and used as the functional templates for the fabrication of free-standing core-shell carbon-titania composites using atomic layer deposition (ALD). The deposition depth into the torturous gyroidal nanonetwork is investigated as a function of ALD conditions and the resulting composites are

  17. Scalable synthesis of palladium nanoparticle catalysts by atomic layer deposition

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) was used to produce Pd/Al2O3 catalysts using sequential exposures of Pd(II) hexafluoroacetylacetonate and formalin at 200 °C in a fluidized bed reactor. The ALD-prepared Pd/alumina catalysts were characterized by various methods including hydrogen chemisorption, XPS, and TEM, and compared with a commercially available 1 wt% Pd/alumina catalyst, which was also characterized. The content of Pd on alumina support and the size of Pd nanoparticles can be controlled by the number of ALD-coating cycles and the dose time of the Pd precursor. One layer of organic component from the Pd precursor remained on the Pd particle surface. The ALD 0.9 wt% Pd/alumina had greater active metal surface area and percent metal dispersion than the commercial 1 wt% Pd/alumina catalyst. The ALD and commercial catalysts were subjected to catalytic testing to determine their relative activities for glucose oxidation to gluconic acid in aqueous solution. The ALD 0.9 wt% Pd/alumina catalyst had comparable activity as compared to the commercial 1 wt% Pd catalyst. No noticeable amount of Pd leaching was observed for the ALD-prepared catalysts during the vigorously stirred reaction.

  18. Atomic layer deposition and post-deposition annealing of PbTiO3 thin films

    International Nuclear Information System (INIS)

    Lead titanate thin films were deposited by atomic layer deposition on Si(100) using Ph4Pb and Ti(O-i-Pr)4 as metal precursors and O3 and H2O as oxygen sources. The influence of the Ti : Pb precursor pulsing ratio on the film growth, stoichiometry and quality was studied at two different temperatures, i.e. 250 and 300 deg. C. Uniform and stoichiometric films were obtained using a Ti : Pb precursor pulsing ratio of 1 : 10 at 250 deg. C or 1 : 28 at 300 deg. C. The as-deposited films were amorphous but the crystalline PbTiO3 phase was obtained by rapid thermal annealing at 600-900 deg. C both in N2 and O2 ambient. Thin PbTiO3 films were visually uniform and roughness values for as-deposited and annealed films were observed by atomic force microscopy

  19. Film-coupled nanoparticles by atomic layer deposition: Comparison with organic spacing layers

    Energy Technology Data Exchange (ETDEWEB)

    Ciracì, Cristian, E-mail: cristian.ciraci@duke.edu; Mock, Jack J.; McGuire, Felicia; Liu, Xiaojun; Smith, David R. [Center for Metamaterials and Integrated Plasmonics and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Chen, Xiaoshu; Oh, Sang-Hyun [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2014-01-13

    Film-coupled nanoparticle systems have proven a reliable platform for exploring the field enhancement associated with sub-nanometer sized gaps between plasmonic nanostructures. In this Letter, we present a side-by-side comparison of the spectral properties of film-coupled plasmon-resonant, gold nanoparticles, with dielectric spacer layers fabricated either using atomic layer deposition or using organic layers (polyelectrolytes or self-assembled monolayers of molecules). In either case, large area, uniform spacer layers with sub-nanometer thicknesses can be accurately deposited, allowing extreme coupling regimes to be probed. The observed spectral shifts of the nanoparticles as a function of spacer layer thickness are similar for the organic and inorganic films and are consistent with numerical calculations taking into account the nonlocal response of the metal.

  20. Channel cracks in atomic-layer and molecular-layer deposited multilayer thin film coatings

    International Nuclear Information System (INIS)

    Metal oxide thin film coatings produced by atomic layer deposition have been shown to be an effective permeation barrier. The primary failure mode of such coatings under tensile loads is the propagation of channel cracks that penetrate vertically into the coating films. Recently, multi-layer structures that combine the metal oxide material with relatively soft polymeric layers produced by molecular layer deposition have been proposed to create composite thin films with desired properties, including potentially enhanced resistance to fracture. In this paper, we study the effects of layer geometry and material properties on the critical strain for channel crack propagation in the multi-layer composite films. Using finite element simulations and a thin-film fracture mechanics formalism, we show that if the fracture energy of the polymeric layer is lower than that of the metal oxide layer, the channel crack tends to penetrate through the entire composite film, and dividing the metal oxide and polymeric materials into thinner layers leads to a smaller critical strain. However, if the fracture energy of the polymeric material is high so that cracks only run through the metal oxide layers, more layers can result in a larger critical strain. For intermediate fracture energy of the polymer material, we developed a design map that identifies the optimal structure for given fracture energies and thicknesses of the metal oxide and polymeric layers. These results can facilitate the design of mechanically robust permeation barriers, an important component for the development of flexible electronics.

  1. High Gradient Accelerator Cavities Using Atomic Layer Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Parsons, Gregory [North Carolina State Univ., Raleigh, NC (United States); Williams, Philip [North Carolina State Univ., Raleigh, NC (United States); Oldham, Christopher [North Carolina State Univ., Raleigh, NC (United States); Mundy, Zach [North Carolina State Univ., Raleigh, NC (United States); Dolgashev, Valery [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2014-12-09

    In the Phase I program, Calabazas Creek Research, Inc. (CCR), in collaboration with North Carolina State University (NCSU), fabricated copper accelerator cavities and used Atomic Layer Deposition (ALD) to apply thin metal coatings of tungsten and platinum. It was hypothesized that a tungsten coating would provide a robust surface more resistant to arcing and arc damage. The platinum coating was predicted to reduce processing time by inhibiting oxides that form on copper surfaces soon after machining. Two sets of cavity parts were fabricated. One was coated with 35 nm of tungsten, and the other with approximately 10 nm of platinum. Only the platinum cavity parts could be high power tested during the Phase I program due to schedule and funding constraints. The platinum coated cavity exhibit poor performance when compared with pure copper cavities. Not only did arcing occur at lower power levels, but the processing time was actually longer. There were several issues that contributed to the poor performance. First, machining of the base copper cavity parts failed to achieve the quality and cleanliness standards specified to SLAC National Accelerator Center. Secondly, the ALD facilities were not configured to provide the high levels of cleanliness required. Finally, the nanometer coating applied was likely far too thin to provide the performance required. The coating was ablated or peeled from the surface in regions of high fields. It was concluded that the current ALD process could not provide improved performance over cavities produced at national laboratories using dedicated facilities.

  2. Copper reduction and atomic layer deposition by oxidative decomposition of formate by hydrazine

    OpenAIRE

    Dey, Gangotri; Elliott, Simon D.

    2014-01-01

    We have used density functional theory (DFT) to study the mechanism of three step atomic layer deposition (ALD) of copper via formate and hydrazine. The technique holds promise for deposition of other transition metals.

  3. Atomic Layer Deposition to Enable the Production, Optimization and Protection of Spaceflight Hardware Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Atomic Layer Deposition (ALD) is a cost effective nano-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign...

  4. Characterization of dielectric layers grown at low temperature by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gieraltowska, Sylwia, E-mail: sgieral@ifpan.edu.pl [Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Wachnicki, Lukasz; Witkowski, Bartlomiej S. [Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Mroczynski, Robert [Warsaw University of Technology, Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Dluzewski, Piotr [Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Godlewski, Marek [Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science, Cardinal S. Wyszyński University, Dewajtis 5, 01-815 Warsaw (Poland)

    2015-02-27

    Dielectric films, such as hafnium dioxide (HfO{sub 2}), aluminum oxide (Al{sub 2}O{sub 3}), zirconium dioxide (ZrO{sub 2}), titanium dioxide (TiO{sub 2}) and their composite layers are deposited on polycrystalline and amorphous substrates by the atomic layer deposition (ALD) method. We demonstrate that the use of this technology guarantees a uniform and controlled surface coverage in the nanometer scale at low temperatures (in our case, below 100 °C). Modification of the composition of oxide layers allows the deposition of materials with quite different absorption coefficients, refractive indexes and dielectric constants. In particular, we demonstrate structural, electrical and optical properties of dielectric layers and test metal-oxide-semiconductor structures with these oxide materials. Our good quality dielectric layers, obtained at low-temperature ALD, are characterized by a high dielectric constant (above 10), very smooth surface, wide energy gap (above 3 eV), low leakage current (in the range of 10{sup −8} A/cm{sup 2} at 1 V), high dielectric strength (even 6 MV/cm) and high refractive indexes (above 1.5 in the visible spectral range). - Highlights: • We demonstrate the use of atomic layer deposition (ALD) at low temperatures (LT). • LT ALD guarantees a uniform and controlled surface coverage of dielectrics. • In our case, the dielectric films were deposited at very LT, below 100 °C. • Dielectrics (HfO{sub 2}, Al{sub 2}O{sub 3}, ZrO{sub 2}, TiO{sub 2} and composite layers) are obtained by ALD. • Our results also indicate high-quality dielectric films.

  5. Influence of atomic layer deposition valve temperature on ZrN plasma enhanced atomic layer deposition growth

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) relies on a sequence of self-limiting surface reactions for thin film growth. The effect of non-ALD side reactions, from insufficient purging between pulses and from precursor self-decomposition, on film growth is well known. In this article, precursor condensation within an ALD valve is described, and the effect of the continuous precursor source from condensate evaporation on ALD growth is discussed. The influence of the ALD valve temperature on growth and electrical resistivity of ZrN plasma enhanced ALD (PEALD) films is reported. Increasing ALD valve temperature from 75 to 95 °C, with other process parameters being identical, decreased both the growth per cycle and electrical resistivity (ρ) of ZrN PEALD films from 0.10 to 0.07 nm/cycle and from 560 to 350 μΩ cm, respectively. Our results show that the non-ALD growth resulting from condensate accumulation is eliminated at valve temperatures close to the pressure corrected boiling point of precursor

  6. Influence of atomic layer deposition valve temperature on ZrN plasma enhanced atomic layer deposition growth

    Energy Technology Data Exchange (ETDEWEB)

    Muneshwar, Triratna, E-mail: muneshwa@ualberta.ca; Cadien, Ken [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)

    2015-11-15

    Atomic layer deposition (ALD) relies on a sequence of self-limiting surface reactions for thin film growth. The effect of non-ALD side reactions, from insufficient purging between pulses and from precursor self-decomposition, on film growth is well known. In this article, precursor condensation within an ALD valve is described, and the effect of the continuous precursor source from condensate evaporation on ALD growth is discussed. The influence of the ALD valve temperature on growth and electrical resistivity of ZrN plasma enhanced ALD (PEALD) films is reported. Increasing ALD valve temperature from 75 to 95 °C, with other process parameters being identical, decreased both the growth per cycle and electrical resistivity (ρ) of ZrN PEALD films from 0.10 to 0.07 nm/cycle and from 560 to 350 μΩ cm, respectively. Our results show that the non-ALD growth resulting from condensate accumulation is eliminated at valve temperatures close to the pressure corrected boiling point of precursor.

  7. Gas permeation barriers deposited by atmospheric pressure plasma enhanced atomic layer deposition

    International Nuclear Information System (INIS)

    This paper reports on aluminum oxide (Al2O3) thin film gas permeation barriers fabricated by atmospheric pressure atomic layer deposition (APPALD) using trimethylaluminum and an Ar/O2 plasma at moderate temperatures of 80 °C in a flow reactor. The authors demonstrate the ALD growth characteristics of Al2O3 films on silicon and indium tin oxide coated polyethylene terephthalate. The properties of the APPALD-grown layers (refractive index, density, etc.) are compared to that deposited by conventional thermal ALD at low pressures. The films films deposited at atmospheric pressure show water vapor transmission rates as low as 5 × 10−5 gm−2d−1

  8. Selective deposition contact patterning using atomic layer deposition for the fabrication of crystalline silicon solar cells

    International Nuclear Information System (INIS)

    Selective deposition contact (SDC) patterning was applied to fabricate the rear side passivation of crystalline silicon (Si) solar cells. By this method, using screen printing for contact patterning and atomic layer deposition for the passivation of Si solar cells with Al2O3, we produced local contacts without photolithography or any laser-based processes. Passivated emitter and rear-contact solar cells passivated with ozone-based Al2O3 showed, for the SDC process, an up-to-0.7% absolute conversion-efficiency improvement. The results of this experiment indicate that the proposed method is feasible for conversion-efficiency improvement of industrial crystalline Si solar cells. - Highlights: • We propose a local contact formation process. • Local contact forms a screen print and an atomic layer deposited-Al2O3 film. • Ozone-based Al2O3 thin film was selectively deposited onto patterned silicon. • Selective deposition contact patterning method can increase cell-efficiency by 0.7%

  9. Characterization and modeling of atomic layer deposited high-density trench capacitors in silicon

    NARCIS (Netherlands)

    Matters-Kammerer, M.K.; Jinesh, K.B.; Rijks, T.G.S.M.; Roozeboom, F.; Klootwijk, J.H.

    2012-01-01

    A detailed electrical analysis of multiple layer trench capacitors fabricated in silicon with atomic-layer-deposited Al 2O 3 and TiN is presented. It is shown that in situ ozone annealing of the Al 2O 3 layers prior to the TiN electrode deposition significantly improves the electric properties of th

  10. Hydroquinone-ZnO nano-laminate deposited by molecular-atomic layer deposition

    International Nuclear Information System (INIS)

    In this study, we have deposited organic-inorganic hybrid semiconducting hydroquinone (HQ)/zinc oxide (ZnO) superlattices using molecular-atomic layer deposition, which enables accurate control of film thickness, excellent uniformity, and sharp interfaces at a low deposition temperature (150 °C). Self-limiting growth of organic layers is observed for the HQ precursor on ZnO surface. Nano-laminates were prepared by varying the number of HQ to ZnO cycles in order to investigate the physical and electrical effects of different HQ to ZnO ratios. It is indicated that the addition of HQ layer results in enhanced mobility and reduced carrier concentration. The highest Hall mobility of approximately 2.3 cm2/V·s and the lowest n-type carrier concentration of approximately 1.0 × 1018/cm3 were achieved with the organic-inorganic superlattice deposited with a ratio of 10 ZnO cycles to 1 HQ cycle. This study offers an approach to tune the electrical transport characteristics of ALD ZnO matrix thin films using an organic dopant. Moreover, with organic embedment, this nano-laminate material may be useful for flexible electronics

  11. The kinetics of low-temperature spatial atomic layer deposition of aluminum oxide

    NARCIS (Netherlands)

    Poodt, P.W.G.; Illiberi, A.; Roozeboom, F.

    2013-01-01

    Spatial atomic layer deposition can be used as a high-throughput manufacturing technique in functional thin film deposition for applications such as flexible electronics. This, however, requires low-temperature deposition processes. We have investigated the kinetics of low-temperature (< 100 C) spat

  12. Atomic layer deposition of copper nitride film and its application to copper seed layer for electrodeposition

    International Nuclear Information System (INIS)

    We report the formation of smooth and conformal copper seed layer for electrodeposition by atomic layer deposition (ALD) and reducing anneal of a copper nitride film. The ALD copper nitride film was prepared at 100–140 °C using bis(1-dimethylamino-2-methyl-2-butoxy)copper(II) and NH3, and reduced to metallic copper film by annealing at 200 °C or higher temperatures. The growth rate of ALD copper nitride was 0.1 nm/cycle at 120–140 °C on both ruthenium and silicon oxide substrates, and the thickness of film was reduced approximately 20% by annealing. The resistivity of the 4.2 nm-thick copper film was 30 μΩ·cm. Both the ALD copper nitride and the reduced copper films exhibited extremely smooth surface and excellent step coverage, whereas the copper film deposited using alternating exposures to the copper precursor and H2 showed a rough surface. The copper film electrodeposited on the copper seed of this study exhibited lower resistivity and smoother surface as compared to the copper film electrodeposited on the ALD ruthenium seed. - Highlights: • Copper nitride thin film was grown by atomic layer deposition (ALD) at 100–140 °C. • Copper nitride was reduced to metallic copper by annealing in H2 at ≥ 200 °C. • Copper nitride and copper films showed smooth surface and excellent step coverage. • The copper film was better than ALD Ru as the seed layer for electrodeposition

  13. Effects of Ar plasma treatment for deposition of ruthenium film by remote plasma atomic layer deposition

    International Nuclear Information System (INIS)

    Ruthenium thin films were deposited on argon plasma-treated SiO2 and untreated SiO2 substrates by remote plasma atomic layer deposition using bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)2] as a Ru precursor and ammonia plasma as a reactant. The results of in situ Auger electron spectroscopy (AES) analysis indicate that the initial transient region of Ru deposition was decreased by Ar plasma treatment at 400 deg. C, but did not change significantly at 300 deg. C The deposition rate exhibited linearity after continuous film formation and the deposition rates were about 1.7 A/cycle and 0.4 A/cycle at 400 deg. C and 300 deg. C, respectively. Changes of surface energy and polar and dispersive components were measured by the sessile drop test. The quantity of surface amine groups was measured from the surface nitrogen concentration with AES. Furthermore, the Ar plasma-treated SiO2 contained more amine groups and less hydroxyl groups on the surface than on untreated SiO2. Auger spectra exhibited chemical shifts by Ru-O bonding, and larger shifts were observed on untreated substrates due to the strong adhesion of Ru films.

  14. Microwave annealing effects on ZnO films deposited by atomic layer deposition

    Institute of Scientific and Technical Information of China (English)

    Zhao Shirui; Dong Yabin; Yu Mingyan; Guo Xiaolong; Xu Xinwei; Jing Yupeng; Xia Yang

    2014-01-01

    Zinc oxide thin films deposited on glass substrate at 150 ℃ by atomic layer deposition were annealed by the microwave method at temperatures below 500 ℃.The microwave annealing effects on the structural and luminescent properties of ZnO films have been investigated by X-ray diffraction and photoluminescence.The results show that the MWA process can increase the crystal quality of ZnO thin films with a lower annealing temperature than RTA and relatively decrease the green luminescence of ZnO films.The observed changes have demonstrated that MWA is a viable technique for improving the crystalline quality of ZnO thin film on glass.

  15. CMUTs with high-K atomic layer deposition dielectric material insulation layer.

    Science.gov (United States)

    Xu, Toby; Tekes, Coskun; Degertekin, F

    2014-12-01

    Use of high-κ dielectric, atomic layer deposition (ALD) materials as an insulation layer material for capacitive micromachined ultrasonic transducers (CMUTs) is investigated. The effect of insulation layer material and thickness on CMUT performance is evaluated using a simple parallel plate model. The model shows that both high dielectric constant and the electrical breakdown strength are important for the dielectric material, and significant performance improvement can be achieved, especially as the vacuum gap thickness is reduced. In particular, ALD hafnium oxide (HfO2) is evaluated and used as an improvement over plasma-enhanced chemical vapor deposition (PECVD) silicon nitride (Six)Ny)) for CMUTs fabricated by a low-temperature, complementary metal oxide semiconductor transistor-compatible, sacrificial release method. Relevant properties of ALD HfO2) such as dielectric constant and breakdown strength are characterized to further guide CMUT design. Experiments are performed on parallel fabricated test CMUTs with 50-nm gap and 16.5-MHz center frequency to measure and compare pressure output and receive sensitivity for 200-nm PECVD Six)Ny) and 100-nm HfO2) insulation layers. Results for this particular design show a 6-dB improvement in receiver output with the collapse voltage reduced by one-half; while in transmit mode, half the input voltage is needed to achieve the same maximum output pressure. PMID:25474786

  16. Ultraviolet optical properties of aluminum fluoride thin films deposited by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hennessy, John, E-mail: john.j.hennessy@jpl.nasa.gov; Jewell, April D.; Balasubramanian, Kunjithapatham; Nikzad, Shouleh [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109 (United States)

    2016-01-15

    Aluminum fluoride (AlF{sub 3}) is a low refractive index material with promising optical applications for ultraviolet (UV) wavelengths. An atomic layer deposition process using trimethylaluminum and anhydrous hydrogen fluoride has been developed for the deposition of AlF{sub 3} at substrate temperatures between 100 and 200 °C. This low temperature process has resulted in thin films with UV-optical properties that have been characterized by ellipsometric and reflection/transmission measurements at wavelengths down to 200 nm. The optical loss for 93 nm thick films deposited at 100 °C was measured to be less than 0.2% from visible wavelengths down to 200 nm, and additional microstructural characterization demonstrates that the films are amorphous with moderate tensile stress of 42–105 MPa as deposited on silicon substrates. X-ray photoelectron spectroscopy analysis shows no signature of residual aluminum oxide components making these films good candidates for a variety of applications at even shorter UV wavelengths.

  17. Ultraviolet optical properties of aluminum fluoride thin films deposited by atomic layer deposition

    International Nuclear Information System (INIS)

    Aluminum fluoride (AlF3) is a low refractive index material with promising optical applications for ultraviolet (UV) wavelengths. An atomic layer deposition process using trimethylaluminum and anhydrous hydrogen fluoride has been developed for the deposition of AlF3 at substrate temperatures between 100 and 200 °C. This low temperature process has resulted in thin films with UV-optical properties that have been characterized by ellipsometric and reflection/transmission measurements at wavelengths down to 200 nm. The optical loss for 93 nm thick films deposited at 100 °C was measured to be less than 0.2% from visible wavelengths down to 200 nm, and additional microstructural characterization demonstrates that the films are amorphous with moderate tensile stress of 42–105 MPa as deposited on silicon substrates. X-ray photoelectron spectroscopy analysis shows no signature of residual aluminum oxide components making these films good candidates for a variety of applications at even shorter UV wavelengths

  18. Atomic layer deposition of ultrathin blocking layer for low-temperature solid oxide fuel cell on nanoporous substrate

    International Nuclear Information System (INIS)

    An ultrathin yttria-stabilized zirconia (YSZ) blocking layer deposited by atomic layer deposition (ALD) was utilized for improving the performance and reliability of low-temperature solid oxide fuel cells (SOFCs) supported by an anodic aluminum oxide substrate. Physical vapor-deposited YSZ and gadolinia-doped ceria (GDC) electrolyte layers were deposited by a sputtering method. The ultrathin ALD YSZ blocking layer was inserted between the YSZ and GDC sputtered layers. To investigate the effects of an inserted ultrathin ALD blocking layer, SOFCs with and without an ultrathin ALD blocking layer were electrochemically characterized. The open circuit voltage (1.14 V) of the ALD blocking-layered SOFC was visibly higher than that (1.05 V) of the other cell. Furthermore, the ALD blocking layer augmented the power density and improved the reproducibility

  19. Atomic layer deposition of ultrathin blocking layer for low-temperature solid oxide fuel cell on nanoporous substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Wonjong; Cho, Gu Young; Noh, Seungtak; Tanveer, Waqas Hassan; Cha, Suk Won, E-mail: swcha@snu.ac.kr [School of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Daehak dong, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Ji, Sanghoon [Graduate School of Convergence Science and Technology, Seoul National University, 864-1, Iui-dong, Yeongtong-gu, Suwon 443-270 (Korea, Republic of); An, Jihwan [Manufacturing Systems and Design Engineering Program, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul 139-743 (Korea, Republic of)

    2015-01-15

    An ultrathin yttria-stabilized zirconia (YSZ) blocking layer deposited by atomic layer deposition (ALD) was utilized for improving the performance and reliability of low-temperature solid oxide fuel cells (SOFCs) supported by an anodic aluminum oxide substrate. Physical vapor-deposited YSZ and gadolinia-doped ceria (GDC) electrolyte layers were deposited by a sputtering method. The ultrathin ALD YSZ blocking layer was inserted between the YSZ and GDC sputtered layers. To investigate the effects of an inserted ultrathin ALD blocking layer, SOFCs with and without an ultrathin ALD blocking layer were electrochemically characterized. The open circuit voltage (1.14 V) of the ALD blocking-layered SOFC was visibly higher than that (1.05 V) of the other cell. Furthermore, the ALD blocking layer augmented the power density and improved the reproducibility.

  20. Transparent conductive gas-permeation barriers on plastics by atomic layer deposition.

    Science.gov (United States)

    Chou, Chun-Ting; Yu, Pei-Wei; Tseng, Ming-Hung; Hsu, Che-Chen; Shyue, Jing-Jong; Wang, Ching-Chiun; Tsai, Feng-Yu

    2013-03-25

    A mixed-deposition atomic layer deposition process produces Hf:ZnO films with uniform dopant distribution and high electrical conductivity (resistivity = 4.5 × 10(-4) W cm), optical transparency (>85% from 400-1800 nm), and moisture-barrier property (water vapor transmission rate = 6.3 × 10(-6) g m(-2) day(-1)). PMID:23386315

  1. Atomic layer deposition of platinum clusters on titania nanoparticles at atmospheric pressure

    NARCIS (Netherlands)

    Goulas, A.; Van Ommen, J.R.

    2013-01-01

    We report the fabrication of platinum nanoclusters with a narrow size distribution on TiO2 nanoparticles using atomic layer deposition. With MeCpPtMe3 and ozone as reactants, the deposition can be carried out at a relatively low temperature of 250 degrees C. Our approach of working with suspended na

  2. Electrocatalytic activity of atomic layer deposited Pt–Ru catalysts onto N-doped carbon nanotubes

    DEFF Research Database (Denmark)

    Johansson, Anne-Charlotte Elisabeth Birgitta; Larsen, Jackie Vincent; Verheijen, Marcel A.;

    2014-01-01

    Pt–Ru catalysts of various compositions, between 0 and 100at.% of Ru, were deposited onto N-doped multi-walled carbon nanotubes (N-CNTs) by atomic layer deposition (ALD) at 250°C. The Pt and Ru precursors were trimethyl(methylcyclopentadienyl)platinum (MeCpPtMe3) and bis...

  3. Influence of Atomic Layer Deposition Temperatures on TiO2/n-Si MOS Capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Daming [Kansas State University; Hossain, T [Kansas State University; Garces, N. Y. [Naval Research Laboratory, Washington, D.C.; Nepal, N. [Naval Research Laboratory, Washington, D.C.; Meyer III, Harry M [ORNL; Kirkham, Melanie J [ORNL; Eddy, C.R., Jr. [Naval Research Laboratory, Washington, D.C.; Edgar, J H [Kansas State University

    2013-01-01

    This paper reports on the influence of temperature on the structure, composition, and electrical properties of TiO2 thin films deposited on n-type silicon (100) by atomic layer deposition (ALD). TiO2 layers around 20nm thick, deposited at temperatures ranging from 100 to 300 C, were studied. Samples deposited at 250 C and 200 C had the most uniform coverage as determined by atomic force microscopy. The average carbon concentration throughout the oxide layer and at the TiO2/Si interface was lowest at 200 C. Metal oxide semiconductor capacitors (MOSCAPs) were fabricated, and profiled by capacitance-voltage techniques. Negligible hysteresis was observed from a capacitance-voltage plot and the capacitance in the accumulation region was constant for the sample prepared at a 200 C ALD growth temperature. The interface trap density was on the order of 1013 eV-1cm-2 regardless of the deposition temperature.

  4. Atomic layer deposition of ZnO thin films and dot structures

    International Nuclear Information System (INIS)

    Successful growth of thin films and quantum dots of ZnO by atomic layer deposition (ALD) is reported. Properties of ZnO films produced by four different ALD-procedures and by oxidation of ALD-grown ZnS films are discussed. The use of thin ZnO films as buffer layers for GaN deposition is also shortly described. (author)

  5. Thermal and plasma enhanced atomic layer deposition of SiO2 using commercial silicon precursors

    International Nuclear Information System (INIS)

    In this paper, we report ALD deposition of silicon dioxide using either thermal or plasma enhanced atomic layer deposition (PEALD). Several aminosilanes with differing structures and reactivity were used as silicon precursors in R and D single wafer ALD tools. One of the precursors was also tested on pilot scale batch ALD using O3 as oxidant and with substrates measuring 150 × 400 mm. The SiO2 film deposition rate was greatly dependent on the precursors used, highest values being 1.5–2.0 Å/cycle at 30–200 °C for one precursor with an O2 plasma. According to time-of-flight-elastic recoil detection analysis measurements carbon and nitrogen impurities were relatively low, but hydrogen content increased at low deposition temperatures. - Highlights: • SiO2 thin film is deposited by thermal and plasma enhanced atomic layer deposition (PEALD). • We report low-temperature deposition of SiO2 even at 30 °C by PEALD. • Scaling up of the atomic layer deposition processes to industrial batch is reported. • Deposited films had low low compressive residual stress and good conformality

  6. MoS2 functionalization for ultra-thin atomic layer deposited dielectrics

    International Nuclear Information System (INIS)

    The effect of room temperature ultraviolet-ozone (UV-O3) exposure of MoS2 on the uniformity of subsequent atomic layer deposition of Al2O3 is investigated. It is found that a UV-O3 pre-treatment removes adsorbed carbon contamination from the MoS2 surface and also functionalizes the MoS2 surface through the formation of a weak sulfur-oxygen bond without any evidence of molybdenum-sulfur bond disruption. This is supported by first principles density functional theory calculations which show that oxygen bonded to a surface sulfur atom while the sulfur is simultaneously back-bonded to three molybdenum atoms is a thermodynamically favorable configuration. The adsorbed oxygen increases the reactivity of MoS2 surface and provides nucleation sites for atomic layer deposition of Al2O3. The enhanced nucleation is found to be dependent on the thin film deposition temperature

  7. Evaluation of Atomic Layer Deposition coating as gas barrier against hydrogen gas and humidity

    International Nuclear Information System (INIS)

    Graphical abstract: ALD coating can provide a continuous and conformal barrier between the substrate and ambient atmosphere. - Abstract: Effectiveness of HfO2 Atomic Layer Deposition coatings has been studied on ZnO varistors by I–V tests, impedance spectroscopy, and highly accelerated life test. Based on impedance spectroscopy analyses, the proton diffusion coefficient was measured to be 400 K times less in the coating. Transmission electron microscopy analysis shows that Atomic Layer Deposition films are continuous and conformal. After exposure to high temperature, partial crystallization was detected in the coating and increases proton diffusion coefficient by 150 times

  8. Conduction mechanisms in thin atomic layer deposited Al{sub 2}O{sub 3} layers

    Energy Technology Data Exchange (ETDEWEB)

    Spahr, Holger; Montzka, Sebastian; Reinker, Johannes; Hirschberg, Felix; Kowalsky, Wolfgang; Johannes, Hans-Hermann, E-mail: h2.johannes@ihf.tu-bs.de [Institut für Hochfrequenztechnik, Technische Universität Braunschweig, Schleinitzstraße 22, 38106 Braunschweig (Germany)

    2013-11-14

    Thin Al{sub 2}O{sub 3} layers of 2–135 nm thickness deposited by thermal atomic layer deposition at 80 °C were characterized regarding the current limiting mechanisms by increasing voltage ramp stress. By analyzing the j(U)-characteristics regarding ohmic injection, space charge limited current (SCLC), Schottky-emission, Fowler-Nordheim-tunneling, and Poole-Frenkel-emission, the limiting mechanisms were identified. This was performed by rearranging and plotting the data in a linear scale, such as Schottky-plot, Poole-Frenkel-plot, and Fowler-Nordheim-plot. Linear regression then was applied to the data to extract the values of relative permittivity from Schottky-plot slope and Poole-Frenkel-plot slope. From Fowler-Nordheim-plot slope, the Fowler-Nordheim-energy-barrier was extracted. Example measurements in addition to a statistical overview of the results of all investigated samples are provided. Linear regression was applied to the region of the data that matches the realistic values most. It is concluded that ohmic injection and therefore SCLC only occurs at thicknesses below 12 nm and that the Poole-Frenkel-effect is no significant current limiting process. The extracted Fowler-Nordheim-barriers vary in the range of up to approximately 4 eV but do not show a specific trend. It is discussed whether the negative slope in the Fowler-Nordheim-plot could in some cases be a misinterpreted trap filled limit in the case of space charge limited current.

  9. Atomic-layer deposited thulium oxide as a passivation layer on germanium

    Energy Technology Data Exchange (ETDEWEB)

    Mitrovic, I. Z., E-mail: ivona@liverpool.ac.uk; Hall, S.; Weerakkody, A. D.; Sedghi, N. [Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); Althobaiti, M.; Hesp, D.; Dhanak, V. R. [Department of Physics and Stephenson Institute for Renewable Energy, University of Liverpool, Liverpool L69 7ZF (United Kingdom); Santoni, A. [ENEA, Frascati Research Centre, via E. Fermi 45, 00044 Frascati (Italy); Chalker, P. R. [Department of Engineering, University of Liverpool, Brownlow Hill, Liverpool L69 3GH (United Kingdom); Henkel, C.; Dentoni Litta, E.; Hellström, P.-E.; Östling, M. [School of ICT, KTH Royal Institute of Technology, Isafjordsgatan 22, 164 40 Kista (Sweden); Tan, H.; Schamm-Chardon, S. [CEMES-CNRS and Université de Toulouse, nMat group, BP 94347, 31055 Toulouse Cedex 4 (France)

    2015-06-07

    A comprehensive study of atomic-layer deposited thulium oxide (Tm{sub 2}O{sub 3}) on germanium has been conducted using x-ray photoelectron spectroscopy (XPS), vacuum ultra-violet variable angle spectroscopic ellipsometry, high-resolution transmission electron microscopy (HRTEM), and electron energy-loss spectroscopy. The valence band offset is found to be 3.05 ± 0.2 eV for Tm{sub 2}O{sub 3}/p-Ge from the Tm 4d centroid and Ge 3p{sub 3/2} charge-corrected XPS core-level spectra taken at different sputtering times of a single bulk thulium oxide sample. A negligible downward band bending of ∼0.12 eV is observed during progressive differential charging of Tm 4d peaks. The optical band gap is estimated from the absorption edge and found to be 5.77 eV with an apparent Urbach tail signifying band gap tailing at ∼5.3 eV. The latter has been correlated to HRTEM and electron diffraction results corroborating the polycrystalline nature of the Tm{sub 2}O{sub 3} films. The Tm{sub 2}O{sub 3}/Ge interface is found to be rather atomically abrupt with sub-nanometer thickness. In addition, the band line-up of reference GeO{sub 2}/n-Ge stacks obtained by thermal oxidation has been discussed and derived. The observed low reactivity of thulium oxide on germanium as well as the high effective barriers for holes (∼3 eV) and electrons (∼2 eV) identify Tm{sub 2}O{sub 3} as a strong contender for interfacial layer engineering in future generations of scaled high-κ gate stacks on Ge.

  10. Atomic layer deposition of platinum with enhanced nucleation and coalescence by trimethylaluminum pre-pulsing

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yoontae; Dayeh, Shadi A., E-mail: sdayeh@ece.ucsd.edu [Department of Electrical and Computer Engineering, University of California, San Diego, California 92093 (United States); Nguyen, Binh-Minh [Department of Electrical and Computer Engineering, University of California, San Diego, California 92093 (United States); Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2013-12-23

    Conformal coating of metal layers on three-dimensional structures is essential for advanced electronic devices such as storage elements, transistors, and sensors. The quality of atomic layer deposited platinum on oxide surfaces was enhanced by adding pre-deposition pulses of trimethylaluminum (TMA) for improved wetting. With an optimal number of TMA pre-pulses, a 6 nm thick Pt film was perfectly coalesced in contrast to only Pt island formation without TMA pre-pulses. A Pt gate all around Ge/Si nanowire field effect transistor was realized highlighting the potential of this approach for efficient deposition of Pt on 3D nanoelectronic devices.

  11. GaAs surface passivation by plasma-enhanced atomic-layer-deposited aluminum nitride

    International Nuclear Information System (INIS)

    A low-temperature passivation method for GaAs surfaces is investigated. Ultrathin AlN layers are deposited by plasma-enhanced atomic-layer-deposition at 200 deg. C on top of near-surface InGaAs/GaAs quantum well structures. A significant passivation effect is seen as shown by up to 30 times higher photoluminescence intensity and up to seven times longer lifetime compared to uncoated reference samples. The improved optical properties are accompanied by a redshift of the quantum well photoluminescence peak likely caused by a combination of the nitridation of the GaAs capping layer and a surface coupling effect.

  12. GaAs surface passivation by plasma-enhanced atomic-layer-deposited aluminum nitride

    Energy Technology Data Exchange (ETDEWEB)

    Bosund, M., E-mail: Markus.Bosund@tkk.fi [Department of Micro and Nanosciences, Aalto University School of Science and Technology, P.O. Box 13500, FI-00076 Aalto (Finland); Mattila, P.; Aierken, A.; Hakkarainen, T.; Koskenvaara, H.; Sopanen, M.; Airaksinen, V.-M.; Lipsanen, H. [Department of Micro and Nanosciences, Aalto University School of Science and Technology, P.O. Box 13500, FI-00076 Aalto (Finland)

    2010-10-01

    A low-temperature passivation method for GaAs surfaces is investigated. Ultrathin AlN layers are deposited by plasma-enhanced atomic-layer-deposition at 200 deg. C on top of near-surface InGaAs/GaAs quantum well structures. A significant passivation effect is seen as shown by up to 30 times higher photoluminescence intensity and up to seven times longer lifetime compared to uncoated reference samples. The improved optical properties are accompanied by a redshift of the quantum well photoluminescence peak likely caused by a combination of the nitridation of the GaAs capping layer and a surface coupling effect.

  13. Initial tests of atomic layer deposition (ALD) coatings for superconducting RF systems

    International Nuclear Information System (INIS)

    Atomic Layer Deposition (ALD) is a method of synthesizing materials in single atomic layers. We are studying this technique as a method of producing highly controlled surfaces for superconducting RF systems. We have begun tests of ALD coatings of single cells that will involve RF measurements of a cell before and after coating at Argonne. In addition to the tests on complete cells, we are also beginning a program of point contact tunneling measurements to determine the properties of the superconductors at the interface between the bulk niobium and the oxide layer. We describe the method, and tests we are beginning with single cell resonators and small samples.

  14. Effect of substrate composition on atomic layer deposition using self-assembled monolayers as blocking layers

    International Nuclear Information System (INIS)

    The authors have examined the effect of two molecules that form self-assembled monolayers (SAMs) on the subsequent growth of TaNx by atomic layer deposition (ALD) on two substrate surfaces, SiO2 and Cu. The SAMs that the authors have investigated include two vapor phase deposited, fluorinated alkyl silanes: Cl3Si(CH2)2(CF2)5CF3 (FOTS) and (C2H5O)3Si(CH2)2(CF2)7CF3 (HDFTEOS). Both the SAMs themselves and the TaNx thin films, grown using Ta[N(CH3)2]5 and NH3, were analyzed ex situ using contact angle, spectroscopic ellipsometry, x-ray photoelectron spectroscopy (XPS), and low energy ion-scattering spectroscopy (LEISS). First, the authors find that both SAMs on SiO2 are nominally stable at Ts ∼ 300 °C, the substrate temperature used for ALD, while on Cu, the authors find that HDFTEOS thermally desorbs, while FOTS is retained on the surface. The latter result reflects the difference in the head groups of these two molecules. The authors find that both SAMs strongly attenuate the ALD growth of TaNx on SiO2, by about a factor of 10, while on Cu, the SAMs have no effect on ALD growth. Results from LEISS and XPS are decisive in determining the nature of the mechanism of growth of TaNx on all surfaces. Growth on SiO2 is 2D and approximately layer-by-layer, while on the surfaces terminated by the SAMs, it nucleates at defect sites, is islanded, and is 3D. In the latter case, our results support growth of the TaNx thin film over the SAM, with a considerable delay in formation of a continuous thin film. Growth on Cu, with or without the SAMs, is also 3D and islanded, and there is also a delay in the formation of a continuous thin film as compared to growth on SiO2. These results highlight the power of coupling measurements from both LEISS and XPS in examinations of ultrathin films formed by ALD

  15. Effect of substrate composition on atomic layer deposition using self-assembled monolayers as blocking layers

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenyu; Engstrom, James R., E-mail: jre7@cornell.edu [School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853 (United States)

    2016-01-15

    The authors have examined the effect of two molecules that form self-assembled monolayers (SAMs) on the subsequent growth of TaN{sub x} by atomic layer deposition (ALD) on two substrate surfaces, SiO{sub 2} and Cu. The SAMs that the authors have investigated include two vapor phase deposited, fluorinated alkyl silanes: Cl{sub 3}Si(CH{sub 2}){sub 2}(CF{sub 2}){sub 5}CF{sub 3} (FOTS) and (C{sub 2}H{sub 5}O){sub 3}Si(CH{sub 2}){sub 2}(CF{sub 2}){sub 7}CF{sub 3} (HDFTEOS). Both the SAMs themselves and the TaN{sub x} thin films, grown using Ta[N(CH{sub 3}){sub 2}]{sub 5} and NH{sub 3}, were analyzed ex situ using contact angle, spectroscopic ellipsometry, x-ray photoelectron spectroscopy (XPS), and low energy ion-scattering spectroscopy (LEISS). First, the authors find that both SAMs on SiO{sub 2} are nominally stable at T{sub s} ∼ 300 °C, the substrate temperature used for ALD, while on Cu, the authors find that HDFTEOS thermally desorbs, while FOTS is retained on the surface. The latter result reflects the difference in the head groups of these two molecules. The authors find that both SAMs strongly attenuate the ALD growth of TaN{sub x} on SiO{sub 2}, by about a factor of 10, while on Cu, the SAMs have no effect on ALD growth. Results from LEISS and XPS are decisive in determining the nature of the mechanism of growth of TaN{sub x} on all surfaces. Growth on SiO{sub 2} is 2D and approximately layer-by-layer, while on the surfaces terminated by the SAMs, it nucleates at defect sites, is islanded, and is 3D. In the latter case, our results support growth of the TaN{sub x} thin film over the SAM, with a considerable delay in formation of a continuous thin film. Growth on Cu, with or without the SAMs, is also 3D and islanded, and there is also a delay in the formation of a continuous thin film as compared to growth on SiO{sub 2}. These results highlight the power of coupling measurements from both LEISS and XPS in examinations of ultrathin films formed by ALD.

  16. Atomic Layer Deposition of Al2O3 on WSe2 Functionalized by Titanyl Phthalocyanine.

    Science.gov (United States)

    Park, Jun Hong; Fathipour, Sara; Kwak, Iljo; Sardashti, Kasra; Ahles, Christopher F; Wolf, Steven F; Edmonds, Mary; Vishwanath, Suresh; Xing, Huili Grace; Fullerton-Shirey, Susan K; Seabaugh, Alan; Kummel, Andrew C

    2016-07-26

    To deposit an ultrathin dielectric onto WSe2, monolayer titanyl phthalocyanine (TiOPc) is deposited by molecular beam epitaxy as a seed layer for atomic layer deposition (ALD) of Al2O3 on WSe2. TiOPc molecules are arranged in a flat monolayer with 4-fold symmetry as measured by scanning tunneling microscopy. ALD pulses of trimethyl aluminum and H2O nucleate on the TiOPc, resulting in a uniform deposition of Al2O3, as confirmed by atomic force microscopy and cross-sectional transmission electron microscopy. The field-effect transistors (FETs) formed using this process have a leakage current of 0.046 pA/μm(2) at 1 V gate bias with 3.0 nm equivalent oxide thickness, which is a lower leakage current than prior reports. The n-branch of the FET yielded a subthreshold swing of 80 mV/decade. PMID:27305595

  17. Dynamic Modeling for the Design and Cyclic Operation of an Atomic Layer Deposition (ALD) Reactor

    OpenAIRE

    Curtisha D. Travis; Raymond A. Adomaitis

    2013-01-01

    A laboratory-scale atomic layer deposition (ALD) reactor system model is derived for alumina deposition using trimethylaluminum and water as precursors. Model components describing the precursor thermophysical properties, reactor-scale gas-phase dynamics and surface reaction kinetics derived from absolute reaction rate theory are integrated to simulate the complete reactor system. Limit-cycle solutions defining continuous cyclic ALD reactor operation are computed with a fixed point algorithm ...

  18. Dispersion engineered high-Q silicon Nitride Ring-Resonators via Atomic Layer Deposition

    CERN Document Server

    Riemensberger, Johann; Herr, Tobias; Brasch, Victor; Holzwarth, Ronald; Kippenberg, Tobias J

    2012-01-01

    We demonstrate dispersion engineering of integrated silicon nitride based ring resonators through conformal coating with hafnium dioxide deposited on top of the structures via atomic layer deposition (ALD). Both, magnitude and bandwidth of anomalous dispersion can be significantly increased. All results are confirmed by high resolution frequency-comb-assisted-diode-laser spectroscopy and are in very good agreement with the simulated modification of the mode spectrum.

  19. Plasma-enhanced atomic layer deposition: a gas-phase route to hydrophilic, glueable polytetrafluoroethylene.

    Science.gov (United States)

    Roy, Amit K; Dendooven, Jolien; Deduytsche, Davy; Devloo-Casier, Kilian; Ragaert, Kim; Cardon, Ludwig; Detavernier, Christophe

    2015-02-28

    This communication reports an approach based on plasma-enhanced atomic layer deposition of aluminium oxide for the functionalization of polytetrafluoroethylene (PTFE or "Teflon") surfaces. Alternating exposure of PTFE to oxygen plasma and trimethylaluminium causes a permanent hydrophilic effect, and a more than 10-fold improvement of the "glueability" of PTFE to aluminium. PMID:25631168

  20. Atmospheric spatial atomic layer deposition of in-doped ZnO

    NARCIS (Netherlands)

    Illiberi, A.; Scherpenborg, R.; Roozeboom, F.; Poodt, P.

    2014-01-01

    Indium-doped zinc oxide (ZnO:In) has been grown by spatial atomic layer deposition at atmospheric pressure (spatial-ALD). Trimethyl indium (TMIn), diethyl zinc (DEZ) and deionized water have been used as In, Zn and O precursor, respectively. The metal content of the films is controlled in the range

  1. Spatial atmospheric atomic layer deposition of InxGayZnzO for thin film transistors

    NARCIS (Netherlands)

    Illiberi, A.; Cobb, B.; Sharma, A.; Grehl, T.; Brongersma, H.; Roozeboom, F.; Gelinck, G.; Poodt, P.

    2015-01-01

    We have investigated the nucleation and growth of InGaZnO thin films by spatial atmospheric atomic layer deposition. Diethyl zinc (DEZ), trimethyl indium (TMIn), triethyl gallium (TEGa), and water were used as Zn, In, Ga and oxygen precursors, respectively. The vaporized metal precursors have been c

  2. Equipment for atmospheric, spatial atomic layer deposition in roll-to-roll processes

    NARCIS (Netherlands)

    Knaapen, R.; Poodt, P.; Olieslagers, R.; Lankhorst, A.; Boer, M. van den; Berg, D. van den; Asten, A. van; Roozeboom, F.

    2012-01-01

    A novel type of reactor has been designed for atmospheric atomic layer deposition (ALD) on flexible substrates. In the reactor, a flexible substrate slowly advances around a fast rotating drum. Gas bearing technology is used to prevent physical contact between the flexible substrate and the drum, an

  3. Fabrication and surface passivation of porous 6H-SiC by atomic layer deposited films

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Petersen, Paul Michael;

    2016-01-01

    photoluminescence was observed and the etching process was optimized in terms of etching time and thickness. Enormous enhancement as well as redshift and broadening of photoluminescence spectra were observed after the passivation by atomic layer deposited Al2O3 and TiO2 films. No obvious luminescence was observed...

  4. Enhancement of barrier properties of aluminum oxide layer by optimization of plasma-enhanced atomic layer deposition process

    International Nuclear Information System (INIS)

    Aluminum oxide (AlxOy) layers were deposited on polyethylene naphthalate substrates by low frequency plasma-enhanced atomic layer deposition process for barrier property enhancement. Trimethylaluminum and oxygen plasma were used as precursor and reactant materials, respectively. In order to enhance the barrier properties several process parameters were examined such as plasma power, working pressure and electrode–substrate distance. Increase of plasma power enhanced the reactivity of activated atomic and molecular oxygen to reduce the carbon contents in AlxOy layer, which appeared to enhance the barrier properties. But too high power caused generation of byproducts which were reincorporated in AlxOy layer to reduce the barrier properties. Plasma generated at lower working pressure was provided with an additional energy for reactions and had more diffusion of the plasma. The O/Al ratio of the layer approached the stoichiometric value by increasing the electrode–substrate distance. At the following conditions: 300 W of plasma power, 26.7 Pa of working pressure and 50 mm of electrode–substrate distance, water vapor transmission rates of the AlxOy layer reached 8.85 × 10−4 g/m2 day. - Highlights: • Aluminum oxide layer was well formed by plasma enhanced atomic layer deposition. • Process parameters were optimized to enhance the barrier properties. • Barrier coating of plastic substrate can be applied to flexible display devices

  5. Enhancing of catalytic properties of vanadia via surface doping with phosphorus using atomic layer deposition

    International Nuclear Information System (INIS)

    Atomic layer deposition is mainly used to deposit thin films on flat substrates. Here, the authors deposit a submonolayer of phosphorus on V2O5 in the form of catalyst powder. The goal is to prepare a model catalyst related to the vanadyl pyrophosphate catalyst (VO)2P2O7 industrially used for the oxidation of n-butane to maleic anhydride. The oxidation state of vanadium in vanadyl pyrophosphate is 4+. In literature, it was shown that the surface of vanadyl pyrophosphate contains V5+ and is enriched in phosphorus under reaction conditions. On account of this, V2O5 with the oxidation state of 5+ for vanadium partially covered with phosphorus can be regarded as a suitable model catalyst. The catalytic performance of the model catalyst prepared via atomic layer deposition was measured and compared to the performance of catalysts prepared via incipient wetness impregnation and the original V2O5 substrate. It could be clearly shown that the dedicated deposition of phosphorus by atomic layer deposition enhances the catalytic performance of V2O5 by suppression of total oxidation reactions, thereby increasing the selectivity to maleic anhydride

  6. Enhancing of catalytic properties of vanadia via surface doping with phosphorus using atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Strempel, Verena E.; Naumann d' Alnoncourt, Raoul, E-mail: r.naumann@bascat.tu-berlin.de [BasCat - UniCat BASF JointLab, Technische Universität Berlin, Sekr. EW K 01, Hardenbergstraße 36, 10623 Berlin (Germany); Löffler, Daniel [Process Research and Chemical Engineering, BASF SE, Carl-Bosch-Straße 38, 67056 Ludwigshafen (Germany); Kröhnert, Jutta; Skorupska, Katarzyna; Johnson, Benjamin [Department of Inorganic Chemistry, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Driess, Matthias [BasCat - UniCat BASF JointLab, Technische Universität Berlin, Sekr. EW K 01, Hardenbergstraße 36, 10623 Berlin, Germany and Technische Universität Berlin, Institut für Chemie, Sekr. C2, Straße des 17. Juni 135, 10623 Berlin (Germany); Rosowski, Frank [BasCat - UniCat BASF JointLab, Technische Universität Berlin, Sekr. EW K 01, Hardenbergstraße 36, 10623 Berlin, Germany and Process Research and Chemical Engineering, BASF SE, Carl-Bosch-Straße 38, 67056 Ludwigshafen (Germany)

    2016-01-15

    Atomic layer deposition is mainly used to deposit thin films on flat substrates. Here, the authors deposit a submonolayer of phosphorus on V{sub 2}O{sub 5} in the form of catalyst powder. The goal is to prepare a model catalyst related to the vanadyl pyrophosphate catalyst (VO){sub 2}P{sub 2}O{sub 7} industrially used for the oxidation of n-butane to maleic anhydride. The oxidation state of vanadium in vanadyl pyrophosphate is 4+. In literature, it was shown that the surface of vanadyl pyrophosphate contains V{sup 5+} and is enriched in phosphorus under reaction conditions. On account of this, V{sub 2}O{sub 5} with the oxidation state of 5+ for vanadium partially covered with phosphorus can be regarded as a suitable model catalyst. The catalytic performance of the model catalyst prepared via atomic layer deposition was measured and compared to the performance of catalysts prepared via incipient wetness impregnation and the original V{sub 2}O{sub 5} substrate. It could be clearly shown that the dedicated deposition of phosphorus by atomic layer deposition enhances the catalytic performance of V{sub 2}O{sub 5} by suppression of total oxidation reactions, thereby increasing the selectivity to maleic anhydride.

  7. Tuning the mechanical properties of vertical graphene sheets through atomic layer deposition

    Science.gov (United States)

    Davami, Keivan; Jiang, Yijie; Cortes, John; Lin, Chen; Shaygan, Mehrdad; Turner, Kevin T.; Bargatin, Igor

    2016-04-01

    We report the fabrication and characterization of graphene nanostructures with mechanical properties that are tuned by conformal deposition of alumina. Vertical graphene (VG) sheets, also called carbon nanowalls (CNWs), were grown on copper foil substrates using a radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) technique and conformally coated with different thicknesses of alumina (Al2O3) using atomic layer deposition (ALD). Nanoindentation was used to characterize the mechanical properties of pristine and alumina-coated VG sheets. Results show a significant increase in the effective Young’s modulus of the VG sheets with increasing thickness of deposited alumina. Deposition of only a 5 nm thick alumina layer on the VG sheets nearly triples the effective Young’s modulus of the VG structures. Both energy absorption and strain recovery were lower in VG sheets coated with alumina than in pure VG sheets (for the same peak force). This may be attributed to the increase in bending stiffness of the VG sheets and the creation of connections between the sheets after ALD deposition. These results demonstrate that the mechanical properties of VG sheets can be tuned over a wide range through conformal atomic layer deposition, facilitating the use of VG sheets in applications where specific mechanical properties are needed.

  8. Atomic layer deposition of epitaxial layers of anatase on strontium titanate single crystals: Morphological and photoelectrochemical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, Theodore J.; Nepomnyashchii, Alexander B.; Parkinson, B. A., E-mail: bparkin1@uwyo.edu [Department of Chemistry, School of Energy Resources, University of Wyoming, Laramie, Wyoming 82071 (United States)

    2015-01-15

    Atomic layer deposition was used to grow epitaxial layers of anatase (001) TiO{sub 2} on the surface of SrTiO{sub 3} (100) crystals with a 3% lattice mismatch. The epilayers grow as anatase (001) as confirmed by x-ray diffraction. Atomic force microscope images of deposited films showed epitaxial layer-by-layer growth up to about 10 nm, whereas thicker films, of up to 32 nm, revealed the formation of 2–5 nm anatase nanocrystallites oriented in the (001) direction. The anatase epilayers were used as substrates for dye sensitization. The as received strontium titanate crystal was not sensitized with a ruthenium-based dye (N3) or a thiacyanine dye (G15); however, photocurrent from excited state electron injection from these dyes was observed when adsorbed on the anatase epilayers. These results show that highly ordered anatase surfaces can be grown on an easily obtained substrate crystal.

  9. Tribological Properties of Nanometric Atomic Layer Depositions Applied on AISI 420 Stainless Steel

    OpenAIRE

    Marin, E.; Lanzutti, A.; Fedrizzi, L.

    2013-01-01

    Atomic Layer Deposition ( ALD ) is a modern technique that Allows to deposit nanometric, conformal coatings on almost any kind of substrates, from plastics to ceramic, metals or even composites. ALD coatings are not dependent on the morphology of the substrate and are only regulated by the composition of the precursors, the chamber temperature and the number of cycles. In this work, mono- and bi -layer nanometric, protective low-temperature ALD Coatings, based on Al2O3 and TiO2 were applied o...

  10. Suppressed grain-boundary scattering in atomic layer deposited Nb:TiO2 thin films

    Science.gov (United States)

    Niemelä, Janne-Petteri; Hirose, Yasushi; Shigematsu, Kei; Sano, Masahito; Hasegawa, Tetsuya; Karppinen, Maarit

    2015-11-01

    We have fabricated high-quality thin films of the transparent conducting anatase Nb:TiO2 on glass substrates through atomic layer deposition, and a subsequent reductive heat treatment of the as-deposited amorphous films. Hall-effect measurements and Drude-fitting of the Vis-NIR spectra indicate that for lightly doped films deposited at temperatures around 170 °C, grain boundary scattering becomes negligible and the mobility is predominately limited by phonon-electron scattering inherent to the anatase lattice and by impurities. Simultaneously, such lighter doping leads to reduced plasma absorption, thereby improving material's performance as a transparent conductor.

  11. Mechanistic Details of Surface Reactions in Atomic Layer Deposition (ALD) Processes

    Institute of Scientific and Technical Information of China (English)

    Menno; Bouman; Christopher; Clark; Hugo; Tiznado; Francisco; Zaera

    2007-01-01

    1 Results The reaction mechanisms of the atomic layer deposition (ALD) processes used for thin-film growth have been characterized by a combination of surface sensitive techniques. Our early studies focused on the deposition of TiN films from TiCl4 and ammonia,starting with the independent characterization of each of the two half steps comprising the ALD process. It was found that exposure of the substrate to TiCl4 leads to the initial deposition of titanium in the +3 oxidation state; only at a later st...

  12. Integration of atomic layer deposition-grown copper for advanced interconnect applications

    Science.gov (United States)

    Wu, Liqi

    While copper damascene processes currently utilize physically vapor deposited (PVD) Cu seed layers, the continued scaling of interconnect feature sizes in advanced nanoelectronic devices requires the development of a more conformal, controllable Cu seed layer technology for use with electrochemically deposited (ECD) copper interconnects. Atomic layer deposition (ALD) is a promising alternative because of its excellent conformality and precise thickness control capability. In this research, a self-limiting plasma-enhanced ALD (PEALD) Cu process, employing Cu(II) acetylacetonate (Cu(acac)2) and atomic hydrogen, was employed to deposit high quality PEALD Cu films. In addition, substrate surface hydrogen plasma treatments prior to PEALD Cu growth were observed to enhance Cu nucleation, decrease Cu surface roughness, and reduce Cu resistivity. The performance characteristics of ECD/PEALD-grown Cu interconnects were compared with those of a conventional ECD/PVD Cu stack. Finally, void-free electroplated Cu was demonstrated on 60 and 35 nm patterned via structures using both ALD Ru/TaN and conventional PVD Ta/TaN liner/barrier structures coupled with PEALD Cu seed layers. The film properties and resulting integration characteristics suggest that PEALD Cu is a promising approach for advanced seed layer applications in CMOS metallization.

  13. Dominant shallow donors in zinc oxide layers obtained by low-temperature atomic layer deposition: Electrical and optical investigations

    International Nuclear Information System (INIS)

    This work is focused on the electrical and optical analyses used to estimate the activation energy of the dominant shallow donor in thin ZnO films obtained at low temperature by the atomic layer deposition process. These two approaches, based on the temperature-dependent classical Hall effect and photoluminescence investigations, yielded a donor activation energy ED in the range of 30–40 meV, including the estimated error margins. This value, as confirmed by layer composition studies, is attributed to the presence of zinc atoms in the interstitial positions of the ZnO lattice

  14. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO2 layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10−2 A W−1 and a shot-derived specific detectivity of 3 × 109 Jones at 1530 nm wavelength

  15. Atomic Layer Deposited Corrosion Protection: A Path to Stable and Efficient Photoelectrochemical Cells.

    Science.gov (United States)

    Scheuermann, Andrew G; McIntyre, Paul C

    2016-07-21

    A fundamental challenge in developing photoelectrochemical cells for the renewable production of solar chemicals and fuels is the simultaneous requirement of efficient light absorption and robust stability under corrosive conditions. Schemes for corrosion protection of semiconductor photoelectrodes such as silicon using deposited layers were proposed and attempted for several decades, but increased operational lifetimes were either insufficient or the resulting penalties for device efficiency were prohibitive. In recent years, advances in atomic layer deposition (ALD) of thin coatings have made novel materials engineering possible, leading to substantial and simultaneous improvements in stability and efficiency of photoelectrochemical cells. The self-limiting, layer-by-layer growth of ALD makes thin films with low pinhole densities possible and may also provide a path to defect control that can generalize this protection technology to a large set of materials necessary to fully realize photoelectrochemical cell technology for artificial photosynthesis. PMID:27359352

  16. Supercritical Fluid Atomic Layer Deposition: Base-Catalyzed Deposition of SiO2.

    Science.gov (United States)

    Kalan, Roghi E; McCool, Benjamin A; Tripp, Carl P

    2016-07-19

    An in situ FTIR thin film technique was used to study the sequential atomic layer deposition (ALD) reactions of SiCl4, tetraethyl orthosilicate (TEOS) precursors, and water on nonporous silica powder using supercritical CO2 (sc-CO2) as the solvent. The IR work on nonporous powders was used to identify the reaction sequence for using a sc-CO2-based ALD to tune the pore size of a mesoporous silica. The IR studies showed that only trace adsorption of SiCl4 occurred on the silica, and this was due to the desiccating power of sc-CO2 to remove the adsorbed water from the surface. This was overcome by employing a three-step reaction scheme involving a first step of adsorption of triethylamine (TEA), followed by SiCl4 and then H2O. For TEOS, a three-step reaction sequence using TEA, TEOS, and then water offered no advantage, as the TEOS simply displaced the TEA from the silica surface. A two-step reaction involving the addition of TEOS followed by H2O in a second step did lead to silica film growth. However, higher growth rates were obtained when using a mixture of TEOS/TEA in the first step. The hydrolysis of the adsorbed TEOS was also much slower than that of the adsorbed SiCl4, and this was overcome by using a mixture of water/TEA during the second step. While the three-step process with SiCl4 showed a higher linear growth rate than obtained with two-step process using TEOS/TEA, its use was not practical, as the HCl generated led to corrosion of our sc-CO2 delivery system. However, when applying the two-step ALD reaction using TEOS on an MCM-41 powder, a 0.21 nm decrease in pore diameter was obtained after the first ALD cycle whereas further ALD cycles did not lead to further pore size reduction. This was attributed to the difficulty in removal of the H2O in the pores after the first cycle. PMID:27338186

  17. Low temperature temporal and spatial atomic layer deposition of TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Aghaee, Morteza, E-mail: m.aghaee@tue.nl; Maydannik, Philipp S. [ASTRaL Group, Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Johansson, Petri; Kuusipalo, Jurkka [Paper Converting and Packaging Technology, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Creatore, Mariadriana [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Homola, Tomáš; Cameron, David C. [R& D Center for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic)

    2015-07-15

    Titanium dioxide films were grown by atomic layer deposition (ALD) using titanium tetraisopropoxide as a titanium precursor and water, ozone, or oxygen plasma as coreactants. Low temperatures (80–120 °C) were used to grow moisture barrier TiO{sub 2} films on polyethylene naphthalate. The maximum growth per cycle for water, ozone, and oxygen plasma processes were 0.33, 0.12, and 0.56 Å/cycle, respectively. X-ray photoelectron spectrometry was used to evaluate the chemical composition of the layers and the origin of the carbon contamination was studied by deconvoluting carbon C1s peaks. In plasma-assisted ALD, the film properties were dependent on the energy dose supplied by the plasma. TiO{sub 2} films were also successfully deposited by using a spatial ALD (SALD) system based on the results from the temporal ALD. Similar properties were measured compared to the temporal ALD deposited TiO{sub 2}, but the deposition time could be reduced using SALD. The TiO{sub 2} films deposited by plasma-assisted ALD showed better moisture barrier properties than the layers deposited by thermal processes. Water vapor transmission rate values lower than 5 × 10{sup −4} g day{sup −1} m{sup −2} (38 °C and 90% RH) was measured for 20 nm of TiO{sub 2} film deposited by plasma-assisted ALD.

  18. Conditions for the deposition of CdTe by electrochemical atomic layer epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, B.W.; Suggs, D.W.; Stickney, J.L. (School of Chemical Sciences, Univ. of Georgia, Athens, GA (US))

    1991-05-01

    In this paper the method of electrochemical atomic layer epitaxy (ECALE) is described. It involves the alternated electrochemical deposition of atomic layers of elements to form compound semiconductors. It is being investigated as a method for forming epitaxial thin films. Presently, it appears that the method is applicable to a wide range of compound semiconductors composed of a metal and one of the following main group elements: S, Se, Te, As, Sb, or Br. Initial studies have involved CdTe deposition. Factors controlling deposit structure and composition are discussed here. Preliminary results which show that ordered electrodeposits of CdTe can be formed by the ECALE method are also presented. Results reported here were obtained with both a polycrystalline Au thin-layer electrochemical cell and a single-crystal Au electrode with faces oriented to the (111), (110), and (100) planes. The single-crystal electrode was contained in a UHV surface analysis instrument with an integral electrochemical cell. Deposits were examined without their exposure to air using LEED and Auger electron spectroscopy. Coverages were determined using coulometry in the thin-layer electrochemical cell.

  19. CoFe2/Al2O3/PMNPT multiferroic heterostructures by atomic layer deposition

    Science.gov (United States)

    Zhou, Ziyao; Grocke, Garrett; Yanguas-Gil, Angel; Wang, Xinjun; Gao, Yuan; Sun, Nianxiang; Howe, Brandon; Chen, Xing

    2016-05-01

    Multiferroic materials and applications allow electric bias control of magnetism or magnetic bias control of polarization, enabling fast, compact, energy-efficient devices in RF/microwave communication systems such as filters, shifters, and antennas; electronics devices such as inductors and capacitors; and other magnetic material related applications including sensors and memories. In this manuscript, we utilize atomic layer deposition technology to grow magnetic CoFe metallic thin films onto PMNPT, with a ˜110 Oe electric field induced ferromagnetic resonance field shift in the CoFe/Al2O3/PMNPT multiferroic heterostructure. Our work demonstrates an atomic layer deposition fabricated multiferroic heterostructure with significant tunability and shows that the unique thin film growth mechanism will benefit integrated multiferroic application in near future.

  20. Atomic layer deposition of TiO2 thin films on nanoporous alumina templates: Medical applications

    Science.gov (United States)

    Narayan, Roger J.; Monteiro-Riviere, Nancy A.; Brigmon, Robin L.; Pellin, Michael J.; Elam, Jeffrey W.

    2009-06-01

    Nanostructured materials may play a significant role in controlled release of pharmacologic agents for treatment of cancer. Many nanoporous polymer materials are inadequate for use in drug delivery. Nanoporous alumina provides several advantages over other materials for use in controlled drug delivery and other medical applications. Atomic layer deposition was used to coat all the surfaces of a nanoporous alumina membrane in order to reduce the pore size in a controlled manner. Neither the 20 nm nor the 100 nm TiO2-coated nanoporous alumina membranes exhibited statistically lower viability compared to the uncoated nanoporous alumina membrane control materials. Nanostructured materials prepared using atomic layer deposition may be useful for delivering a pharmacologic agent at a precise rate to a specific location in the body. These materials may serve as the basis for “smart” drug delivery devices, orthopedic implants, or self-sterilizing medical devices.

  1. Nanomechanical properties of platinum thin films synthesized by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mamun, M.A.; Gu, D.; Baumgart, H.; Elmustafa, A.A.

    2015-03-01

    The nanomechanical properties of Pt thin films grown on Si (100) using atomic layer deposition (ALD) were investigated using nanoindentation. Recently, atomic layer deposition (ALD) has successfully demonstrated the capability to deposit ultra-thin films of platinum (Pt). Using (methylcyclopentadienyl) trimethylplatinum (MeCpPtMe3) as chemical platinum precursor and oxygen (O2) as the oxidizing agent, the ALD synthesis of Pt can be achieved with high conformity and excellent film uniformity. The ALD process window for Pt films was experimentally established in the temperature range between 270 °C and 320 °C, where the sheet conductance was constant over that temperature range, indicating stable ALD Pt film growth rate. ALD growth of Pt films exhibits very poor nucleation and adhesion characteristics on bare Si surfaces when the native oxide was removed by 2% HF etch. Pt adhesion improves for thermally oxidized Si wafers and for Si wafers covered with native oxide. Three ALD Pt films deposited at 800, 900, and 1000 ALD deposition cycles were tested for the structural and mechanical properties. Additionally, the sample with 900 ALD deposition cycles was further annealed in forming gas (95% N2 and 5% H2) at 450 °C for 30 min in order to passivate dangling bonds in the grain boundaries of the polycrystalline Pt film. Cross-sectional transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscope (SEM) were employed to characterize the films' surface structure and morphology. Nanoindentation technique was used to evaluate the hardness and modulus of the ALD Pt films of various film thicknesses. The results indicate that the films depict comparable hardness and modulus results; however, the 800 and 1000 ALD deposition cycles films without forming gas annealing experienced significant amount of pileup, whereas the 900 ALD deposition cycles sample annealed in forming gas resulted in a smaller pileup.

  2. Deposition of O atomic layers on Si(100) substrates for epitaxial Si-O superlattices: investigation of the surface chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Jayachandran, Suseendran, E-mail: suseendran.jayachandran@imec.be [KU Leuven, Department of Metallurgy and Materials, Castle Arenberg 44, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Delabie, Annelies; Billen, Arne [KU Leuven, Department of Chemistry, Celestijnenlaan 200F, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Dekkers, Harold; Douhard, Bastien; Conard, Thierry; Meersschaut, Johan; Caymax, Matty [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Vandervorst, Wilfried [KU Leuven, Department of Physics and Astronomy, Celestijnenlaan 200D, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Heyns, Marc [KU Leuven, Department of Metallurgy and Materials, Castle Arenberg 44, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium)

    2015-01-01

    Highlights: • Atomic layer is deposited by O{sub 3} chemisorption reaction on H-terminated Si(100). • O-content has critical impact on the epitaxial thickness of the above-deposited Si. • Oxygen atoms at dimer/back bond configurations enable epitaxial Si on O atomic layer. • Oxygen atoms at hydroxyl and more back bonds, disable epitaxial Si on O atomic layer. - Abstract: Epitaxial Si-O superlattices consist of alternating periods of crystalline Si layers and atomic layers of oxygen (O) with interesting electronic and optical properties. To understand the fundamentals of Si epitaxy on O atomic layers, we investigate the O surface species that can allow epitaxial Si chemical vapor deposition using silane. The surface reaction of ozone on H-terminated Si(100) is used for the O deposition. The oxygen content is controlled precisely at and near the atomic layer level and has a critical impact on the subsequent Si deposition. There exists only a small window of O-contents, i.e. 0.7–0.9 atomic layers, for which the epitaxial deposition of Si can be realized. At these low O-contents, the O atoms are incorporated in the Si-Si dimers or back bonds (-OSiH), with the surface Si atoms mainly in the 1+ oxidation state, as indicated by infrared spectroscopy. This surface enables epitaxial seeding of Si. For O-contents higher than one atomic layer, the additional O atoms are incorporated in the Si-Si back bonds as well as in the Si-H bonds, where hydroxyl groups (-Si-OH) are created. In this case, the Si deposition thereon becomes completely amorphous.

  3. Deposition of O atomic layers on Si(100) substrates for epitaxial Si-O superlattices: investigation of the surface chemistry

    International Nuclear Information System (INIS)

    Highlights: • Atomic layer is deposited by O3 chemisorption reaction on H-terminated Si(100). • O-content has critical impact on the epitaxial thickness of the above-deposited Si. • Oxygen atoms at dimer/back bond configurations enable epitaxial Si on O atomic layer. • Oxygen atoms at hydroxyl and more back bonds, disable epitaxial Si on O atomic layer. - Abstract: Epitaxial Si-O superlattices consist of alternating periods of crystalline Si layers and atomic layers of oxygen (O) with interesting electronic and optical properties. To understand the fundamentals of Si epitaxy on O atomic layers, we investigate the O surface species that can allow epitaxial Si chemical vapor deposition using silane. The surface reaction of ozone on H-terminated Si(100) is used for the O deposition. The oxygen content is controlled precisely at and near the atomic layer level and has a critical impact on the subsequent Si deposition. There exists only a small window of O-contents, i.e. 0.7–0.9 atomic layers, for which the epitaxial deposition of Si can be realized. At these low O-contents, the O atoms are incorporated in the Si-Si dimers or back bonds (-OSiH), with the surface Si atoms mainly in the 1+ oxidation state, as indicated by infrared spectroscopy. This surface enables epitaxial seeding of Si. For O-contents higher than one atomic layer, the additional O atoms are incorporated in the Si-Si back bonds as well as in the Si-H bonds, where hydroxyl groups (-Si-OH) are created. In this case, the Si deposition thereon becomes completely amorphous

  4. Mechanical and structural characterization of atomic layer deposition-based ZnO films

    International Nuclear Information System (INIS)

    Zinc oxide thin films were deposited by atomic layer deposition (ALD). The structural and mechanical properties of the thin films were investigated by x-ray diffraction, transmission electron microscopy, atomic force microscopy, and nanoindentation. Diethyl zinc was used as the chemical precursor for zinc and water vapor was used as the oxidation agent. The samples were deposited at 150 °C and at a pressure of 2.1 × 10−1 Torr in the ALD reactor. A growth rate of 2 Å per cycle was calculated in the ALD process window. The Nano Indenter XP was used in conjunction with the continuous stiffness method in depth control mode in order to measure and to analyze the mechanical properties of hardness and modulus of ALD ZnO thin film samples. For comparison, we benchmarked the mechanical properties of single crystal bulk ZnO samples against those of our ALD ZnO thin films

  5. Mechanical and structural characterization of atomic layer deposition-based ZnO films

    Science.gov (United States)

    Tapily, K.; Gu, D.; Baumgart, H.; Namkoong, G.; Stegall, D.; Elmustafa, A. A.

    2011-11-01

    Zinc oxide thin films were deposited by atomic layer deposition (ALD). The structural and mechanical properties of the thin films were investigated by x-ray diffraction, transmission electron microscopy, atomic force microscopy, and nanoindentation. Diethyl zinc was used as the chemical precursor for zinc and water vapor was used as the oxidation agent. The samples were deposited at 150 °C and at a pressure of 2.1 × 10-1 Torr in the ALD reactor. A growth rate of 2 Å per cycle was calculated in the ALD process window. The Nano Indenter XP was used in conjunction with the continuous stiffness method in depth control mode in order to measure and to analyze the mechanical properties of hardness and modulus of ALD ZnO thin film samples. For comparison, we benchmarked the mechanical properties of single crystal bulk ZnO samples against those of our ALD ZnO thin films.

  6. A brief review of atomic layer deposition: from fundamentals to applications

    OpenAIRE

    Johnson, Richard W.; Adam Hultqvist; Bent, Stacey F.

    2014-01-01

    Atomic layer deposition (ALD) is a vapor phase technique capable of producing thin films of a variety of materials. Based on sequential, self-limiting reactions, ALD offers exceptional conformality on high-aspect ratio structures, thickness control at the Angstrom level, and tunable film composition. With these advantages, ALD has emerged as a powerful tool for many industrial and research applications. In this review, we provide a brief introduction to ALD and highlight select applications, ...

  7. Enhanced initial growth of atomic-layer-deposited metal oxides on hydrogen-terminated silicon

    International Nuclear Information System (INIS)

    A route is presented for activation of hydrogen-terminated Si(100) prior to atomic layer deposition. It is based on our discovery from in situ infrared spectroscopy that organometallic precursors can effectively initiate oxide growth. Narrow nuclear resonance profiling and Rutherford backscattering spectrometry show that surface functionalization by pre-exposure to 108 Langmuir trimethylaluminum at 300 deg. C leads to enhanced nucleation and to nearly linear growth kinetics of the high-permittivity gate dielectrics aluminum oxide and hafnium oxide

  8. On model materials designed by atomic layer deposition for catalysis purposes

    OpenAIRE

    2011-01-01

    The aim of this work was to investigate the potential of model materials designed by atomic layer deposition toward applications in catalysis research. Molybdenum based catalysts promoted with cobalt were selected as target materials, considering their important roles in various industrial processes. Particular attention was paid to understand the growth dynamics of the ALD processes involved and further to characterize the obtained materials carefully. It was of main concern to verify the fe...

  9. Atomic layer deposition of copper – study through density functional theory

    OpenAIRE

    Dey, Gangotri

    2014-01-01

    The wonder of the last century has been the rapid development in technology. One of the sectors that it has touched immensely is the electronic industry. There has been exponential development in the field and scientists are pushing new horizons. There is an increased dependence in technology for every individual from different strata in the society. Atomic Layer Deposition (ALD) is a unique technique for growing thin films. It is widely used in the semiconductor industry. Films as thin as fe...

  10. Role of plasma enhanced atomic layer deposition reactor wall conditions on radical and ion substrate fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Mark J., E-mail: msowa@ultratech.com [Ultratech/Cambridge NanoTech, 130 Turner Street, Building 2, Waltham, Massachusetts 02453 (United States)

    2014-01-15

    Chamber wall conditions, such as wall temperature and film deposits, have long been known to influence plasma source performance on thin film processing equipment. Plasma physical characteristics depend on conductive/insulating properties of chamber walls. Radical fluxes depend on plasma characteristics as well as wall recombination rates, which can be wall material and temperature dependent. Variations in substrate delivery of plasma generated species (radicals, ions, etc.) impact the resulting etch or deposition process resulting in process drift. Plasma enhanced atomic layer deposition is known to depend strongly on substrate radical flux, but film properties can be influenced by other plasma generated phenomena, such as ion bombardment. In this paper, the chamber wall conditions on a plasma enhanced atomic layer deposition process are investigated. The downstream oxygen radical and ion fluxes from an inductively coupled plasma source are indirectly monitored in temperature controlled (25–190 °C) stainless steel and quartz reactors over a range of oxygen flow rates. Etch rates of a photoresist coated quartz crystal microbalance are used to study the oxygen radical flux dependence on reactor characteristics. Plasma density estimates from Langmuir probe ion saturation current measurements are used to study the ion flux dependence on reactor characteristics. Reactor temperature was not found to impact radical and ion fluxes substantially. Radical and ion fluxes were higher for quartz walls compared to stainless steel walls over all oxygen flow rates considered. The radical flux to ion flux ratio is likely to be a critical parameter for the deposition of consistent film properties. Reactor wall material, gas flow rate/pressure, and distance from the plasma source all impact the radical to ion flux ratio. These results indicate maintaining chamber wall conditions will be important for delivering consistent results from plasma enhanced atomic layer deposition

  11. Integrating Atomic Layer Deposition and Ultra-High Vacuum Physical Vapor Deposition for In Situ Fabrication of Tunnel Junctions

    OpenAIRE

    Elliot, Alan J.; Malek, Gary A.; Lu, Rongtao; Han, Siyuan; Yiu, Haifeng; Zhao, Shiping; Wu, Judy Z.

    2014-01-01

    Atomic Layer Deposition (ALD) is a promising technique for growing ultrathin, pristine dielectrics on metal substrates, which is essential to many electronic devices. Tunnel junctions are an excellent example which require a leak-free, ultrathin dielectric tunnel barrier of typical thickness around 1 nm between two metal electrodes. A challenge in the development of ultrathin dielectric tunnel barrier using ALD is controlling the nucleation of dielectrics on metals with minimal formation of n...

  12. The effect of substrate temperature on atomic layer deposited zinc tin oxide

    International Nuclear Information System (INIS)

    Zinc tin oxide (ZTO) thin films were deposited on glass substrates by atomic layer deposition (ALD), and the film properties were investigated for varying deposition temperatures in the range of 90 to 180 °C. It was found that the [Sn]/([Sn] + [Zn]) composition is only slightly temperature dependent, while properties such as growth rate, film density, material structure and band gap are more strongly affected. The growth rate dependence on deposition temperature varies with the relative number of zinc or tin containing precursor pulses and it correlates with the growth rate behavior of pure ZnO and SnOx ALD. In contrast to the pure ZnO phase, the density of the mixed ZTO films is found to depend on the deposition temperature and it increases linearly with about 1 g/cm3 in total over the investigated range. Characterization by transmission electron microscopy suggests that zinc rich ZTO films contain small (~ 10 nm) ZnO or ZnO(Sn) crystallites embedded in an amorphous matrix, and that these crystallites increase in size with increasing zinc content and deposition temperature. These crystallites are small enough for quantum confinement effects to reduce the optical band gap of the ZTO films as they grow in size with increasing deposition temperature. - Highlights: • Zinc tin oxide thin films were deposited by atomic layer deposition. • The structure and optical properties were studied at different growth temperatures. • The growth temperature had only a small effect on the composition of the films. • Small ZnO or ZnO(Sn) crystallites were observed by TEM in zinc rich ZTO films. • The growth temperature affects the crystallite size, which influences the band gap

  13. GaAs interfacial self-cleaning by atomic layer deposition

    Science.gov (United States)

    Hinkle, C. L.; Sonnet, A. M.; Vogel, E. M.; McDonnell, S.; Hughes, G. J.; Milojevic, M.; Lee, B.; Aguirre-Tostado, F. S.; Choi, K. J.; Kim, H. C.; Kim, J.; Wallace, R. M.

    2008-02-01

    The reduction and removal of surface oxides from GaAs substrates by atomic layer deposition (ALD) of Al2O3 and HfO2 are studied using in situ monochromatic x-ray photoelectron spectroscopy. Using the combination of in situ deposition and analysis techniques, the interfacial "self-cleaning" is shown to be oxidation state dependent as well as metal organic precursor dependent. Thermodynamics, charge balance, and oxygen coordination drive the removal of certain species of surface oxides while allowing others to remain. These factors suggest proper selection of surface treatments and ALD precursors can result in selective interfacial bonding arrangements.

  14. (Invited) Atomic Layer Deposition for Novel Dye-Sensitized Solar Cells

    KAUST Repository

    Tétreault, Nicolas

    2011-01-01

    Herein we present the latest fabrication and characterization techniques for atomic layer deposition of Al 2O 3, ZnO, SnO 2, Nb 2O 5, HfO 2, Ga 2O 3 and TiO 2 for research on dye-sensitized solar cell. In particular, we review the fabrication of state-of-the-art 3D host-passivation-guest photoanodes and ZnO nanowires as well as characterize the deposited thin films using spectroscopic ellipsometry, X-ray diffraction, Hall effect, J-V curves and electrochemical impedance spectroscopy. ©The Electrochemical Society.

  15. Improvement and protection of niobium surface superconductivity by atomic layer deposition and heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Proslier, T.; /IIT, Chicago /Argonne; Zasadzinski, J.; /IIT, Chicago; Moore, J.; Pellin, M.; Elam, J.; /Argonne; Cooley, L.; /Fermilab; Antoine, C.; /Saclay

    2008-11-01

    A method to treat the surface of Nb is described, which potentially can improve the performance of superconducting rf cavities. We present tunneling and x-ray photoemission spectroscopy measurements at the surface of cavity-grade niobium samples coated with a 3 nm alumina overlayer deposited by atomic layer deposition. The coated samples baked in ultrahigh vacuum at low temperature degraded superconducting surface. However, at temperatures above 450 C, the tunneling conductance curves show significant improvements in the superconducting density of states compared with untreated surfaces.

  16. Low-temperature SiON films deposited by plasma-enhanced atomic layer deposition method using activated silicon precursor

    International Nuclear Information System (INIS)

    It has not been an easy task to deposit SiN at low temperature by conventional plasma-enhanced atomic layer deposition (PE-ALD) since Si organic precursors generally have high activation energy for adsorption of the Si atoms on the Si-N networks. In this work, in order to achieve successful deposition of SiN film at low temperature, the plasma processing steps in the PE-ALD have been modified for easier activation of Si precursors. In this modification, the efficiency of chemisorption of Si precursor has been improved by additional plasma steps after purging of the Si precursor. As the result, the SiN films prepared by the modified PE-ALD processes demonstrated higher purity of Si and N atoms with unwanted impurities such as C and O having below 10 at. % and Si-rich films could be formed consequently. Also, a very high step coverage ratio of 97% was obtained. Furthermore, the process-optimized SiN film showed a permissible charge-trapping capability with a wide memory window of 3.1 V when a capacitor structure was fabricated and measured with an insertion of the SiN film as the charge-trap layer. The modified PE-ALD process using the activated Si precursor would be one of the most practical and promising solutions for SiN deposition with lower thermal budget and higher cost-effectiveness

  17. Low-temperature SiON films deposited by plasma-enhanced atomic layer deposition method using activated silicon precursor

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Sungin; Kim, Jun-Rae; Kim, Seongkyung; Hwang, Cheol Seong; Kim, Hyeong Joon, E-mail: thinfilm@snu.ac.kr [Department of Materials Science and Engineering with Inter-University Semiconductor Research Center (ISRC), Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Ryu, Seung Wook, E-mail: tazryu78@gmail.com [Department of Electrical Engineering, Stanford University, Stanford, California 94305-2311 (United States); Cho, Seongjae [Department of Electronic Engineering and New Technology Component & Material Research Center (NCMRC), Gachon University, Seongnam-si, Gyeonggi-do 13120 (Korea, Republic of)

    2016-01-15

    It has not been an easy task to deposit SiN at low temperature by conventional plasma-enhanced atomic layer deposition (PE-ALD) since Si organic precursors generally have high activation energy for adsorption of the Si atoms on the Si-N networks. In this work, in order to achieve successful deposition of SiN film at low temperature, the plasma processing steps in the PE-ALD have been modified for easier activation of Si precursors. In this modification, the efficiency of chemisorption of Si precursor has been improved by additional plasma steps after purging of the Si precursor. As the result, the SiN films prepared by the modified PE-ALD processes demonstrated higher purity of Si and N atoms with unwanted impurities such as C and O having below 10 at. % and Si-rich films could be formed consequently. Also, a very high step coverage ratio of 97% was obtained. Furthermore, the process-optimized SiN film showed a permissible charge-trapping capability with a wide memory window of 3.1 V when a capacitor structure was fabricated and measured with an insertion of the SiN film as the charge-trap layer. The modified PE-ALD process using the activated Si precursor would be one of the most practical and promising solutions for SiN deposition with lower thermal budget and higher cost-effectiveness.

  18. Controlled growth of rutile TiO{sub 2} by atomic layer deposition on oxidized ruthenium

    Energy Technology Data Exchange (ETDEWEB)

    Popovici, Mihaela; Swerts, Johan; Tomida, Kazuyuki; Radisic, Dunja; Kim, Min-Soo; Kaczer, Ben; Richard, Olivier; Bender, Hugo; Delabie, Annelies; Moussa, Alain; Vrancken, Christa; Opsomer, Karl; Franquet, Alexis; Pawlak, Malgorzata A.; Schaekers, Marc; Altimime, Laith; Elshocht, Sven van; Kittl, Jorge A. [Imec, Kapeldreef 75, 3001, Leuven (Belgium)

    2011-01-15

    Crystalline rutile TiO{sub 2} films were grown by atomic layer deposition on oxidized Ru electrodes using a titanium methoxide as the metal precursor and O{sub 3} as the oxidant. A protective layer of {proportional_to}0.3 nm TiO{sub 2} grown with H{sub 2}O as the oxidant was first deposited in order to avoid etching of the Ru bottom electrode by the O{sub 3} used for the growth of the TiO{sub 2} (bulk) layer. Electrical evaluation of the capacitor stacks with TiO{sub 2} as dielectric, RuO{sub 2}/Ru and Pt as the bottom and top electrodes respectively, resulted in superior characteristics of the rutile phase as compared to the anatase. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Passivation of GaAs surface by atomic-layer-deposited titanium nitride

    International Nuclear Information System (INIS)

    The suitability of titanium nitride (TiN) for GaAs surface passivation and protection is investigated. A 2-6-nm thick TiN passivation layer is deposited by atomic layer deposition (ALD) at 275 deg. C on top of InGaAs/GaAs near surface quantum well (NSQW) structures to study the surface passivation. X-ray reflectivity measurements are used to determine the physical properties of the passivation layer. TiN passivation does not affect the surface morphology of the samples, but increases significantly the photoluminescence intensity and carrier lifetime of the NSQWs, and also provides long-term protection of the sample surface. This study shows that ALD TiN coating is a promising low-temperature method for ex situ GaAs surface passivation

  20. Passivation of GaAs surface by atomic-layer-deposited titanium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Bosund, M. [Micro and Nanosciences Laboratory, Helsinki University of Technology, P.O. Box 3500, FI-02015 TKK (Finland)], E-mail: Markus.Bosund@tkk.fi; Aierken, A.; Tiilikainen, J.; Hakkarainen, T.; Lipsanen, H. [Micro and Nanosciences Laboratory, Helsinki University of Technology, P.O. Box 3500, FI-02015 TKK (Finland)

    2008-06-30

    The suitability of titanium nitride (TiN) for GaAs surface passivation and protection is investigated. A 2-6-nm thick TiN passivation layer is deposited by atomic layer deposition (ALD) at 275 deg. C on top of InGaAs/GaAs near surface quantum well (NSQW) structures to study the surface passivation. X-ray reflectivity measurements are used to determine the physical properties of the passivation layer. TiN passivation does not affect the surface morphology of the samples, but increases significantly the photoluminescence intensity and carrier lifetime of the NSQWs, and also provides long-term protection of the sample surface. This study shows that ALD TiN coating is a promising low-temperature method for ex situ GaAs surface passivation.

  1. Atomic layer deposition of two dimensional MoS2 on 150 mm substrates

    International Nuclear Information System (INIS)

    Low temperature atomic layer deposition (ALD) of monolayer to few layer MoS2 uniformly across 150 mm diameter SiO2/Si and quartz substrates is demonstrated. Purge separated cycles of MoCl5 and H2S precursors are used at reactor temperatures of up to 475 °C. Raman scattering studies show clearly the in-plane (E12g) and out-of-plane (A1g) modes of MoS2. The separation of the E12g and A1g peaks is a function of the number of ALD cycles, shifting closer together with fewer layers. X-ray photoelectron spectroscopy indicates that stoichiometry is improved by postdeposition annealing in a sulfur ambient. High resolution transmission electron microscopy confirms the atomic spacing of monolayer MoS2 thin films

  2. Ti–Al–O nanocrystal charge trapping memory cells fabricated by atomic layer deposition

    International Nuclear Information System (INIS)

    Charge trapping memory cells using Ti–Al–O (TAO) film as charge trapping layer and amorphous Al2O3 as the tunneling and blocking layers were fabricated on Si substrates by atomic layer deposition method. As-deposited TAO films were annealed at 700 °C, 800 °C and 900 °C for 3 min in N2 with a rapid thermal annealing process to form nanocrystals. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the microstructure and band diagram of the heterostructures. The electrical characteristics and charge storage properties of the Al2O3/TAO/Al2O3/Si stack structures were also evaluated. Compared to 700 °C and 900 °C samples, the memory cells annealed at 800 °C exhibit better memory performance with larger memory window of 4.8 V at ± 6 V sweeping, higher program/erase speed and excellent endurance. - Highlights: • The charge trapping memory cells were fabricated by atomic layer deposition method. • The anneal temperature plays a key role in forming nanocrystals. • The memory cells annealed at 800 °C exhibit better memory performance. • The band alignment is beneficial to enhance the retention characteristics

  3. Enhanced Barrier Performance of Engineered Paper by Atomic Layer Deposited Al2O3 Thin Films.

    Science.gov (United States)

    Mirvakili, Mehr Negar; Van Bui, Hao; van Ommen, J Ruud; Hatzikiriakos, Savvas G; Englezos, Peter

    2016-06-01

    Surface modification of cellulosic paper is demonstrated by employing plasma assisted atomic layer deposition. Al2O3 thin films are deposited on paper substrates, prepared with different fiber sizes, to improve their barrier properties. Thus, a hydrophobic paper is created with low gas permeability by combining the control of fiber size (and structure) with atomic layer deposition of Al2O3 films. Papers are prepared using Kraft softwood pulp and thermomechanical pulp. The cellulosic wood fibers are refined to obtain fibers with smaller length and diameter. Films of Al2O3, 10, 25, and 45 nm in thickness, are deposited on the paper surface. The work demonstrates that coating of papers prepared with long fibers efficiently reduces wettability with slight enhancement in gas permeability, whereas on shorter fibers, it results in significantly lower gas permeability. Wettability studies on Al2O3 deposited paper substrates have shown water wicking and absorption over time only in papers prepared with highly refined fibers. It is also shown that there is a certain fiber size at which the gas permeability assumes its minimum value, and further decrease in fiber size will reverse the effect on gas permeability. PMID:27165172

  4. Patterning of hafnia and titania via gas-phase soft lithography combined with atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Notley, Shannon M., E-mail: snotley@swin.edu.au [Faculty of Life and Social Sciences, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia); Fogden, Andrew [Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

    2013-11-15

    Novel titania and hafnia structures on top of silica wafer were produced using atomic layer deposition through the accessible pores created by a patterned polydimethylsiloxane (PDMS) stamp in conformal contact. Typically, the processing temperature was in the range of 125 °C in order to avoid damaging the stamp and also to create an amorphous metal oxide deposit. Interestingly, the deposit formation tended to be dominated by condensation of the metal oxide precursor and water in the vicinity of the contact edges of the stamp and substrate. Upon removal of the stamp, the deposit patterns thus exhibited narrow features of much finer lateral resolution than the channel width of the stamp. Furthermore, it was demonstrated that oxide patterns of complex geometries were formed through the accessible pores.

  5. Atomic layer deposition by reaction of molecular oxygen with tetrakisdimethylamido-metal precursors

    International Nuclear Information System (INIS)

    Tetrakisdimethylamido (TDMA) based precursors are commonly used to deposit metal oxides such as TiO2, ZrO2, and HfO2 by means of chemical vapor deposition and atomic layer deposition (ALD). Both thermal and plasma enhanced ALD (PEALD) have been demonstrated with TDMA-metal precursors. While the reactions of TDMA-type precursors with water and oxygen plasma have been studied in the past, their reactivity with pure O2 has been overlooked. This paper reports on experimental evaluation of the reaction of molecular oxygen (O2) and several metal organic precursors based on TDMA ligands. The effect of O2 exposure duration and substrate temperature on deposition and film morphology is evaluated and compared to thermal reactions with H2O and PEALD with O2 plasma

  6. Patterning of hafnia and titania via gas-phase soft lithography combined with atomic layer deposition

    International Nuclear Information System (INIS)

    Novel titania and hafnia structures on top of silica wafer were produced using atomic layer deposition through the accessible pores created by a patterned polydimethylsiloxane (PDMS) stamp in conformal contact. Typically, the processing temperature was in the range of 125 °C in order to avoid damaging the stamp and also to create an amorphous metal oxide deposit. Interestingly, the deposit formation tended to be dominated by condensation of the metal oxide precursor and water in the vicinity of the contact edges of the stamp and substrate. Upon removal of the stamp, the deposit patterns thus exhibited narrow features of much finer lateral resolution than the channel width of the stamp. Furthermore, it was demonstrated that oxide patterns of complex geometries were formed through the accessible pores.

  7. Fracture properties of atomic layer deposited aluminum oxide free-standing membranes

    Energy Technology Data Exchange (ETDEWEB)

    Berdova, Maria, E-mail: maria.berdova@aalto.fi; Rontu, Ville; Franssila, Sami [Department of Materials Science and Engineering, Aalto University, P.O. Box 16200, FI-00076 Aalto (Finland); Ylivaara, Oili M. E.; Puurunen, Riikka L. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044VTT (Finland); Törmä, Pekka T. [Department of Micro- and Nanosciences, Aalto University, P.O. Box 13500, 00076 Aalto (Finland)

    2015-01-01

    The fracture strength of Al{sub 2}O{sub 3} membranes deposited by atomic layer deposition at 110, 150, 200, and 300 °C was investigated. The fracture strength was found to be in the range of 2.25–3.00 GPa using Weibull statistics and nearly constant as a function of deposition temperature. This strength is superior to common microelectromechanical systems materials such as diamondlike carbon, SiO{sub 2}, or SiC. As-deposited membranes sustained high cycling pressure loads >10 bar/s without fracture. Films featured, however, significant reduction in the resistance to failure after annealing (800 °C) or high humidity (95%, 60 °C) treatments.

  8. Atomic layer deposition by reaction of molecular oxygen with tetrakisdimethylamido-metal precursors

    Energy Technology Data Exchange (ETDEWEB)

    Provine, J, E-mail: jprovine@stanford.edu; Schindler, Peter; Torgersen, Jan; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Karnthaler, Hans-Peter [Physics of Nanostructured Materials, University of Vienna, 1090 Vienna (Austria); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 and Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-01-15

    Tetrakisdimethylamido (TDMA) based precursors are commonly used to deposit metal oxides such as TiO{sub 2}, ZrO{sub 2}, and HfO{sub 2} by means of chemical vapor deposition and atomic layer deposition (ALD). Both thermal and plasma enhanced ALD (PEALD) have been demonstrated with TDMA-metal precursors. While the reactions of TDMA-type precursors with water and oxygen plasma have been studied in the past, their reactivity with pure O{sub 2} has been overlooked. This paper reports on experimental evaluation of the reaction of molecular oxygen (O{sub 2}) and several metal organic precursors based on TDMA ligands. The effect of O{sub 2} exposure duration and substrate temperature on deposition and film morphology is evaluated and compared to thermal reactions with H{sub 2}O and PEALD with O{sub 2} plasma.

  9. Heteroepitaxy of group IV-VI nitrides by atomic layer deposition

    Science.gov (United States)

    Klug, Jeffrey; Becker, Nicholas; Alvarez, Carlos; Groll, Nickolas; Cao, Chaoyue; Weimer, Matthew; Pellin, Michael; Zasadzinski, John; Proslier, Thomas

    2014-03-01

    Heteroepitaxial growth of selected group IV-VI nitrides on various orientations of α-Al2O3 and MgO is demonstrated using atomic layer deposition. High quality, epitaxial films are produced at significantly lower temperatures than required by conventional deposition methods. The influence of substrate orientation on film structure and morphology as well as film resistivity and superconductivity are discussed. Transport measurements reveal a reduced room temperature resistivity and increased residual resistance ratio (RRR) for films deposited on lattice-matched substrates compared to polycrystalline samples deposited concurrently on native-oxide Si(001) and fused quartz substrates. This work was supported by the U.S. Department of Energy, Office of Science under contract No. DE-AC02-06CH11357.

  10. Atomic layer deposition of MnS: phase control and electrochemical applications.

    Energy Technology Data Exchange (ETDEWEB)

    Riha, Shannon C.; Koegel, Alexandria A.; Meng, Xiangbo; Kim, In Soo; Cao, Yanqiang; Pellin, Michael J.; Elam, Jeffrey W.; Martinson, Alex B. F.

    2016-02-03

    Manganese sulfide (MnS) thin films were synthesized via atomic layer deposition (ALD) using gaseous manganese bis(ethylcyclopentadienyl) and hydrogen sulfide as precursors. At deposition temperatures ≤150 °C phase-pure r-MnS thin films were deposited, while at temperatures >150 °C, a mixed phase, consisting of both r- and a-MnS resulted. In situ quartz crystal microbalance (QCM) studies validate the self-limiting behavior of both ALD half-reactions and, combined with quadrupole mass spectrometry (QMS) allow the derivation of a self-consistent reaction mechanism. Finally, MnS thin films were deposited on copper foil and tested as a Li-ion battery anode. The MnS coin cells showed exceptional cycle stability and near-theoretical capacity.

  11. Atomic Layer Deposited Zinc Tin Oxide Channel for Amorphous Oxide Thin Film Transistors

    OpenAIRE

    Heo, Jaeyeong; Kim, Sang Bok; Gordon, Roy Gerald

    2012-01-01

    Bottom-gate thin film transistors with amorphous zinc tin oxide channels were grown by atomic layer deposition (ALD). The films maintained their amorphous character up to temperatures over 500 \\(^{\\circ}\\)C. The highest field effect mobility was ~13 \\(cm^2/V^.s\\) with on-to-off ratios of drain current ~10\\(^9\\)-10\\(^{10}\\). The lowest subthreshold swing of 0.27 V/decade was observed with thermal oxide as a gate insulator. The channel layers grown at 170 \\(^{\\circ}\\)C showed better transistor ...

  12. Thermodynamics and kinetic behaviors of thickness-dependent crystallization in high-k thin films deposited by atomic layer deposition

    International Nuclear Information System (INIS)

    Atomic layer deposition is adopted to prepare HfO2 and Al2O3 high-k thin films. The HfO2 thin films are amorphous at the initial growth stage, but become crystallized when the film thickness (h) exceeds a critical value (hcritical*). This phase transition from amorphous to crystalline is enhanced at higher temperatures and is discussed, taking into account the effect of kinetic energy. At lower temperatures, the amorphous state can be maintained even when h>hcritical* owing to the small number of activated atoms. However, the number of activated atoms increases with the temperature, allowing crystallization to occur even in films with smaller thickness. The Al2O3 thin films, on the other hand, maintain their amorphous state independent of the film thickness and temperature owing to the limited number of activated atoms. A thermodynamic model is proposed to describe the thickness-dependent phase transition

  13. Atomic layer deposited titanium dioxide coatings on KD-II silicon carbide fibers and their characterization

    Science.gov (United States)

    Cao, Shiyi; Wang, Jun; Wang, Hao

    2016-03-01

    To provide oxidation protection and/or to act as an interfacial coating, titanium oxide (TiO2) coatings were deposited on KD-II SiC fibers by employing atomic layer deposition (ALD) technique with tetrakis(dimethylamido)titanium (TDMAT) and water (H2O) as precursors. The average deposition rate was about 0.08 nm per cycle, and the prepared coatings were smooth, uniform and conformal, shielding the fibers entirely. The as-deposited coatings were amorphous regardless of the coating thickness, and changed to anatase and rutile crystal phase after annealing at 600 °C and 1000 °C, respectively. The oxidation measurement suggests that the TiO2 coating enhanced the oxidation resistance of SiC fibers obviously. SiC fibers coated with a 70-nm-thick TiO2 layer retained a relatively high tensile strength of 1.66 GPa even after exposition to air at 1400 °C for 1 h, and thick silica layer was not observed. In contrast, uncoated SiC fibers were oxidized dramatically through the same oxidation treatment, covered with a macro-cracked thick silica film, and the tensile strength was not measurable due to interfilament adhesion. The above results indicate that TiO2 films deposited by ALD are a promising oxidation resistance coating for SiC fibers.

  14. Low-temperature atomic layer deposition of MgO thin films on Si

    International Nuclear Information System (INIS)

    Magnesium oxide (MgO) films have been grown by atomic layer deposition in the wide deposition temperature window of 80–350 °C by using bis(cyclopentadienyl)magnesium and H2O precursors. MgO thin films are deposited on both HF-last Si(1 0 0) and SiO2/Si substrates at a constant growth rate of ∼0.12 nm cycle−1. The structural, morphological and chemical properties of the synthesized MgO thin films are investigated by x-ray reflectivity, grazing incidence x-ray diffraction, time-of-flight secondary ion mass spectrometry and atomic force microscopy measurements. MgO layers are characterized by sharp interface with the substrate and limited surface roughness, besides good chemical uniformity and polycrystalline structure for thickness above 7 nm. C–V measurements performed on Al/MgO/Si MOS capacitors, with MgO in the 4.6–11 nm thickness range, allow determining a dielectric constant (κ) ∼ 11. Co layers are grown by chemical vapour deposition in direct contact with MgO without vacuum-break (base pressure 10−5–10−6 Pa). The as-grown Co/MgO stacks show sharp interfaces and no elements interdiffusion among layers. C–V and I–V measurements have been conducted on Co/MgO/Si MOS capacitors. The dielectric properties of MgO are not influenced by the further process of Co deposition. (paper)

  15. Atomic layer deposition of perovskite oxides and their epitaxial integration with Si, Ge, and other semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    McDaniel, Martin D.; Ngo, Thong Q.; Hu, Shen; Ekerdt, John G., E-mail: ekerdt@utexas.edu [Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Posadas, Agham; Demkov, Alexander A. [Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-12-15

    Atomic layer deposition (ALD) is a proven technique for the conformal deposition of oxide thin films with nanoscale thickness control. Most successful industrial applications have been with binary oxides, such as Al{sub 2}O{sub 3} and HfO{sub 2}. However, there has been much effort to deposit ternary oxides, such as perovskites (ABO{sub 3}), with desirable properties for advanced thin film applications. Distinct challenges are presented by the deposition of multi-component oxides using ALD. This review is intended to highlight the research of the many groups that have deposited perovskite oxides by ALD methods. Several commonalities between the studies are discussed. Special emphasis is put on precursor selection, deposition temperatures, and specific property performance (high-k, ferroelectric, ferromagnetic, etc.). Finally, the monolithic integration of perovskite oxides with semiconductors by ALD is reviewed. High-quality epitaxial growth of oxide thin films has traditionally been limited to physical vapor deposition techniques (e.g., molecular beam epitaxy). However, recent studies have demonstrated that epitaxial oxide thin films may be deposited on semiconductor substrates using ALD. This presents an exciting opportunity to integrate functional perovskite oxides for advanced semiconductor applications in a process that is economical and scalable.

  16. Atomic layer deposition of perovskite oxides and their epitaxial integration with Si, Ge, and other semiconductors

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) is a proven technique for the conformal deposition of oxide thin films with nanoscale thickness control. Most successful industrial applications have been with binary oxides, such as Al2O3 and HfO2. However, there has been much effort to deposit ternary oxides, such as perovskites (ABO3), with desirable properties for advanced thin film applications. Distinct challenges are presented by the deposition of multi-component oxides using ALD. This review is intended to highlight the research of the many groups that have deposited perovskite oxides by ALD methods. Several commonalities between the studies are discussed. Special emphasis is put on precursor selection, deposition temperatures, and specific property performance (high-k, ferroelectric, ferromagnetic, etc.). Finally, the monolithic integration of perovskite oxides with semiconductors by ALD is reviewed. High-quality epitaxial growth of oxide thin films has traditionally been limited to physical vapor deposition techniques (e.g., molecular beam epitaxy). However, recent studies have demonstrated that epitaxial oxide thin films may be deposited on semiconductor substrates using ALD. This presents an exciting opportunity to integrate functional perovskite oxides for advanced semiconductor applications in a process that is economical and scalable

  17. Growth, intermixing, and surface phase formation for zinc tin oxide nanolaminates produced by atomic layer deposition

    International Nuclear Information System (INIS)

    A broad and expanding range of materials can be produced by atomic layer deposition at relatively low temperatures, including both oxides and metals. For many applications of interest, however, it is desirable to grow more tailored and complex materials such as semiconductors with a certain doping, mixed oxides, and metallic alloys. How well such mixed materials can be accomplished with atomic layer deposition requires knowledge of the conditions under which the resulting films will be mixed, solid solutions, or laminated. The growth and lamination of zinc oxide and tin oxide is studied here by means of the extremely surface sensitive technique of low energy ion scattering, combined with bulk composition and thickness determination, and x-ray diffraction. At the low temperatures used for deposition (150 °C), there is little evidence for atomic scale mixing even with the smallest possible bilayer period, and instead a morphology with small ZnO inclusions in a SnOx matrix is deduced. Postannealing of such laminates above 400 °C however produces a stable surface phase with a 30% increased density. From the surface stoichiometry, this is likely the inverted spinel of zinc stannate, Zn2SnO4. Annealing to 800 °C results in films containing crystalline Zn2SnO4, or multilayered films of crystalline ZnO, Zn2SnO4, and SnO2 phases, depending on the bilayer period

  18. Epitaxial Growth of Perovskite Strontium Titanate on Germanium via Atomic Layer Deposition.

    Science.gov (United States)

    Lin, Edward L; Edmondson, Bryce I; Hu, Shen; Ekerdt, John G

    2016-01-01

    Atomic layer deposition (ALD) is a commercially utilized deposition method for electronic materials. ALD growth of thin films offers thickness control and conformality by taking advantage of self-limiting reactions between vapor-phase precursors and the growing film. Perovskite oxides present potential for next-generation electronic materials, but to-date have mostly been deposited by physical methods. This work outlines a method for depositing SrTiO3 (STO) on germanium using ALD. Germanium has higher carrier mobilities than silicon and therefore offers an alternative semiconductor material with faster device operation. This method takes advantage of the instability of germanium's native oxide by using thermal deoxidation to clean and reconstruct the Ge (001) surface to the 2×1 structure. 2-nm thick, amorphous STO is then deposited by ALD. The STO film is annealed under ultra-high vacuum and crystallizes on the reconstructed Ge surface. Reflection high-energy electron diffraction (RHEED) is used during this annealing step to monitor the STO crystallization. The thin, crystalline layer of STO acts as a template for subsequent growth of STO that is crystalline as-grown, as confirmed by RHEED. In situ X-ray photoelectron spectroscopy is used to verify film stoichiometry before and after the annealing step, as well as after subsequent STO growth. This procedure provides framework for additional perovskite oxides to be deposited on semiconductors via chemical methods in addition to the integration of more sophisticated heterostructures already achievable by physical methods. PMID:27501462

  19. Optical coatings grown by atomic layer deposition for high-power laser applications

    International Nuclear Information System (INIS)

    We prepared optical coatings with low (Al2O3) and high (TiO2) refractive index materials using the sequential chemical reaction process of atomic layer deposition (ALD). Also, we examined the laser damage thresholds of the films for high-power laser applications. The highest damage thresholds were obtained for amorphous films grown at room temperature. For TiO2 and Al2O3 films they equalled 5 and 5.2 J/cm2, respectively. Finally, we employed ALD for growing desired refractive index coatings consisting of alternating nanoscale Al2O3-TiO2 laminated layers. The refractive index of the stack of these layers could be varied linearly from 1.61 to 2.39 by adjusting the thickness of the component layers. (author)

  20. Atomic layer deposition TiO2 coated porous silicon surface: Structural characterization and morphological features

    International Nuclear Information System (INIS)

    TiO2 thin films were grown on highly-doped p-Si (100) macro- and mesoporous structures by atomic layer deposition (ALD) using TiCl4 and deionized water as precursors at 300 °C. The crystalline structure, chemical composition, and morphology of the deposited films and initial silicon nanostructures were investigated by scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy and X-ray diffraction (XRD). The mean size of TiO2 crystallites was determined by TEM, XRD and Raman spectroscopy. It was shown that the mean crystallite size and the crystallinity of the TiO2 are influenced dramatically by the morphology of the porous silicon, with the mesoporous silicon resulting in a much finer grain size and amorphous structure than the macroporous silicon having a partially crystal anatase phase. A simple model of the ALD layer growth inside the pores was presented. - Highlights: • The morphology and chemical composition of TiO2 and porous Si were established. • The approximate size of TiO2 nanocrystals was estimated. • The model of the atomic layer deposition coating in the porous Si was presented

  1. Low temperature atomic layer deposition of noble metals using ozone and molecular hydrogen as reactants

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) of noble metals by thermal processes has relied mostly on the use of molecular oxygen as a reactant at temperatures of 200 °C and above. In this study, the concept of using consecutive ozone and molecular hydrogen pulses with noble metal precursors in ALD is introduced for palladium, rhodium, and platinum metals. This approach facilitates the growth of noble metal thin films below 200 °C. Also the ALD of palladium oxide thin films is demonstrated by the ozone-based chemistry. The growth rates, resistivities, crystallinities, surface roughnesses, impurity contents, and adhesion of the films to the underlying Al2O3 starting surface are reported and the results are compared with the most common noble metal ALD processes. - Highlights: ► Atomic layer deposition used to deposit Rh, Pd, and Pt films below 200 °C. ► Noble metal film growth examined using ozone and molecular H2 as reactants. ► Deposition of palladium oxide films with ozone

  2. Ag films grown by remote plasma enhanced atomic layer deposition on different substrates

    Energy Technology Data Exchange (ETDEWEB)

    Amusan, Akinwumi A., E-mail: akinwumi.amusan@ovgu.de; Kalkofen, Bodo; Burte, Edmund P. [Institute of Micro and Sensor Systems, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg (Germany); Gargouri, Hassan; Wandel, Klaus; Pinnow, Cay [SENTECH Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin (Germany); Lisker, Marco [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany)

    2016-01-15

    Silver (Ag) layers were deposited by remote plasma enhanced atomic layer deposition (PALD) using Ag(fod)(PEt{sub 3}) (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluorooctane-3,5-dionato) as precursor and hydrogen plasma on silicon substrate covered with thin films of SiO{sub 2}, TiN, Ti/TiN, Co, Ni, and W at different deposition temperatures from 70  to 200 °C. The deposited silver films were analyzed by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive x-ray spectroscopy, four point probe measurement, ellipsometric measurement, x-ray fluorescence (XRF), and x-ray diffraction (XRD). XPS revealed pure Ag with carbon and oxygen contamination close to the detection limit after 30 s argon sputtering for depositions made at 120 and 200 °C substrate temperatures. However, an oxygen contamination was detected in the Ag film deposited at 70 °C after 12 s argon sputtering. A resistivity of 5.7 × 10{sup −6} Ω cm was obtained for approximately 97 nm Ag film on SiO{sub 2}/Si substrate. The thickness was determined from the SEM cross section on the SiO{sub 2}/Si substrate and also compared with XRF measurements. Polycrystalline cubic Ag reflections were identified from XRD for PALD Ag films deposited at 120 and 200 °C. Compared to W surface, where poor adhesion of the films was found, Co, Ni, TiN, Ti/TiN and SiO{sub 2} surfaces had better adhesion for silver films as revealed by SEM, TEM, and AFM images.

  3. Ag films grown by remote plasma enhanced atomic layer deposition on different substrates

    International Nuclear Information System (INIS)

    Silver (Ag) layers were deposited by remote plasma enhanced atomic layer deposition (PALD) using Ag(fod)(PEt3) (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluorooctane-3,5-dionato) as precursor and hydrogen plasma on silicon substrate covered with thin films of SiO2, TiN, Ti/TiN, Co, Ni, and W at different deposition temperatures from 70  to 200 °C. The deposited silver films were analyzed by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive x-ray spectroscopy, four point probe measurement, ellipsometric measurement, x-ray fluorescence (XRF), and x-ray diffraction (XRD). XPS revealed pure Ag with carbon and oxygen contamination close to the detection limit after 30 s argon sputtering for depositions made at 120 and 200 °C substrate temperatures. However, an oxygen contamination was detected in the Ag film deposited at 70 °C after 12 s argon sputtering. A resistivity of 5.7 × 10−6 Ω cm was obtained for approximately 97 nm Ag film on SiO2/Si substrate. The thickness was determined from the SEM cross section on the SiO2/Si substrate and also compared with XRF measurements. Polycrystalline cubic Ag reflections were identified from XRD for PALD Ag films deposited at 120 and 200 °C. Compared to W surface, where poor adhesion of the films was found, Co, Ni, TiN, Ti/TiN and SiO2 surfaces had better adhesion for silver films as revealed by SEM, TEM, and AFM images

  4. Atomic layer deposition of an Al2O3 dielectric on ultrathin graphite by using electron beam irradiation

    Institute of Scientific and Technical Information of China (English)

    Jiang Ran; Meng Lingguo; Zhang Xijian; Hyung-Suk Jung; Cheol Seong Hwang

    2012-01-01

    Atomic layer deposition ofan Al2O3 dielectric on ultrathin graphite is studied in order to investigate the integration of a high k dielectric with graphite-based substrates.Electron beam irradiation on the graphite surface is followed by a standard atomic layer deposition of Al2O3.Improvement of the Al2O3 layer deposition morphology was observed when using this radiation exposure on graphite.This result may be attributed to the amorphous change of the graphite layers during electron beam irradiation.

  5. Ozone-assisted atomic layer deposited ZnO thin films for multifunctional device applications

    International Nuclear Information System (INIS)

    We demonstrate the growth temperature dependence of film thickness and surface roughness of ZnO films grown by atomic layer deposition using ozone as an oxidizer. The significantly low growth rate of the film using O3 precursor is attributed to the recombinative surface loss of O3. The variation of the spatial uniformity inferred from the surface roughness of the ZnO films and the O3 concentration was explained by a transition from reaction- to recombination-limited growth. We have fabricated a metal–oxide–semiconductor device, consisting of an insulating ZnO layer using an O3 source, between metallic and semiconducting Al : ZnO layers. The device demonstrates a remarkable resistive switching behaviour. The electrochemical migration of oxygen vacancies, which is created in the vicinity of the interface of ZnO semiconductor–ZnO insulator, drives the resistive switching behaviour. This significant result produced on the all-oxide-based device fabricated by atomic layer deposited ZnO can have significant impact for multifunctional applications. (paper)

  6. Electrowetting properties of atomic layer deposited Al2O3 decorated silicon nanowires

    International Nuclear Information System (INIS)

    This paper reports the electrowetting properties of liquid droplet on superhydrophobic silicon nanowires with Atomic layer deposited (ALD) Al2O3 as dielectric layer. Silicon wafer were etched by metal assisted wet chemical etching with silver as catalyst. ALD Al2O3 films of 10nm thickness were conformally deposited over silicon nanowires. Al2O3 dielectric film coated silicon nanowires was chemically modified with Trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane to make it superhydrophobic(SHP). The contact angle was measured and all the samples exhibited superhydrophobic nature with maximum contact angles of 163° and a minimum contact angle hysteresis of 6°. Electrowetting induced a maximum reversible decrease of the contact angle of 20°at 150V in air

  7. Atomic layer deposited TiO2 for implantable brain-chip interfacing devices

    International Nuclear Information System (INIS)

    In this paper we investigated atomic layer deposition (ALD) TiO2 thin films deposited on implantable neuro-chips based on electrolyte-oxide-semiconductor (EOS) junctions, implementing both efficient capacitive neuron-silicon coupling and biocompatibility for long-term implantable functionality. The ALD process was performed at 295 °C using titanium tetraisopropoxide and ozone as precursors on needle-shaped silicon substrates. Engineering of the capacitance of the EOS junctions introducing a thin Al2O3 buffer layer between TiO2 and silicon resulted in a further increase of the specific capacitance. Biocompatibility for long-term implantable neuroprosthetic systems was checked upon in-vitro treatment.

  8. Atomic layer deposited TiO{sub 2} for implantable brain-chip interfacing devices

    Energy Technology Data Exchange (ETDEWEB)

    Cianci, E., E-mail: elena.cianci@mdm.imm.cnr.it [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (MB) (Italy); Lattanzio, S. [Istituto di Fisiologia, Dipartimento di Anatomia Umana e Fisiologia, Universita di Padova, 35131 Padova (Italy); Dipartimento di Ingegneria dell' Informazione, Universita di Padova, 35131 Padova (Italy); Seguini, G. [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (Italy); Vassanelli, S. [Istituto di Fisiologia, Dipartimento di Anatomia Umana e Fisiologia, Universita di Padova, 35131 Padova (Italy); Fanciulli, M. [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (Italy); Dipartimento di Scienza dei Materiali, Universita degli Studi di Milano-Bicocca, 20126 Milano (Italy)

    2012-05-01

    In this paper we investigated atomic layer deposition (ALD) TiO{sub 2} thin films deposited on implantable neuro-chips based on electrolyte-oxide-semiconductor (EOS) junctions, implementing both efficient capacitive neuron-silicon coupling and biocompatibility for long-term implantable functionality. The ALD process was performed at 295 Degree-Sign C using titanium tetraisopropoxide and ozone as precursors on needle-shaped silicon substrates. Engineering of the capacitance of the EOS junctions introducing a thin Al{sub 2}O{sub 3} buffer layer between TiO{sub 2} and silicon resulted in a further increase of the specific capacitance. Biocompatibility for long-term implantable neuroprosthetic systems was checked upon in-vitro treatment.

  9. Application of atomic layer deposited microchannel plates to imaging photodetectors with high time resolution

    International Nuclear Information System (INIS)

    Novel microchannel plates have been constructed using borosilicate glass micro-capillary array substrates with 20 µm and 10 µm pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass microchannel plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate microchannel plates have been fabricated. Considerable progress has also been made with 20 cm microchannel plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection

  10. Application of atomic layer deposited microchannel plates to imaging photodetectors with high time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Siegmund, O.H.W., E-mail: ossy@ssl.berkeley.edu [Experimental Astrophysics Group, Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); McPhate, J.B.; Tremsin, A.S.; Vallerga, J.V.; Ertley, C.D.; Richner, N.J.; Gerard, T.M. [Experimental Astrophysics Group, Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); Frisch, H.J. [University of Chicago, 5640 S. Ellis Ave., Chicago, Il 60637 (United States); Elam, J.W.; Mane, A.U.; Wagner, R.G. [Argonne National Laboratory, 9700 S. Cass Ave. Lemont, Il 60439 (United States); Minot, M.J.; O' Mahony, A.; Craven, C.A. [Incom Inc., 294 Southbridge Road, Charlton, MA, 01507 (United States)

    2015-07-01

    Novel microchannel plates have been constructed using borosilicate glass micro-capillary array substrates with 20 µm and 10 µm pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass microchannel plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate microchannel plates have been fabricated. Considerable progress has also been made with 20 cm microchannel plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection.

  11. Influence of surface preparation on atomic layer deposition of Pt films

    Institute of Scientific and Technical Information of China (English)

    Ge Liang; Hu Cheng; Zhu Zhiwei; Zhang Wei; Wu Dongping; Zhang Shili

    2012-01-01

    We report Pt deposition on a Si substrate by means of atomic layer deposition (ALD) using (methylcyclopentadienyl) trimethylplatinum (CH3CsH4Pt(CH3)3) and O2.Silicon substrates with both HF-last and oxidelast surface treatments are employed to investigate the influence of surface preparation on Pt-ALD.A significantlylonger incubation time and less homogeneity are observed for Pt growth on the HF-last substrate compared to the oxide-last substrate.An interfacial oxide layer at the Pt-Si interface is found inevitable even with HF treatment of the Si substrate immediately prior to ALD processing.A plausible explanation to the observed difference of Pt-ALD is discussed.

  12. Atomic layer deposition of titanium sulfide and its application in extremely thin absorber solar cells

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) of TiS2 is investigated with titanium tetrachloride and hydrogen sulfide precursors. In-situ quartz crystal microbalance and ex-situ x-ray reflectivity measurements are carried out to study self-limiting deposition chemistry and material growth characteristics. The saturated growth rate is found to be ca. 0.5 Å/cycle within the ALD temperature window of 125–200 °C. As grown material is found poorly crystalline. ALD grown TiS2 is applied as a photon harvesting material for solid state sensitized solar cells with TiO2 as electron transport medium. Initial results with Spiro-OMeTAD as hole conducting layer show ca. 0.6% energy conversion efficiency under 1 sun illumination

  13. Atomic layer deposition of zinc sulfide with Zn(TMHD){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Short, Andrew; Jewell, Leila; Doshay, Sage; Church, Carena; Keiber, Trevor; Bridges, Frank; Carter, Sue; Alers, Glenn [Department of Physics, University of California at Santa Cruz, 1156 High Street, Santa Cruz, California 95064 (United States)

    2013-01-15

    The atomic layer deposition (ALD) of ZnS films with Zn(TMHD){sub 2} and in situ generated H{sub 2}S as precursors was investigated, over a temperature range of 150-375 Degree-Sign C. ALD behavior was confirmed by investigation of growth behavior and saturation curves. The properties of the films were studied with atomic force microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, ultraviolet-visible-infrared spectroscopy, and extended x-ray absorption fine structure. The results demonstrate a film that can penetrate a porous matrix, with a local Zn structure of bulk ZnS, and a band gap between 3.5 and 3.6 eV. The ZnS film was used as a buffer layer in nanostructured PbS quantum dot solar cell devices.

  14. Flat metallic surface gratings with sub-10 nm gaps controlled by atomic-layer deposition

    Science.gov (United States)

    Chen, Borui; Ji, Dengxin; Cheney, Alec; Zhang, Nan; Song, Haomin; Zeng, Xie; Thomay, Tim; Gan, Qiaoqiang; Cartwright, Alexander

    2016-09-01

    Atomic layer lithography is a recently reported new technology to fabricate deep-subwavelength features down to 1–2 nm, based on combinations of electron beam lithography (EBL) and atomic layer deposition (ALD). However, the patterning area is relatively small as limited by EBL, and the fabrication yield is not very high due to technical challenges. Here we report an improved procedure to fabricate flat metallic surfaces with sub-10 nm features based on ALD processes. To demonstrate the scalability of the new manufacturing method, we combine the ALD process with large area optical interference patterning, which is particularly promising for the development of practical applications for nanoelectronics and nanophotonics with extremely strong confinement of electromagnetic fields.

  15. Atomic layer deposition grown MOx thin films for solar water splitting: Prospects and challenges

    International Nuclear Information System (INIS)

    The magnitude of energy challenge not only calls for efficient devices but also for abundant, inexpensive, and stable photoactive materials that can enable efficient light harvesting, charge separation and collection, as well as chemical transformations. Photoelectrochemical systems based on semiconductor materials have the possibility to transform solar energy directly into chemical energy the so-called “solar hydrogen.” The current challenge lies in the harvesting of a larger fraction of electromagnetic spectrum by enhancing the absorbance of electrode materials. In this context, atomically precise thin films of metal oxide semiconductors and their multilayered junctions are promising candidates to integrate high surface areas with well-defined electrode–substrate interface. Given its self-limited growth mechanism, the atomic layer deposition (ALD) technique offers a wide range of capabilities to deposit and modify materials at the nanoscale. In addition, it opens new frontiers for developing precursor chemistry that is inevitable to design new processes. Herein, the authors review the properties and potential of metal oxide thin films deposited by ALD for their application in photoelectrochemical water splitting application. The first part of the review covers the basics of ALD processes followed by a brief discussion on the electrochemistry of water splitting reaction. The second part focuses on different MOx films deposited by atomic layer deposition for water splitting applications; in this section, The authors discuss the most explored MOx semiconductors, namely, Fe2O3, TiO2, WO3, and ZnO, as active materials and refer to their application as protective coatings, conductive scaffolds, or in heterojunctions. The third part deals with the current challenges and future prospects of ALD processed MOx thin films for water splitting reactions

  16. Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Kaeaeriaeinen, Tommi O., E-mail: tommi.kaariainen@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Cameron, David C., E-mail: david.cameron@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Lahtinen, Kimmo, E-mail: kimmo.lahtinen@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Johansson, Petri, E-mail: petri.johansson@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland)

    2011-03-01

    One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O{sub 2}TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O{sub 2}TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

  17. Selective atomic layer deposition with electron-beam patterned self-assembled monolayers

    International Nuclear Information System (INIS)

    The authors selectively deposited nanolines of titanium oxide (TiO2) through atomic layer deposition (ALD) using an octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) as a nucleation inhibition layer. Electron-beam (e-beam) patterning is used to prepare nanoline patterns in the OTS SAM on SiO2/Si substrates suitable for selective ALD. The authors have investigated the effect of an e-beam dose on the pattern width of the selectively deposited TiO2 lines. A high dose (e.g., 20 nC/cm) causes broadening of the linewidth possibly due to scattering, while a low dose (e.g., 5 nC/cm) results in a low TiO2 deposition rate because of incomplete exposure of the OTS SAMs. The authors have confirmed that sub-30 nm isolated TiO2 lines can be achieved by selective ALD combined with OTS patterned by EBL at an accelerating voltage of 2 kV and line dose of 10 nC/cm. This research offers a new approach for patterned gate dielectric layer fabrication, as well as potential applications for nanosensors and solar cells.

  18. Area-selective atomic layer deposition of platinum using photosensitive polyimide.

    Science.gov (United States)

    Vervuurt, René H J; Sharma, Akhil; Jiao, Yuqing; Kessels, Wilhelmus Erwin M M; Bol, Ageeth A

    2016-10-01

    Area-selective atomic layer deposition (AS-ALD) of platinum (Pt) was studied using photosensitive polyimide as a masking layer. The polyimide films were prepared by spin-coating and patterned using photolithography. AS-ALD of Pt using poly(methyl-methacrylate) (PMMA) masking layers was used as a reference. The results show that polyimide has excellent selectivity towards the Pt deposition, after 1000 ALD cycles less than a monolayer of Pt is deposited on the polyimide surface. The polyimide film could easily be removed after ALD using a hydrogen plasma, due to a combination of weakening of the polyimide resist during Pt ALD and the catalytic activity of Pt traces on the polyimide surface. Compared to PMMA for AS-ALD of Pt, polyimide has better temperature stability. This resulted in an improved uniformity of the Pt deposits and superior definition of the Pt patterns. In addition, due to the absence of reflow contamination using polyimide the nucleation phase during Pt ALD is drastically shortened. Pt patterns down to 3.5 μm were created with polyimide, a factor of ten smaller than what is possible using PMMA, at the typical Pt ALD processing temperature of 300 °C. Initial experiments indicate that after further optimization of the polyimide process Pt features down to 100 nm should be possible, which makes AS-ALD of Pt using photosensitive polyimide a promising candidate for patterning at the nanoscale. PMID:27581085

  19. Atomic layer deposition of molybdenum oxide using bis(tert-butylimido)bis(dimethylamido) molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Bertuch, Adam, E-mail: abertuch@ultratech.com; Sundaram, Ganesh [Ultratech/Cambridge NanoTech, 130 Turner Street, Waltham, Massachusetts 02453 (United States); Saly, Mark; Moser, Daniel; Kanjolia, Ravi [SAFC Hitech, 1429 Hilldale Avenue, Haverhill, Massachusetts 01832 (United States)

    2014-01-15

    Molybdenum trioxide films have been deposited using thermal atomic layer deposition techniques with bis(tert-butylimido)bis(dimethylamido)molybdenum. Films were deposited at temperatures from 100 to 300 °C using ozone as the oxidant for the process. The Mo precursor was evaluated for thermal stability and volatility using thermogravimetric analysis and static vapor pressure measurements. Film properties were evaluated with ellipsometry, x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and secondary electron microscopy. The growth rate per cycle was determined to extend from 0.3 to 2.4 Å/cycle with <4% nonuniformity (1-sigma) with-in-wafer across a 150 mm wafer for the investigated temperature range.

  20. Design and implementation of an integral wall-mounted quartz crystal microbalance for atomic layer deposition.

    Science.gov (United States)

    Riha, Shannon C; Libera, Joseph A; Elam, Jeffrey W; Martinson, Alex B F

    2012-09-01

    Quartz crystal microbalance (QCM) measurements have played a vital role in understanding and expediting new atomic layer deposition (ALD) processes; however, significant barriers remain to their routine use and accurate execution. In order to turn this exclusively in situ technique into a routine characterization method, an integral QCM fixture was developed. This new design is easily implemented on a variety of chemical vapor deposition (CVD) tools, allows rapid sample exchange, prevents backside deposition, and minimizes both the footprint and flow disturbance. Unlike previous QCM designs, the fast thermal equilibration enables tasks such as temperature-dependent studies and ex situ sample exchange, further highlighting the utility of this QCM design for day-to-day use. Finally, the in situ mapping of thin film growth rates across the ALD reactor was demonstrated in a popular commercial tool operating in both continuous and quasi-static ALD modes. PMID:23020393

  1. Transparent ferrimagnetic semiconducting CuCr2O4 thin films by atomic layer deposition

    Science.gov (United States)

    Tripathi, T. S.; Yadav, C. S.; Karppinen, M.

    2016-04-01

    We report the magnetic and optical properties of CuCr2O4 thin films fabricated by atomic layer deposition (ALD) from Cu(thd)2, Cr(acac)3, and ozone; we deposit 200 nm thick films and anneal them at 700 °C in oxygen atmosphere to crystallize the spinel phase. A ferrimagnetic transition at 140 K and a direct bandgap of 1.36 eV are determined for the films from magnetic and UV-vis spectrophotometric measurements. Electrical transport measurements confirm the p-type semiconducting behavior of the films. As the ALD technique allows the deposition of conformal pin-hole-free coatings on complex 3D surfaces, our CuCr2O4 films are interesting material candidates for various frontier applications.

  2. Dynamic Modeling for the Design and Cyclic Operation of an Atomic Layer Deposition (ALD Reactor

    Directory of Open Access Journals (Sweden)

    Curtisha D. Travis

    2013-08-01

    Full Text Available A laboratory-scale atomic layer deposition (ALD reactor system model is derived for alumina deposition using trimethylaluminum and water as precursors. Model components describing the precursor thermophysical properties, reactor-scale gas-phase dynamics and surface reaction kinetics derived from absolute reaction rate theory are integrated to simulate the complete reactor system. Limit-cycle solutions defining continuous cyclic ALD reactor operation are computed with a fixed point algorithm based on collocation discretization in time, resulting in an unambiguous definition of film growth-per-cycle (gpc. A key finding of this study is that unintended chemical vapor deposition conditions can mask regions of operation that would otherwise correspond to ideal saturating ALD operation. The use of the simulator for assisting in process design decisions is presented.

  3. Atomic layer deposition of aluminum sulfide thin films using trimethylaluminum and hydrogen sulfide

    International Nuclear Information System (INIS)

    Sequential exposures of trimethylaluminum and hydrogen sulfide are used to deposit aluminum sulfide thin films by atomic layer deposition (ALD) in the temperature ranging from 100 to 200 °C. Growth rate of 1.3 Å per ALD cycle is achieved by in-situ quartz crystal microbalance measurements. It is found that the growth rate per ALD cycle is highly dependent on the purging time between the two precursors. Increased purge time results in higher growth rate. Surface limited chemistry during each ALD half cycle is studied by in-situ Fourier transformed infrared vibration spectroscopy. Time of flight secondary ion-mass spectroscopy measurement is used to confirm elemental composition of the deposited films

  4. Controllable fabrication of nanostructured materials for photoelectrochemical water splitting via atomic layer deposition.

    Science.gov (United States)

    Wang, Tuo; Luo, Zhibin; Li, Chengcheng; Gong, Jinlong

    2014-11-21

    Photoelectrochemical (PEC) water splitting is an attractive approach to generate hydrogen as a clean chemical fuel from solar energy. But there remain many fundamental issues to be solved, including inadequate photon absorption, short carrier diffusion length, surface recombination, vulnerability to photo-corrosion, and unfavorable reaction kinetics. Owing to its self-limiting surface reaction mechanism, atomic layer deposition (ALD) is capable of depositing thin films in a highly controllable manner, which makes it an enabling technique to overcome some of the key challenges confronted by PEC water splitting. This tutorial review describes some unique and representative applications of ALD in fabricating high performance PEC electrodes with various nanostructures, including (i) coating conformal thin films on three-dimensional scaffolds to facilitate the separation and migration of photocarriers and enhance light trapping, as well as realizing controllable doping for bandgap engineering and forming homojunctions for carrier separation; (ii) achieving surface modification through deposition of anti-corrosion layers, surface state passivation layers, and surface catalytic layers; and (iii) identifying the main rate limiting steps with model electrodes with highly defined thickness, composition, and interfacial structure. PMID:24500041

  5. Atomic layer deposited cobalt oxide: An efficient catalyst for NaBH{sub 4} hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Dip K.; Manna, Joydev; Dhara, Arpan; Sharma, Pratibha; Sarkar, Shaibal K., E-mail: shaibal.sarkar@iitb.ac.in [Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)

    2016-01-15

    Thin films of cobalt oxide are deposited by atomic layer deposition using dicobalt octacarbonyl [Co{sub 2}(CO){sub 8}] and ozone (O{sub 3}) at 50 °C on microscope glass substrates and polished Si(111) wafers. Self-saturated growth mechanism is verified by x-ray reflectivity measurements. As-deposited films consist of both the crystalline phases; CoO and Co{sub 3}O{sub 4} that gets converted to pure cubic-Co{sub 3}O{sub 4} phase upon annealing at 500 °C under ambient condition. Elemental composition and uniformity of the films is examined by x-ray photoelectron spectroscopy and secondary ion-mass spectroscopy. Both as-deposited and the annealed films have been successfully tested as a catalyst for hydrogen evolution from sodium borohydride hydrolysis. The activation energy of the hydrolysis reaction in the presence of the as-grown catalyst is found to be ca. 38 kJ mol{sup −1}. Further implementation of multiwalled carbon nanotube, as a scaffold layer, improves the hydrogen generation rate by providing higher surface area of the deposited catalyst.

  6. UV protective zinc oxide coating for biaxially oriented polypropylene packaging film by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Kimmo, E-mail: kimmo.lahtinen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kääriäinen, Tommi, E-mail: tommi.kaariainen@colorado.edu [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Johansson, Petri, E-mail: petri.johansson@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Kotkamo, Sami, E-mail: sami.kotkamo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Seppänen, Tarja, E-mail: tarja.seppanen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Cameron, David C., E-mail: david.cameron@miktech.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland)

    2014-11-03

    Biaxially oriented polypropylene (BOPP) packaging film was coated with zinc oxide (ZnO) coatings by atomic layer deposition (ALD) in order to protect the film from UV degradation. The coatings were made at a process temperature of 100 °C using diethylzinc and water as zinc and oxygen precursors, respectively. The UV protective properties of the coatings were tested by using UV–VIS and infrared spectrometry, differential scanning calorimetry (DSC) and a mechanical strength tester, which characterised the tensile and elastic properties of the film. The results obtained with 36 and 67 nm ZnO coatings showed that the ZnO UV protective layer is able to provide a significant decrease in photodegradation of the BOPP film under UV exposure. While the uncoated BOPP film suffered a complete degradation after a 4-week UV exposure, the 67 nm ZnO coated BOPP film was able to preserve half of its original tensile strength and 1/3 of its elongation at break after a 6-week exposure period. The infrared analysis and DSC measurements further proved the UV protection of the ZnO coatings. The results show that a nanometre scale ZnO coating deposited by ALD is a promising option when a transparent UV protection layer is sought for polymer substrates. - Highlights: • Atomic layer deposited zinc oxide coatings were used as UV protection layers. • Biaxially oriented polypropylene (BOPP) film was well protected against UV light. • Formation of UV degradation products in BOPP was significantly reduced. • Mechanical properties of the UV exposed BOPP film were significantly improved.

  7. UV protective zinc oxide coating for biaxially oriented polypropylene packaging film by atomic layer deposition

    International Nuclear Information System (INIS)

    Biaxially oriented polypropylene (BOPP) packaging film was coated with zinc oxide (ZnO) coatings by atomic layer deposition (ALD) in order to protect the film from UV degradation. The coatings were made at a process temperature of 100 °C using diethylzinc and water as zinc and oxygen precursors, respectively. The UV protective properties of the coatings were tested by using UV–VIS and infrared spectrometry, differential scanning calorimetry (DSC) and a mechanical strength tester, which characterised the tensile and elastic properties of the film. The results obtained with 36 and 67 nm ZnO coatings showed that the ZnO UV protective layer is able to provide a significant decrease in photodegradation of the BOPP film under UV exposure. While the uncoated BOPP film suffered a complete degradation after a 4-week UV exposure, the 67 nm ZnO coated BOPP film was able to preserve half of its original tensile strength and 1/3 of its elongation at break after a 6-week exposure period. The infrared analysis and DSC measurements further proved the UV protection of the ZnO coatings. The results show that a nanometre scale ZnO coating deposited by ALD is a promising option when a transparent UV protection layer is sought for polymer substrates. - Highlights: • Atomic layer deposited zinc oxide coatings were used as UV protection layers. • Biaxially oriented polypropylene (BOPP) film was well protected against UV light. • Formation of UV degradation products in BOPP was significantly reduced. • Mechanical properties of the UV exposed BOPP film were significantly improved

  8. Atomic layer deposition of environmentally benign SnTiOx as a potential ferroelectric material

    International Nuclear Information System (INIS)

    Inspired by the need to discover environmentally friendly, lead-free ferroelectric materials, here the authors report the atomic layer deposition of tin titanate (SnTiOx) aiming to obtain the theoretically predicted perovskite structure that possesses ferroelectricity. In order to establish the growth conditions and probe the film structure and ferroelectric behavior, the authors grew SnTiOx films on the commonly used Si(100) substrate. Thin films of SnTiOx have been successfully grown at a deposition temperature of 200 °C, with a Sn/Ti atomic layer deposition (ALD) cycle ratio of 2:3 and postdeposition heat treatments under different conditions. X-ray photoelectron spectroscopy revealed excellent composition tunability of ALD. X-ray diffraction spectra suggested anatase phase for all films annealed at 650 and 350 °C, with peak positions shifted toward lower 2-theta angles indicating enlarged unit cell volume. The film annealed in O2 at 350 °C exhibited piezoresponse amplitude and phase hysteresis loops, indicative of the existence of switchable polarization

  9. Initiation of atomic layer deposition of metal oxides on polymer substrates by water plasma pretreatment

    International Nuclear Information System (INIS)

    The role of surface hydroxyl content in atomic layer deposition (ALD) of aluminum oxide (AO) on polymers is demonstrated by performing an atomic layer deposition of AO onto a variety of polymer types, before and after pretreatment in a plasma struck in water vapor. The treatment and deposition reactions are performed in situ in a high vacuum chamber that is interfaced to an x-ray photoelectron spectrometer to prevent adventitious exposure to atmospheric contaminants. X-ray photoelectron spectroscopy is used to follow the surface chemistries of the polymers, including theformation of surface hydroxyls and subsequent growth of AO by ALD. Using dimethyl aluminum isopropoxide and water as reactants, ALD is obtained for water-plasma-treated poly(styrene) (PS), poly(propylene) (PP), poly(vinyl alcohol) (PVA), and poly(ethylene naphthalate) (PEN). For PS, PP, and PEN, initial growth rates of AO on the native (untreated) polymers are at least an order of magnitude lower than on the same polymer surface following the plasma treatment. By contrast, native PVA is shown to initiate ALD of AO as a result of the presence of intrinsic surface hydroxyls that are derived from the repeat unit of this polymer.

  10. Nucleation and growth of ZnO on PMMA by low-temperature atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Napari, Mari, E-mail: mari.napari@jyu.fi; Malm, Jari; Lehto, Roope; Julin, Jaakko; Arstila, Kai; Sajavaara, Timo [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland); Lahtinen, Manu [Department of Chemistry, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)

    2015-01-15

    ZnO films were grown by atomic layer deposition at 35 °C on poly(methyl methacrylate) substrates using diethylzinc and water precursors. The film growth, morphology, and crystallinity were studied using Rutherford backscattering spectrometry, time-of-flight elastic recoil detection analysis, atomic force microscopy, scanning electron microscopy, and x-ray diffraction. The uniform film growth was reached after several hundreds of deposition cycles, preceded by the precursor penetration into the porous bulk and island-type growth. After the full surface coverage, the ZnO films were stoichiometric, and consisted of large grains (diameter 30 nm) with a film surface roughness up to 6 nm (RMS). The introduction of Al{sub 2}O{sub 3} seed layer enhanced the initial ZnO growth substantially and changed the surface morphology as well as the crystallinity of the deposited ZnO films. Furthermore, the water contact angles of the ZnO films were measured, and upon ultraviolet illumination, the ZnO films on all the substrates became hydrophilic, independent of the film crystallinity.

  11. Atomic-layer electroless deposition: a scalable approach to surface-modified metal powders.

    Science.gov (United States)

    Cappillino, Patrick J; Sugar, Joshua D; El Gabaly, Farid; Cai, Trevor Y; Liu, Zhi; Stickney, John L; Robinson, David B

    2014-04-29

    Palladium has a number of important applications in energy and catalysis in which there is evidence that surface modification leads to enhanced properties. A strategy for preparing such materials is needed that combines the properties of (i) scalability (especially on high-surface-area substrates, e.g. powders); (ii) uniform deposition, even on substrates with complex, three-dimensional features; and (iii) low-temperature processing conditions that preserve nanopores and other nanostructures. Presented herein is a method that exhibits these properties and makes use of benign reagents without the use of specialized equipment. By exposing Pd powder to dilute hydrogen in nitrogen gas, sacrificial surface PdH is formed along with a controlled amount of dilute interstitial hydride. The lattice expansion that occurs in Pd under higher H2 partial pressures is avoided. Once the flow of reagent gas is terminated, addition of metal salts facilitates controlled, electroless deposition of an overlayer of subnanometer thickness. This process can be cycled to create thicker layers. The approach is carried out under ambient processing conditions, which is an advantage over some forms of atomic layer deposition. The hydride-mediated reaction is electroless in that it has no need for connection to an external source of electrical current and is thus amenable to deposition on high-surface-area substrates having rich, nanoscale topography as well as on insulator-supported catalyst particles. STEM-EDS measurements show that conformal Rh and Pt surface layers can be formed on Pd powder with this method. A growth model based on energy-resolved XPS depth profiling of Rh-modified Pd powder is in general agreement. After two cycles, deposits are consistent with 70-80% coverage and a surface layer with a thickness from 4 to 8 Å. PMID:24738575

  12. Synthesis of multiferroic Er-Fe-O thin films by atomic layer and chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mantovan, R., E-mail: roberto.mantovan@mdm.imm.cnr.it; Vangelista, S.; Wiemer, C.; Lamperti, A.; Tallarida, G. [Laboratorio MDM IMM-CNR, I-20864 Agrate Brianza (MB) (Italy); Chikoidze, E.; Dumont, Y. [GEMaC, Université de Versailles St. Quentin en Yvelines-CNRS, Versailles (France); Fanciulli, M. [Laboratorio MDM IMM-CNR, I-20864 Agrate Brianza (MB) (Italy); Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Milano (Italy)

    2014-05-07

    R-Fe-O (R = rare earth) compounds have recently attracted high interest as potential new multiferroic materials. Here, we report a method based on the solid-state reaction between Er{sub 2}O{sub 3} and Fe layers, respectively grown by atomic layer deposition and chemical vapor deposition, to synthesize Er-Fe-O thin films. The reaction is induced by thermal annealing and evolution of the formed phases is followed by in situ grazing incidence X-ray diffraction. Dominant ErFeO{sub 3} and ErFe{sub 2}O{sub 4} phases develop following subsequent thermal annealing processes at 850 °C in air and N{sub 2}. Structural, chemical, and morphological characterization of the layers are conducted through X-ray diffraction and reflectivity, time-of-flight secondary ion-mass spectrometry, and atomic force microscopy. Magnetic properties are evaluated by magnetic force microscopy, conversion electron Mössbauer spectroscopy, and vibrating sample magnetometer, being consistent with the presence of the phases identified by X-ray diffraction. Our results constitute a first step toward the use of cost-effective chemical methods for the synthesis of this class of multiferroic thin films.

  13. Bipolar resistive switching properties of AlN films deposited by plasma-enhanced atomic layer deposition

    International Nuclear Information System (INIS)

    Highlights: • AlN films were grown by plasma-enhanced atomic layer deposition. • Bipolar resistive switching properties were observed in Cu/PEALD-AlN/Pt devices. • The properties are induced upon the formation/disruption of Cu conducting filaments. • PEALD-AlN films have a great potential for the applications in 3D ReRAM. - Abstract: AlN thin films deposited by plasma-enhanced atomic layer deposition (PEALD) have been used to investigate the resistive switching (RS) behavior. The bipolar RS properties were observed in the Cu/PEALD-AlN/Pt devices, which are induced upon the formation/disruption of Cu conducting filaments, as confirmed by the temperature dependent resistances relationships at different resistance states. The resistance ratio of the high and low resistance states (HRS/LRS) is 102–105. The dominant conduction mechanisms at HRS and LRS are trap-controlled space charge limited current and Ohmic behavior, respectively. This study demonstrated that the PEALD-AlN films have a great potential for the applications in high-density resistance random access memory

  14. Atomic Layer Deposition of Pt Nanoparticles for Microengine with Promoted Catalytic Motion

    Science.gov (United States)

    Jiang, Chi; Huang, Gaoshan; Ding, Shi-Jin; Dong, Hongliang; Men, Chuanling; Mei, Yongfeng

    2016-06-01

    Nanoparticle-decorated tubular microengines were synthesized by a combination of rolled-up nanotechnology and atomic layer deposition. The presence of Pt nanoparticles with different sizes and distributions on the walls of microengines fabricated from bilayer nanomembranes with different materials results in promoted catalytic reaction efficiency, which leads to an ultrafast speed (the highest speed 3200 μm/s). The motion speed of the decorated microengines fits the theoretical model very well, suggesting that the larger surface area is mainly responsible for the acceleration of the motion speed. The high-speed nanoparticle-decorated microengines hold considerable promise for a variety of applications.

  15. Growth and characterization of titanium oxide by plasma enhanced atomic layer deposition

    KAUST Repository

    Zhao, Chao

    2013-09-01

    The growth of TiO2 films by plasma enhanced atomic layer deposition using Star-Ti as a precursor has been systematically studied. The conversion from amorphous to crystalline TiO2 was observed either during high temperature growth or annealing process of the films. The refractive index and bandgap of TiO2 films changed with the growth and annealing temperatures. The optimization of the annealing conditions for TiO2 films was also done by morphology and density studies. © 2013 Elsevier B.V. All rights reserved.

  16. Surface engineering of nanoporous substrate for solid oxide fuel cells with atomic layer-deposited electrolyte

    Directory of Open Access Journals (Sweden)

    Sanghoon Ji

    2015-08-01

    Full Text Available Solid oxide fuel cells with atomic layer-deposited thin film electrolytes supported on anodic aluminum oxide (AAO are electrochemically characterized with varying thickness of bottom electrode catalyst (BEC; BECs which are 0.5 and 4 times thicker than the size of AAO pores are tested. The thicker BEC ensures far more active mass transport on the BEC side and resultantly the thicker BEC cell generates ≈11 times higher peak power density than the thinner BEC cell at 500 °C.

  17. Atomic Layer Deposition of Pt Nanoparticles for Microengine with Promoted Catalytic Motion.

    Science.gov (United States)

    Jiang, Chi; Huang, Gaoshan; Ding, Shi-Jin; Dong, Hongliang; Men, Chuanling; Mei, Yongfeng

    2016-12-01

    Nanoparticle-decorated tubular microengines were synthesized by a combination of rolled-up nanotechnology and atomic layer deposition. The presence of Pt nanoparticles with different sizes and distributions on the walls of microengines fabricated from bilayer nanomembranes with different materials results in promoted catalytic reaction efficiency, which leads to an ultrafast speed (the highest speed 3200 μm/s). The motion speed of the decorated microengines fits the theoretical model very well, suggesting that the larger surface area is mainly responsible for the acceleration of the motion speed. The high-speed nanoparticle-decorated microengines hold considerable promise for a variety of applications. PMID:27295257

  18. Controlled Phase and Tunable Magnetism in Ordered Iron Oxide Nanotube Arrays Prepared by Atomic Layer Deposition

    Science.gov (United States)

    Zhang, Yijun; Liu, Ming; Peng, Bin; Zhou, Ziyao; Chen, Xing; Yang, Shu-Ming; Jiang, Zhuang-De; Zhang, Jie; Ren, Wei; Ye, Zuo-Guang

    2016-01-01

    Highly-ordered and conformal iron oxide nanotube arrays on an atomic scale are successfully prepared by atomic layer deposition (ALD) with controlled oxidization states and tunable magnetic properties between superparamagnetism and ferrimagnetism. Non-magnetic α-Fe2O3 and superparamagnetic Fe3O4 with a blocking temperature of 120 K are in-situ obtained by finely controlling the oxidation reaction. Both of them exhibit a very small grain size of only several nanometers due to the nature of atom-by-atom growth of the ALD technique. Post-annealing α-Fe2O3 in a reducing atmosphere leads to the formation of the spinel Fe3O4 phase which displays a distinct ferrimagnetic anisotropy and the Verwey metal-insulator transition that usually takes place only in single crystal magnetite or thick epitaxial films at low temperatures. The ALD deposition of iron oxide with well-controlled phase and tunable magnetism demonstrated in this work provides a promising opportunity for the fabrication of 3D nano-devices to be used in catalysis, spintronics, microelectronics, data storages and bio-applications.

  19. Photoluminescence enhancement in porous SiC passivated by atomic layer deposited Al2O3 films

    DEFF Research Database (Denmark)

    Lu, Weifang; Iwasa, Yoshimi; Ou, Yiyu;

    2016-01-01

    Porous SiC co-doped with B and N was passivated by atomic layer deposited (ALD) Al2O3 films to enhance the photoluminescence. After optimizing the deposition conditions, as high as 14.9 times photoluminescence enhancement has been achieved.......Porous SiC co-doped with B and N was passivated by atomic layer deposited (ALD) Al2O3 films to enhance the photoluminescence. After optimizing the deposition conditions, as high as 14.9 times photoluminescence enhancement has been achieved....

  20. Atomic layer deposition of hafnium oxide and hafnium silicate thin films using liquid precursors and ozone

    Science.gov (United States)

    Senzaki, Yoshihide; Park, Seung; Chatham, Hood; Bartholomew, Lawrence; Nieveen, Wesley

    2004-07-01

    Atomic layer deposition (ALD) processes for HfO2 and HfxSi1-xO2 high-k dielectric thin films using liquid precursors and ozone were evaluated. Tetrakis(ethylmethylamino)hafnium (TEMAHf) precursor provides HfO2 films with superior quality as compared to Hf(t-butoxide)4 precursor in terms of deposition rate, purity, and electrical properties of the films. ALD processes for hafnium silicate films have been developed by co-injection of TEMAHf and tetrakis(ethylmethylamino) silicon precursors. Alternating pulses of the Hf/Si precursor vapor mixture and ozone allow process temperatures below 400 °C to grow HfxSi1-xO2 film. The Hf and Si precursors can be converted to vapor for delivery to the deposition chamber either by bubbling an inert carrier gas separately through each liquid or by using a liquid vaporization unit. The co-injection process enables the formation of homogeneous single-layer hafnium silicate films as deposited. .

  1. Protecting BOPP film from UV degradation with an atomic layer deposited titanium oxide surface coating

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Kimmo, E-mail: kimmo.lahtinen@lut.fi [ASTRaL, Lappeenranta University of Technology, Mikkeli (Finland); Maydannik, Philipp; Seppänen, Tarja; Cameron, David C. [ASTRaL, Lappeenranta University of Technology, Mikkeli (Finland); Johansson, Petri; Kotkamo, Sami; Kuusipalo, Jurkka [Paper Converting and Packaging Technology, Tampere University of Technology, Tampere (Finland)

    2013-10-01

    Titanium oxide layers were deposited onto a BOPP film by atomic layer deposition in order to prevent UV degradation of the film. The coatings were deposited in a low-temperature process at 80 °C by using tetrakis(dimethylamido)titanium and ozone as titanium and oxygen precursors, respectively. UV block characteristics of the coatings and their effect on the polymer were measured by using UV–vis and IR spectrometry, and differential scanning calorimetry. According to the results, the coatings provided a considerable decrease in the photodegradation of the BOPP film during UV exposure. IR spectra showed that during a 6-week UV exposure, a 67 nm titanium oxide coating was able to almost completely prevent the formation of photodegradation products in the film. The mechanical properties of the film were also protected by the coating, but as opposed to what the IR study suggested they were still somewhat compromised by the UV light. After a 6-week exposure, the tensile strength and elongation at break of the 67 nm titanium oxide coated film decreased to half of the values measured before the treatment. This should be compared to the complete degradation suffered by the uncoated base sheet already after only 4 weeks of treatment. The results show that nanometre scale inorganic films deposited by ALD show a promising performance as effective UV protection for BOPP substrates.

  2. Atomic layer deposition growth of a novel mixed-phase barrier for seedless copper electroplating applications

    International Nuclear Information System (INIS)

    A novel plasma-enhanced atomic layer deposition-grown mixed-phase/nanolaminate Ru-TaN barrier has been investigated, and it was confirmed that the copper diffusion barrier and direct-plate characteristics of the mixed-phase barrier can be modulated by varying the metal ratio in the film. This liner was subsequently optimized to yield a composition that combines the robust barrier properties of TaN with direct-plate characteristics of Ru. It was found that the deposited multicomponent system consists of individual crystalline and amorphous phase regions distributed across the barrier. The resulting optimized mixed-phase barrier was found to exhibit excellent copper diffusion barrier characteristics in layers as thin as 2 nm. A high degree of (111) texture (>84%) was observed for the direct-plated copper on this Ru-TaN barrier, which was very similar to the electroplated Cu deposited on a physical vapor deposition copper-seed control sample. Additionally, the filling characteristics in sub-50-nm features were found to be equivalent to those of conventionally copper-seeded interconnect structures.

  3. Protecting BOPP film from UV degradation with an atomic layer deposited titanium oxide surface coating

    International Nuclear Information System (INIS)

    Titanium oxide layers were deposited onto a BOPP film by atomic layer deposition in order to prevent UV degradation of the film. The coatings were deposited in a low-temperature process at 80 °C by using tetrakis(dimethylamido)titanium and ozone as titanium and oxygen precursors, respectively. UV block characteristics of the coatings and their effect on the polymer were measured by using UV–vis and IR spectrometry, and differential scanning calorimetry. According to the results, the coatings provided a considerable decrease in the photodegradation of the BOPP film during UV exposure. IR spectra showed that during a 6-week UV exposure, a 67 nm titanium oxide coating was able to almost completely prevent the formation of photodegradation products in the film. The mechanical properties of the film were also protected by the coating, but as opposed to what the IR study suggested they were still somewhat compromised by the UV light. After a 6-week exposure, the tensile strength and elongation at break of the 67 nm titanium oxide coated film decreased to half of the values measured before the treatment. This should be compared to the complete degradation suffered by the uncoated base sheet already after only 4 weeks of treatment. The results show that nanometre scale inorganic films deposited by ALD show a promising performance as effective UV protection for BOPP substrates.

  4. Distinguishing plasmonic absorption modes by virtue of inversed architectures with tunable atomic-layer-deposited spacer layer

    International Nuclear Information System (INIS)

    We demonstrated the distinguishing between plasmonic absorption modes by exploiting an inversed architecture with tunable atomic-layer-deposited dielectric spacer layer. The dielectric spacer layer was manipulated between the bottom metal–nanoparticle monolayer and the upper metal film to inspect the contributions of metal nanoparticles and dielectric film in a step-by-step manner. The experimental and simulated differences between the two peak absorption positions (Δf) and between the corresponding half width at half maxima (Δw) confirmed the evolutions of gap plasmon and interference-enhanced local surface plasmon resonance absorption modes in the plasmonic metamaterial absorbers (PMAs), which were useful for understanding the underlying mechanism of amorphous PMAs. (paper)

  5. Influence of atomic layer deposition Al2O3 nano-layer on the surface passivation of silicon solar cells

    International Nuclear Information System (INIS)

    A stack of Al2O3/SiNx dual layer was applied for the back side surface passivation of p-type multi-crystalline silicon solar cells, with laser-opened line metal contacts, forming a local aluminum back surface field (local Al-BSF) structure. A slight amount of Al2O3, wrapping around to the front side of the wafer during the thermal atomic layer deposition process, was found to have a negative influence on cell performance. The different process flow was found to lead to a different cell performance, because of the Al2O3 wrapping around the front surface. The best cell performance, with an absolute efficiency gain of about 0.6% compared with the normal full Al-BSF structure solar cell, was achieved when the Al2O3 layer was deposited after the front surface of the wafer had been covered by a SiNx layer. We discuss the possible reasons for this phenomenon, and propose three explanations as the Ag paste, being hindered from firing through the front passivation layer, degraded the SiNx passivation effect and the Al2O3 induced an inversion effect on the front surface. Characterization methods like internal quantum efficiency and contact resistance scanning were used to assist our understanding of the underlying mechanisms. (semiconductor physics)

  6. Interface Engineering for Atomic Layer Deposited Alumina Gate Dielectric on SiGe Substrates.

    Science.gov (United States)

    Zhang, Liangliang; Guo, Yuzheng; Hassan, Vinayak Vishwanath; Tang, Kechao; Foad, Majeed A; Woicik, Joseph C; Pianetta, Piero; Robertson, John; McIntyre, Paul C

    2016-07-27

    Optimization of the interface between high-k dielectrics and SiGe substrates is a challenging topic due to the complexity arising from the coexistence of Si and Ge interfacial oxides. Defective high-k/SiGe interfaces limit future applications of SiGe as a channel material for electronic devices. In this paper, we identify the surface layer structure of as-received SiGe and Al2O3/SiGe structures based on soft and hard X-ray photoelectron spectroscopy. As-received SiGe substrates have native SiOx/GeOx surface layers, where the GeOx-rich layer is beneath a SiOx-rich surface. Silicon oxide regrows on the SiGe surface during Al2O3 atomic layer deposition, and both SiOx and GeOx regrow during forming gas anneal in the presence of a Pt gate metal. The resulting mixed SiOx-GeOx interface layer causes large interface trap densities (Dit) due to distorted Ge-O bonds across the interface. In contrast, we observe that oxygen-scavenging Al top gates decompose the underlying SiOx/GeOx, in a selective fashion, leaving an ultrathin SiOx interfacial layer that exhibits dramatically reduced Dit. PMID:27345195

  7. Characterization of ZnO film grown on polycarbonate by atomic layer deposition at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gyeong Beom; Han, Gwon Deok; Shim, Joon Hyung; Choi, Byoung-Ho, E-mail: bhchoi@korea.ac.kr [School of Mechanical Engineering, Korea University, Seoul 136-707 (Korea, Republic of)

    2015-01-15

    ZnO is an attractive material for use in various technological products such as phosphors, gas sensors, and transparent conductors. Recently, aluminum-doped zinc oxide has received attention as a potential replacement for indium tin oxide, which is one of the transparent conductive oxides used in flat panel displays, organic light-emitting diodes, and organic solar cells. In this study, the characteristics of ZnO films deposited on polycarbonate (PC) substrates by atomic layer deposition (ALD) are investigated for various process temperatures. The growth mechanism of these films was investigated at low process temperatures using x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). XRD and XPS were used to determine the preferred orientation and chemical composition of the films, respectively. Furthermore, the difference of the deposition mechanisms on an amorphous organic material, i.e., PC substrate and an inorganic material such as silicon was discussed from the viewpoint of the diffusion and deposition of precursors. The structure of the films was also investigated by chemical analysis in order to determine the effect of growth temperature on the films deposited by ALD.

  8. Atomic layer deposition of MgO films on yttria-stabilized zirconia microtubes

    International Nuclear Information System (INIS)

    Deposition of MgO thin film on nanocrystalline yttria-stabilized zirconia microtubes was investigated. The microtubes were prepared by self-formation from threads drawn directly from zirconium butoxide [Zr(OBu)4] precursor and heat treated at 800 °C. The tubes possessed 100% tetragonal phase, their typical outer diameter was 50 μm, inner diameter 30 μm and length 1 cm. MgO films were deposited from β-diketonate-type precursor 2,2,6,6-tetramethyl-heptanedionato-3,5-magnesium(II) at 220 °C by atomic layer deposition. Thickness of MgO film on microtubes was 15.8 nm and growth rate 0.105 Å/cycle. - Highlights: • MgO films were deposited on the surface of yttria-stabilized zirconia microtubes. • The studies are carried out on the basis of surface modification of microtubes. • Films were deposited from β-diketonate-type precursor Mg(thd)2. • The growth temperature of MgO film was 220 °C

  9. Characterization of ZnO film grown on polycarbonate by atomic layer deposition at low temperature

    International Nuclear Information System (INIS)

    ZnO is an attractive material for use in various technological products such as phosphors, gas sensors, and transparent conductors. Recently, aluminum-doped zinc oxide has received attention as a potential replacement for indium tin oxide, which is one of the transparent conductive oxides used in flat panel displays, organic light-emitting diodes, and organic solar cells. In this study, the characteristics of ZnO films deposited on polycarbonate (PC) substrates by atomic layer deposition (ALD) are investigated for various process temperatures. The growth mechanism of these films was investigated at low process temperatures using x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). XRD and XPS were used to determine the preferred orientation and chemical composition of the films, respectively. Furthermore, the difference of the deposition mechanisms on an amorphous organic material, i.e., PC substrate and an inorganic material such as silicon was discussed from the viewpoint of the diffusion and deposition of precursors. The structure of the films was also investigated by chemical analysis in order to determine the effect of growth temperature on the films deposited by ALD

  10. Growth, intermixing, and surface phase formation for zinc tin oxide nanolaminates produced by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hägglund, Carl, E-mail: carl.hagglund@angstrom.uu.se [Department of Chemical Engineering, Stanford University, Stanford, California 94305 and Department of Engineering Sciences, Division of Solid State Electronics, Uppsala University, 75121 Uppsala (Sweden); Grehl, Thomas; Brongersma, Hidde H. [ION-TOF GmbH, Heisenbergstraße 15, 48149 Münster (Germany); Tanskanen, Jukka T.; Mullings, Marja N.; Mackus, Adriaan J. M.; MacIsaac, Callisto; Bent, Stacey Francine, E-mail: sbent@stanford.edu [Department of Chemical Engineering, Stanford University, Stanford, California 94305 (United States); Yee, Ye Sheng [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Clemens, Bruce M. [Department of Material Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-03-15

    A broad and expanding range of materials can be produced by atomic layer deposition at relatively low temperatures, including both oxides and metals. For many applications of interest, however, it is desirable to grow more tailored and complex materials such as semiconductors with a certain doping, mixed oxides, and metallic alloys. How well such mixed materials can be accomplished with atomic layer deposition requires knowledge of the conditions under which the resulting films will be mixed, solid solutions, or laminated. The growth and lamination of zinc oxide and tin oxide is studied here by means of the extremely surface sensitive technique of low energy ion scattering, combined with bulk composition and thickness determination, and x-ray diffraction. At the low temperatures used for deposition (150 °C), there is little evidence for atomic scale mixing even with the smallest possible bilayer period, and instead a morphology with small ZnO inclusions in a SnO{sub x} matrix is deduced. Postannealing of such laminates above 400 °C however produces a stable surface phase with a 30% increased density. From the surface stoichiometry, this is likely the inverted spinel of zinc stannate, Zn{sub 2}SnO{sub 4}. Annealing to 800 °C results in films containing crystalline Zn{sub 2}SnO{sub 4}, or multilayered films of crystalline ZnO, Zn{sub 2}SnO{sub 4}, and SnO{sub 2} phases, depending on the bilayer period.

  11. Fabrication of ion conductive tin oxide-phosphate amorphous thin films by atomic layer deposition

    International Nuclear Information System (INIS)

    This work reports the atomic layer deposition (ALD) of tin oxide-phosphate films using tetrakis(dimethylamino)tin and trimethyl phosphate as precursors. The growth rates were 1.23–1.84 Å/cycle depending upon the deposition temperature and precursor combination. The ionic conductivity of the ALD tin oxide-phosphate films was evaluated by cross-plane impedance measurements in the temperature range of 50–300 °C under atmospheric air, with the highest conductivity measured as 1.92 × 10−5 S cm−1 at 300 °C. Furthermore, high-resolution x-ray photoelectron spectroscopy exhibited two O1s peaks that were classified as two subpeaks of hydroxyl ions and oxygen ions, revealing that the quantity of hydroxyl ions in the ALD tin oxide-phosphate films influences their ionic conductivity

  12. Conformal nanocoating of zirconia nanoparticles by atomic layer deposition in a fluidized bed reactor

    Science.gov (United States)

    Hakim, Luis F.; George, Steven M.; Weimer, Alan W.

    2005-07-01

    Primary zirconia nanoparticles were conformally coated with alumina ultrathin films using atomic layer deposition (ALD) in a fluidized bed reactor. Alternating doses of trimethylaluminium and water vapour were performed to deposit Al2O3 nanolayers on the surface of 26 nm zirconia nanoparticles. Transmission Fourier transform infrared spectroscopy was performed ex situ. Bulk Al2O3 vibrational modes were observed for coated particles after 50 and 70 cycles. Coated nanoparticles were also examined with transmission electron microscopy, high-resolution field emission scanning electron microscopy and energy dispersive spectroscopy. Analysis revealed highly conformal and uniform alumina nanofilms throughout the surface of zirconia nanoparticles. The particle size distribution and surface area of the nanoparticles are not affected by the coating process. Primary nanoparticles are coated individually despite their high aggregation tendency during fluidization. The dynamic aggregation behaviour of zirconia nanoparticles in the fluidized bed plays a key role in the individual coating of nanoparticles.

  13. Enhancing the platinum atomic layer deposition infiltration depth inside anodic alumina nanoporous membrane

    International Nuclear Information System (INIS)

    Nanoporous platinum membranes can be straightforwardly fabricated by forming a Pt coating inside the nanopores of anodic alumina membranes (AAO) using atomic layer deposition (ALD). However, the high-aspect-ratio of AAO makes Pt ALD very challenging. By tuning the process deposition temperature and precursor exposure time, enhanced infiltration depth along with conformal coating was achieved for Pt ALD inside the AAO templates. Cross-sectional scanning electron microscopy/energy dispersive x-ray spectroscopy and small angle neutron scattering were employed to analyze the Pt coverage and thickness inside the AAO nanopores. Additionally, one application of platinum-coated membrane was demonstrated by creating a high-density protein-functionalized interface

  14. Enhancing the platinum atomic layer deposition infiltration depth inside anodic alumina nanoporous membrane

    Energy Technology Data Exchange (ETDEWEB)

    Vaish, Amit, E-mail: anv@udel.edu; Krueger, Susan; Dimitriou, Michael; Majkrzak, Charles [National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, MD 20899-8313 (United States); Vanderah, David J. [Institute for Bioscience and Biotechnology Research, NIST, Rockville, Maryland 20850 (United States); Chen, Lei, E-mail: lei.chen@nist.gov [NIST Center for Nanoscale Science and Technology, Gaithersburg, Maryland 20899-8313 (United States); Gawrisch, Klaus [Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892 (United States)

    2015-01-15

    Nanoporous platinum membranes can be straightforwardly fabricated by forming a Pt coating inside the nanopores of anodic alumina membranes (AAO) using atomic layer deposition (ALD). However, the high-aspect-ratio of AAO makes Pt ALD very challenging. By tuning the process deposition temperature and precursor exposure time, enhanced infiltration depth along with conformal coating was achieved for Pt ALD inside the AAO templates. Cross-sectional scanning electron microscopy/energy dispersive x-ray spectroscopy and small angle neutron scattering were employed to analyze the Pt coverage and thickness inside the AAO nanopores. Additionally, one application of platinum-coated membrane was demonstrated by creating a high-density protein-functionalized interface.

  15. Analysis of scattering mechanisms in zinc oxide films grown by the atomic layer deposition technique

    International Nuclear Information System (INIS)

    In this work, the analysis of the temperature-dependent electrical conductivity of highly crystalline zinc oxide (ZnO) thin films obtained by the Atomic Layer Deposition (ALD) method is performed. It is deduced that the most important scattering mechanisms are: scattering by ionized defects (at low temperatures) as well as by phonons (mainly optical ones) at higher temperatures. Nevertheless, the role of grain boundaries in the carrier mobility limitation ought to be included as well. These conclusions are based on theoretical analysis and temperature-dependent Hall mobility measurements. The presented results prove that existing models can explain the mobility behavior in the ALD-ZnO films, being helpful for understanding their transport properties, which are strongly related both to the crystalline quality of deposited ZnO material and defects in its lattice

  16. Designing high performance precursors for atomic layer deposition of silicon oxide

    Energy Technology Data Exchange (ETDEWEB)

    Mallikarjunan, Anupama, E-mail: mallika@airproducts.com; Chandra, Haripin; Xiao, Manchao; Lei, Xinjian; Pearlstein, Ronald M.; Bowen, Heather R.; O' Neill, Mark L. [Air Products and Chemicals, Inc., 1969 Palomar Oaks Way, Carlsbad, California 92011 (United States); Derecskei-Kovacs, Agnes [Air Products and Chemicals, Inc., 7201 Hamilton Blvd., Allentown, Pennsylvania 18195 (United States); Han, Bing [Air Products and Chemicals, Inc., 2 Dongsanhuan North Road, Chaoyang District, Beijing 100027 (China)

    2015-01-15

    Conformal and continuous silicon oxide films produced by atomic layer deposition (ALD) are enabling novel processing schemes and integrated device structures. The increasing drive toward lower temperature processing requires new precursors with even higher reactivity. The aminosilane family of precursors has advantages due to their reactive nature and relative ease of use. In this paper, the authors present the experimental results that reveal the uniqueness of the monoaminosilane structure [(R{sub 2}N)SiH{sub 3}] in providing ultralow temperature silicon oxide depositions. Disubstituted aminosilanes with primary amines such as in bis(t-butylamino)silane and with secondary amines such as in bis(diethylamino)silane were compared with a representative monoaminosilane: di-sec-butylaminosilane (DSBAS). DSBAS showed the highest growth per cycle in both thermal and plasma enhanced ALD. These findings show the importance of the arrangement of the precursor's organic groups in an ALD silicon oxide process.

  17. Designing high performance precursors for atomic layer deposition of silicon oxide

    International Nuclear Information System (INIS)

    Conformal and continuous silicon oxide films produced by atomic layer deposition (ALD) are enabling novel processing schemes and integrated device structures. The increasing drive toward lower temperature processing requires new precursors with even higher reactivity. The aminosilane family of precursors has advantages due to their reactive nature and relative ease of use. In this paper, the authors present the experimental results that reveal the uniqueness of the monoaminosilane structure [(R2N)SiH3] in providing ultralow temperature silicon oxide depositions. Disubstituted aminosilanes with primary amines such as in bis(t-butylamino)silane and with secondary amines such as in bis(diethylamino)silane were compared with a representative monoaminosilane: di-sec-butylaminosilane (DSBAS). DSBAS showed the highest growth per cycle in both thermal and plasma enhanced ALD. These findings show the importance of the arrangement of the precursor's organic groups in an ALD silicon oxide process

  18. Synthesis and characterization of PbTe thin films by atomic layer deposition

    International Nuclear Information System (INIS)

    PbTe thin films on silicon substrates were prepared by an atomic layer deposition (ALD) for the first time, using lead (II) bis (2,2,6,6-tetramethyl-3,5-heptanedionato) and (trimethylsilyl) telluride as ALD precursors, at deposition temperature as low as 170 C. The formation of a PbTe thin film on the Si substrates was strongly dependent on the growth temperature. X-ray diffraction measurement indicated that thin films were polycrystalline and have characteristic face-centered cubic rock salt structure with a preferential (200) orientation. Scanning electron microscopy showed PbTe thin films were grown in the Volmer-Weber island mode. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Synthesis and characterization of PbTe thin films by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, K.; Pillai, A.D. Ramalingom; Tangirala, M.; Nminibapiel, D.; Bollenbach, K.; Cao, W. [Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA (United States); Applied Research Center at Thomas Jefferson National Accelerator Laboratories, Newport News, VA (United States); Baumgart, H. [Applied Research Center at Thomas Jefferson National Accelerator Laboratories, Newport News, VA (United States); Chakravadhanula, V.S.K. [Karlsruhe Nano Micro Facility, Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm (HIU), Electrochemical Energy Storage, Ulm (Germany); Institute for Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) - Campus Nord, Hermann-von-Helmholtz-Platz 1, Building 640, 76344, Eggenstein-Leopoldshafen (Germany); Kuebel, C. [Karlsruhe Nano Micro Facility, Eggenstein-Leopoldshafen (Germany); Institute for Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) - Campus Nord, Hermann-von-Helmholtz-Platz 1, Building 640, 76344, Eggenstein-Leopoldshafen (Germany); Kochergin, V. [MicroXact Inc., 295 Industrial Drive, Christiansburg, VA (United States)

    2014-06-15

    PbTe thin films on silicon substrates were prepared by an atomic layer deposition (ALD) for the first time, using lead (II) bis (2,2,6,6-tetramethyl-3,5-heptanedionato) and (trimethylsilyl) telluride as ALD precursors, at deposition temperature as low as 170 C. The formation of a PbTe thin film on the Si substrates was strongly dependent on the growth temperature. X-ray diffraction measurement indicated that thin films were polycrystalline and have characteristic face-centered cubic rock salt structure with a preferential (200) orientation. Scanning electron microscopy showed PbTe thin films were grown in the Volmer-Weber island mode. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Thermal stability of atomic layer deposition Al2O3 film on HgCdTe

    Science.gov (United States)

    Zhang, P.; Sun, C. H.; Zhang, Y.; Chen, X.; He, K.; Chen, Y. Y.; Ye, Z. H.

    2015-06-01

    Thermal stability of Atomic Layer Deposition Al2O3 film on HgCdTe was investigated by Al2O3 film post-deposition annealing treatment and Metal-Insulator-Semiconductor device low-temperature baking treatment. The effectiveness of Al2O3 film was evaluated by measuring the minority carrier lifetime and capacitance versus voltage characteristics. After annealing treatment, the minority carrier lifetime of the HgCdTe sample presented a slight decrease. Furthermore, the fixed charge density and the slow charge density decreased significantly in the annealed MIS device. After baking treatment, the fixed charge density and the slow charge density of the unannealed and annealed MIS devices decreased and increased, respectively.

  1. Growing aluminum nitride films by Plasma-Enhanced Atomic Layer Deposition at low temperatures

    Science.gov (United States)

    Tarala, V. A.; Altakhov, A. S.; Martens, V. Ya; Lisitsyn, S. V.

    2015-11-01

    Aluminum nitride films have been grown by Plasma-Enhanced Atomic Layer Deposition method. It was found that at temperatures of 250 °C and 280 °C increase of the plasma exposure step duration over 6 s, as well as increase of reactor purge step duration over 1 s does not affect the growth rate, however, it affects the microstructure of the films. It was found that crystalline aluminum nitride films deposit with plasma exposure duration over 10 s and the reactor purging over 10 s. When the temperature drops the increase of reactor purge step duration and plasma exposure step duration over 20 s is required for crystalline AlN film growth.

  2. Atomic layer deposition of HfO2 on graphene through controlled ion beam treatment

    Science.gov (United States)

    Kim, Ki Seok; Oh, Il-Kwon; Jung, Hanearl; Kim, Hyungjun; Yeom, Geun Young; Kim, Kyong Nam

    2016-05-01

    The polymer residue generated during the graphene transfer process to the substrate tends to cause problems (e.g., a decrease in electron mobility, unwanted doping, and non-uniform deposition of the dielectric material). In this study, by using a controllable low-energy Ar+ ion beam, we cleaned the polymer residue without damaging the graphene network. HfO2 grown by atomic layer deposition on graphene cleaned using an Ar+ ion beam showed a dense uniform structure, whereas that grown on the transferred graphene (before Ar+ ion cleaning) showed a non-uniform structure. A graphene-HfO2-metal capacitor fabricated by growing 20-nm thick HfO2 on graphene exhibited a very low leakage current (graphene, whereas a similar capacitor grown using the transferred graphene showed high leakage current.

  3. Low-temperature atomic layer deposition of copper(II) oxide thin films

    International Nuclear Information System (INIS)

    Copper(II) oxide thin films were grown by atomic layer deposition (ALD) using bis-(dimethylamino-2-propoxide)copper [Cu(dmap)2] and ozone in a temperature window of 80–140 °C. A thorough characterization of the films was performed using x-ray diffraction, x-ray reflectivity, UV‐Vis spectrophotometry, atomic force microscopy, field emission scanning electron microscopy, x-ray photoelectron spectroscopy, and time-of-flight elastic recoil detection analysis techniques. The process was found to produce polycrystalline copper(II) oxide films with a growth rate of 0.2–0.3 Å per cycle. Impurity content in the films was relatively small for a low temperature ALD process

  4. Low-temperature atomic layer deposition of copper(II) oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Iivonen, Tomi, E-mail: tomi.iivonen@helsinki.fi; Hämäläinen, Jani; Mattinen, Miika; Popov, Georgi; Leskelä, Markku [Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland); Marchand, Benoît; Mizohata, Kenichiro [Division of Materials Physics, Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki (Finland); Kim, Jiyeon; Fischer, Roland A. [Chair of Inorganic Chemistry II, Ruhr-University Bochum, Universitätsstrasse 150, 44780 Bochum (Germany)

    2016-01-15

    Copper(II) oxide thin films were grown by atomic layer deposition (ALD) using bis-(dimethylamino-2-propoxide)copper [Cu(dmap){sub 2}] and ozone in a temperature window of 80–140 °C. A thorough characterization of the films was performed using x-ray diffraction, x-ray reflectivity, UV‐Vis spectrophotometry, atomic force microscopy, field emission scanning electron microscopy, x-ray photoelectron spectroscopy, and time-of-flight elastic recoil detection analysis techniques. The process was found to produce polycrystalline copper(II) oxide films with a growth rate of 0.2–0.3 Å per cycle. Impurity content in the films was relatively small for a low temperature ALD process.

  5. Surface passivation and antireflectance performances for atomic-layer-deposited Al2O3 films

    International Nuclear Information System (INIS)

    Al2O3 films were deposited on single crystalline silicon wafers by atomic layer deposition. Both passivation and antireflectance performances are studied in detail. 30 nm Al2O3 passivated n-type and p-type Si shows a maximum effective minority carrier lifetime (τeff) of ∼5.2 ms and ∼4.7 ms, corresponding to a low surface recombination velocity of ∼3.8 cm s−1 and ∼4.2 cm s−1, respectively. By drawing a contour map of post-deposition annealing (PDA) temperature, PDA time and τeff, a wide PDA window is obtained for obtaining good passivation performances. The excellent passivation performances are related to the large, negative fixed charge density within Al2O3 films and the formation of interfacial SiO2 layer at the Al2O3/Si interface. Antireflectance performances are also studied in detail for Al2O3 and Al2O3/SiNx double-layer on textured Si. For obtaining a low average reflectance between 2.6% and 3%, a wide film-thickness window of ∼30 nm for Al2O3 and SiNx layer is observed for Al2O3/SiNx double-layer on textured Si. Our results indicate that Al2O3 films have excellent surface passivation and antireflectance performances with a wide processing window, which is favorable for c-Si solar cell applications. (paper)

  6. Mechanistic modeling study on process optimization and precursor utilization with atmospheric spatial atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Zhang; He, Wenjie; Duan, Chenlong [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Shan, Bin [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2016-01-15

    Spatial atomic layer deposition (SALD) is a promising technology with the aim of combining the advantages of excellent uniformity and conformity of temporal atomic layer deposition (ALD), and an industrial scalable and continuous process. In this manuscript, an experimental and numerical combined model of atmospheric SALD system is presented. To establish the connection between the process parameters and the growth efficiency, a quantitative model on reactant isolation, throughput, and precursor utilization is performed based on the separation gas flow rate, carrier gas flow rate, and precursor mass fraction. The simulation results based on this model show an inverse relation between the precursor usage and the carrier gas flow rate. With the constant carrier gas flow, the relationship of precursor usage and precursor mass fraction follows monotonic function. The precursor concentration, regardless of gas velocity, is the determinant factor of the minimal residual time. The narrow gap between precursor injecting heads and the substrate surface in general SALD system leads to a low Péclet number. In this situation, the gas diffusion act as a leading role in the precursor transport in the small gap rather than the convection. Fluid kinetics from the numerical model is independent of the specific structure, which is instructive for the SALD geometry design as well as its process optimization.

  7. Mechanistic modeling study on process optimization and precursor utilization with atmospheric spatial atomic layer deposition

    International Nuclear Information System (INIS)

    Spatial atomic layer deposition (SALD) is a promising technology with the aim of combining the advantages of excellent uniformity and conformity of temporal atomic layer deposition (ALD), and an industrial scalable and continuous process. In this manuscript, an experimental and numerical combined model of atmospheric SALD system is presented. To establish the connection between the process parameters and the growth efficiency, a quantitative model on reactant isolation, throughput, and precursor utilization is performed based on the separation gas flow rate, carrier gas flow rate, and precursor mass fraction. The simulation results based on this model show an inverse relation between the precursor usage and the carrier gas flow rate. With the constant carrier gas flow, the relationship of precursor usage and precursor mass fraction follows monotonic function. The precursor concentration, regardless of gas velocity, is the determinant factor of the minimal residual time. The narrow gap between precursor injecting heads and the substrate surface in general SALD system leads to a low Péclet number. In this situation, the gas diffusion act as a leading role in the precursor transport in the small gap rather than the convection. Fluid kinetics from the numerical model is independent of the specific structure, which is instructive for the SALD geometry design as well as its process optimization

  8. ATOMIC LAYER DEPOSITION OF TITANIUM OXIDE THIN FILMS ONNANOPOROUS ALUMINA TEMPLATES FOR MEDICAL APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.

    2009-05-05

    Nanostructured materials may play a significant role in controlled release of pharmacologic agents for treatment of cancer. Many nanoporous polymer materials are inadequate for use in drug delivery. Nanoporous alumina provides several advantages over other materials for use in controlled drug delivery and other medical applications. Atomic layer deposition was used to coat all the surfaces of the nanoporous alumina membrane in order to reduce the pore size in a controlled manner. Both the 20 nm and 100 nm titanium oxide-coated nanoporous alumina membranes did not exhibit statistically lower viability compared to the uncoated nanoporous alumina membrane control materials. In addition, 20 nm pore size titanium oxide-coated nanoporous alumina membranes exposed to ultraviolet light demonstrated activity against Escherichia coli and Staphylococcus aureus bacteria. Nanostructured materials prepared using atomic layer deposition may be useful for delivering a pharmacologic agent at a precise rate to a specific location in the body. These materials may serve as the basis for 'smart' drug delivery devices, orthopedic implants, or self-sterilizing medical devices.

  9. Photoluminescence of atomic layer deposited ZrO2:Dy3+ thin films

    International Nuclear Information System (INIS)

    Atomic layer deposition based on alternate cycling of ZrCl4, Dy(thd)3 and H2O as precursors was applied for preparation of nanocrystalline ZrO2:Dy thin films. Photoluminescence (PL) properties of Dy3+ in the ZrO2 films were studied at several laser excitations. Substantial activation of Dy3+ PL required thermal treatment at 900 °C. As a result of annealing, thinner (~ 80 nm) films with higher Dy content retained relatively high amount of tetragonal phase and remained crack-free. In thicker (~ 140 nm) films, considerable amount of monoclinic phase was formed and a peculiar microscale cracking pattern was developed along with phase segregation. It is demonstrated that the crystal structure of ZrO2 significantly influences the Dy3+ emission spectrum and, at least for ZrO2-type matrices, Dy3+ is an excellent luminescent microprobe in comparison with micro-Raman scattering. A Förster-like PL decay profile allowed a conclusion that the self-quenching due to cross-relaxation between Dy3+ ions had a marked impact on emission intensity. - Highlights: • Atomic layer deposition of luminescent Dy-doped ZrO2 thin films was demonstrated. • Dy3+ luminescence was significantly activated only after high-temperature annealing. • Correlation between luminescent and structural properties was obtained. • Dy3+ luminescent probe showed superior performance compared to Raman-scattering. • Presence of several quenching processes was deduced from luminescence behavior

  10. Fabrication and design of metal nano-accordion structures using atomic layer deposition and interference lithography

    Science.gov (United States)

    Min, J.-H.; Bagal, A.; Mundy, J. Z.; Oldham, C. J.; Wu, B.-I.; Parsons, G. N.; Chang, C.-H.

    2016-02-01

    Metal nanostructures have attractive electrical and thermal properties as well as structural stability, and are important for applications in flexible conductors. In this study, we have developed a method to fabricate and control novel complex platinum nanostructures with accordion-like profile using atomic layer deposition on lithographically patterned polymer templates. The template removal process results in unique structural transformation of the nanostructure profile, which has been studied and modeled. Using different template duty cycles and aspect ratios, we have demonstrated a wide variety of cross-sectional profiles from wavy geometry to pipe array patterns. These complex thin metal nanostructures can find applications in flexible/stretchable electronics, photonics and nanofluidics.Metal nanostructures have attractive electrical and thermal properties as well as structural stability, and are important for applications in flexible conductors. In this study, we have developed a method to fabricate and control novel complex platinum nanostructures with accordion-like profile using atomic layer deposition on lithographically patterned polymer templates. The template removal process results in unique structural transformation of the nanostructure profile, which has been studied and modeled. Using different template duty cycles and aspect ratios, we have demonstrated a wide variety of cross-sectional profiles from wavy geometry to pipe array patterns. These complex thin metal nanostructures can find applications in flexible/stretchable electronics, photonics and nanofluidics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08566g

  11. Bipolar resistive switching properties of AlN films deposited by plasma-enhanced atomic layer deposition

    Science.gov (United States)

    Zhang, Jian; Zhang, Qilong; Yang, Hui; Wu, Huayu; Zhou, Juehui; Hu, Liang

    2014-10-01

    AlN thin films deposited by plasma-enhanced atomic layer deposition (PEALD) have been used to investigate the resistive switching (RS) behavior. The bipolar RS properties were observed in the Cu/PEALD-AlN/Pt devices, which are induced upon the formation/disruption of Cu conducting filaments, as confirmed by the temperature dependent resistances relationships at different resistance states. The resistance ratio of the high and low resistance states (HRS/LRS) is 102-105. The dominant conduction mechanisms at HRS and LRS are trap-controlled space charge limited current and Ohmic behavior, respectively. This study demonstrated that the PEALD-AlN films have a great potential for the applications in high-density resistance random access memory.

  12. Atomic layer deposition to prevent metal transfer from implants: An X-ray fluorescence study

    Science.gov (United States)

    Bilo, Fabjola; Borgese, Laura; Prost, Josef; Rauwolf, Mirjam; Turyanskaya, Anna; Wobrauschek, Peter; Kregsamer, Peter; Streli, Christina; Pazzaglia, Ugo; Depero, Laura E.

    2015-12-01

    We show that Atomic Layer Deposition is a suitable coating technique to prevent metal diffusion from medical implants. The metal distribution in animal bone tissue with inserted bare and coated Co-Cr alloys was evaluated by means of micro X-ray fluorescence mapping. In the uncoated implant, the migration of Co and Cr particles from the bare alloy in the biological tissues is observed just after one month and the number of particles significantly increases after two months. In contrast, no metal diffusion was detected in the implant coated with TiO2. Instead, a gradient distribution of the metals was found, from the alloy surface going into the tissue. No significant change was detected after two months of aging. As expected, the thicker is the TiO2 layer, the lower is the metal migration.

  13. Intrinsic electron traps in atomic-layer deposited HfO2 insulators

    Science.gov (United States)

    Cerbu, F.; Madia, O.; Andreev, D. V.; Fadida, S.; Eizenberg, M.; Breuil, L.; Lisoni, J. G.; Kittl, J. A.; Strand, J.; Shluger, A. L.; Afanas'ev, V. V.; Houssa, M.; Stesmans, A.

    2016-05-01

    Analysis of photodepopulation of electron traps in HfO2 films grown by atomic layer deposition is shown to provide the trap energy distribution across the entire oxide bandgap. The presence is revealed of two kinds of deep electron traps energetically distributed at around Et ≈ 2.0 eV and Et ≈ 3.0 eV below the oxide conduction band. Comparison of the trapped electron energy distributions in HfO2 layers prepared using different precursors or subjected to thermal treatment suggests that these centers are intrinsic in origin. However, the common assumption that these would implicate O vacancies cannot explain the charging behavior of HfO2, suggesting that alternative defect models should be considered.

  14. Uniform GaN thin films grown on (100) silicon by remote plasma atomic layer deposition.

    Science.gov (United States)

    Shih, Huan-Yu; Lin, Ming-Chih; Chen, Liang-Yih; Chen, Miin-Jang

    2015-01-01

    The growth of uniform gallium nitride (GaN) thin films was reported on (100) Si substrate by remote plasma atomic layer deposition (RP-ALD) using triethylgallium (TEG) and NH3 as the precursors. The self-limiting growth of GaN was manifested by the saturation of the deposition rate with the doses of TEG and NH3. The increase in the growth temperature leads to the rise of nitrogen content and improved crystallinity of GaN thin films, from amorphous at a low deposition temperature of 200 °C to polycrystalline hexagonal structures at a high growth temperature of 500 °C. No melting-back etching was observed at the GaN/Si interface. The excellent uniformity and almost atomic flat surface of the GaN thin films also infer the surface control mode of the GaN thin films grown by the RP-ALD technique. The GaN thin films grown by RP-ALD will be further applied in the light-emitting diodes and high electron mobility transistors on (100) Si substrate. PMID:25494474

  15. Uniform GaN thin films grown on (100) silicon by remote plasma atomic layer deposition

    International Nuclear Information System (INIS)

    The growth of uniform gallium nitride (GaN) thin films was reported on (100) Si substrate by remote plasma atomic layer deposition (RP-ALD) using triethylgallium (TEG) and NH3 as the precursors. The self-limiting growth of GaN was manifested by the saturation of the deposition rate with the doses of TEG and NH3. The increase in the growth temperature leads to the rise of nitrogen content and improved crystallinity of GaN thin films, from amorphous at a low deposition temperature of 200 °C to polycrystalline hexagonal structures at a high growth temperature of 500 °C. No melting-back etching was observed at the GaN/Si interface. The excellent uniformity and almost atomic flat surface of the GaN thin films also infer the surface control mode of the GaN thin films grown by the RP-ALD technique. The GaN thin films grown by RP-ALD will be further applied in the light-emitting diodes and high electron mobility transistors on (100) Si substrate. (paper)

  16. Thermal chemistry of the Cu-KI5 atomic layer deposition precursor on a copper surface

    International Nuclear Information System (INIS)

    The thermal chemistry of a Cu(I) ketoiminate complex, Cu-KI5, resulting from the modification of the known Air Products CupraSelect® copper CVD precursor Cu(hfac)(tmvs) designed to tether the two ligands via an isopropoxide linker, was studied under ultrahigh vacuum on a Cu(110) single-crystal surface by using a combination of temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy. Adsorption at low temperatures was determined to take place via the displacement of the vinyl ligand by the surface. Molecular desorption was seen at 210 K, and the evolution of Cu(II)-KI52 was established to take place at 280 K, presumably from a disproportionation reaction that also leads to the deposition of Cu(0). Other sets of desorption products were seen at 150, 250, and 430 K, all containing copper atoms and small organic moieties with molecular masses below 100 amu. The latter TPD peak in particular indicates significant fragmentation of the ligands, likely at the C–N bond that holds the vinylsilane-isopropoxide moiety tethered to the ketoimine fragment, and possibly also at the union between the vinylsilane and the alkoxide linker. The 430 K temperature measured for this chemistry may set an upper limit for clean Cu film deposition, but since reactivity on the surface was also found to be inhibited at higher surface coverages, it may be delayed to higher temperatures under atomic layer deposition conditions

  17. Plasma-enhanced atomic layer deposition and etching of high-k gadolinium oxide

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) of high-quality gadolinium oxide thin films is achieved using Gd(iPrCp)3 and O2 plasma. Gd2O3 growth is observed from 150 to 350 deg. C, though the optical properties of the film improve at higher temperature. True layer-by-layer ALD growth of Gd2O3 occurred in a relatively narrow window of temperature and precursor dose. A saturated growth rate of 1.4 A/cycle was observed at 250 deg. C. As the temperature increases, high-quality films are deposited, but the growth mechanism appears to become CVD-like, indicating the onset of precursor decomposition. At 250 deg. C, the refractive index of the film is stable at ∼1.80 regardless of other deposition conditions, and the measured dispersion characteristics are comparable to those of bulk Gd2O3. XPS data show that the O/Gd ratio is oxygen deficient at 1.3, and that it is also very hygroscopic. The plasma etching rate of the ALD Gd2O3 film in a high-density helicon reactor is very low. Little difference is observed in etching rate between Cl2 and pure Ar plasmas, suggesting that physical sputtering dominates the etching. A threshold bias power exists below which etching does not occur; thus it may be possible to etch a metal gate material and stop easily on the Gd2O3 gate dielectric. The Gd2O3 film has a dielectric constant of about 16, exhibits low C-V hysteresis, and allows a 50 x reduction in gate leakage compared to SiO2. However, the plasma enhanced atomic layer deposition (PE-ALD) process causes formation of an ∼1.8 nm SiO2 interfacial layer, and generates a fixed charge of -1.21 x 1012 cm-2, both of which may limit use of PE-ALD Gd2O3 as a gate dielectric.

  18. Vanadium dioxide film protected with an atomic-layer-deposited Al2O3 thin film

    International Nuclear Information System (INIS)

    A VO2 film exposed to ambient air is prone to oxidation, which will degrade its thermochromic properties. In this work, the authors deposited an ultrathin Al2O3 film with atomic layer deposition (ALD) to protect the underlying VO2 film from degradation, and then studied the morphology and crystalline structure of the films. To assess the protectiveness of the Al2O3 capping layer, the authors performed a heating test and a damp heating test. An ultrathin 5-nm-thick ALD Al2O3 film was sufficient to protect the underlying VO2 film heated at 350 °C. However, in a humid environment at prolonged durations, a thicker ALD Al2O3 film (15 nm) was required to protect the VO2. The authors also deposited and studied a TiO2/Al2O3 bilayer, which significantly improved the protectiveness of the Al2O3 film in a humid environment

  19. Current transport mechanisms in plasma-enhanced atomic layer deposited AlN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Altuntas, Halit, E-mail: altunhalit@gmail.com, E-mail: biyikli@unam.bilkent.edu.tr [Faculty of Science, Department of Physics, Cankiri Karatekin University, Cankiri 18100 (Turkey); Ozgit-Akgun, Cagla; Donmez, Inci; Biyikli, Necmi, E-mail: altunhalit@gmail.com, E-mail: biyikli@unam.bilkent.edu.tr [National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800 (Turkey)

    2015-04-21

    Here, we report on the current transport mechanisms in AlN thin films deposited at a low temperature (i.e., 200 °C) on p-type Si substrates by plasma-enhanced atomic layer deposition. Structural characterization of the deposited AlN was carried out using grazing-incidence X-ray diffraction, revealing polycrystalline films with a wurtzite (hexagonal) structure. Al/AlN/ p-Si metal-insulator-semiconductor (MIS) capacitor structures were fabricated and investigated under negative bias by performing current-voltage measurements. As a function of the applied electric field, different types of current transport mechanisms were observed; i.e., ohmic conduction (15.2–21.5 MV/m), Schottky emission (23.6–39.5 MV/m), Frenkel-Poole emission (63.8–211.8 MV/m), trap-assisted tunneling (226–280 MV/m), and Fowler-Nordheim tunneling (290–447 MV/m). Electrical properties of the insulating AlN layer and the fabricated Al/AlN/p-Si MIS capacitor structure such as dielectric constant, flat-band voltage, effective charge density, and threshold voltage were also determined from the capacitance-voltage measurements.

  20. High aspect ratio iridescent three-dimensional metal–insulator–metal capacitors using atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Micheal, E-mail: micheal.burke@tyndall.ie; Blake, Alan; Djara, Vladimir; O' Connell, Dan; Povey, Ian M.; Cherkaoui, Karim; Monaghan, Scott; Scully, Jim; Murphy, Richard; Hurley, Paul K.; Pemble, Martyn E.; Quinn, Aidan J., E-mail: aidan.quinn@tyndall.ie [Tyndall National Institute, University College Cork, Cork (Ireland)

    2015-01-01

    The authors report on the structural and electrical properties of TiN/Al{sub 2}O{sub 3}/TiN metal–insulator–metal (MIM) capacitor structures in submicron three-dimensional (3D) trench geometries with an aspect ratio of ∼30. A simplified process route was employed where the three layers for the MIM stack were deposited using atomic layer deposition (ALD) in a single run at a process temperature of 250 °C. The TiN top and bottom electrodes were deposited via plasma-enhanced ALD using a tetrakis(dimethylamino)titanium precursor. 3D trench devices yielded capacitance densities of 36 fF/μm{sup 2} and quality factors >65 at low frequency (200 Hz), with low leakage current densities (<3 nA/cm{sup 2} at 1 V). These devices also show strong optical iridescence which, when combined with the covert embedded capacitance, show potential for system in package (SiP) anticounterfeiting applications.

  1. Growth of crystalline Al2O3 via thermal atomic layer deposition: Nanomaterial phase stabilization

    Directory of Open Access Journals (Sweden)

    S. M. Prokes

    2014-03-01

    Full Text Available We report the growth of crystalline Al2O3 thin films deposited by thermal Atomic Layer Deposition (ALD at 200 °C, which up to now has always resulted in the amorphous phase. The 5 nm thick films were deposited on Ga2O3, ZnO, and Si nanowire substrates 100 nm or less in diameter. The crystalline nature of the Al2O3 thin film coating was confirmed using Transmission Electron Microscopy (TEM, including high-resolution TEM lattice imaging, selected area diffraction, and energy filtered TEM. Al2O3 coatings on nanowires with diameters of 10 nm or less formed a fully crystalline phase, while those with diameters in the 20–25 nm range resulted in a partially crystalline coating, and those with diameters in excess of 50 nm were fully amorphous. We suggest that the amorphous Al2O3 phase becomes metastable with respect to a crystalline alumina polymorph, due to the nanometer size scale of the film/substrate combination. Since ALD Al2O3 films are widely used as protective barriers, dielectric layers, as well as potential coatings in energy materials, these findings may have important implications.

  2. Inorganic hollow nanotube aerogels by atomic layer deposition onto native nanocellulose templates.

    Science.gov (United States)

    Korhonen, Juuso T; Hiekkataipale, Panu; Malm, Jari; Karppinen, Maarit; Ikkala, Olli; Ras, Robin H A

    2011-03-22

    Hollow nano-objects have raised interest in applications such as sensing, encapsulation, and drug-release. Here we report on a new class of porous materials, namely inorganic nanotube aerogels that, unlike other aerogels, have a framework consisting of inorganic hollow nanotubes. First we show a preparation method for titanium dioxide, zinc oxide, and aluminum oxide nanotube aerogels based on atomic layer deposition (ALD) on biological nanofibrillar aerogel templates, that is, nanofibrillated cellulose (NFC), also called microfibrillated cellulose (MFC) or nanocellulose. The aerogel templates are prepared from nanocellulose hydrogels either by freeze-drying in liquid nitrogen or liquid propane or by supercritical drying, and they consist of a highly porous percolating network of cellulose nanofibrils. They can be prepared as films on substrates or as freestanding objects. We show that, in contrast to freeze-drying, supercritical drying produces nanocellulose aerogels without major interfibrillar aggregation even in thick films. Uniform oxide layers are readily deposited by ALD onto the fibrils leading to organic-inorganic core-shell nanofibers. We further demonstrate that calcination at 450 °C removes the organic core leading to purely inorganic self-supporting aerogels consisting of hollow nanotubular networks. They can also be dispersed by grinding, for example, in ethanol to create a slurry of inorganic hollow nanotubes, which in turn can be deposited to form a porous film. Finally we demonstrate the use of a titanium dioxide nanotube network as a resistive humidity sensor with a fast response. PMID:21361349

  3. Low temperature platinum atomic layer deposition on nylon-6 for highly conductive and catalytic fiber mats

    Energy Technology Data Exchange (ETDEWEB)

    Mundy, J. Zachary; Shafiefarhood, Arya; Li, Fanxing; Khan, Saad A.; Parsons, Gregory N., E-mail: gnp@ncsu.edu [Department of Chemical and Biomolecular Engineering, North Carolina State University, Engineering Building I, 911 Partners Way, Raleigh, North Carolina 27695-7905 (United States)

    2016-01-15

    Low temperature platinum atomic layer deposition (Pt-ALD) via (methylcyclopentadienyl)trimethyl platinum and ozone (O{sub 3}) is used to produce highly conductive nonwoven nylon-6 (polyamide-6, PA-6) fiber mats, having effective conductivities as high as ∼5500–6000 S/cm with only a 6% fractional increase in mass. The authors show that an alumina ALD nucleation layer deposited at high temperature is required to promote Pt film nucleation and growth on the polymeric substrate. Fractional mass gain scales linearly with Pt-ALD cycle number while effective conductivity exhibits a nonlinear trend with cycle number, corresponding to film coalescence. Field-emission scanning electron microscopy reveals island growth mode of the Pt film at low cycle number with a coalesced film observed after 200 cycles. The metallic coating also exhibits exceptional resistance to mechanical flexing, maintaining up to 93% of unstressed conductivity after bending around cylinders with radii as small as 0.3 cm. Catalytic activity of the as-deposited Pt film is demonstrated via carbon monoxide oxidation to carbon dioxide. This novel low temperature processing allows for the inclusion of highly conductive catalytic material on a number of temperature-sensitive substrates with minimal mass gain for use in such areas as smart textiles and flexible electronics.

  4. Low temperature platinum atomic layer deposition on nylon-6 for highly conductive and catalytic fiber mats

    International Nuclear Information System (INIS)

    Low temperature platinum atomic layer deposition (Pt-ALD) via (methylcyclopentadienyl)trimethyl platinum and ozone (O3) is used to produce highly conductive nonwoven nylon-6 (polyamide-6, PA-6) fiber mats, having effective conductivities as high as ∼5500–6000 S/cm with only a 6% fractional increase in mass. The authors show that an alumina ALD nucleation layer deposited at high temperature is required to promote Pt film nucleation and growth on the polymeric substrate. Fractional mass gain scales linearly with Pt-ALD cycle number while effective conductivity exhibits a nonlinear trend with cycle number, corresponding to film coalescence. Field-emission scanning electron microscopy reveals island growth mode of the Pt film at low cycle number with a coalesced film observed after 200 cycles. The metallic coating also exhibits exceptional resistance to mechanical flexing, maintaining up to 93% of unstressed conductivity after bending around cylinders with radii as small as 0.3 cm. Catalytic activity of the as-deposited Pt film is demonstrated via carbon monoxide oxidation to carbon dioxide. This novel low temperature processing allows for the inclusion of highly conductive catalytic material on a number of temperature-sensitive substrates with minimal mass gain for use in such areas as smart textiles and flexible electronics

  5. Growth of Few-Layer Graphene on Sapphire Substrates by Directly Depositing Carbon Atoms

    Institute of Scientific and Technical Information of China (English)

    KANG Chao-Yang; TANG Jun; LIU Zhong-Liang; LI Li-Min; YAN Wen-Sheng; WEI Shi-Qiang; XU Peng-Shou

    2011-01-01

    Few-layer graphene (FLG) is successfully grown on sapphire substrates by directly depositing carbon atoms at the substrate temperature of 1300℃ in a molecular beam epitaxy chamber.The reflection high energy diffraction,Raman spectroscopy and near-edge x-ray absorption fine structure are used to characterize the sample,which confirm the formation of graphene layers.The mean domain size of FLG is around 29.2 nm and the layer number is about 2-3.The results demonstrate that the grown FLG displays a turbostratic stacking structure similar to that of the FLG produced by annealing C-terminated a-SiC surface.Graphene,a monolayer of sp2-bonded carbon atoms,is a quasi two-dimensional (2D) material.It has attracted great interest because of its distinctive band structure and physical properties.[1] Graphene can now be obtained by several different approaches including micromechanical[1] and chemical[2] exfoliation of graphite,epitaxial growth on hexagonal SiC substrates by Si sublimation in vacuum,[3] and CVD growth on metal substrates.[4] However,these preparation methods need special substrates,otherwise,in order to design microelectronic devices,the prepared graphene should be transferred to other appropriate substrates.Thus the growth of graphene on the suitable substrates is motivated.%Few-layer graphene (FLG) is successfully grown on sapphire substrates by directly depositing carbon atoms at the substrate temperature of 1300℃ in a molecular beam epitaxy chamber. The reflection high energy diffraction, Raman spectroscopy and near-edge x-ray absorption fine structure are used to characterize the sample, which confirm the formation of graphene layers. The mean domain size of FLG is around 29.2nm and the layer number is about 2-3. The results demonstrate that the grown FLG displays a turbostratic stacking structure similar to that of the FLG produced by annealing C-terminated α-SiC surface.

  6. Atomic layer deposition grown composite dielectric oxides and ZnO for transparent electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Gieraltowska, S., E-mail: sgieral@ifpan.edu.pl [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland); Wachnicki, L.; Witkowski, B.S. [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland); Godlewski, M. [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland); Cardinal Stefan Wyszynski University, College of Science, Department of Mathematics and Natural Sciences, Warszawa (Poland); Guziewicz, E. [Polish Academy of Sciences, Institute of Physics, al. Lotnikow 32/46, Warszawa 02-668 (Poland)

    2012-05-01

    In this paper, we report on transparent transistor obtained using laminar structure of two high-k dielectric oxides (hafnium dioxide, HfO{sub 2} and aluminum oxide, Al{sub 2}O{sub 3}) and zinc oxide (ZnO) layer grown at low temperature (60 Degree-Sign C-100 Degree-Sign C) using Atomic Layer Deposition (ALD) technology. Our research was focused on the optimization of technological parameters for composite layers Al{sub 2}O{sub 3}/HfO{sub 2}/Al{sub 2}O{sub 3} for thin film transistor structures with ZnO as a channel and a gate layer. We elaborate on the ALD growth of these oxides, finding that the 100 nm thick layers of HfO{sub 2} and Al{sub 2}O{sub 3} exhibit fine surface flatness and required amorphous microstructure. Growth parameters are optimized for the monolayer growth mode and maximum smoothness required for gating.

  7. Inhibition of Crystal Growth during Plasma Enhanced Atomic Layer Deposition by Applying BIAS

    Directory of Open Access Journals (Sweden)

    Stephan Ratzsch

    2015-11-01

    Full Text Available In this study, the influence of direct current (DC biasing on the growth of titanium dioxide (TiO2 layers and their nucleation behavior has been investigated. Titania films were prepared by plasma enhanced atomic layer deposition (PEALD using Ti(OiPr4 as metal organic precursor. Oxygen plasma, provided by remote inductively coupled plasma, was used as an oxygen source. The TiO2 films were deposited with and without DC biasing. A strong dependence of the applied voltage on the formation of crystallites in the TiO2 layer is shown. These crystallites form spherical hillocks on the surface which causes high surface roughness. By applying a higher voltage than the plasma potential no hillock appears on the surface. Based on these results, it seems likely, that ions are responsible for the nucleation and hillock growth. Hence, the hillock formation can be controlled by controlling the ion energy and ion flux. The growth per cycle remains unchanged, whereas the refractive index slightly decreases in the absence of energetic oxygen ions.

  8. A study of highly crystalline novel beryllium oxide film using atomic layer deposition

    Science.gov (United States)

    Yum, J. H.; Akyol, T.; Lei, M.; Ferrer, D. A.; Hudnall, Todd. W.; Downer, M.; Bielawski, C. W.; Bersuker, G.; Lee, J. C.; Banerjee, S. K.

    2011-11-01

    Beryllium oxide (BeO), which has excellent electrical insulating characteristics and high thermal stability, is a promising gate dielectric and interface passivation layer (IPL), because of its high energy bandgap (10.6 eV) and short bond distance between Be and O atoms. In a previous study, we demonstrated the excellent electrical and physical characteristics of BeO grown after atomic layer deposition (ALD) on Si and GaAs substrates. Here we report, for the first time, ALD growth of crystalline BeO as a potential high-k gate dielectric and IPL. From TEM, SAD, RHEED, and XRD, we have found that highly crystalline BeO thin film may be grown in a wurtzite structure as a (101) plane on a Si (100) oriented surface. We have also investigated a germanium epitaxial layer grown on BeO as a semiconductor-on-insulator (SOI) application, and the crystallinity of BeO on a GaAs (100) substrate for III-V MOS device applications.

  9. Tribological Properties of Nanometric Atomic Layer Depositions Applied on AISI 420 Stainless Steel

    Directory of Open Access Journals (Sweden)

    E. Marin

    2013-09-01

    Full Text Available Atomic Layer Deposition ( ALD is a modern technique that Allows to deposit nanometric, conformal coatings on almost any kind of substrates, from plastics to ceramic, metals or even composites. ALD coatings are not dependent on the morphology of the substrate and are only regulated by the composition of the precursors, the chamber temperature and the number of cycles. In this work, mono- and bi -layer nanometric, protective low-temperature ALD Coatings, based on Al2O3 and TiO2 were applied on AISI 420 Stainless Steel in orderto enhance its relatively low corrosion resistance in chloride containing environments. Tribological testing were also performed on the ALD coated AISI 420 in order to evaluate the wear and scratch resistance of these nanometric layers and thus evaluate their durability. Scratch tests were performed using a standard Rockwell C indenter, under a variable load condition, in order to evaluate the critical loading condition for each coating. Wear testing were performed using a stainless steel counterpart, in ball-on-discconfiguration, in order to measure the friction coefficient and wear to confront the resistance. All scratch tests scars and wear tracks were then observed by means of Scanning Electron Microscopy (SEM in order to understand the wear mechanisms that occurred on the sample surfaces. Corrosion testing, performed under immersion in 0.2 M NaCl solutions, clearly showed that the ALD coatings have a strong effect in protecting the Stainless Steel Substrate against corrosion, reducing the corrosion current density by two orders of magnitude.Tribological The preliminary results showed that ALD depositions obtained at low Temperatures have a brittle behavior caused by the amorphous nature of their structure, and thus undergo delamination phenomena during Scratch Testing at relatively low applied loads. During ball-on-disc testing, the coatings were removed from the substrate, in particular for monolayer ALD configurations

  10. Plasma enhanced atomic layer deposition of magnesium oxide as a passivation layer for enhanced photoluminescence of ZnO nanowires

    International Nuclear Information System (INIS)

    The growth characteristics and film properties of magnesium oxide (MgO) thin films fabricated by plasma enhanced atomic layer deposition (PE-ALD) and thermal ALD (Th-ALD) were comparatively investigated for passivation layer applications. For both processes, well-saturated growth characteristics were observed, with a higher saturated growth rate for Th-ALD. X-ray photoemission analysis showed that very high purity MgO film with virtually no carbon contamination was deposited by PE-ALD. X-ray diffraction and transmission electron microscopy analysis showed that the PE-ALD MgO thin films had a larger grain size than the Th-ALD MgO thin films and were predominantly (1 1 1) crystal orientation. The photoluminescence analysis showed enhanced luminescence properties of the ALD MgO shell/ZnO nanowires. In particular, PE-ALD MgO showed greater enhancement of the luminescence properties than Th-ALD MgO. -- Highlights: • Atomic layer deposition of Magnesium oxide (MgO) thin films were studied using Magnesium bis(cyclopentadienyl) (MgCp2) with H2O and O2 plasma. • PE-ALD MgO thin films show (1 1 1) orientation and have larger grain size than Th-ALD MgO thin films. • Enhanced luminescence properties of the ALD MgO shell/ZnO nanowires are observed. • PE-ALD MgO showed greater enhancement of the luminescence properties than Th-ALD MgO

  11. Crystallization and semiconductor-metal switching behavior of thin VO2 layers grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Crystalline vanadium dioxide (VO2) thin films were prepared by annealing amorphous VO2 films which were deposited by atomic layer deposition on a SiO2 substrate. A large influence of the oxygen partial pressure in the annealing ambient was observed by means of in-situ X-ray diffraction. In the range between 1 and 10 Pa of oxygen the interesting VO2(R) phase crystallized near 450 °C. Between 2 and 10 Pa of oxygen, metastable VO2(B) was observed as an intermediate crystalline phase before it transformed to VO2(R). Anneals in inert gas did not show any crystallization, while oxygen partial pressures above 10 Pa resulted in oxidation into the higher oxide phase V6O13. Film thickness did not have much effect on the crystallization behavior, but thinner films suffered more from agglomeration during the high-temperature crystallization on the SiO2 substrate. Nevertheless, continuous polycrystalline VO2(R) films were obtained with thicknesses down to 11 nm. In the case where VO2(R) was formed, the semiconductor–metal transition was observed by three complementary techniques. This transition near 68 °C was characterized by X-ray diffraction, showing the transformation of the crystal structure, by spectroscopic ellipsometry, mapping optical changes, and by sheet resistance measurements, showing resistance changes larger than 2 orders of magnitude between the low-temperature semiconducting state and the high-temperature metallic state. - Highlights: • Amorphous VO2 films were grown by atomic layer deposition. • Crystallization was studied by means of in-situ X-ray diffraction (XRD). • The optimal oxygen partial pressure during annealing was found to be around 1 Pa. • Continuous crystalline VO2 layers down to 11 nm thickness were obtained at 450 °C. • XRD, ellipsometry and sheet resistance showed the semiconductor–metal transition

  12. Thermoelectric material including conformal oxide layers and method of making the same using atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jung Young; Ahn, Dongjoon; Salvador, James R.; Meisner, Gregory P.

    2016-06-07

    A thermoelectric material includes a substrate particle and a plurality of conformal oxide layers formed on the substrate particle. The plurality of conformal oxide layers has a total oxide layer thickness ranging from about 2 nm to about 20 nm. The thermoelectric material excludes oxide nanoparticles. A method of making the thermoelectric material is also disclosed herein.

  13. Multi-Directional Growth of Aligned Carbon Nanotubes Over Catalyst Film Prepared by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Zhou Kai

    2010-01-01

    Full Text Available Abstract The structure of vertically aligned carbon nanotubes (CNTs severely depends on the properties of pre-prepared catalyst films. Aiming for the preparation of precisely controlled catalyst film, atomic layer deposition (ALD was employed to deposit uniform Fe2O3 film for the growth of CNT arrays on planar substrate surfaces as well as the curved ones. Iron acetylacetonate and ozone were introduced into the reactor alternately as precursors to realize the formation of catalyst films. By varying the deposition cycles, uniform and smooth Fe2O3 catalyst films with different thicknesses were obtained on Si/SiO2 substrate, which supported the growth of highly oriented few-walled CNT arrays. Utilizing the advantage of ALD process in coating non-planar surfaces, uniform catalyst films can also be successfully deposited onto quartz fibers. Aligned few-walled CNTs can be grafted on the quartz fibers, and they self-organized into a leaf-shaped structure due to the curved surface morphology. The growth of aligned CNTs on non-planar surfaces holds promise in constructing hierarchical CNT architectures in future.

  14. Preparation of Supported Metal Catalysts by Atomic and Molecular Layer Deposition for Improved Catalytic Performance

    Science.gov (United States)

    Gould, Troy D.

    Creating catalysts with enhanced selectivity and activity requires precise control over particle shape, composition, and size. Here we report the use of atomic layer deposition (ALD) to synthesize supported Ni, Pt, and Ni-Pt catalysts in the size regime (number of ALD cycles, Ni weight loadings were varied from 4.7 wt% to 16.7 wt% and the average particle sizes ranged from 2.5 to 3.3 nm, which increased the selectivity for C 3H6 hydrogenolysis by an order of magnitude over a much larger Ni/Al2O3 catalyst. Pt particles were deposited by varying the number of ALD cycles and the reaction chemistry (H2 or O 2) to control the particle size from approximately 1 to 2 nm, which allowed lower-coordinated surface atoms to populate the particle surface. These Pt ALD catalysts demonstrated some of the highest oxidative dehydrogenation of propane selectivities (37%) of a Pt catalyst synthesized by a scalable technique. Dry reforming of methane (DRM) is a reaction of interest due to the recent increased recovery of natural gas, but this reaction is hindered from industrial implementation because the Ni catalysts are plagued by deactivation from sintering and coking. This work utilized Ni ALD and NiPt ALD catalysts for the DRM reaction. These catalysts did not form destructive carbon whiskers and had enhanced reaction rates due to increased bimetallic interaction. To further limit sintering, the Ni and NiPt ALD catalysts were coated with a porous alumina matrix by molecular layer deposition (MLD). The catalysts were evaluated for DRM at 973 K, and the MLD-coated Ni catalysts outperformed the uncoated Ni catalysts in either activity (with 5 MLD cycles) or stability (with 10 MLD cycles). In summary, this thesis developed a new Ni nanoparticle ALD chemistry, explored possibilities for changing Pt ALD particle size, brought the two techniques together to create enhanced bimetallic catalysts, and stabilized the catalysts using MLD.

  15. Barrier performance optimization of atomic layer deposited diffusion barriers for organic light emitting diodes using x-ray reflectivity investigations

    International Nuclear Information System (INIS)

    The importance of O3 pulse duration for encapsulation of organic light emitting diodes (OLEDs) with ultra thin inorganic atomic layer deposited Al2O3 layers is demonstrated for deposition temperatures of 50 °C. X-ray reflectivity (XRR) measurements show that O3 pulse durations longer than 15 s produce dense and thin Al2O3 layers. Correspondingly, black spot growth is not observed in OLEDs encapsulated with such layers during 91 days of aging under ambient conditions. This implies that XRR can be used as a tool for process optimization of OLED encapsulation layers leading to devices with long lifetimes

  16. Multilayer Al2O3/TiO2 Atomic Layer Deposition coatings for the corrosion protection of stainless steel

    International Nuclear Information System (INIS)

    Atomic Layer Deposition (ALD) is used to deposit conformal nanometric layers onto different substrates. In this paper, characterization of different ALD layers has been carried out in order to evaluate the suitability of this deposition technolnique for the corrosion protection of stainless steel substrates. Al2O3, TiO2 and multilayer configurations, have been deposited on AISI 316 austenitic stainless steel and have then been investigated using atomic force microscopy (AFM), glow discharge optical emission spectrometry (GDOES), scanning electron microscopy (SEM), Vickers indentation and potentiodynamic polarizations (PP). AFM has been used to obtain a morphological characterization and to evaluate the thickness of the depositions. SEM has been used to investigate the presence of deposition defects. GDOES has been used to obtain a compositional profile. Vickers indentations were used in order to evaluate the resistance to delamination. PPs have been used in order to evaluate the corrosion protection. The results have showed that corrosion resistance can be effectively enhanced. Multilayer configuration proved to be more effective than single layers configurations. - Highlights: ► Atomic Layer Deposition (ALD) coatings with different thicknesses were tested. ► Glow Discharge Optical Emission Spectroscopy gave in-depth composition profiles. ► Corrosion resistance was strongly enhanced by ALD. ► Coating to substrate adhesion was improved for thin and multilayer coatings. ► Multilayer ALD configurations proved to be more protective than single layers.

  17. Atomic layer deposition of zirconium dioxide from zirconium tetrachloride and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Kukli, Kaupo, E-mail: kaupo.kukli@helsinki.fi [Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland); Kemell, Marianna; Köykkä, Joel [Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland); Mizohata, Kenichiro [Accelerator Laboratory, Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki (Finland); Vehkamäki, Marko; Ritala, Mikko; Leskelä, Markku [Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland)

    2015-08-31

    ZrO{sub 2} films were grown by atomic layer deposition using ZrCl{sub 4} and O{sub 3} as precursors. The films were grown on silicon substrates in the temperature range of 220–500 °C. The ALD rate was monotonously decreasing from 0.085 to 0.060 nm/cycle in this temperature range towards the highest temperatures studied. The content of chlorine in the films did not exceed 0.2 at.% as measured by elastic recoil detection analysis. The content of hydrogen was 0.30 and 0.14 at.% in the films grown at 300 and 400 °C, respectively. Structural studies revealed the films consisting of mixtures of stable monoclinic and metastable tetragonal/cubic polymorphs of ZrO{sub 2}, and dominantly metastable phases of ZrO{sub 2} below and above 300 °C, respectively. Permittivity of dielectric layers in Al/Ti/ZrO{sub 2}/(TiN/)Si capacitors with 15–40 nm thick ZrO{sub 2} ranged between 12 and 25 at 100 kHz and the dielectric breakdown fields were in the range of 1.5–3.0 MV/cm. - Highlights: • ZrO{sub 2} thin films were grown by atomic layer deposition from ZrCl{sub 4} and O{sub 3}. • Relatively high substrate temperatures promoted growth of metastable ZrO{sub 2} phases. • ZrO{sub 2} films exhibited electric properties characteristic of dielectric metal oxides. • ZrO{sub 2} grown in hydrogen- and carbon free process contained low amounts of impurities.

  18. Atomic layer deposition of zirconium dioxide from zirconium tetrachloride and ozone

    International Nuclear Information System (INIS)

    ZrO2 films were grown by atomic layer deposition using ZrCl4 and O3 as precursors. The films were grown on silicon substrates in the temperature range of 220–500 °C. The ALD rate was monotonously decreasing from 0.085 to 0.060 nm/cycle in this temperature range towards the highest temperatures studied. The content of chlorine in the films did not exceed 0.2 at.% as measured by elastic recoil detection analysis. The content of hydrogen was 0.30 and 0.14 at.% in the films grown at 300 and 400 °C, respectively. Structural studies revealed the films consisting of mixtures of stable monoclinic and metastable tetragonal/cubic polymorphs of ZrO2, and dominantly metastable phases of ZrO2 below and above 300 °C, respectively. Permittivity of dielectric layers in Al/Ti/ZrO2/(TiN/)Si capacitors with 15–40 nm thick ZrO2 ranged between 12 and 25 at 100 kHz and the dielectric breakdown fields were in the range of 1.5–3.0 MV/cm. - Highlights: • ZrO2 thin films were grown by atomic layer deposition from ZrCl4 and O3. • Relatively high substrate temperatures promoted growth of metastable ZrO2 phases. • ZrO2 films exhibited electric properties characteristic of dielectric metal oxides. • ZrO2 grown in hydrogen- and carbon free process contained low amounts of impurities

  19. Atomic Layer Deposition of a High-k Dielectric on MoS2 Using Trimethylaluminum and Ozone

    OpenAIRE

    Cheng, Lanxia; Qin, Xiaoye; Lucero, Antonio T.; Azcatl, Angelica; Huang, Jie; Wallace, Robert M.; Cho, Kyeongjae; Kim, Jiyoung

    2014-01-01

    We present an Al2O3 dielectric layer on molybdenum disulfide (MoS2), deposited using atomic layer deposition (ALD) with ozone/trimethylaluminum (TMA) and water/TMA as precursors. The results of atomic force microscopy and low-energy ion scattering spectroscopy show that using TMA and ozone as precursors leads to the formation of uniform Al2O3 layers, in contrast to the incomplete coverage we observe when using TMA/H2O as precursors. Our Raman and X-ray photoelectron spectroscopy measurements ...

  20. Roll-to-roll atomic layer deposition process for flexible electronics encapsulation applications

    Energy Technology Data Exchange (ETDEWEB)

    Maydannik, Philipp S., E-mail: philipp.maydannik@lut.fi; Kääriäinen, Tommi O.; Lahtinen, Kimmo; Cameron, David C. [Advanced Surface Technology Research Laboratory, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Söderlund, Mikko; Soininen, Pekka [Beneq Oy, P.O. Box 262, 01511 Vantaa (Finland); Johansson, Petri; Kuusipalo, Jurkka [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 589, 33101 Tampere (Finland); Moro, Lorenza; Zeng, Xianghui [Samsung Cheil Industries, San Jose R and D Center, 2186 Bering Drive, San Jose, California 95131 (United States)

    2014-09-01

    At present flexible electronic devices are under extensive development and, among them, flexible organic light-emitting diode displays are the closest to a large market deployment. One of the remaining unsolved challenges is high throughput production of impermeable flexible transparent barrier layers that protect sensitive light-emitting materials against ambient moisture. The present studies deal with the adaptation of the atomic layer deposition (ALD) process to high-throughput roll-to-roll production using the spatial ALD concept. We report the development of such a process for the deposition of 20 nm thickness Al{sub 2}O{sub 3} diffusion barrier layers on 500 mm wide polymer webs. The process uses trimethylaluminum and water as precursors at a substrate temperature of 105 °C. The observation of self-limiting film growth behavior and uniformity of thickness confirms the ALD growth mechanism. Water vapor transmission rates for 20 nm Al{sub 2}O{sub 3} films deposited on polyethylene naphthalate (PEN) substrates were measured as a function of substrate residence time, that is, time of exposure of the substrate to one precursor zone. Moisture permeation levels measured at 38 °C/90% relative humidity by coulometric isostatic–isobaric method were below the detection limit of the instrument (<5 × 10{sup −4} g/m{sup 2} day) for films coated at web moving speed of 0.25 m/min. Measurements using the Ca test indicated water vapor transmission rates ∼5 × 10{sup −6} g/m{sup 2} day. Optical measurements on the coated web showed minimum transmission of 80% in the visible range that is the same as the original PEN substrate.

  1. Roll-to-roll atomic layer deposition process for flexible electronics encapsulation applications

    International Nuclear Information System (INIS)

    At present flexible electronic devices are under extensive development and, among them, flexible organic light-emitting diode displays are the closest to a large market deployment. One of the remaining unsolved challenges is high throughput production of impermeable flexible transparent barrier layers that protect sensitive light-emitting materials against ambient moisture. The present studies deal with the adaptation of the atomic layer deposition (ALD) process to high-throughput roll-to-roll production using the spatial ALD concept. We report the development of such a process for the deposition of 20 nm thickness Al2O3 diffusion barrier layers on 500 mm wide polymer webs. The process uses trimethylaluminum and water as precursors at a substrate temperature of 105 °C. The observation of self-limiting film growth behavior and uniformity of thickness confirms the ALD growth mechanism. Water vapor transmission rates for 20 nm Al2O3 films deposited on polyethylene naphthalate (PEN) substrates were measured as a function of substrate residence time, that is, time of exposure of the substrate to one precursor zone. Moisture permeation levels measured at 38 °C/90% relative humidity by coulometric isostatic–isobaric method were below the detection limit of the instrument (−4 g/m2 day) for films coated at web moving speed of 0.25 m/min. Measurements using the Ca test indicated water vapor transmission rates ∼5 × 10−6 g/m2 day. Optical measurements on the coated web showed minimum transmission of 80% in the visible range that is the same as the original PEN substrate

  2. Atomic layer deposition of tin oxide and zinc tin oxide using tetraethyltin and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Warner, Ellis J.; Gladfelter, Wayne L., E-mail: wlg@umn.edu [Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Johnson, Forrest; Campbell, Stephen A. [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2015-03-15

    Silicon or glass substrates exposed to sequential pulses of tetraethyltin (TET) and ozone (O{sub 3}) were coated with thin films of SnO{sub 2}. Self-limiting deposition was found using 8 s pulse times, and a uniform thickness per cycle (TPC) of 0.2 nm/cycle was observed in a small, yet reproducible, temperature window from 290 to 320 °C. The as-deposited, stoichiometric SnO{sub 2} films were amorphous and transparent above 400 nm. Interspersing pulses of diethylzinc and O{sub 3} among the TET:O{sub 3} pulses resulted in deposition of zinc tin oxide films, where the fraction of tin, defined as [at. % Sn/(at. % Sn + at. % Zn)], was controlled by the ratio of TET pulses, specifically n{sub TET}:(n{sub TET} + n{sub DEZ}) where n{sub TET} and n{sub DEZ} are the number of precursor/O{sub 3} subcycles within each atomic layer deposition (ALD) supercycle. Based on film thickness and composition measurements, the TET pulse time required to reach saturation in the TPC of SnO{sub 2} on ZnO surfaces was increased to >30 s. Under these conditions, film stoichiometry as a function of the TET pulse ratio was consistent with the model devised by Elliott and Nilsen. The as-deposited zinc tin oxide (ZTO) films were amorphous and remained so even after annealing at 450 °C in air for 1 h. The optical bandgap of the transparent ZTO films increased as the tin concentration increased. Hall measurements established that the n-type ZTO carrier concentration was 3 × 10{sup 17} and 4 × 10{sup 18} cm{sup −3} for fractional tin concentrations of 0.28 and 0.63, respectively. The carrier mobility decreased as the concentration of tin increased. A broken gap pn junction was fabricated using ALD-deposited ZTO and a sputtered layer of cuprous oxide. The junction demonstrated ohmic behavior and low resistance consistent with similar junctions prepared using sputter-deposited ZTO.

  3. Atomic layer deposition of tin oxide and zinc tin oxide using tetraethyltin and ozone

    International Nuclear Information System (INIS)

    Silicon or glass substrates exposed to sequential pulses of tetraethyltin (TET) and ozone (O3) were coated with thin films of SnO2. Self-limiting deposition was found using 8 s pulse times, and a uniform thickness per cycle (TPC) of 0.2 nm/cycle was observed in a small, yet reproducible, temperature window from 290 to 320 °C. The as-deposited, stoichiometric SnO2 films were amorphous and transparent above 400 nm. Interspersing pulses of diethylzinc and O3 among the TET:O3 pulses resulted in deposition of zinc tin oxide films, where the fraction of tin, defined as [at. % Sn/(at. % Sn + at. % Zn)], was controlled by the ratio of TET pulses, specifically nTET:(nTET + nDEZ) where nTET and nDEZ are the number of precursor/O3 subcycles within each atomic layer deposition (ALD) supercycle. Based on film thickness and composition measurements, the TET pulse time required to reach saturation in the TPC of SnO2 on ZnO surfaces was increased to >30 s. Under these conditions, film stoichiometry as a function of the TET pulse ratio was consistent with the model devised by Elliott and Nilsen. The as-deposited zinc tin oxide (ZTO) films were amorphous and remained so even after annealing at 450 °C in air for 1 h. The optical bandgap of the transparent ZTO films increased as the tin concentration increased. Hall measurements established that the n-type ZTO carrier concentration was 3 × 1017 and 4 × 1018 cm−3 for fractional tin concentrations of 0.28 and 0.63, respectively. The carrier mobility decreased as the concentration of tin increased. A broken gap pn junction was fabricated using ALD-deposited ZTO and a sputtered layer of cuprous oxide. The junction demonstrated ohmic behavior and low resistance consistent with similar junctions prepared using sputter-deposited ZTO

  4. Fluidized bed coupled rotary reactor for nanoparticles coating via atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Chen-Long; Liu, Xiao; Chen, Rong, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Shan, Bin, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)

    2015-07-15

    A fluidized bed coupled rotary reactor has been designed for coating on nanoparticles (NPs) via atomic layer deposition. It consists of five major parts: reaction chamber, dosing and fluidizing section, pumping section, rotary manipulator components, as well as a double-layer cartridge for the storage of particles. In the deposition procedure, continuous fluidization of particles enlarges and homogenizes the void fraction in the particle bed, while rotation enhances the gas-solid interactions to stabilize fluidization. The particle cartridge presented here enables both the fluidization and rotation acting on the particle bed, demonstrated by the analysis of pressure drop. Moreover, enlarged interstitials and intense gas–solid contact under sufficient fluidizing velocity and proper rotation speed facilitate the precursor delivery throughout the particle bed and consequently provide a fast coating process. The cartridge can ensure precursors flowing through the particle bed exclusively to achieve high utilization without static exposure operation. By optimizing superficial gas velocities and rotation speeds, minimum pulse time for complete coating has been shortened in experiment, and in situ mass spectrometry showed the precursor usage can reach 90%. Inductively coupled plasma-optical emission spectroscopy results suggested a saturated growth of nanoscale Al{sub 2}O{sub 3} films on spherical SiO{sub 2} NPs. Finally, the uniformity and composition of the shells were characterized by high angle annular dark field-transmission electron microscopy and energy dispersive X-ray spectroscopy.

  5. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    International Nuclear Information System (INIS)

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al2O3 layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al2O3 films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed

  6. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    Energy Technology Data Exchange (ETDEWEB)

    Dechana, A. [Program of Physics and General Science, Faculty of Science and Technology, Songkhla Rajabhat University, Songkhla 90000 (Thailand); Thamboon, P. [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand); Boonyawan, D., E-mail: dheerawan.b@cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-10-15

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al{sub 2}O{sub 3} layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al{sub 2}O{sub 3} films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

  7. Fluidized bed coupled rotary reactor for nanoparticles coating via atomic layer deposition

    International Nuclear Information System (INIS)

    A fluidized bed coupled rotary reactor has been designed for coating on nanoparticles (NPs) via atomic layer deposition. It consists of five major parts: reaction chamber, dosing and fluidizing section, pumping section, rotary manipulator components, as well as a double-layer cartridge for the storage of particles. In the deposition procedure, continuous fluidization of particles enlarges and homogenizes the void fraction in the particle bed, while rotation enhances the gas-solid interactions to stabilize fluidization. The particle cartridge presented here enables both the fluidization and rotation acting on the particle bed, demonstrated by the analysis of pressure drop. Moreover, enlarged interstitials and intense gas–solid contact under sufficient fluidizing velocity and proper rotation speed facilitate the precursor delivery throughout the particle bed and consequently provide a fast coating process. The cartridge can ensure precursors flowing through the particle bed exclusively to achieve high utilization without static exposure operation. By optimizing superficial gas velocities and rotation speeds, minimum pulse time for complete coating has been shortened in experiment, and in situ mass spectrometry showed the precursor usage can reach 90%. Inductively coupled plasma-optical emission spectroscopy results suggested a saturated growth of nanoscale Al2O3 films on spherical SiO2 NPs. Finally, the uniformity and composition of the shells were characterized by high angle annular dark field-transmission electron microscopy and energy dispersive X-ray spectroscopy

  8. Fabrication of AlN/BN bishell hollow nanofibers by electrospinning and atomic layer deposition

    Directory of Open Access Journals (Sweden)

    Ali Haider

    2014-09-01

    Full Text Available Aluminum nitride (AlN/boron nitride (BN bishell hollow nanofibers (HNFs have been fabricated by successive atomic layer deposition (ALD of AlN and sequential chemical vapor deposition (CVD of BN on electrospun polymeric nanofibrous template. A four-step fabrication process was utilized: (i fabrication of polymeric (nylon 6,6 nanofibers via electrospinning, (ii hollow cathode plasma-assisted ALD of AlN at 100 °C onto electrospun polymeric nanofibers, (iii calcination at 500 °C for 2 h in order to remove the polymeric template, and (iv sequential CVD growth of BN at 450 °C. AlN/BN HNFs have been characterized for their chemical composition, surface morphology, crystal structure, and internal nanostructure using X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction. Measurements confirmed the presence of crystalline hexagonal BN and AlN within the three dimensional (3D network of bishell HNFs with relatively low impurity content. In contrast to the smooth surface of the inner AlN layer, outer BN coating showed a highly rough 3D morphology in the form of BN nano-needle crystallites. It is shown that the combination of electrospinning and plasma-assisted low-temperature ALD/CVD can produce highly controlled multi-layered bishell nitride ceramic hollow nanostructures. While electrospinning enables easy fabrication of nanofibrous template, self-limiting reactions of plasma-assisted ALD and sequential CVD provide control over the wall thicknesses of AlN and BN layers with sub-nanometer accuracy.

  9. AxBAxB… pulsed atomic layer deposition: Numerical growth model and experiments

    Science.gov (United States)

    Muneshwar, Triratna; Cadien, Ken

    2016-02-01

    Atomic layer deposition (ALD) is widely used for the fabrication of advanced semiconductor devices and related nanoscale structures. During ALD, large precursor doses (>1000 L per pulse) are often required to achieve surface saturation, of which only a small fraction is utilized in film growth while the rest is pumped from the system. Since the metal precursor constitutes a significant cost of ALD, strategies to enhance precursor utilization are essential for the scaling of ALD processes. In the precursor reaction step, precursor physisorption is restricted by steric hindrance (mA1) from ligands on the precursor molecules. On reaction, some of these ligands are removed as by-products resulting in chemisorbed species with reduced steric hindrance (mA1 → mA2, where mA2 1, x ∈ I) short-pulses rather than a single pulse. A numerical first-order surface reaction kinetics growth model is presented and applied to study the effect of AxBAxB… pulsed ALD on the growth per cycle (GPC). The model calculations predict higher GPC for AxBAxB… pulsing than with ABAB… deposition. In agreement with the model predictions, with AxBAxB… pulsed deposition, the GPC was found to increase by ˜46% for ZrN plasma enhanced ALD (PEALD), ˜49% for HfO2 PEALD, and ˜8% for thermal Al2O3 ALD with respect to conventional ABAB… pulsed growth.

  10. Controllable atomic layer deposition of one-dimensional nanotubular TiO2

    Science.gov (United States)

    Meng, Xiangbo; Banis, Mohammad Norouzi; Geng, Dongsheng; Li, Xifei; Zhang, Yong; Li, Ruying; Abou-Rachid, Hakima; Sun, Xueliang

    2013-02-01

    This study aimed at synthesizing one-dimensional (1D) nanostructures of TiO2 using atomic layer deposition (ALD) on anodic aluminum oxide (AAO) templates and carbon nanotubes (CNTs). The precursors used are titanium tetraisopropoxide (TTIP, Ti(OCH(CH3)2)4) and deionized water. It was found that the morphologies and structural phases of as-deposited TiO2 are controllable through adjusting cycling numbers of ALD and growth temperatures. Commonly, a low temperature (150 °C) produced amorphous TiO2 while a high temperature (250 °C) led to crystalline anatase TiO2 on both AAO and CNTs. In addition, it was revealed that the deposition of TiO2 is also subject to the influences of the applied substrates. The work well demonstrated that ALD is a precise route to synthesize 1D nanostructures of TiO2. The resultant nanostructured TiO2 can be important candidates in many applications, such as water splitting, solar cells, lithium-ion batteries, and gas sensors.

  11. Patterning of Solid Films via Selective Atomic Layer Deposition Based on Silylation and UV/Ozonolysis.

    Science.gov (United States)

    Guo, Lei; Lee, Ilkeun; Zaera, Francisco

    2016-08-01

    A simple methodology was successfully demonstrated for the nanoscale patterning of silicon wafers. Thin films are grown by atomic layer deposition (ALD) and patterned by using selective surface chemistry: First, all the nucleation sites on the original oxide surface are silylated in order to render them unreactive; then, a pattern is developed by selective removal of the silylation agent using a mask and a combination of ultraviolet radiation and ozonolysis. Subsequent ALD is carried out selectively on the areas where the silylation moieties have been removed. This simple procedure affords patterning of oxide surfaces with monolayer control and a lateral resolution on the order of a few tens of nanometers or better. Other selective ALD processes have shown only limited discrimination during deposition, but our method shows absolute inhibition of film growth on the silylated areas while films as thick as 10 nm are grown on the re-exposed sectors. Our example involved the deposition of hafnium oxide films on the native silicon oxide film that forms on Si(100) wafers, but we believe that the approach is general and easily extendable to other ALD processes. PMID:27455137

  12. In situ gas phase measurements during metal alkylamide atomic layer deposition.

    Science.gov (United States)

    Maslar, J E; Kimes, W A; Sperling, B A

    2011-09-01

    Metal alkylamide compounds, such as tetrakis(ethylmethylamido) hafnium (TEMAH), represent a technologically important class of metalorganic precursors for the deposition of metal oxides and metal nitrides via atomic layer deposition (ALD) or chemical vapor deposition. The development of in situ diagnostics for processes involving these compounds could be beneficial in, e.g., developing deposition recipes and validating equipment-scale simulations. This report describes the performance of the combination of two techniques for the simultaneous, rapid measurement of the three major gas phase species during hafnium oxide thermal ALD using TEMAH and water: TEMAH, water, and methylethyl amine (MEA), the only major reaction by-product. For measurement of TEMAH and MEA, direct absorption methods based on a broadband infrared source with different mid-IR bandpass filters and utilizing amplitude modulation and synchronous detection were developed. For the measurement of water, wavelength modulation spectroscopy utilizing a near-IR distributed feedback diode laser was used. Despite the relatively simple reactor geometry employed here (a flow tube), differences were easily observed in the time-dependent species distributions in 300 mL/min of a helium carrier gas and in 1000 mL/min of a nitrogen carrier gas. The degree of TEMAH entrainment was lower in 300 mL/min of helium compared to that in 1000 mL/min of nitrogen. The capability to obtain detailed time-dependent species concentrations during ALD could potentially allow for the selection of carrier gas composition and flow rates that would minimize parasitic wall reactions. However, when nitrogen was employed at the higher flow rates, various flow effects were observed that, if detrimental to a deposition process, would effectively limit the upper range of useful flow rates. PMID:22097559

  13. Influence of different oxidants on the band alignment of HfO2 films deposited by atomic layer deposition

    Institute of Scientific and Technical Information of China (English)

    Fan Ji-Bin; Liu Hong-Xia; Gao Bo; Ma Fei; Zhuo Qing-Qing; Hao Yue

    2012-01-01

    Based on X-ray photoelectron spectroscopy (XPS),influences of different oxidants on band alignment of HfO2 films deposited by atomic layer deposition (ALD) are investigated in this paper.The measured valence band offset (VBO) value for H2O-based HfO2 increases from 3.17 eV to 3.32 eV after annealing,whereas the VBO value for O3-based HfO2 decreases from 3.57 eV to 3.46 eV.The research results indicate that the silicate layer changes in different ways for H2O-based and O3-based HfO2 films after the annealing process,which plays a key role in generating the internal electric field formed by the dipoles.The variations of the dipoles at the interface between the HfO2 and SiO2 after annealing may lead the VBO values of H2O-based and O3-based HfO2 to vary in different ways,which fits with the variation of fiat band (VFB) voltage.

  14. Zinc oxide grown by atomic layer deposition - a material for novel 3D electronics

    Energy Technology Data Exchange (ETDEWEB)

    Guziewicz, Elzbieta; Krajewski, Tomasz A.; Wachnicki, Lukasz; Luka, Grzegorz; Domagala, Jaroslaw Z.; Paszkowicz, Wojciech; Kowalski, Bogdan J.; Witkowski, Bartlomiej S.; Suchocki, Andrzej [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Godlewski, Marek [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science Cardinal Stefan Wyszynski University, Warsaw (Poland); Duzynska, Anna [Department of Mathematics and Natural Sciences, College of Science Cardinal Stefan Wyszynski University, Warsaw (Poland)

    2010-07-15

    Last years we observe a booming interest in materials which can be successfully grown at low temperature limits showing good structural and electrical characteristics. This trend is closely related to the novel three-dimensional (3D) architecture which seems to be a prospective solution for miniaturization of electronic devices after the 22 nm node. We demonstrate that electrical parameters of ZnO grown by the atomic layer deposition (ALD) method at low temperature limit (100-200 C) fulfil requirements for 3D electronic devices, because electron carrier mobility is above 10 cm{sup 2}/Vs and n concentration at the level of 1 x 10{sup 17} cm{sup -3}. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  15. Using atomic layer deposited tungsten to increase thermal conductivity of a packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Van Norman, Staci A.; Falconer, John L.; Weimer, Alan W., E-mail: alan.weimer@colorado.edu [Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309-0596 (United States); Tringe, Joseph W.; Sain, John D. [Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California 94550 (United States); Yang, Ronggui [Department of Mechanical Engineering, University of Colorado, UCB 427, Boulder, Colorado 80309-0427 (United States)

    2015-04-13

    This study investigated the effective thermal conductivity (k{sub eff}) of packed-beds that contained porous particles with nanoscale tungsten (W) films of different thicknesses formed by atomic layer deposition (ALD). A continuous film on the particles is vital towards increasing k{sub eff} of the packed beds. For example, the k{sub eff} of an alumina packed bed was increased by three times after an ∼8-nm continuous W film with 20 cycles of W ALD, whereas k{sub eff} was decreased on a polymer packed bed with discontinuous, evenly dispersed W-islands due to nanoparticle scattering of phonons. For catalysts, understanding the thermal properties of these packed beds is essential for developing thermally conductive supports as alternatives to structured supports.

  16. Atmospheric pressure spatial atomic layer deposition web coating with in situ monitoring of film thickness

    International Nuclear Information System (INIS)

    Spectral reflectometry was implemented as a method for in situ thickness monitoring in a spatial atomic layer deposition (ALD) system. Al2O3 films were grown on a moving polymer web substrate at 100 °C using an atmospheric pressure ALD web coating system, with film growth of 0.11–0.13 nm/cycle. The modular coating head design and the in situ monitoring allowed for the characterization and optimization of the trimethylaluminum and water precursor exposures, purge flows, and web speed. A thickness uniformity of ±2% was achieved across the web. ALD cycle times as low as 76 ms were demonstrated with a web speed of 1 m/s and a vertical gap height of 0.5 mm. This atmospheric pressure ALD system with in situ process control demonstrates the feasibility of low-cost, high throughput roll-to-roll ALD

  17. Building a Better Capacitor with Thin-Film Atomic Layer Deposition Processing

    Energy Technology Data Exchange (ETDEWEB)

    Pike, Christopher [North Seattle College, WA (United States)

    2015-08-28

    The goal of this research is to determine procedures for creating ultra-high capacity supercapacitors by using nanofabrication techniques and high k-value dielectrics. One way to potentially solve the problem of climate change is to switch the source of energy to a source that doesn’t release many tons of greenhouse gases, gases which cause global warming, into the Earth’s atmosphere. These trap in more heat from the Sun’s solar energy and cause global temperatures to rise. Atomic layer deposition will be used to create a uniform thin-film of dielectric to greatly enhance the abilities of our capacitors and will build them on the nanoscale.

  18. Preparation of ZnO films with variable electric field-assisted atomic layer deposition technique

    International Nuclear Information System (INIS)

    The ZnO films have been prepared by a variable electric field-assisted atomic layer deposition method (ALD). By applying electric fields during the precursor pulses, we can modulate both the crystal orientation and structure of the obtained ZnO films. The ZnO films with c-axis preferred orientation and the least oxygen vacancy defect were obtained when the holder electric polarities were positive and negative during the DEZn and H2O pulse, respectively. It is supported that when electric field was applied in the chamber, the torque may lead to the precursor molecular alignments along the electric field direction, which could affect the film growth process and then influence their structures and properties. This variable electric field-assisted ALD approach would provide an efficient protocol for the growth of semiconductor films with designed properties.

  19. Using atomic layer deposited tungsten to increase thermal conductivity of a packed bed

    International Nuclear Information System (INIS)

    This study investigated the effective thermal conductivity (keff) of packed-beds that contained porous particles with nanoscale tungsten (W) films of different thicknesses formed by atomic layer deposition (ALD). A continuous film on the particles is vital towards increasing keff of the packed beds. For example, the keff of an alumina packed bed was increased by three times after an ∼8-nm continuous W film with 20 cycles of W ALD, whereas keff was decreased on a polymer packed bed with discontinuous, evenly dispersed W-islands due to nanoparticle scattering of phonons. For catalysts, understanding the thermal properties of these packed beds is essential for developing thermally conductive supports as alternatives to structured supports

  20. Spectroscopic investigation of the electronic structure of thin atomic layer deposition HfO2 films

    International Nuclear Information System (INIS)

    The electronic structure of HfO2 thin films is investigated employing resonant photoelectron spectroscopy (resPES). The detailed analysis of the O1s resonance profile enables the determination of the partial density of states for the valence and the conduction bands as well as the electronic band gap to be 6.2 eV. The position of the charge neutrality level is evaluated. Thereby, it is demonstrated that the resPES data are able to combine information both for the valence as well as for the conduction band states. In addition, evidences for intrinsic in-gap states attributed to polaronic and charge transfer states are given. Electronic charges within the atomic layer deposition-HfO2 films are identified, pointing out that the amount of charges is essential to determine the accurate position of the surface potentials

  1. Plasma-enhanced atomic layer deposition of titanium oxynitrides films: A comparative spectroscopic and electrical study

    International Nuclear Information System (INIS)

    The process parameters' impact of the plasma-enhanced atomic layer deposition (PE-ALD) method on the oxygen to nitrogen (O/N) ratio in titanium oxynitride (TiOxNy) films was studied. Titanium(IV)isopropoxide in combination with NH3 plasma and tetrakis(dimethylamino)titanium by applying N2 plasma processes were investigated. Samples were characterized by the in situ spectroscopic ellipsometry, x-ray photoelectron spectroscopy, and electrical characterization (current–voltage: I-V and capacitance–voltage: C-V) methods. The O/N ratio in the TiOxNy films is found to be very sensitive for their electric properties such as conductivity, dielectric breakdown, and permittivity. Our results indicate that these PE-ALD film properties can be tuned, via the O/N ratio, by the selection of the process parameters and precursor/coreactant combination

  2. Large-area thermoelectric high-aspect-ratio nanostructures by atomic layer deposition

    Science.gov (United States)

    Ruoho, Mikko; Juntunen, Taneli; Tittonen, Ilkka

    2016-09-01

    We report on the thermoelectric properties of large-area high-aspect-ratio nanostructures. We fabricate the structures by atomic layer deposition of conformal ZnO thin films on track-etched polycarbonate substrate. The resulting structure consists of ZnO tubules which continue through the full thickness of the substrate. The electrical and thermal properties of the structures are studied both in-plane and out-of-plane. They exhibit very low out-of-plane thermal conductivity down to 0.15 W m‑1 K‑1 while the in-plane sheet resistance of the films was found to be half that of the same film on glass substrate, allowing material-independent doubling of output power of any planar thin-film thermoelectric generator. The wall thickness of the fabricated nanotubes was varied within a range of up to 100 nm. The samples show polycrystalline nature with (002) preferred crystal orientation.

  3. Temperature-dependent magnetic properties of Ni nanotubes synthesized by atomic layer deposition

    Science.gov (United States)

    Pereira, Alejandro; Palma, Juan L.; Denardin, Juliano C.; Escrig, Juan

    2016-08-01

    Highly-ordered and conformal Ni nanotube arrays were prepared by combining atomic layer deposition (ALD) in a porous alumina matrix with a subsequent thermal reduction process. In order to obtain NiO tubes, one ALD NiCp2/O3 cycle was repeated 2000 times. After the ALD process, the sample is reduced from NiO to metallic Ni under hydrogen atmosphere. Their magnetic properties such as coercivity and squareness have been determined in a vibrating sample magnetometer in the temperature range from 5–300 K for applied magnetic fields parallel and perpendicular to the nanotube axis. Ni nanotubes synthesized by ALD provide a promising opportunity for potential applications in spintronics, data storage and bio-applications.

  4. Improved efficiency of aluminum doping in ZnO thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hui Kyung; Heo, Jaeyeong, E-mail: jheo@jnu.ac.kr

    2014-08-01

    The improved efficiency of aluminum doping in ZnO (AZO) thin films grown by atomic layer deposition was demonstrated by controlling the number of surface reaction sites for trimethylalumium (TMA). Prolonged purge time (120 s) for deionized water used as an oxidant decreased the number of hydroxyl groups on the surface via dehydration reaction, resulting in the reduced chemisorption of TMA. The enhanced doping efficiency by sparse distribution of Al dopants was demonstrated by the increased carrier concentration from ~4 × 10²⁰ to ~6 × 10²⁰ cm⁻³ for the same Al doping cycle ratio. A comparison was made among the AZO films formed by using the control and modified recipes, focusing on their electrical, structural, and optical properties.

  5. Interface control of atomic layer deposited oxide coatings by filtered cathodic arc deposited sublayers for improved corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Härkönen, Emma, E-mail: emma.harkonen@helsinki.fi [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Tervakangas, Sanna; Kolehmainen, Jukka [DIARC-Technology Inc., Espoo (Finland); Díaz, Belén; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7075) – Chimie ParisTech (ENSCP), F-75005 Paris (France); Fenker, Martin [FEM Research Institute, Precious Metals and Metals Chemistry, D-73525 Schwäbisch Gmünd (Germany); Tóth, Lajos; Radnóczi, György [Research Centre for Natural Sciences HAS, (MTA TKK), Budapest (Hungary); Ritala, Mikko [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland)

    2014-10-15

    Sublayers grown with filtered cathodic arc deposition (FCAD) were added under atomic layer deposited (ALD) oxide coatings for interface control and improved corrosion protection of low alloy steel. The FCAD sublayer was either Ta:O or Cr:O–Ta:O nanolaminate, and the ALD layer was Al{sub 2}O{sub 3}–Ta{sub 2}O{sub 5} nanolaminate, Al{sub x}Ta{sub y}O{sub z} mixture or graded mixture. The total thicknesses of the FCAD/ALD duplex coatings were between 65 and 120 nm. Thorough analysis of the coatings was conducted to gain insight into the influence of the FCAD sublayer on the overall coating performance. Similar characteristics as with single FCAD and ALD coatings on steel were found in the morphology and composition of the duplex coatings. However, the FCAD process allowed better control of the interface with the steel by reducing the native oxide and preventing its regrowth during the initial stages of the ALD process. Residual hydrocarbon impurities were buried in the interface between the FCAD layer and steel. This enabled growth of ALD layers with improved electrochemical sealing properties, inhibiting the development of localized corrosion by pitting during immersion in acidic NaCl and enhancing durability in neutral salt spray testing. - Highlights: • Corrosion protection properties of ALD coatings were improved by FCAD sublayers. • The FCAD sublayer enabled control of the coating-substrate interface. • The duplex coatings offered improved sealing properties and durability in NSS. • The protective properties were maintained during immersion in a corrosive solution. • The improvements were due to a more ideal ALD growth on the homogeneous FCAD oxide.

  6. Morphology and crystallinity control of ultrathin TiO2 layers deposited on carbon nanotubes by temperature-step atomic layer deposition

    Science.gov (United States)

    Guerra-Nuñez, Carlos; Zhang, Yucheng; Li, Meng; Chawla, Vipin; Erni, Rolf; Michler, Johann; Park, Hyung Gyu; Utke, Ivo

    2015-06-01

    Carbon nanotubes (CNTs) coated with titanium oxide (TiO2) have generated considerable interest over the last decade and become a promising nanomaterial for a wide range of energy applications. The efficient use of the outstanding electrical properties of this nanostructure relies heavily on the quality of the interface and the thickness and morphology of the TiO2 layer. However, complete surface coverage of the chemically inert CNTs and appropriate control of the morphology of the TiO2 layer have not been achieved so far. Here, we report a new strategy to obtain ultrathin TiO2 coatings deposited by ``Temperature-step'' Atomic Layer Deposition (TS-ALD) with complete surface coverage of non-functionalized multiwall carbon nanotubes (MWCNTs) and controlled morphology and crystallinity of the TiO2 film. This strategy consists of adjusting the temperature during the ALD deposition to obtain the desired morphology. Complete coverage of long non-functionalized MWCNTs with conformal anatase layers was obtained by using a low temperature of 60 °C during the nucleation stage followed by an increase to 220 °C during the growth stage. This resulted in a continuous and amorphous TiO2 layer, covered with a conformal anatase coating. Starting with the deposition at 220 °C and reducing to 60 °C resulted in sporadic crystal grains at the CNT/TiO2 interface covered with an amorphous TiO2 layer. The results were accomplished through an extensive study of nucleation and growth of titanium oxide films on MWCNTs, of which a detailed characterization is presented in this work.Carbon nanotubes (CNTs) coated with titanium oxide (TiO2) have generated considerable interest over the last decade and become a promising nanomaterial for a wide range of energy applications. The efficient use of the outstanding electrical properties of this nanostructure relies heavily on the quality of the interface and the thickness and morphology of the TiO2 layer. However, complete surface coverage of the

  7. Photoluminescence of atomic layer deposited ZrO{sub 2}:Dy{sup 3+} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kiisk, Valter, E-mail: valter.kiisk@ut.ee; Tamm, Aile; Utt, Kathriin; Kozlova, Jekaterina; Mändar, Hugo; Puust, Laurits; Aarik, Jaan; Sildos, Ilmo

    2015-05-29

    Atomic layer deposition based on alternate cycling of ZrCl{sub 4}, Dy(thd){sub 3} and H{sub 2}O as precursors was applied for preparation of nanocrystalline ZrO{sub 2}:Dy thin films. Photoluminescence (PL) properties of Dy{sup 3+} in the ZrO{sub 2} films were studied at several laser excitations. Substantial activation of Dy{sup 3+} PL required thermal treatment at 900 °C. As a result of annealing, thinner (~ 80 nm) films with higher Dy content retained relatively high amount of tetragonal phase and remained crack-free. In thicker (~ 140 nm) films, considerable amount of monoclinic phase was formed and a peculiar microscale cracking pattern was developed along with phase segregation. It is demonstrated that the crystal structure of ZrO{sub 2} significantly influences the Dy{sup 3+} emission spectrum and, at least for ZrO{sub 2}-type matrices, Dy{sup 3+} is an excellent luminescent microprobe in comparison with micro-Raman scattering. A Förster-like PL decay profile allowed a conclusion that the self-quenching due to cross-relaxation between Dy{sup 3+} ions had a marked impact on emission intensity. - Highlights: • Atomic layer deposition of luminescent Dy-doped ZrO{sub 2} thin films was demonstrated. • Dy{sup 3+} luminescence was significantly activated only after high-temperature annealing. • Correlation between luminescent and structural properties was obtained. • Dy{sup 3+} luminescent probe showed superior performance compared to Raman-scattering. • Presence of several quenching processes was deduced from luminescence behavior.

  8. Influences of different oxidants on the characteristics of HfAlOx films deposited by atomic layer deposition

    Institute of Scientific and Technical Information of China (English)

    Fan Ji-Bin; Liu Hong-Xia; Ma Fei; Zhuo Qing-Qing; Hao Yue

    2013-01-01

    A comparative study of two kinds of oxidants (H2O and O3) with the combinations of two metal precursors [trimethylaluminum (TMA) and tetrakis(ethylmethylamino) hafnium (TEMAH)] for atomic layer deposition (ALD) hafnium aluminum oxide (HfAlOx) films is carried out.The effects of different oxidants on the physical properties and electrical characteristics of HfAlOx films are studied.The preliminary testing results indicate that the impurity level of HfAlOx films grown with both H2O and O3 used as oxidants can be well controlled,which has significant effects on the dielectric constant,valence band,electrical properties,and stability of HfAlOx film.Additional thermal annealing effects on the properties of HfAlOx films grown with different oxidants are also investigated.

  9. Thermal chemistry of the Cu-KI5 atomic layer deposition precursor on a copper surface

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qiang; Zaera, Francisco, E-mail: zaera@ucr.edu [Department of Chemistry, University of California, Riverside, California 92521 (United States)

    2015-01-01

    The thermal chemistry of a Cu(I) ketoiminate complex, Cu-KI5, resulting from the modification of the known Air Products CupraSelect{sup ®} copper CVD precursor Cu(hfac)(tmvs) designed to tether the two ligands via an isopropoxide linker, was studied under ultrahigh vacuum on a Cu(110) single-crystal surface by using a combination of temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy. Adsorption at low temperatures was determined to take place via the displacement of the vinyl ligand by the surface. Molecular desorption was seen at 210 K, and the evolution of Cu(II)-KI5{sub 2} was established to take place at 280 K, presumably from a disproportionation reaction that also leads to the deposition of Cu(0). Other sets of desorption products were seen at 150, 250, and 430 K, all containing copper atoms and small organic moieties with molecular masses below 100 amu. The latter TPD peak in particular indicates significant fragmentation of the ligands, likely at the C–N bond that holds the vinylsilane-isopropoxide moiety tethered to the ketoimine fragment, and possibly also at the union between the vinylsilane and the alkoxide linker. The 430 K temperature measured for this chemistry may set an upper limit for clean Cu film deposition, but since reactivity on the surface was also found to be inhibited at higher surface coverages, it may be delayed to higher temperatures under atomic layer deposition conditions.

  10. In-situ atomic layer deposition growth of Hf-oxide

    International Nuclear Information System (INIS)

    We have grown HfO2 on Si(001) by atomic layer deposition (ALD) using HfCl4, TEMAHf, TDMAHf and H2O as precursors. The early stages of the ALD were investigated with high-resolution photoelectron spectroscopy and X-ray absorption spectroscopy. We observed the changes occurring in the Si 2p, O 1s, Hf 4f, Hf 4d, and Cl 2p (for HfCl4 experiment) core level lines after each ALD cycle up to the complete formation of two layers of HfO2. The investigation was carried out in situ giving the possibility to determine the properties of the grown film after every ALD cycle or even after a half cycle. This work focused on the advantages in-situ approach in comparison with ex-situ experiments. The study provides to follow the evolution of the important properties of HfO2: contamination level, density and stoichiometry, and influence of the experimental parameters to the interface layer formation during ALD. Our investigation shows that in-situ XPS approach for ALD gives much more information than ex-situ experiments. (orig.)

  11. In-situ atomic layer deposition growth of Hf-oxide

    Energy Technology Data Exchange (ETDEWEB)

    Karavaev, Konstantin

    2010-06-17

    We have grown HfO{sub 2} on Si(001) by atomic layer deposition (ALD) using HfCl{sub 4}, TEMAHf, TDMAHf and H{sub 2}O as precursors. The early stages of the ALD were investigated with high-resolution photoelectron spectroscopy and X-ray absorption spectroscopy. We observed the changes occurring in the Si 2p, O 1s, Hf 4f, Hf 4d, and Cl 2p (for HfCl{sub 4} experiment) core level lines after each ALD cycle up to the complete formation of two layers of HfO{sub 2}. The investigation was carried out in situ giving the possibility to determine the properties of the grown film after every ALD cycle or even after a half cycle. This work focused on the advantages in-situ approach in comparison with ex-situ experiments. The study provides to follow the evolution of the important properties of HfO{sub 2}: contamination level, density and stoichiometry, and influence of the experimental parameters to the interface layer formation during ALD. Our investigation shows that in-situ XPS approach for ALD gives much more information than ex-situ experiments. (orig.)

  12. Wafer-scale growth of MoS2 thin films by atomic layer deposition

    Science.gov (United States)

    Pyeon, Jung Joon; Kim, Soo Hyun; Jeong, Doo Seok; Baek, Seung-Hyub; Kang, Chong-Yun; Kim, Jin-Sang; Kim, Seong Keun

    2016-05-01

    The wafer-scale synthesis of MoS2 layers with precise thickness controllability and excellent uniformity is essential for their application in the nanoelectronics industry. Here, we demonstrate the atomic layer deposition (ALD) of MoS2 films with Mo(CO)6 and H2S as the Mo and S precursors, respectively. A self-limiting growth behavior is observed in the narrow ALD window of 155-175 °C. Long H2S feeding times are necessary to reduce the impurity contents in the films. The as-grown MoS2 films are amorphous due to the low growth temperature. Post-annealing at high temperatures under a H2S atmosphere efficiently improves the film properties including the crystallinity and chemical composition. An extremely uniform film growth is achieved even on a 4 inch SiO2/Si wafer. These results demonstrate that the current ALD process is well suited for the synthesis of MoS2 layers for application in industry.

  13. Wafer-scale growth of MoS2 thin films by atomic layer deposition.

    Science.gov (United States)

    Pyeon, Jung Joon; Kim, Soo Hyun; Jeong, Doo Seok; Baek, Seung-Hyub; Kang, Chong-Yun; Kim, Jin-Sang; Kim, Seong Keun

    2016-05-19

    The wafer-scale synthesis of MoS2 layers with precise thickness controllability and excellent uniformity is essential for their application in the nanoelectronics industry. Here, we demonstrate the atomic layer deposition (ALD) of MoS2 films with Mo(CO)6 and H2S as the Mo and S precursors, respectively. A self-limiting growth behavior is observed in the narrow ALD window of 155-175 °C. Long H2S feeding times are necessary to reduce the impurity contents in the films. The as-grown MoS2 films are amorphous due to the low growth temperature. Post-annealing at high temperatures under a H2S atmosphere efficiently improves the film properties including the crystallinity and chemical composition. An extremely uniform film growth is achieved even on a 4 inch SiO2/Si wafer. These results demonstrate that the current ALD process is well suited for the synthesis of MoS2 layers for application in industry. PMID:27166838

  14. Integrating atomic layer deposition and ultra-high vacuum physical vapor deposition for in situ fabrication of tunnel junctions

    International Nuclear Information System (INIS)

    Atomic Layer Deposition (ALD) is a promising technique for growing ultrathin, pristine dielectrics on metal substrates, which is essential to many electronic devices. Tunnel junctions are an excellent example which require a leak-free, ultrathin dielectric tunnel barrier of typical thickness around 1 nm between two metal electrodes. A challenge in the development of ultrathin dielectric tunnel barriers using ALD is controlling the nucleation of dielectrics on metals with minimal formation of native oxides at the metal surface for high-quality interfaces between the tunnel barrier and metal electrodes. This poses a critical need for integrating ALD with ultra-high vacuum (UHV) physical vapor deposition. In order to address these challenges, a viscous-flow ALD chamber was designed and interfaced to an UHV magnetron sputtering chamber via a load lock. A sample transportation system was implemented for in situ sample transfer between the ALD, load lock, and sputtering chambers. Using this integrated ALD-UHV sputtering system, superconductor-insulator-superconductor (SIS) Nb-Al/Al2O2/Nb Josephson tunnel junctions were fabricated with tunnel barriers of thickness varied from sub-nm to ∼1 nm. The suitability of using an Al wetting layer for initiation of the ALD Al2O3 tunnel barrier was investigated with ellipsometry, atomic force microscopy, and electrical transport measurements. With optimized processing conditions, leak-free SIS tunnel junctions were obtained, demonstrating the viability of this integrated ALD-UHV sputtering system for the fabrication of tunnel junctions and devices comprised of metal-dielectric-metal multilayers

  15. Electromagnetic interference shielding behaviors of Zn-based conducting oxide films prepared by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-June; Kang, Kyung-Mun; Lee, Hong-Sub; Park, Hyung-Ho, E-mail: hhpark@yonsei.ac.kr

    2015-05-29

    The structural, electrical, and optical properties of undoped ZnO, F-doped ZnO (ZnO:F), and Al-doped ZnO (ZnO:Al) thin films with two different thicknesses deposited by atomic layer deposition (ALD) were investigated to evaluate the electromagnetic interference shielding effectiveness (EMI-SE). A diluted fluoride hydroxide was used as a single reactant source for F doping in a ZnO matrix, and the F doping concentration was about 1 at.% in the ZnO:F films. The fabrication of the ZnO:Al films was followed by the typical ALD method, and the Al doping concentration of about 2 at.% was adjusted by the dopant deposition intervals of the ZnO:Al{sub 2}O{sub 3} precursor pulse cycle ratios, which were fixed at 19:1. The film thickness variations were controlled with 600 and 1600 total ALD cycles of approximately 100 nm and 300 nm, respectively. The carrier concentration of the films is monotonically increased in order of the undoped ZnO, ZnO:F, and ZnO:Al films. The EMI-SE values of the undoped ZnO, ZnO:F, and ZnO:Al films at 1 GHz were 0.9 dB, 2.6 dB, and 6.0 dB for ~ 100 nm, and were 2.1 dB, 9.7 dB, and 13.1 dB for ~ 300 nm, respectively. In our work, the EMI-SE value was increased by the enhancement of both the carrier concentration and film thickness due to reflection via the free carrier scattering effect. - Highlights: • Fluorine or aluminum doped ZnO thin films prepared by atomic layer deposition • Electromagnetic interference shielding effectiveness (EMI-SE) of ZnO thin films • Carrier concentration and film thickness enhanced the EMI-SE. • The enhancement of EMI-SE was due to reflection via free carrier scattering effect.

  16. Design of step composition gradient thin film transistor channel layers grown by atomic layer deposition

    International Nuclear Information System (INIS)

    In this study, we proposed the artificially designed channel structure in oxide thin-film transistors (TFTs) called a “step-composition gradient channel.” We demonstrated Al step-composition gradient Al-Zn-O (AZO) channel structures consisting of three AZO layers with different Al contents. The effects of stacking sequence in the step-composition gradient channel on performance and electrical stability of bottom-gate TFT devices were investigated with two channels of inverse stacking order (ascending/descending step-composition). The TFT with ascending step-composition channel structure (5 → 10 → 14 at. % Al composition) showed relatively negative threshold voltage (−3.7 V) and good instability characteristics with a reduced threshold voltage shift (Δ 1.4 V), which was related to the alignment of the conduction band off-set within the channel layer depending on the Al contents. Finally, the reduced Al composition in the initial layer of ascending step-composition channel resulted in the best field effect mobility of 4.5 cm2/V s. We presented a unique active layer of the “step-composition gradient channel” in the oxide TFTs and explained the mechanism of adequate channel design

  17. Design of step composition gradient thin film transistor channel layers grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Cheol Hyoun; Hee Kim, So; Gu Yun, Myeong; Koun Cho, Hyung, E-mail: chohk@skku.edu [School of Advanced Materials Science and Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2014-12-01

    In this study, we proposed the artificially designed channel structure in oxide thin-film transistors (TFTs) called a “step-composition gradient channel.” We demonstrated Al step-composition gradient Al-Zn-O (AZO) channel structures consisting of three AZO layers with different Al contents. The effects of stacking sequence in the step-composition gradient channel on performance and electrical stability of bottom-gate TFT devices were investigated with two channels of inverse stacking order (ascending/descending step-composition). The TFT with ascending step-composition channel structure (5 → 10 → 14 at. % Al composition) showed relatively negative threshold voltage (−3.7 V) and good instability characteristics with a reduced threshold voltage shift (Δ 1.4 V), which was related to the alignment of the conduction band off-set within the channel layer depending on the Al contents. Finally, the reduced Al composition in the initial layer of ascending step-composition channel resulted in the best field effect mobility of 4.5 cm{sup 2}/V s. We presented a unique active layer of the “step-composition gradient channel” in the oxide TFTs and explained the mechanism of adequate channel design.

  18. Electronic structure investigation of atomic layer deposition ruthenium(oxide) thin films using photoemission spectroscopy

    Science.gov (United States)

    Schaefer, Michael; Schlaf, Rudy

    2015-08-01

    Analyzing and manipulating the electronic band line-up of interfaces in novel micro- and nanoelectronic devices is important to achieve further advancement in this field. Such band alignment modifications can be achieved by introducing thin conformal interfacial dipole layers. Atomic layer deposition (ALD), enabling angstrom-precise control over thin film thickness, is an ideal technique for this challenge. Ruthenium (Ru0) and its oxide (RuO2) have gained interest in the past decade as interfacial dipole layers because of their favorable properties like metal-equivalent work functions, conductivity, etc. In this study, initial results of the electronic structure investigation of ALD Ru0 and RuO2 films via photoemission spectroscopy are presented. These experiments give insight into the band alignment, growth behavior, surface structure termination, and dipole formation. The experiments were performed in an integrated vacuum system attached to a home-built, stop-flow type ALD reactor without exposing the samples to the ambient in between deposition and analysis. Bis(ethylcyclopentadienyl)ruthenium(II) was used as precursor and oxygen as reactant. The analysis chamber was outfitted with X-ray photoemission spectroscopy (LIXPS, XPS). The determined growth modes are consistent with a strong growth inhibition situation with a maximum average growth rate of 0.21 Å/cycle for RuO2 and 0.04 Å/cycle for Ru.0 An interface dipole of up to -0.93 eV was observed, supporting the assumption of a strongly physisorbed interface. A separate experiment where the surface of a RuO film was sputtered suggests that the surface is terminated by an intermediate, stable, non-stoichiometric RuO2/OH compound whose surface is saturated with hydroxyl groups.

  19. Electronic structure investigation of atomic layer deposition ruthenium(oxide) thin films using photoemission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Michael, E-mail: mvschaefer@mail.usf.edu, E-mail: schlaf@mail.usf.edu [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States); Schlaf, Rudy, E-mail: mvschaefer@mail.usf.edu, E-mail: schlaf@mail.usf.edu [Department of Electrical Engineering, University of South Florida, Tampa, Florida 33620 (United States)

    2015-08-14

    Analyzing and manipulating the electronic band line-up of interfaces in novel micro- and nanoelectronic devices is important to achieve further advancement in this field. Such band alignment modifications can be achieved by introducing thin conformal interfacial dipole layers. Atomic layer deposition (ALD), enabling angstrom-precise control over thin film thickness, is an ideal technique for this challenge. Ruthenium (Ru{sup 0}) and its oxide (RuO{sub 2}) have gained interest in the past decade as interfacial dipole layers because of their favorable properties like metal-equivalent work functions, conductivity, etc. In this study, initial results of the electronic structure investigation of ALD Ru{sup 0} and RuO{sub 2} films via photoemission spectroscopy are presented. These experiments give insight into the band alignment, growth behavior, surface structure termination, and dipole formation. The experiments were performed in an integrated vacuum system attached to a home-built, stop-flow type ALD reactor without exposing the samples to the ambient in between deposition and analysis. Bis(ethylcyclopentadienyl)ruthenium(II) was used as precursor and oxygen as reactant. The analysis chamber was outfitted with X-ray photoemission spectroscopy (LIXPS, XPS). The determined growth modes are consistent with a strong growth inhibition situation with a maximum average growth rate of 0.21 Å/cycle for RuO{sub 2} and 0.04 Å/cycle for Ru.{sup 0} An interface dipole of up to −0.93 eV was observed, supporting the assumption of a strongly physisorbed interface. A separate experiment where the surface of a RuO film was sputtered suggests that the surface is terminated by an intermediate, stable, non-stoichiometric RuO{sub 2}/OH compound whose surface is saturated with hydroxyl groups.

  20. Electronic structure investigation of atomic layer deposition ruthenium(oxide) thin films using photoemission spectroscopy

    International Nuclear Information System (INIS)

    Analyzing and manipulating the electronic band line-up of interfaces in novel micro- and nanoelectronic devices is important to achieve further advancement in this field. Such band alignment modifications can be achieved by introducing thin conformal interfacial dipole layers. Atomic layer deposition (ALD), enabling angstrom-precise control over thin film thickness, is an ideal technique for this challenge. Ruthenium (Ru0) and its oxide (RuO2) have gained interest in the past decade as interfacial dipole layers because of their favorable properties like metal-equivalent work functions, conductivity, etc. In this study, initial results of the electronic structure investigation of ALD Ru0 and RuO2 films via photoemission spectroscopy are presented. These experiments give insight into the band alignment, growth behavior, surface structure termination, and dipole formation. The experiments were performed in an integrated vacuum system attached to a home-built, stop-flow type ALD reactor without exposing the samples to the ambient in between deposition and analysis. Bis(ethylcyclopentadienyl)ruthenium(II) was used as precursor and oxygen as reactant. The analysis chamber was outfitted with X-ray photoemission spectroscopy (LIXPS, XPS). The determined growth modes are consistent with a strong growth inhibition situation with a maximum average growth rate of 0.21 Å/cycle for RuO2 and 0.04 Å/cycle for Ru.0 An interface dipole of up to −0.93 eV was observed, supporting the assumption of a strongly physisorbed interface. A separate experiment where the surface of a RuO film was sputtered suggests that the surface is terminated by an intermediate, stable, non-stoichiometric RuO2/OH compound whose surface is saturated with hydroxyl groups

  1. Atomic Layer Deposition of Chemical Passivation Layers and High Performance Anti-Reflection Coatings on Back-Illuminated Detectors

    Science.gov (United States)

    Hoenk, Michael E. (Inventor); Greer, Frank (Inventor); Nikzad, Shouleh (Inventor)

    2014-01-01

    A back-illuminated silicon photodetector has a layer of Al2O3 deposited on a silicon oxide surface that receives electromagnetic radiation to be detected. The Al2O3 layer has an antireflection coating deposited thereon. The Al2O3 layer provides a chemically resistant separation layer between the silicon oxide surface and the antireflection coating. The Al2O3 layer is thin enough that it is optically innocuous. Under deep ultraviolet radiation, the silicon oxide layer and the antireflection coating do not interact chemically. In one embodiment, the silicon photodetector has a delta-doped layer near (within a few nanometers of) the silicon oxide surface. The Al2O3 layer is expected to provide similar protection for doped layers fabricated using other methods, such as MBE, ion implantation and CVD deposition.

  2. Growth of highly conformal ruthenium-oxide thin films with enhanced nucleation by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji-Yoon; Yeo, Seungmin [School of Materials Science and Engineering, Yeungnam University, Gyeongsan-si 712-749 (Korea, Republic of); Cheon, Taehoon [School of Materials Science and Engineering, Yeungnam University, Gyeongsan-si 712-749 (Korea, Republic of); Center for Core Research Facilities, Daegu Gyeongbuk Institute of Science and Technology, Dalseong-gun, Daegu 711-873 (Korea, Republic of); Kim, Soo-Hyun, E-mail: soohyun@ynu.ac.kr [School of Materials Science and Engineering, Yeungnam University, Gyeongsan-si 712-749 (Korea, Republic of); Kim, Min-Kyu; Kim, Hyungjun [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Hong, Tae Eun [Busan Center, Republic of Korea Basic Science Institute, 1275 Jisadong, Gangseogu, Busan 618-230 (Korea, Republic of); Lee, Do-Joong [School of Engineering, Brown University, Providence, RI 02912 (United States)

    2014-10-15

    Highlights: • Highly conformal RuO{sub 2} thin films were deposited using a zero-valent Ru precursor by atomic layer deposition (ALD). • Effects of deposition conditions on the formation of RuO{sub 2} phase were elucidated. • The performance as a bottom electrode of a metal–insulator-metal capacitor was evaluated. • The formation of a rutile-structured TiO{sub 2} on top of the ALD-RuO{sub 2} was demonstrated. - Abstract: Highly conformal and conductive RuO{sub 2} thin films were deposited without nucleation delay using atomic layer deposition (ALD) by zero-valent metallorganic precursor, (ethylbenzyl)(1,3-cyclohexadienyl)Ru(0) (EBCHDRu, C{sub 14}H{sub 18}Ru) and molecular oxygen (O{sub 2}) as a precursor and reactant, respectively. RuO{sub 2} thin films could be successfully prepared by controlling the process parameters, such as a reactant flow rate, a reactant pulsing time, a precursor pulsing time, and a deposition temperature. X-ray diffractometry, X-ray photoelectron spectroscopy, and secondary ion mass spectrometry analysis revealed that the formation of a RuO{sub 2} phase became favorable with increasing both the reactant flow rate and the pulsing time and with decreasing the precursor pulsing time and the deposition temperature. With the optimized pulsing conditions, the RuO{sub 2} film deposited at 225 °C had a tetragonal structure and exhibited excellent properties such as the low resistivity of 118 μΩ-cm, the high density of 6.85 g/cm{sup 3} close to the bulk value, and the negligible roughness of 0.33 nm. The growth rate of ALD-RuO{sub 2} was as high as 0.186 nm/cycle on the SiO{sub 2} substrate and the number of incubation cycles was negligible as 2. The film showed excellent step coverage of ∼100% onto 25-nm-width trench structures with an aspect ratio of 4.5. The ALD-RuO{sub 2} was highly stable up to annealing at 700 °C in both O{sub 2} and N{sub 2} ambient. Finally, the ALD-RuO{sub 2} film was evaluated as a bottom electrode of a

  3. Effect of Al 2 O 3 Recombination Barrier Layers Deposited by Atomic Layer Deposition in Solid-State CdS Quantum Dot-Sensitized Solar Cells

    KAUST Repository

    Roelofs, Katherine E.

    2013-03-21

    Despite the promise of quantum dots (QDs) as a light-absorbing material to replace the dye in dye-sensitized solar cells, quantum dot-sensitized solar cell (QDSSC) efficiencies remain low, due in part to high rates of recombination. In this article, we demonstrate that ultrathin recombination barrier layers of Al2O3 deposited by atomic layer deposition can improve the performance of cadmium sulfide (CdS) quantum dot-sensitized solar cells with spiro-OMeTAD as the solid-state hole transport material. We explored depositing the Al2O3 barrier layers either before or after the QDs, resulting in TiO2/Al2O3/QD and TiO 2/QD/Al2O3 configurations. The effects of barrier layer configuration and thickness were tracked through current-voltage measurements of device performance and transient photovoltage measurements of electron lifetimes. The Al2O3 layers were found to suppress dark current and increase electron lifetimes with increasing Al 2O3 thickness in both configurations. For thin barrier layers, gains in open-circuit voltage and concomitant increases in efficiency were observed, although at greater thicknesses, losses in photocurrent caused net decreases in efficiency. A close comparison of the electron lifetimes in TiO2 in the TiO2/Al2O3/QD and TiO2/QD/Al2O3 configurations suggests that electron transfer from TiO2 to spiro-OMeTAD is a major source of recombination in ss-QDSSCs, though recombination of TiO2 electrons with oxidized QDs can also limit electron lifetimes, particularly if the regeneration of oxidized QDs is hindered by a too-thick coating of the barrier layer. © 2013 American Chemical Society.

  4. Electrical and photovoltaic properties of ZnO/Si heterostructures with ZnO films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Pietruszka, R., E-mail: pietruszka@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Luka, G.; Witkowski, B.S.; Kopalko, K. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Zielony, E.; Bieganski, P.; Placzek-Popko, E. [Institute of Physics, Wroclaw University of Technology, Wroclaw (Poland); Godlewski, M. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Department of Mathematics and Natural Sciences College of Science, Cardinal Stefan Wyszynski University, Warsaw (Poland)

    2014-07-31

    We report on the properties of photovoltaic (PV) structures based on thin films of n-type zinc oxide grown by atomic layer deposition method on a cheap silicon substrate. Thin films of ZnO are used as n-type partner to p-type Si (110) and, when doped with Al, as a transparent electrode. PV structures with different thicknesses of ZnO layers (from 600 nm to 1600 nm) were deposited to determine the optimal performance of PV structures. The best response we obtained for the structure with ZnO layer thickness of 800 nm. The so-obtained PV structures show 6% efficiency. - Highlights: • Zinc oxide thin films grown by atomic layer deposition for solar cells application • Optimization of ZnO properties for an efficient photovoltaic response • Evaluation of electrical and photovoltaic performance of fabricated photovoltaic devices.

  5. Spatial atomic layer deposition on flexible substrates using a modular rotating cylinder reactor

    International Nuclear Information System (INIS)

    Spatial atomic layer deposition (ALD) is a new version of ALD based on the separation of reactant gases in space instead of time. In this paper, the authors present results for spatial ALD on flexible substrates using a modular rotating cylinder reactor. The design for this reactor is based on two concentric cylinders. The outer cylinder remains fixed and contains a series of slits. These slits can accept a wide range of modules that attach from the outside. The modules can easily move between the various slit positions and perform precursor dosing, purging, or pumping. The inner cylinder rotates with the flexible substrate and passes underneath the various spatially separated slits in the outer cylinder. Trimethyl aluminum and ozone were used to grow Al2O3 ALD films at 40 °C on metallized polyethylene terephthalate (PET) substrates to characterize this spatial ALD reactor. Spectroscopic ellipsometry measurements revealed a constant Al2O3 ALD growth rate of 1.03 Å/cycle with rotation speeds from 40 to 100 RPM with the outer cylinder configured for one Al2O3 ALD cycle per rotation. The Al2O3 ALD growth rate then decreased at higher rotation rates for reactant residence times < 5 ms. The Al2O3 ALD films were also uniform to within <1% across the central portion of metallized PET substrate. Fixed deposition time experiments revealed that Al2O3 ALD films could be deposited at 2.08 Å/s at higher rotation speeds of 175 RPM. Even faster deposition rates are possible by adding more modules for additional Al2O3 ALD cycles for every one rotation of the inner cylinder

  6. Nanocrystallized Cu2Se grown on electroless Cu coated p-type Si using electrochemical atomic layer deposition

    Science.gov (United States)

    Zhang, Lu; He, Wenya; Chen, Xiang-yu; Du, Yi; Zhang, Xin; Shen, Yehua; Yang, Fengchun

    2015-01-01

    Cuprous selenide (Cu2Se) nanocrystalline thin films are grown onto electroless Cu coating on p-Si (100) substrates using electrochemical atomic layer deposition (EC-ALD), which includes alternate electrodeposition of Cu and Se atomic layers. The obtained films were characterized by X-ray diffraction (XRD), field emission scanning electronic microscopy (FE-SEM), FTIR, and open-circuit potential (OCP) studies. The results show the higher quality and good photoelectric properties of the Cu2Se film, suggesting that the combination of electroless coating and EC-ALD is an ideal method for deposition of compound semiconductor films on p-Si.

  7. Plasma-enhanced atomic layer deposition of Cu–Mn films with formation of a MnSixOy barrier layer

    International Nuclear Information System (INIS)

    Conformal Cu–Mn seed layers were deposited by plasma enhanced atomic layer deposition (PEALD) at low temperature (120 °C), and the Mn content in the Cu–Mn alloys were controlled form 0 to approximately 10 atomic percent with various Mn precursor feeding times. Resistivity of the Cu–Mn alloy films decreased by annealing due to out-diffusion of Mn atoms. Out-diffused Mn atoms were segregated to the surface of the film and interface between a Cu–Mn alloy and SiO2, resulting in self-formed MnOx and MnSixOy, respectively. The adhesion between Cu and SiO2 was enhanced by the formation of MnSixOy. Continuous and conductive Cu–Mn seed layers were deposited with PEALD into 24 nm SiO2 trench, enabling a low temperature process, and the trench was perfectly filled using electrochemical plating under conventional conditions.

  8. High-Performance MEA Prepared by Direct Deposition of Platinum on the Gas Diffusion Layer Using an Atomic Layer Deposition Technique

    International Nuclear Information System (INIS)

    Highlights: • A highly performance membrane electrode assembly was prepared by ALD technique. • The platinum atoms were deposited on the gas diffusion layer directly. • The ALD-electrode achieved 2.5 times mass activity of the conventional electrode. - Abstract: A high-performance membrane electrode assembly (MEA) with low platinum loading was successfully prepared using an atomic layer deposition (ALD) technique, in which the platinum was directly deposited on the gas diffusion layer to form the catalyst layer. MEAs were fabricated with an ALD-prepared electrode as the anode, and assembled with pretreated Nafion® membrane (Nafion® 117) and a commercial cathode. The MEAs were evaluated in a single-cell test station and characterized by cyclic voltammetry (CV), field-emission scanning electron microscope (FE-SEM), high-resolution transmission electron microscope (HRTEM) and grazing incident X-ray diffraction (XRD). The results revealed that the active component, Pt, was highly dispersed in the ALD anode, and the MEA with the ALD anode showed excellent activity and stability. The mass activity reached 4.80 kW g Pt−1, which was 2.53 times higher than that of the MEA with the anode prepared using the commercial catalyst and a conventional screen printing method. In 100 h of durability testing, the ALD–MEA exhibited excellent durability (98.2% voltage retention) compared with the CC–MEA (92.5% voltage retention) when the MEA was discharged at a current density of 400 mA cm−2. The high performance, along with low platinum loading and high platinum utilization, make the ALD technique promising for use in PEM fuel cells

  9. Surface smoothing effect of an amorphous thin film deposited by atomic layer deposition on a surface with nano-sized roughness

    Directory of Open Access Journals (Sweden)

    W. S. Lau

    2014-02-01

    Full Text Available Previously, Lau (one of the authors pointed out that the deposition of an amorphous thin film by atomic layer deposition (ALD on a substrate with nano-sized roughness probably has a surface smoothing effect. In this letter, polycrystalline zinc oxide deposited by ALD onto a smooth substrate was used as a substrate with nano-sized roughness. Atomic force microscopy (AFM and cross-sectional transmission electron microscopy (XTEM were used to demonstrate that an amorphous aluminum oxide thin film deposited by ALD can reduce the surface roughness of a polycrystalline zinc oxide coated substrate.

  10. Low-temperature atomic layer deposition of TiO2 thin layers for the processing of memristive devices

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO2 thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO2 thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO2 thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications

  11. Low-temperature atomic layer deposition of TiO{sub 2} thin layers for the processing of memristive devices

    Energy Technology Data Exchange (ETDEWEB)

    Porro, Samuele, E-mail: samuele.porro@polito.it; Conti, Daniele; Guastella, Salvatore; Ricciardi, Carlo [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Jasmin, Alladin; Pirri, Candido F. [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy and Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Torino (Italy); Bejtka, Katarzyna; Perrone, Denis; Chiolerio, Alessandro [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Torino (Italy)

    2016-01-15

    Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO{sub 2} thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO{sub 2} thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO{sub 2} thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications.

  12. Transparent and conductive undoped zinc oxide thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luka, Grzegorz; Krajewski, Tomasz; Wachnicki, Lukasz; Lusakowska, Elzbieta; Paszkowicz, Wojciech; Guziewicz, Elzbieta [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 00-668 Warsaw (Poland); Witkowski, Bartlomiej [Department of Mathematics and Natural Sciences, Cardinal Stefan Wyszynski University, College of Science, ul. Dewajtis 5, 01-815 Warsaw (Poland); Godlewski, Marek [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 00-668 Warsaw (Poland); Department of Mathematics and Natural Sciences, Cardinal Stefan Wyszynski University, College of Science, ul. Dewajtis 5, 01-815 Warsaw (Poland)

    2010-07-15

    Atomic layer deposition (ALD) was used to fabricate transparent and conductive thin films of ZnO. Two hundred-nano metre thick ZnO films were deposited on glass substrates at low growth temperatures varied between 120 and 240 C. As zinc and oxygen precursors we used diethylzinc (DEZn) and deionized water, respectively. To find optimal film parameters, the structure, surface morphology, optical and electrical measurements were carried on. The films obtained at 200 C show the highest carrier concentration ({proportional_to}10{sup 20} cm{sup -3}) and the lowest resistivity (2 x 10{sup -3}{omega} cm). The films exhibit mobilities up to 37 cm{sup 2}/Vs that we associate to the process technology used. An important point of our approach was that the films studied were not intentionally doped (with Al or other group III elements) but the high electrical conductivity was achieved by playing with the sample stoichiometry and growth conditions. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  13. Protective coatings of hafnium dioxide by atomic layer deposition for microelectromechanical systems applications

    Science.gov (United States)

    Berdova, Maria; Wiemer, Claudia; Lamperti, Alessio; Tallarida, Grazia; Cianci, Elena; Lamagna, Luca; Losa, Stefano; Rossini, Silvia; Somaschini, Roberto; Gioveni, Salvatore; Fanciulli, Marco; Franssila, Sami

    2016-04-01

    This work presents the investigation of HfO2 deposited by atomic layer deposition (ALD) from either HfD-CO4 or TEMAHf and ozone for microelectromechanical systems (MEMS) applications, in particular, for environmental protection of aluminum micromirrors. This work shows that HfO2 films successfully protect aluminum in moist environment and at the same time retain good reflectance properties of underlying material. In our experimental work, the chemical composition, crystal structure, electronic density and roughness of HfO2 films remained the same after one week of humidity treatment (relative humidity of 85%, 85 °C). The reflectance properties underwent only minor changes. The observed shift in reflectance was only from 80-90% to 76-85% in 400-800 nm spectral range when coated with ALD HfO2 films grown with Hf(NMeEt)4 and no shift (remained in the range of 68-83%) for films grown from (CpMe)2Hf(OMe)Me.

  14. Synthesis of Highly Ordered Hydrothermally Stable Mesoporous Niobia Catalysts by Atomic Layer Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Pagan-Torres, Yomaira J; Gallo, Jean Marcel R; Wang, Dong; Pham, Hien N; Libera, J.A.; Marshall, Christopher L; Elam, Jeffrey W.; Datye, Abhaya K; Dumesic, James A

    2011-10-07

    A new class of mesoporous niobia catalysts has been synthesized by atomic layer deposition (ALD) of niobia within the pores of a mesoporous silica (SBA-15). Mesoporous materials after ALD cycles of niobia maintained the structural organization of SBA-15. Increasing loadings of niobia cause a decrease in the surface area, pore volume, and pore diameter due to the conformal coating of niobia within the pores. Materials containing 10, 19, and 30 cycles show remarkable hydrothermal stability, with minimal change in porosity and structural properties upon treatment in liquid water at 473 K. The mesoporous niobia material produced by 19 cycles has been studied as an acid catalyst for the gas-phase dehydration of 2-propanol, and for the dehydration of 2-butanol in both the gas and liquid phases, showing catalytic activity superior to commercial niobia (HY-340) per mass of material. Furthermore, deposition of Pd nanoparticles on this material consisting of SBA-15 coated with 19 cycles of niobia leads to a bifunctional catalyst for the transformation of γ-valerolactone to pentanoic acid, showing better stability versus time-on-stream compared to a conventional catalyst consisting of Pd supported on HY-340.

  15. Low-Temperature Crystalline Titanium Dioxide by Atomic Layer Deposition for Dye-Sensitized Solar Cells

    KAUST Repository

    Chandiran, Aravind Kumar

    2013-04-24

    Low-temperature processing of dye-sensitized solar cells (DSCs) is crucial to enable commercialization with low-cost, plastic substrates. Prior studies have focused on mechanical compression of premade particles on plastic or glass substrates; however, this did not yield sufficient interconnections for good carrier transport. Furthermore, such compression can lead to more heterogeneous porosity. To circumvent these problems, we have developed a low-temperature processing route for photoanodes where crystalline TiO2 is deposited onto well-defined, mesoporous templates. The TiO2 is grown by atomic layer deposition (ALD), and the crystalline films are achieved at a growth temperature of 200 C. The ALD TiO2 thickness was systematically studied in terms of charge transport and performance to lead to optimized photovoltaic performance. We found that a 15 nm TiO2 overlayer on an 8 μm thick SiO2 film leads to a high power conversion efficiency of 7.1% with the state-of-the-art zinc porphyrin sensitizer and cobalt bipyridine redox mediator. © 2013 American Chemical Society.

  16. A brief review of atomic layer deposition: from fundamentals to applications

    Directory of Open Access Journals (Sweden)

    Richard W. Johnson

    2014-06-01

    Full Text Available Atomic layer deposition (ALD is a vapor phase technique capable of producing thin films of a variety of materials. Based on sequential, self-limiting reactions, ALD offers exceptional conformality on high-aspect ratio structures, thickness control at the Angstrom level, and tunable film composition. With these advantages, ALD has emerged as a powerful tool for many industrial and research applications. In this review, we provide a brief introduction to ALD and highlight select applications, including Cu(In,GaSe2 solar cell devices, high-k transistors, and solid oxide fuel cells. These examples are chosen to illustrate the variety of technologies that are impacted by ALD, the range of materials that ALD can deposit – from metal oxides such as Zn1−xSnxOy, ZrO2, Y2O3, to noble metals such as Pt – and the way in which the unique features of ALD can enable new levels of performance and deeper fundamental understanding to be achieved.

  17. Atomic layer deposition of boron-containing films using B2F4

    International Nuclear Information System (INIS)

    Ultrathin and conformal boron-containing atomic layer deposition (ALD) films could be used as a shallow dopant source for advanced transistor structures in microelectronics manufacturing. With this application in mind, diboron tetrafluoride (B2F4) was explored as an ALD precursor for the deposition of boron containing films. Density functional theory simulations for nucleation on silicon (100) surfaces indicated better reactivity of B2F4 in comparison to BF3. Quartz crystal microbalance experiments exhibited growth using either B2F4-H2O for B2O3 ALD, or B2F4-disilane (Si2H6) for B ALD, but in both cases, the initial growth per cycle was quite low (≤0.2 Å/cycle) and decreased to near zero growth after 8–30 ALD cycles. However, alternating between B2F4-H2O and trimethyl aluminum (TMA)-H2O ALD cycles resulted in sustained growth at ∼0.65 Å/cycle, suggesting that the dense –OH surface termination produced by the TMA-H2O combination enhances the uptake of B2F4 precursor. The resultant boron containing films were analyzed for composition by x-ray photoelectron spectroscopy, and capacitance measurements indicated an insulating characteristic. Finally, diffused boron profiles less than 100 Å were obtained after rapid thermal anneal of the boron containing ALD film

  18. Density Functional Theory Study of Atomic Layer Deposition of Zinc Oxide on Graphene

    Science.gov (United States)

    Ali, Amgad Ahmed; Hashim, Abdul Manaf

    2015-07-01

    The dissociation of zinc ions (Zn2+) from vapor-phase zinc acetylacetonate, Zn(C5H7O2)2, or Zn(acac)2 and its adsorption onto graphene oxide via atomic layer deposition (ALD) were studied using a quantum mechanics approach. Density functional theory (DFT) was used to obtain an approximate solution to the Schrödinger equation. The graphene oxide cluster model was used to represent the surface of the graphene film after pre-oxidation. In this study, the geometries of reactants, transition states, and products were optimized using the B3LYB/6-31G** level of theory or higher. Furthermore, the relative energies of the various intermediates and products in the gas-phase radical mechanism were calculated at the B3LYP/6-311++G** and MP2/6-311 + G(2df,2p) levels of theory. Additionally, a molecular orbital (MO) analysis was performed for the products of the decomposition of the Zn(acac)2 complex to investigate the dissociation of Zn2+ and the subsequent adsorption of H atoms on the C5H7O2 cluster to form acetylacetonate enol. The reaction energies were calculated, and the reaction mechanism was accordingly proposed. A simulation of infrared (IR) properties was performed using the same approach to support the proposed mechanism via a complete explanation of bond forming and breaking during each reaction step.

  19. Growth kinetics and initial stage growth during plasma-enhanced Ti atomic layer deposition

    CERN Document Server

    Kim, H

    2002-01-01

    We have investigated the growth kinetics of plasma-enhanced Ti atomic layer deposition (ALD) using a quartz crystal microbalance. Ti ALD films were grown at temperatures from 20 to 200 deg. C using TiCl sub 4 as a source gas and rf plasma-produced atomic H as the reducing agent. Postdeposition ex situ chemical analyses of thin films showed that the main impurity is oxygen, mostly incorporated during the air exposure prior to analysis. The thickness per cycle, corresponding to the growth rate, was measured by quartz crystal microbalance as a function of various key growth parameters, including TiCl sub 4 and H exposure time, rf plasma power, and sample temperature. The growth rates were independent of TiCl sub 4 exposure above 1x10 sup 3 L, indicating typical ALD mode growth. The key kinetic parameters for Cl extraction reaction and TiCl sub 4 adsorption kinetics were obtained and the growth kinetics were modeled to predict the growth rates based upon these results. Also, the dependency of growth kinetics on d...

  20. Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics

    Science.gov (United States)

    Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L.

    2016-03-01

    Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. Electronic supplementary information (ESI) available: (i) Experimental details for ALD and material fabrication, ellipsometry film thickness, preparation of gel electrolyte and separator, details for electrochemical measurements, HRTEM image of VOx coated porous silicon, Raman spectroscopy for VOx as-deposited as well as annealed in air for 1 hour at 450 °C, SEM and transient behavior dissolution tests of uniformly coated VOx on

  1. Influence of titanium-substrate roughness on Ca–P–O thin films grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Amorphous Ca–P–O films were deposited on titanium substrates using atomic layer deposition, while maintaining a uniform Ca/P pulsing ratio of 6/1 with varying number of atomic layer deposition cycles starting from 10 up to 208. Prior to film deposition the titanium substrates were mechanically abraded using SiC abrasive paper of 600, 1200, 2000 grit size and polished with 3 μm diamond paste to obtain surface roughness Rrms values of 0.31 μm, 0.26 μm, 0.16 μm, and 0.10 μm, respectively. The composition and film thickness of as-deposited amorphous films were studied using Time-Of-Flight Elastic Recoil Detection Analysis. The results showed that uniform films could be deposited on rough metal surfaces with a clear dependence of substrate roughness on the Ca/P atomic ratio of thin films. The in vitro cell-culture studies using MC3T3 mouse osteoblast showed a greater coverage of cells on the surface polished with diamond paste in comparison to rougher surfaces after 24 h culture. No statistically significant difference was observed between Ca–P–O coated and un-coated Ti surfaces for the measured roughness value. The deposited 50 nm thick films did not dissolve during the cell culture experiment. - Highlights: ► Atomic layer deposition of Ca–P–O films on abraded Ti substrate ► Surface analysis using Time-Of-Flight Elastic Recoil Detection Analysis ► Dependence of substrate roughness on the Ca/P atomic ratio of thin films ► An increase in Ca/P atomic ratio with decreasing roughness ► Mouse osteoblast showed greater coverage of cells in polished surface

  2. Influence of titanium-substrate roughness on Ca–P–O thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ananda Sagari, A.R., E-mail: arsagari@gmail.com [Department of Physics, P.O. Box 35 (YFL), FIN-40014 University of Jyväskylä (Finland); Malm, Jari [Department of Chemistry, P.O. Box 16100, FI-00076 Aalto University, Espoo (Finland); Laitinen, Mikko [Department of Physics, P.O. Box 35 (YFL), FIN-40014 University of Jyväskylä (Finland); Rahkila, Paavo [Department of Biology of Physical Activity, P.O. Box 35, FIN-40014 University of Jyväskylä (Finland); Hongqiang, Ma [Department of Health Sciences, P.O. Box 35 (L), FIN-40014 University of Jyväskylä (Finland); Putkonen, Matti [Department of Chemistry, P.O. Box 16100, FI-00076 Aalto University, Espoo (Finland); Beneq Oy, P.O. Box 262, FI-01511 Vantaa (Finland); Karppinen, Maarit [Department of Chemistry, P.O. Box 16100, FI-00076 Aalto University, Espoo (Finland); Whitlow, Harry J.; Sajavaara, Timo [Department of Physics, P.O. Box 35 (YFL), FIN-40014 University of Jyväskylä (Finland)

    2013-03-01

    Amorphous Ca–P–O films were deposited on titanium substrates using atomic layer deposition, while maintaining a uniform Ca/P pulsing ratio of 6/1 with varying number of atomic layer deposition cycles starting from 10 up to 208. Prior to film deposition the titanium substrates were mechanically abraded using SiC abrasive paper of 600, 1200, 2000 grit size and polished with 3 μm diamond paste to obtain surface roughness R{sub rms} values of 0.31 μm, 0.26 μm, 0.16 μm, and 0.10 μm, respectively. The composition and film thickness of as-deposited amorphous films were studied using Time-Of-Flight Elastic Recoil Detection Analysis. The results showed that uniform films could be deposited on rough metal surfaces with a clear dependence of substrate roughness on the Ca/P atomic ratio of thin films. The in vitro cell-culture studies using MC3T3 mouse osteoblast showed a greater coverage of cells on the surface polished with diamond paste in comparison to rougher surfaces after 24 h culture. No statistically significant difference was observed between Ca–P–O coated and un-coated Ti surfaces for the measured roughness value. The deposited 50 nm thick films did not dissolve during the cell culture experiment. - Highlights: ► Atomic layer deposition of Ca–P–O films on abraded Ti substrate ► Surface analysis using Time-Of-Flight Elastic Recoil Detection Analysis ► Dependence of substrate roughness on the Ca/P atomic ratio of thin films ► An increase in Ca/P atomic ratio with decreasing roughness ► Mouse osteoblast showed greater coverage of cells in polished surface.

  3. Effect of GeO2 deposition temperature in atomic layer deposition on electrical properties of Ge gate stack

    Science.gov (United States)

    Kanematsu, Masayuki; Shibayama, Shigehisa; Sakashita, Mitsuo; Takeuchi, Wakana; Nakatsuka, Osamu; Zaima, Shigeaki

    2016-08-01

    We investigated the effect of GeO2 deposition temperature (T depo) on electronic properties of Al/Al2O3/GeO2/Ge MOS capacitors. Capacitance–voltage characteristics show frequency dispersions under depletion and strong inversion conditions, which can be attributed from the interface states at the atomic layer deposition (ALD)-GeO2/Ge interface and from the defect states in the quasi-neutral region in the Ge substrate, respectively. We found that the interface state density (D it) shows similar values and energy distributions as T depo decreases to 200 from 300 °C, while a higher D it is observed at a T depo of 150 °C. Also, from the temperature dependence of conductance, the frequency dispersion under the strong inversion condition can be related to the minority carrier diffusion to the quasi-neutral region of the Ge substrate. The frequency dependence of conductance reveals that the undesirable increment of the bulk defect density can be suppressed by decreasing T depo. In this study, the bulk defect density in a MOS capacitor prepared at a T depo of 200 °C decreases one tenth compared with that at a T depo of 300 °C. The ALD of GeO2 at a low temperature of around 200 °C is effective for both obtaining a low D it and preventing the undesirable introduction of bulk defect density.

  4. Ru nanostructure fabrication using an anodic aluminum oxide nanotemplate and highly conformal Ru atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woo-Hee; Park, Sang-Joon; Son, Jong-Yeog; Kim, Hyungjun [Department of Material Science and Engineering, POSTECH Pohang University of Science and Technology, San 31, Hyoja-Dong, Nam-Gu, Pohang 790-784 (Korea, Republic of)

    2008-01-30

    We fabricated metallic nanostructures directly on Si substrates through a hybrid nanoprocess combining atomic layer deposition (ALD) and a self-assembled anodic aluminum oxide (AAO) nanotemplate. ALD Ru films with Ru(DMPD)(EtCp) as a precursor and O{sub 2} as a reactant exhibited high purity and low resistivity with negligible nucleation delay and low roughness. These good growth characteristics resulted in the excellent conformality for nanometer-scale vias and trenches. Additionally, AAO nanotemplates were fabricated directly on Si and Ti/Si substrates through a multiple anodization process. AAO nanotemplates with various hole sizes (30-100 nm) and aspect ratios (2:1-20:1) were fabricated by controlling the anodizing process parameters. The barrier layers between AAO nanotemplates and Si substrates were completely removed by reactive ion etching (RIE) using BCl{sub 3} plasma. By combining the ALD Ru and the AAO nanotemplate, Ru nanostructures with controllable sizes and shapes were prepared on Si and Ti/Si substrates. The Ru nanowire array devices as a platform for sensor devices exhibited befitting properties of good ohmic contact and high surface/volume ratio.

  5. Ru nanostructure fabrication using an anodic aluminum oxide nanotemplate and highly conformal Ru atomic layer deposition.

    Science.gov (United States)

    Kim, Woo-Hee; Park, Sang-Joon; Son, Jong-Yeog; Kim, Hyungjun

    2008-01-30

    We fabricated metallic nanostructures directly on Si substrates through a hybrid nanoprocess combining atomic layer deposition (ALD) and a self-assembled anodic aluminum oxide (AAO) nanotemplate. ALD Ru films with Ru(DMPD)(EtCp) as a precursor and O(2) as a reactant exhibited high purity and low resistivity with negligible nucleation delay and low roughness. These good growth characteristics resulted in the excellent conformality for nanometer-scale vias and trenches. Additionally, AAO nanotemplates were fabricated directly on Si and Ti/Si substrates through a multiple anodization process. AAO nanotemplates with various hole sizes (30-100 nm) and aspect ratios (2:1-20:1) were fabricated by controlling the anodizing process parameters. The barrier layers between AAO nanotemplates and Si substrates were completely removed by reactive ion etching (RIE) using BCl(3) plasma. By combining the ALD Ru and the AAO nanotemplate, Ru nanostructures with controllable sizes and shapes were prepared on Si and Ti/Si substrates. The Ru nanowire array devices as a platform for sensor devices exhibited befitting properties of good ohmic contact and high surface/volume ratio. PMID:21817499

  6. Air-Stable flexible organic light-emitting diodes enabled by atomic layer deposition

    International Nuclear Information System (INIS)

    Organic light-emitting diodes (OLED) are an energy-efficient light source with many desirable attributes, besides being an important display of technology, but its practical application has been limited by its low air-stability. This study demonstrates air-stable flexible OLEDs by utilizing two atomic-layer-deposited (ALD) films: (1) a ZnO film as both a stable electron-injection layer (EIL) and as a gas barrier in plastics-based OLED devices, and (2) an Al2O3/ZnO (AZO) nano-laminated film for encapsulating the devices. Through analyses of the morphology and electrical/gas-permeation properties of the films, we determined that a low ALD temperature of 70 °C resulted in optimal EIL performance from the ZnO film and excellent gas-barrier properties [water vapor transmission rate (WVTR) <5 × 10−4 g m−2 day−1] from both the ZnO EIL and the AZO encapsulating film. The low-temperature ALD processes eliminated thermal damage to the OLED devices, which were severe when a 90 °C encapsulation process was used, while enabling them to achieve an air-storage lifetime of >10 000 h. (paper)

  7. Diffusion barrier properties of atomic-layer-deposited iridium thin films on Cu/Ir/Si structures

    International Nuclear Information System (INIS)

    We investigated the diffusion barrier properties of an atomic-layer-deposited 12-nm-thick iridium (Ir) thin film as functions of the thermal treatment temperature. Up to a temperature of 500 .deg. C, the Ir thin film maintained its initial configuration, preventing the penetration of the Cu layer into Si through the Ir layer. The thermal stability of the Ir layer up to 500 .deg. C was confirmed by using high resolution transmission electron microscopy, Auger electron microscopy, and X-ray diffraction. In contrast, when the Ir layer was thermally annealed at 600 .deg. C, copper silicide was formed, and interdiffusion of Cu and Ir was observed.

  8. The fabrication of tunable nanoporous oxide surfaces by block copolymer lithography and atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Andreozzi, A; Lamagna, L; Seguini, G; Fanciulli, M; Perego, M [Laboratorio MDM, IMM-CNR, Via C Olivetti 2, I-20864 Agrate Brianza (Italy); Schamm-Chardon, S; Castro, C, E-mail: andrea.andreozzi@mdm.imm.cnr.it [CEMES-CNRS and Universite de Toulouse, nMat group, BP 94345, F-31055 Toulouse Cedex 4 (France)

    2011-08-19

    Patterned nanoscale materials with controllable characteristic feature sizes and periodicity are of considerable interest in a wide range of fields, with various possible applications ranging from biomedical to nanoelectronic devices. Block-copolymer (BC)-based lithography is a powerful tool for the fabrication of uniform, densely spaced nanometer-scale features over large areas. Following this bottom-up approach, nanoporous polymeric films can be deposited on any type of substrate. The nanoporous periodic template can be transferred to the underlying substrate by dry anisotropic etching. Nevertheless the physical sizes of the polymeric mask represent an important limitation in the implementation of suitable lithographic protocols based on BC technology, since the diameter and the center-to-center distance of the pores cannot be varied independently in this class of materials. This problem could be overcome by combining block copolymer technology with atomic layer deposition (ALD): by means of BC-based lithography a nanoporous SiO{sub 2} template, with well-reproducible characteristic dimensions, can be fabricated and subsequently used as a backbone for the growth of perfectly conformal thin oxide films by ALD. In this work polystyrene-b-poly(methylmethacrylate) (PS-b-PMMA) BC and reactive ion etching are used to fabricate hexagonally packed 23 nm wide nanopores in a 50 nm thick SiO{sub 2} matrix. By ALD deposition of Al{sub 2}O{sub 3} thin films onto the nanoporous SiO{sub 2} templates, nanostructured Al{sub 2}O{sub 3} surfaces are obtained. By properly adjusting the thickness of the Al{sub 2}O{sub 3} film the dimension of the pores in the oxide films is progressively reduced, with nanometer precision, from the original size down to complete filling of the pores, thus providing a simple and fast strategy for the fabrication of nanoporous Al{sub 2}O{sub 3} surfaces with well-controllable feature size.

  9. Sub-nanometer dimensions control of core/shell nanoparticles prepared by atomic layer deposition

    International Nuclear Information System (INIS)

    Bimetallic core/shell nanoparticles (NPs) are the subject of intense research due to their unique electronic, optical and catalytic properties. Accurate and independent control over the dimensions of both core and shell would allow for unprecedented catalytic performance. Here, we demonstrate that both core and shell dimensions of Pd/Pt core/shell nanoparticles (NPs) supported on Al2O3 substrates can be controlled at the sub-nanometer level by using a novel strategy based on atomic layer deposition (ALD). From the results it is derived that the main conditions for accurate dimension control of these core/shell NPs are: (i) a difference in surface energy between the deposited core metal and the substrate to obtain island growth; (ii) a process yielding linear growth of the NP cores with ALD cycles to obtain monodispersed NPs with a narrow size distribution; (iii) a selective ALD process for the shell metal yielding a linearly increasing thickness to obtain controllable shell growth exclusively on the cores. For Pd/Pt core/shell NPs it is found that a minimum core diameter of 1 nm exists above which the NP cores are able to catalytically dissociate the precursor molecules for shell growth. In addition, initial studies on the stability of these core/shell NPs have been carried out, and it has been demonstrated that core/shell NPs can be deposited by ALD on high aspect ratio substrates such as nanowire arrays. These achievements show therefore that ALD has significant potential for the preparation of tuneable heterogeneous catalyst systems. (paper)

  10. The fabrication of tunable nanoporous oxide surfaces by block copolymer lithography and atomic layer deposition

    International Nuclear Information System (INIS)

    Patterned nanoscale materials with controllable characteristic feature sizes and periodicity are of considerable interest in a wide range of fields, with various possible applications ranging from biomedical to nanoelectronic devices. Block-copolymer (BC)-based lithography is a powerful tool for the fabrication of uniform, densely spaced nanometer-scale features over large areas. Following this bottom-up approach, nanoporous polymeric films can be deposited on any type of substrate. The nanoporous periodic template can be transferred to the underlying substrate by dry anisotropic etching. Nevertheless the physical sizes of the polymeric mask represent an important limitation in the implementation of suitable lithographic protocols based on BC technology, since the diameter and the center-to-center distance of the pores cannot be varied independently in this class of materials. This problem could be overcome by combining block copolymer technology with atomic layer deposition (ALD): by means of BC-based lithography a nanoporous SiO2 template, with well-reproducible characteristic dimensions, can be fabricated and subsequently used as a backbone for the growth of perfectly conformal thin oxide films by ALD. In this work polystyrene-b-poly(methylmethacrylate) (PS-b-PMMA) BC and reactive ion etching are used to fabricate hexagonally packed 23 nm wide nanopores in a 50 nm thick SiO2 matrix. By ALD deposition of Al2O3 thin films onto the nanoporous SiO2 templates, nanostructured Al2O3 surfaces are obtained. By properly adjusting the thickness of the Al2O3 film the dimension of the pores in the oxide films is progressively reduced, with nanometer precision, from the original size down to complete filling of the pores, thus providing a simple and fast strategy for the fabrication of nanoporous Al2O3 surfaces with well-controllable feature size.

  11. Effect of substrate pretreatments on the atomic layer deposited Al{sub 2}O{sub 3} passivation quality

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Yameng; Li, Shuo, E-mail: Shuo.li@beneq.com; Gastrow, Guillaume von; Repo, Päivikki; Savin, Hele [Department of Micro- and Nanosciences, Aalto University School of Electrical Engineering, Tietotie 3, 02150 Espoo (Finland); Putkonen, Matti [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT Espoo (Finland)

    2015-01-15

    The authors show here that the passivation quality of Al{sub 2}O{sub 3} is highly sensitive to the surface condition prior to the atomic layer deposition, affecting especially the thermal stability of the film. Pretreatments like diluted HCl bath or preheating at 200 °C both improved significantly the passivation quality and thermal stability of the films. In addition, the authors observed that a thin chemical SiO{sub 2} layer resulting from diluted HCl solves the blistering problem often encountered in H{sub 2}O based atomic layer deposited process. Finally, the authors show that the chemical oxide protects the surface from contaminants, enabling long storage times in a dirty ambient between the cleaning and the film deposition.

  12. Characterization of Al2O3 Thin Films on GaAs Substrate Grown by Atomic Layer Deposition

    Institute of Scientific and Technical Information of China (English)

    LU Hong-Liang; LI Yan-Bo; XU Min; DING Shi-Jin; SUN Liang; ZHANG Wei; WANG Li-Kang

    2006-01-01

    @@ Al2O3 thin films are grown by atomic layer deposition on GaAs substrates at 300℃. The structural properties of the Al2O3 thin film and the Al2O3/GaAs interface are characterized using x-ray diffraction (XRD), highresolution transmission electron microscopy (HRTEM), and x-ray photoelectron spectroscopy (XPS). The XRD results show that the as-deposited Al2O3 film is amorphous. For 30 atomic layer deposition growth cycles, the thicknesses of the Al2O3 thin film and the interface layer from the HRTEM are 3.3nm and 0.5nm, respectively.XPS analyses reveal that the Al2O3/GaAs interface is almost free from As2O3.

  13. Seeding atomic layer deposition of high-k dielectric on graphene with ultrathin poly(4-vinylphenol) layer for enhanced device performance and reliability

    Science.gov (United States)

    Cheol Shin, Woo; Yong Kim, Taek; Sul, Onejae; Jin Cho, Byung

    2012-07-01

    We demonstrate that ultrathin poly(4-vinylphenol) (PVP) acts as an effective organic seeding layer for atomic layer deposition (ALD) of high-k dielectric on large-scale graphene fabricated by chemical vapor deposition (CVD). While identical ALD conditions result in incomplete and rough dielectric deposition on CVD graphene, the reactive groups provided by the PVP seeding layer yield conformal and pinhole-free dielectric films throughout the large-scale graphene. Top-gate graphene field effect transistors fabricated with the high quality, PVP-seeded Al2O3 gate dielectric show superior carrier mobility and enhanced reliability performance, which are desirable for graphene nanoelectronics.

  14. Protective capping and surface passivation of III-V nanowires by atomic layer deposition

    International Nuclear Information System (INIS)

    Low temperature (∼200 °C) grown atomic layer deposition (ALD) films of AlN, TiN, Al2O3, GaN, and TiO2 were tested for protective capping and surface passivation of bottom-up grown III-V (GaAs and InP) nanowires (NWs), and top-down fabricated InP nanopillars. For as-grown GaAs NWs, only the AlN material passivated the GaAs surface as measured by photoluminescence (PL) at low temperatures (15K), and the best passivation was achieved with a few monolayer thick (2Å) film. For InP NWs, the best passivation (∼2x enhancement in room-temperature PL) was achieved with a capping of 2nm thick Al2O3. All other ALD capping layers resulted in a de-passivation effect and possible damage to the InP surface. Top-down fabricated InP nanopillars show similar passivation effects as InP NWs. In particular, capping with a 2 nm thick Al2O3 layer increased the carrier decay time from 251 ps (as-etched nanopillars) to about 525 ps. Tests after six months ageing reveal that the capped nanostructures retain their optical properties. Overall, capping of GaAs and InP NWs with high-k dielectrics AlN and Al2O3 provides moderate surface passivation as well as long term protection from oxidation and environmental attack

  15. Protective capping and surface passivation of III-V nanowires by atomic layer deposition

    Directory of Open Access Journals (Sweden)

    Veer Dhaka

    2016-01-01

    Full Text Available Low temperature (∼200 °C grown atomic layer deposition (ALD films of AlN, TiN, Al2O3, GaN, and TiO2 were tested for protective capping and surface passivation of bottom-up grown III-V (GaAs and InP nanowires (NWs, and top-down fabricated InP nanopillars. For as-grown GaAs NWs, only the AlN material passivated the GaAs surface as measured by photoluminescence (PL at low temperatures (15K, and the best passivation was achieved with a few monolayer thick (2Å film. For InP NWs, the best passivation (∼2x enhancement in room-temperature PL was achieved with a capping of 2nm thick Al2O3. All other ALD capping layers resulted in a de-passivation effect and possible damage to the InP surface. Top-down fabricated InP nanopillars show similar passivation effects as InP NWs. In particular, capping with a 2 nm thick Al2O3 layer increased the carrier decay time from 251 ps (as-etched nanopillars to about 525 ps. Tests after six months ageing reveal that the capped nanostructures retain their optical properties. Overall, capping of GaAs and InP NWs with high-k dielectrics AlN and Al2O3 provides moderate surface passivation as well as long term protection from oxidation and environmental attack.

  16. Protective capping and surface passivation of III-V nanowires by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Dhaka, Veer, E-mail: veer.dhaka@aalto.fi; Perros, Alexander; Kakko, Joona-Pekko; Haggren, Tuomas; Lipsanen, Harri [Department of Micro- and Nanosciences, Micronova, Aalto University, P.O. Box 13500, FI-00076 (Finland); Naureen, Shagufta; Shahid, Naeem [Research School of Physics & Engineering, Department of Electronic Materials Engineering, Australian National University, Canberra ACT 2601 (Australia); Jiang, Hua; Kauppinen, Esko [Department of Applied Physics and Nanomicroscopy Center, Aalto University, P.O. Box 15100, FI-00076 (Finland); Srinivasan, Anand [School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, S-164 40 Kista (Sweden)

    2016-01-15

    Low temperature (∼200 °C) grown atomic layer deposition (ALD) films of AlN, TiN, Al{sub 2}O{sub 3}, GaN, and TiO{sub 2} were tested for protective capping and surface passivation of bottom-up grown III-V (GaAs and InP) nanowires (NWs), and top-down fabricated InP nanopillars. For as-grown GaAs NWs, only the AlN material passivated the GaAs surface as measured by photoluminescence (PL) at low temperatures (15K), and the best passivation was achieved with a few monolayer thick (2Å) film. For InP NWs, the best passivation (∼2x enhancement in room-temperature PL) was achieved with a capping of 2nm thick Al{sub 2}O{sub 3}. All other ALD capping layers resulted in a de-passivation effect and possible damage to the InP surface. Top-down fabricated InP nanopillars show similar passivation effects as InP NWs. In particular, capping with a 2 nm thick Al{sub 2}O{sub 3} layer increased the carrier decay time from 251 ps (as-etched nanopillars) to about 525 ps. Tests after six months ageing reveal that the capped nanostructures retain their optical properties. Overall, capping of GaAs and InP NWs with high-k dielectrics AlN and Al{sub 2}O{sub 3} provides moderate surface passivation as well as long term protection from oxidation and environmental attack.

  17. A Simple Approach for Molecular Controlled Release based on Atomic Layer Deposition Hybridized Organic-Inorganic Layers.

    Science.gov (United States)

    Boehler, Christian; Güder, Firat; Kücükbayrak, Umut M; Zacharias, Margit; Asplund, Maria

    2016-01-01

    On-demand release of bioactive substances with high spatial and temporal control offers ground-breaking possibilities in the field of life sciences. However, available strategies for developing such release systems lack the possibility of combining efficient control over release with adequate storage capability in a reasonably compact system. In this study we present a new approach to target this deficiency by the introduction of a hybrid material. This organic-inorganic material was fabricated by atomic layer deposition of ZnO into thin films of polyethylene glycol, forming the carrier matrix for the substance to be released. Sub-surface growth mechanisms during this process converted the liquid polymer into a solid, yet water-soluble, phase. This layer permits extended storage for various substances within a single film of only a few micrometers in thickness, and hence demands minimal space and complexity. Improved control over release of the model substance Fluorescein was achieved by coating the hybrid material with a conducting polymer film. Single dosage and repetitive dispensing from this system was demonstrated. Release was controlled by applying a bias potential of ± 0.5 V to the polymer film enabling or respectively suppressing the expulsion of the model drug. In vitro tests showed excellent biocompatibility of the presented system. PMID:26791399

  18. A Simple Approach for Molecular Controlled Release based on Atomic Layer Deposition Hybridized Organic-Inorganic Layers

    Science.gov (United States)

    Boehler, Christian; Güder, Firat; Kücükbayrak, Umut M.; Zacharias, Margit; Asplund, Maria

    2016-01-01

    On-demand release of bioactive substances with high spatial and temporal control offers ground-breaking possibilities in the field of life sciences. However, available strategies for developing such release systems lack the possibility of combining efficient control over release with adequate storage capability in a reasonably compact system. In this study we present a new approach to target this deficiency by the introduction of a hybrid material. This organic-inorganic material was fabricated by atomic layer deposition of ZnO into thin films of polyethylene glycol, forming the carrier matrix for the substance to be released. Sub-surface growth mechanisms during this process converted the liquid polymer into a solid, yet water-soluble, phase. This layer permits extended storage for various substances within a single film of only a few micrometers in thickness, and hence demands minimal space and complexity. Improved control over release of the model substance Fluorescein was achieved by coating the hybrid material with a conducting polymer film. Single dosage and repetitive dispensing from this system was demonstrated. Release was controlled by applying a bias potential of ±0.5 V to the polymer film enabling or respectively suppressing the expulsion of the model drug. In vitro tests showed excellent biocompatibility of the presented system.

  19. Single-Atom Pd₁/Graphene Catalyst Achieved by Atomic Layer Deposition: Remarkable Performance in Selective Hydrogenation of 1,3-Butadiene.

    Science.gov (United States)

    Yan, Huan; Cheng, Hao; Yi, Hong; Lin, Yue; Yao, Tao; Wang, Chunlei; Li, Junjie; Wei, Shiqiang; Lu, Junling

    2015-08-26

    We reported that atomically dispersed Pd on graphene can be fabricated using the atomic layer deposition technique. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy both confirmed that isolated Pd single atoms dominantly existed on the graphene support. In selective hydrogenation of 1,3-butadiene, the single-atom Pd1/graphene catalyst showed about 100% butenes selectivity at 95% conversion at a mild reaction condition of about 50 °C, which is likely due to the changes of 1,3-butadiene adsorption mode and enhanced steric effect on the isolated Pd atoms. More importantly, excellent durability against deactivation via either aggregation of metal atoms or carbonaceous deposits during a total 100 h of reaction time on stream was achieved. Therefore, the single-atom catalysts may open up more opportunities to optimize the activity, selectivity, and durability in selective hydrogenation reactions. PMID:26268551

  20. Research update : Atmospheric pressure spatial atomic layer deposition of ZnO thin films : reactors, doping and devices

    OpenAIRE

    Hoye, Robert L.Z.; David Muñoz-Rojas; Nelson, Shelby F.; Andrea Illiberi; Paul Poodt; Fred Roozeboom; MacManus-Driscoll, Judith L

    2015-01-01

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-S...

  1. CMOS compatible strategy based on selective atomic layer deposition of a hard mask for transferring block copolymer lithography patterns

    International Nuclear Information System (INIS)

    A generic, CMOS compatible strategy for transferring a block copolymer template to a semiconductor substrate is demonstrated. An aluminum oxide (Al2O3) hard mask is selectively deposited by atomic layer deposition in an organized array of holes obtained in a PS matrix via PS-b-PMMA self-assembly. The Al2O3 nanodots act as a highly resistant mask to plasma etching, and are used to pattern high aspect ratio (>10) silicon nanowires and nanopillars.

  2. Photoluminescence Enhancement in Nanotextured Fluorescent SiC Passivated by Atomic Layer Deposited Al2O3 Films

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas;

    2016-01-01

    The influence of thickness of atomic layer deposited Al2O3 films on nano-textured fluorescent 6H-SiC passivation is investigated. The passivation effect on the light emission has been characterized by photoluminescence and time-resolved photoluminescence at room temperature. The results show that...... passivation in fluorescent SiC based white LEDs applications....

  3. Surface passivation of nano-textured fluorescent SiC by atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas;

    2016-01-01

    Nano-textured surfaces have played a key role in optoelectronic materials to enhance the light extraction efficiency. In this work, morphology and optical properties of nano-textured SiC covered with atomic layer deposited (ALD) TiO2 were investigated. In order to obtain a high quality surface for...

  4. Electrical and optical properties of zinc oxide layers grown by the low-temperature atomic layer deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Krajewski, Tomasz A.; Dybko, Krzysztof; Luka, Grzegorz; Wachnicki, Lukasz; Witkowski, Bartlomiej S.; Duzynska, Anna; Kopalko, Krzysztof; Lusakowska, Elzbieta; Kowalski, Bogdan J.; Guziewicz, Elzbieta [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Godlewski, Marek [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science Cardinal Stefan Wyszynski University, ul. Dewajtis 5, 01-815 Warsaw (Poland)

    2010-07-15

    This paper reports on the electrical and optical properties of zinc oxide thin films grown at the temperature range between 160 and 240 C by the atomic layer deposition method using diethylzinc (Zn(C{sub 2}H{sub 5}){sub 2}, DEZn) and deionized water precursors. Silicon and glass were used as substrates for the ZnO growth. These films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), low temperature photoluminescence (LT PL) and low temperature Hall effect measurements. This analysis revealed that all the obtained as-grown ZnO layers are fairly smooth (with a roughness RMS parameter less than 4 nm), show a metallic-like conductivity, exhibited a carriers' concentration (n) of 10{sup 19}-10{sup 20} cm{sup -3} which was found to be practically independent of temperature between 7 and 300 K. From the LT PL spectra, it was established that the carriers' concentration is nearly inversely proportional to the intensity of the LT PL edge emission peak. These observations, together with the fact that the Hall mobility slightly increases at higher temperatures, indicate the existence of a competitive scattering mechanism (on grain boundaries as well as on ionized impurities). However, ionized impurity scattering seems to be the dominant factor limiting the carrier mobility in the discussed case. Moreover, the results suggest that efficient non-radiative Auger processes are responsible for the observed photoluminescence (PL) quenching in the samples with higher electron concentration. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  5. Probing the Structure and Chemistry of Perylenetetracarboxylic Dianhydride on Graphene Before and After Atomic Layer Deposition of Alumina

    OpenAIRE

    Johns, James E.; Karmel, Hunter J.; Alaboson, Justice M. P.; Hersam, Mark C.

    2012-01-01

    The superlative electronic properties of graphene suggest its use as the foundation of next generation integrated circuits. However, this application requires precise control of the interface between graphene and other materials, especially the metal oxides that are commonly used as gate dielectrics. Towards that end, organic seeding layers have been empirically shown to seed ultrathin dielectric growth on graphene via atomic layer deposition (ALD), although the underlying chemical mechanisms...

  6. Growth and electrical properties of atomic-layer deposited ZrO2 /Si-nitride stack gate dielectrics

    OpenAIRE

    Ishii, Hiroyuki; Nakajima, Anri; Yokoyama, Shin

    2004-01-01

    We deposited ZrO2 thin films by atomic-layer deposition (ALD) using zirconium tertiary–butoxide [Zr(t-OC4H9)4, (ZTB)] and H2O source gases on Si substrates at low temperatures. We grew ZrO2 films layer by layer in a temperature range of 175–250 °C to minimize surface roughness. The deposited ZrO2 film thickness had self-limiting properties with the exposure time of ZTB and vapor pressures of ZTB and H2O. The deposition rate per cycle was independent of the vapor pressure of ZTB from 0.01 kPa ...

  7. Surface modification of nitrogen-doped carbon nanotubes by ozone via atomic layer deposition

    International Nuclear Information System (INIS)

    The use of ozone as an oxidizing agent for atomic layer deposition (ALD) processes is rapidly growing due to its strong oxidizing capabilities. However, the effect of ozone on nanostructured substrates such as nitrogen-doped multiwalled carbon nanotubes (NCNTs) and pristine multiwalled carbon nanotubes (PCNTs) are not very well understood and may provide an avenue toward functionalizing the carbon nanotube surface prior to deposition. The effects of ALD ozone treatment on NCNTs and PCNTs using 10 wt. % ozone at temperatures of 150, 250, and 300 °C are studied. The effect of ozone pulse time and ALD cycle number on NCNTs and PCNTs was also investigated. Morphological changes to the substrate were observed by scanning electron microscopy and high resolution transmission electron microscopy. Brunauer-Emmett-Teller measurements were also conducted to determine surface area, pore size, and pore size distribution following ozone treatment. The graphitic nature of both NCNTs and PCNTs was determined using Raman analysis while x-ray photoelectron spectroscopy (XPS) was employed to probe the chemical nature of NCNTs. It was found that O3 attack occurs preferentially to the outermost geometric surface of NCNTs. Our research also revealed that the deleterious effects of ozone are found only on NCNTs while little or no damage occurs on PCNTs. Furthermore, XPS analysis indicated that ALD ozone treatment on NCNTs, at elevated temperatures, results in loss of nitrogen content. Our studies demonstrate that ALD ozone treatment is an effective avenue toward creating low nitrogen content, defect rich substrates for use in electrochemical applications and ALD of various metal/metal oxides

  8. Optical properties of PbS-doped silica optical fiber materials based on atomic layer deposition

    International Nuclear Information System (INIS)

    Highlights: • PbS-doped silica optical fiber materials have been fabricated by ALD technique. • PbS-doped silica optical fiber materials are characterized through XPS, Raman and optical properties. • The local structure model of PbS-3MR for the PbS-doped optical fiber materials is built, and its optical properties are investigated using DFT. • The computed results of absorption and emission peaks are at 325.7 and 769.8 nm, which are good agreement with our experiment results. - Abstract: Optical properties of PbS-doped silica optical fiber materials and theoretical simulation are investigated. PbS is deposited on silica optical fiber materials by Atomic Layer Deposition (ALD) technique with Pb(tmhd)2 and H2S as Pb and S precursors, respectively. Its stoichiometry is confirmed by X-ray photoelectron spectroscopy (XPS). The valence states of S and Pb element are −2 and +2, respectively. The Raman spectra further reveal that PbS has been doped into optical fiber materials almost without destroying irregular rings structure in silica material network. And there are distinct absorption bands at 248 and 352 nm. Fluorescence spectra are obtained with 330 and 350 nm pumping, two fluorescence peaks at 768 and 808 nm, respectively. In addition, the microstructure models for PbS-doped optical fiber materials are built on Gaussian09 platform, and its optical properties of the absorption and emission spectra are calculated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. There are obvious absorption and emission peaks at 325.7 and 769.8 nm, respectively, which are in good agreement with experiments

  9. Thermal chemistry of copper acetamidinate atomic layer deposition precursors on silicon oxide surfaces studied by XPS

    International Nuclear Information System (INIS)

    The thermal surface chemistry of copper(I)-N,N′-di-sec-butylacetamidinate, [Cu(sBu-amd)]2, a metalorganic complex recently proposed for the chemical-based deposition of copper films, has been characterized on SiO2 films under ultrahigh vacuum conditions by x-ray photoelectron spectroscopy (XPS). Initial adsorption at cryogenic temperatures results in the oxidation of the copper centers with Cu 2p3/2 XPS binding energies close to those seen for a +2 oxidation state, an observation that the authors interpret as the result of the additional coordination of oxygen atoms from the surface to the Cu atoms of the molecular acetamidinate dimer. Either heating to 300 K or dosing the precursor directly at that temperature leads to the loss of one of its two ligands, presumably via hydrogenation/protonation with a hydrogen/proton from a silanol group, or following a similar reaction on a defect site. By approximately 500 K the Cu 2p3/2, C 1s, and N 1s XPS data suggest that the remaining acetamidinate ligand is displaced from the copper center and bonds to the silicon oxide directly, after which temperatures above 900 K need to be reached to promote further (and only partial) decomposition of those organic moieties. It was also shown that the uptake of the Cu precursor is self-limiting at either 300 or 500 K, although the initial chemistry is somewhat different at the two temperatures, and that the nature of the substrate also defines reactivity, with the thin native silicon oxide layer always present on Si(100) surfaces being less reactive than thicker films grown by evaporation, presumably because of the lower density of surface nucleation sites

  10. Thermal chemistry of copper acetamidinate atomic layer deposition precursors on silicon oxide surfaces studied by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yunxi; Zaera, Francisco, E-mail: zaera@ucr.edu [Department of Chemistry, University of California, Riverside, California 92521 (United States)

    2016-01-15

    The thermal surface chemistry of copper(I)-N,N′-di-sec-butylacetamidinate, [Cu({sup s}Bu-amd)]{sub 2}, a metalorganic complex recently proposed for the chemical-based deposition of copper films, has been characterized on SiO{sub 2} films under ultrahigh vacuum conditions by x-ray photoelectron spectroscopy (XPS). Initial adsorption at cryogenic temperatures results in the oxidation of the copper centers with Cu 2p{sub 3/2} XPS binding energies close to those seen for a +2 oxidation state, an observation that the authors interpret as the result of the additional coordination of oxygen atoms from the surface to the Cu atoms of the molecular acetamidinate dimer. Either heating to 300 K or dosing the precursor directly at that temperature leads to the loss of one of its two ligands, presumably via hydrogenation/protonation with a hydrogen/proton from a silanol group, or following a similar reaction on a defect site. By approximately 500 K the Cu 2p{sub 3/2}, C 1s, and N 1s XPS data suggest that the remaining acetamidinate ligand is displaced from the copper center and bonds to the silicon oxide directly, after which temperatures above 900 K need to be reached to promote further (and only partial) decomposition of those organic moieties. It was also shown that the uptake of the Cu precursor is self-limiting at either 300 or 500 K, although the initial chemistry is somewhat different at the two temperatures, and that the nature of the substrate also defines reactivity, with the thin native silicon oxide layer always present on Si(100) surfaces being less reactive than thicker films grown by evaporation, presumably because of the lower density of surface nucleation sites.

  11. Well-ordered ZnO nanotube arrays and networks grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Highlights: • ZnO nanotube networks and well-ordered ZnO nanotube arrays are fabricated by ALD. • The wall thickness of the ZnO nanotubes can be well-controlled at the angstrom level. • The fishing net-like networks of ZnO nanotubes with an ultra thin wall thickness are fabricated. • The ZnO nanotube arrays have an aspect ratio as high as 1000:1. - Abstract: Semiconductor ZnO, possessing a large exciton binding energy and wide band gap, has received a great deal of attention because it shows great potential for applications in optoelectronics. Precisely controlling the growth of three-dimensional ZnO nanotube structures with a uniform morphology constitutes an important step forward toward integrating ZnO nanostructures into microelectronic devices. Atomic layer deposition (ALD) technique, featured with self-limiting surface reactions, is an ideal approach to the fabrication of ZnO nanostructures, because it allows for accurate control of the thickness at atomic level and conformal coverage in complex 3D structures. In this work, well-ordered ZnO nanotube arrays and networks are prepared by ALD. The morphology, crystallinity and wall thickness of these nanotube structures are examined for different growth conditions. The microstructure of the ZnO nanotubes is investigated by transmission electron microscopy and X-ray diffraction. The high aspect ratio of ZnO nanotubes provides a large specific area which could enhance the kinetics of chemical reactions taking place between the ZnO and its surroundings, making the potential devices more efficient and compact

  12. Development of atomic layer deposition-activated microchannel plates for single particle detection at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Gorelikov, Dmitry, E-mail: dmitry@arradiance.com; Sullivan, Neal; Rouffignac, Philippe de; Li, Huazhi; Narayanamoorthy, Jayasri; Tremsin, Anton S. [Arradiance Inc., 142 North Road, Sudbury, Massachusetts 01776 (United States)

    2014-03-15

    Atomic layer deposition (ALD) technology is used to nanoengineer functional films inside the pores of microchannel plate (MCP) electron multipliers, enabling a novel MCP manufacturing technology that substantially improves performance and opens novel applications. The authors have developed custom tools and recipes for the growth of conformal films, with optimized conductance and secondary electron emission inside very long channels (∼6–20 μm diameter and >600 μm length, with tens of millions of channels per single MCP) by ALD. The unique ability to tune the characteristics of these ALD films enables their optimization to applications where time-resolved single particle imaging can be performed in extreme conditions, such as high counting rates at cryogenic temperatures. Adhesion of the conductive and emissive nanofilms to the 20 μm pore MCP glass substrates and their mechanical stability over a very wide range of temperatures (10–700 K) were confirmed experimentally. Resistance of ALD MCPs was reproducible during multiple cool-down cycles with no film degradation observed. Optimizing resistance of novel MCPs for operation at cryogenic temperature should enable high count rate event detection at temperatures below 20 K.

  13. Atomic layer deposition of ytterbium oxide using β-diketonate and ozone precursors

    International Nuclear Information System (INIS)

    Yb2O3 thin films were grown onto Si(1 0 0) and glass substrates by atomic layer deposition using Yb(thd)3 and ozone precursors. Self saturating growth appeared when the growth temperature was between 300 and 350 deg. C. Polycrystalline BCC structure with (2 2 2), (4 0 0), (4 1 1), (4 4 0), (6 1 1) and (6 2 2) orientations was observed using X-ray diffraction measurements with lattice constant a0=10.4 A. The mass density for the films grown at 300 and 350 o C was found to be 8.9 and 9.0 g/cm3, respectively. The film roughness increased with growth temperature from 0.9 (at 300 deg. C) to 1.3 nm (350 deg. C). Elastic recoil detection analysis revealed that the Yb/O ratio of the films grown at 350 deg. C was 0.63 and the films contained 1.1% hydrogen, 0.7% carbon and 0.08% nitrogen impurities. The refractive index of the film was about 1.9 at near-IR wavelength.

  14. Electrical behavior of atomic layer deposited high quality SiO{sub 2} gate dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Sangram K.; Tanyi, Ekembu K.; Skuza, Jonathan R.; Xiao, Bo; Pradhan, Aswini K., E-mail: apradhan@nsu.edu [Center for Materials Research, Norfolk State University, 700 Park Ave., Norfolk, Virginia 23504 (United States)

    2015-01-01

    Comprehensive and systematic electrical studies were performed on fabrication of high quality SiO{sub 2} thin films MOS capacitor using the robust, novel, and simple atomic layer deposition (ALD) technique using highly reactive ozone and tris (dimethylamino) silane (TDMAS) precursors. Ideal capacitance–voltage curve exhibits a very small frequency dispersion and hysteresis behavior of the SiO{sub 2} MOS capacitor grown at 1 s TDMAS pulse, suggesting excellent interfacial quality and purity of the film as probed using x-ray photoelectron studies. The flat-band voltage of the device shifted from negative toward positive voltage axis with increase of TDMAS pulses from 0.2 to 2 s. Based on an equivalent oxide thickness point of view, all SiO{sub 2} films have gate leakage current density of (5.18 × 10{sup −8} A/cm{sup 2}) as well as high dielectric break down fields of more than (∼10 MV/cm), which is better and comparable to that of thermally grown SiO{sub 2} at temperatures above 800 °C. These appealing electrical properties of ALD grown SiO{sub 2} thin films enable its potential applications such as high-quality gate insulators for thin film MOS transistors, as well as insulators for sensor and nanostructures on nonsilicon substrates.

  15. Periodic oxidation for fabricating titanium oxynitride thin films via atomic layer deposition

    International Nuclear Information System (INIS)

    This paper demonstrates thermal atomic layer deposition (ALD) combined with periodic oxidation for synthesizing titanium oxynitride (TiON) thin films. The process used a typical ALD reactor for the synthesis of titanium nitride (TiN) films wherein oxygen was supplied periodically between the ALD-TiN cycles. The great advantage of the process proposed here was that it allowed the TiN films to be oxidized efficiently. Also, a uniform depth profile of the oxygen concentration in the films could be obtained by tuning the oxidation conditions, allowing the process to produce a wide variety of TiON films. The resistivity measurement is a convenient method to confirm the reproducibility of metal film fabrication but may not be applicable for TiON films depending upon the oxidation condition because the films can easily turn into insulators when subjected to periodic oxidation. Therefore, an alternative reproducibility confirmation method was required. In this study, spectroscopic ellipsometry was applied to monitor the variation of TiON films and was able to detect changes in film structures such as conductor–insulator transitions in the TiON films

  16. Probabilistic distributions of pinhole defects in atomic layer deposited films on polymeric substrates

    International Nuclear Information System (INIS)

    Pinhole defects in atomic layer deposition (ALD) coatings were measured in an area of 30 cm2 in an ALD reactor, and these defects were represented by a probabilistic cluster model instead of a single defect density value with number of defects over area. With the probabilistic cluster model, the pinhole defects were simulated over a manufacturing scale surface area of ∼1 m2. Large-area pinhole defect simulations were used to develop an improved and enhanced design method for ALD-based devices. A flexible thermal ground plane (FTGP) device requiring ALD hermetic coatings was used as an example. Using a single defect density value, it was determined that for an application with operation temperatures higher than 60 °C, the FTGP device would not be possible. The new probabilistic cluster model shows that up to 40.3% of the FTGP would be acceptable. With this new approach the manufacturing yield of ALD-enabled or other thin film based devices with different design configurations can be determined. It is important to guide process optimization and control and design for manufacturability

  17. Large-area thermoelectric high-aspect-ratio nanostructures by atomic layer deposition.

    Science.gov (United States)

    Ruoho, Mikko; Juntunen, Taneli; Tittonen, Ilkka

    2016-09-01

    We report on the thermoelectric properties of large-area high-aspect-ratio nanostructures. We fabricate the structures by atomic layer deposition of conformal ZnO thin films on track-etched polycarbonate substrate. The resulting structure consists of ZnO tubules which continue through the full thickness of the substrate. The electrical and thermal properties of the structures are studied both in-plane and out-of-plane. They exhibit very low out-of-plane thermal conductivity down to 0.15 W m(-1) K(-1) while the in-plane sheet resistance of the films was found to be half that of the same film on glass substrate, allowing material-independent doubling of output power of any planar thin-film thermoelectric generator. The wall thickness of the fabricated nanotubes was varied within a range of up to 100 nm. The samples show polycrystalline nature with (002) preferred crystal orientation. PMID:27454037

  18. Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis-catalysis testing tool

    Science.gov (United States)

    Camacho-Bunquin, Jeffrey; Shou, Heng; Aich, Payoli; Beaulieu, David R.; Klotzsch, Helmut; Bachman, Stephen; Marshall, Christopher L.; Hock, Adam; Stair, Peter

    2015-08-01

    An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10-3 to 1 bar and 300-1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al2O3 overcoats, and evaluation of catalyst propylene hydrogenation activity.

  19. Composite organic-inorganic butterfly scales: production of photonic structures with atomic layer deposition.

    Science.gov (United States)

    Gaillot, Davy P; Deparis, Olivier; Welch, Victoria; Wagner, Brent K; Vigneron, Jean Pol; Summers, Christopher J

    2008-09-01

    Recent advances in the photonics and optics industries have produced great demand for ever more sophisticated optical devices, such as photonic crystals. However, photonic crystals are notoriously difficult to manufacture. Increasingly, therefore, researchers have turned towards naturally occurring photonic structures for inspiration and a wide variety of elaborate techniques have been attempted to copy and harness biological processes to manufacture artificial photonic structures. Here, we describe a simple, direct process for producing an artificial photonic device by using a naturally occurring structure from the wings of the butterfly Papilio blumei as a template and low-temperature atomic layer deposition of TiO2 to create a faithful cast of the structure. The optical properties of the organic-inorganic diffraction structures produced are assessed by normal-incidence specular reflectance and found to be well described by multilayer computation method using a two-dimensional photonic crystal model. Depending on the structural integrity of the initially sealed scale, it was found possible not only to replicate the outer but also the inner and more complex surfaces of the structure, each resulting in distinct multicolor optical behavior as revealed by experimental and theoretical data. In this paper, we also explore tailoring the process to design composite skeleton architectures with desired optical properties and integrated multifunctional (mechanical, thermal, optical, fluidic) properties. PMID:18851080

  20. In situ measurement of fixed charge evolution at silicon surfaces during atomic layer deposition

    International Nuclear Information System (INIS)

    Interfacial fixed charge or interfacial dipoles are present at many semiconductor-dielectric interfaces and have important effects upon device behavior, yet the chemical origins of these electrostatic phenomena are not fully understood. We report the measurement of changes in Si channel conduction in situ during atomic layer deposition (ALD) of aluminum oxide using trimethylaluminum and water to probe changes in surface electrostatics. Current-voltage data were acquired continually before, during, and after the self-limiting chemical reactions that result in film growth. Our measurements indicated an increase in conductance on p-type samples with p+ ohmic contacts and a decrease in conductance on analogous n-type samples. Further, p+ contacted samples with n-type channels exhibited an increase in measured current and n+ contacted p-type samples exhibited a decrease in current under applied voltage. Device physics simulations, where a fixed surface charge was parameterized on the channel surface, connect the surface charge to changes in current-voltage behavior. The simulations and analogous analytical relationships for near-surface conductance were used to explain the experimental results. Specifically, the changes in current-voltage behavior can be attributed to the formation of a fixed negative charge or the modification of a surface dipole upon chemisorption of trimethylaluminum. These measurements allow for the observation of fixed charge or dipole formation during ALD and provide further insight into the electrostatic behavior at semiconductor-dielectric interfaces during film nucleation

  1. Emerging applications of atomic layer deposition for lithium-ion battery studies

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiangbo [Department of Mechanical and Materials Engineering, University of Western Ontario, London (Canada); Chemistry Department, Brookhaven National Laboratory, Upton, NY (United States); Yang, Xiao-Qing [Chemistry Department, Brookhaven National Laboratory, Upton, NY (United States); Sun, Xueliang [Department of Mechanical and Materials Engineering, University of Western Ontario, London (Canada)

    2012-07-17

    Lithium-ion batteries (LIBs) are used widely in today's consumer electronics and offer great potential for hybrid electric vehicles (HEVs), plug-in HEVs, pure EVs, and also in smart grids as future energy-storage devices. However, many challenges must be addressed before these future applications of LIBs are realized, such as the energy and power density of LIBs, their cycle and calendar life, safety characteristics, and costs. Recently, a technique called atomic layer deposition (ALD) attracted great interest as a novel tool and approach for resolving these issues. In this article, recent advances in using ALD for LIB studies are thoroughly reviewed, covering two technical routes: 1) ALD for designing and synthesizing new LIB components, i.e., anodes, cathodes, and solid electrolytes, and; 2) ALD used in modifying electrode properties via surface coating. This review will hopefully stimulate more extensive and insightful studies on using ALD for developing high-performance LIBs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Standing and sitting adlayers in atomic layer deposition of ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhengning; Banerjee, Parag, E-mail: parag.banerjee@wustl.edu [Department of Mechanical Engineering & Material Science, Washington University in St. Louis, Missouri 63130 and Institute of Materials Science & Engineering, Washington University in St. Louis, Missouri 63130 (United States); Wu, Fei; Myung, Yoon [Department of Mechanical Engineering & Material Science, Washington University in St. Louis, Missouri 63130 (United States); Fei, Ruixiang [Department of Physics, Washington University in St. Louis, Missouri 63130 (United States); Kanjolia, Ravindra [SAFC Hitech, 1429 Hilldale Ave., Haverhill, Massachusetts 01832 (United States); Yang, Li [Institute of Materials Science & Engineering, Washington University in St. Louis, Missouri 63130 and Department of Physics, Washington University in St. Louis, Missouri 63130 (United States)

    2016-01-15

    The extent of reactivity of diethyl zinc (DEZ) with a hydroxylated surface during atomic layer deposition (ALD) of ZnO using DEZ and water is measured. Two adlayer configurations of DEZ are possible. The “standing” adlayer releases one ethyl group from DEZ. The “sitting” adlayer releases both ethyl groups, thus forming a Zn bridge between two O anions. Density functional theory calculations suggest the sitting configuration is more stable than the standing configuration by 790 meV. In situ quadrupole mass spectroscopy of by-product ethane generated in ALD half cycles indicate that ∼1.56 OH sites react with a DEZ molecule resulting in 71.6% of sitting sites. A simple simulation of a “ball-and-stick” DEZ molecule randomly collapsing on a neighboring site remarkably captures this adlayer behavior. It is concluded that DEZ fraction sitting is a competitive process of a standing DEZ molecule collapsing onto an available neighboring hydroxyl site, as sites vie for occupancy via adsorption and surface diffusion.

  3. Thermal properties of TiO2 films fabricated by atomic layer deposition

    International Nuclear Information System (INIS)

    Thin, amorphous, high index, dense, low scattering and absorption (low extinction coefficient) and optical grade TiO2 films of various thicknesses are prepared by Atomic layer deposition (ALD) technique and investigated in terms of thermo-optic coefficient (dn/dT) and temperature dependent density (dρ/dT). The dρ/dT and dρ/dT are calculated by modeling ellipsometric experimental data by developing appropriate optical model such as Cauchy Model. The modeled data was further modeled with Lorentz-Lorenz relation under least-square approach. The dn/dT of TiO2 films shows negative values for thin and positive values for relatively thicker films and reveals no significant changes in dn/dT and dρ/dT when film thickness increases more than ∼ 200 nm. The coefficient values are calculated for a wavelength range of 380–1800 nm. The average values of (dn/dT)60nm= −4.2 ± 0.7 × 10−5°C−1 and (dρ/dT)60nm= −6.6 ± 1.1 × 10−5gcm−3 °C−1 at wavelength of 640 nm. The reported coefficients values are measured and calculated for TiO2 film of thickness t = 60 nm and described in detail

  4. Thermal properties of TiO/sub 2/ films fabricated by atomic layer deposition

    International Nuclear Information System (INIS)

    Thin, amorphous, high index, dense, low scattering and absorption (low extinction coefficient) and optical grade TiO/sub 2/ films of various thicknesses are prepared by Atomic layer deposition (ALD) technique and investigated in terms of thermo-optic coefficient (d eta /d Tau) and temperature dependent density (d rho /d Tau). The d rho /d Tau and d rho /d Tau are calculated by modeling ellipsometric experimental data by developing appropriate optical model such as Cauchy Model. The modeled data was further modeled with Lorentz-Lorenz relation under least-square approach. The d rho /d Tau of TiO/sub 2/ films shows negative values for thin and positive values for relatively thicker films and reveals no significant changes in dn/dT and d rho /d Tau when film thickness increases more than approx 200 nm. The coefficient values are calculated for a wavelength range of 380-1800 nm. The average values of (d rho /d Tau)60nm= -4.2 ± 0.7 * 10-5 degree C-1 and (d rho /d Tau)60nm= -6.6 ± 1.1 * 10-/sup 5/gcm -/sup 3/ degree C-/sup 1/ at wavelength of 640 nm. The reported coefficients values are measured and calculated for TiO/sub 2/ film of thickness t = 60 nm and described in detail. (author)

  5. Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis–catalysis testing tool

    Energy Technology Data Exchange (ETDEWEB)

    Camacho-Bunquin, Jeffrey; Shou, Heng; Marshall, Christopher L. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Aich, Payoli [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Beaulieu, David R.; Klotzsch, Helmut; Bachman, Stephen [Arradiance Inc., Sudbury, Massachusetts 01776 (United States); Hock, Adam [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Stair, Peter [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)

    2015-08-15

    An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10{sup −3} to 1 bar and 300–1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al{sub 2}O{sub 3} overcoats, and evaluation of catalyst propylene hydrogenation activity.

  6. Probabilistic distributions of pinhole defects in atomic layer deposited films on polymeric substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yersak, Alexander S., E-mail: alexander.yersak@colorado.edu; Lee, Yung-Cheng [Department of Mechanical Engineering, University of Colorado at Boulder, 1045 Regent Drive, 422 UCB, Boulder, Colorado 80309-0422 (United States)

    2016-01-15

    Pinhole defects in atomic layer deposition (ALD) coatings were measured in an area of 30 cm{sup 2} in an ALD reactor, and these defects were represented by a probabilistic cluster model instead of a single defect density value with number of defects over area. With the probabilistic cluster model, the pinhole defects were simulated over a manufacturing scale surface area of ∼1 m{sup 2}. Large-area pinhole defect simulations were used to develop an improved and enhanced design method for ALD-based devices. A flexible thermal ground plane (FTGP) device requiring ALD hermetic coatings was used as an example. Using a single defect density value, it was determined that for an application with operation temperatures higher than 60 °C, the FTGP device would not be possible. The new probabilistic cluster model shows that up to 40.3% of the FTGP would be acceptable. With this new approach the manufacturing yield of ALD-enabled or other thin film based devices with different design configurations can be determined. It is important to guide process optimization and control and design for manufacturability.

  7. Plasma-enhanced atomic layer deposition of titanium oxynitrides films: A comparative spectroscopic and electrical study

    Energy Technology Data Exchange (ETDEWEB)

    Sowińska, Małgorzata, E-mail: malgorzata.sowinska@b-tu.de; Henkel, Karsten; Schmeißer, Dieter [Brandenburg University of Technology Cottbus-Senftenberg, Applied Physics and Sensors, K.-Wachsmann-Allee 17, 03046 Cottbus (Germany); Kärkkänen, Irina; Schneidewind, Jessica; Naumann, Franziska; Gruska, Bernd; Gargouri, Hassan [SENTECH Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin (Germany)

    2016-01-15

    The process parameters' impact of the plasma-enhanced atomic layer deposition (PE-ALD) method on the oxygen to nitrogen (O/N) ratio in titanium oxynitride (TiO{sub x}N{sub y}) films was studied. Titanium(IV)isopropoxide in combination with NH{sub 3} plasma and tetrakis(dimethylamino)titanium by applying N{sub 2} plasma processes were investigated. Samples were characterized by the in situ spectroscopic ellipsometry, x-ray photoelectron spectroscopy, and electrical characterization (current–voltage: I-V and capacitance–voltage: C-V) methods. The O/N ratio in the TiO{sub x}N{sub y} films is found to be very sensitive for their electric properties such as conductivity, dielectric breakdown, and permittivity. Our results indicate that these PE-ALD film properties can be tuned, via the O/N ratio, by the selection of the process parameters and precursor/coreactant combination.

  8. Evidence for hydrogen two-level systems in atomic layer deposition oxides

    Science.gov (United States)

    Khalil, M. S.; Stoutimore, M. J. A.; Gladchenko, S.; Holder, A. M.; Musgrave, C. B.; Kozen, A. C.; Rubloff, G.; Liu, Y. Q.; Gordon, R. G.; Yum, J. H.; Banerjee, S. K.; Lobb, C. J.; Osborn, K. D.

    2013-10-01

    Two-level system (TLS) defects in dielectrics are known to limit the performance of electronic devices. We study TLS using millikelvin microwave (6.4 GHz) loss measurements of three atomic layer deposited (ALD) oxide films-crystalline BeO (c-BeO), amorphous Al2O3 (a-Al2O3), and amorphous LaAlO3 (a-LaAlO3)-and interpret them with room temperature characterization measurements. We find that the bulk loss tangent in the crystalline film is 6 times higher than in the amorphous films. In addition, its power saturation agrees with an amorphous distribution of TLS. Secondary ion mass spectrometry (SIMS) impurity analysis of the c-BeO film showed excess surface carbon (C) impurities and a uniform hydrogen (H) impurity distribution, which coupled with the analysis of loss tangent strongly suggests H limited loss. Impurity analysis of the amorphous films reveals that they have excess H impurities at the ambient-exposed surface, and we extract the associated H-based surface loss tangent. We compare two a-Al2O3 films with drastically different C impurity concentrations and similar H impurity concentrations and conclude that H rather than C is the likely source of loss in the amorphous films and we find the loss per H concentration in a-Al2O3 to be KH =3×10-24 cm3.

  9. Atomic layer deposition of ytterbium oxide using {beta}-diketonate and ozone precursors

    Energy Technology Data Exchange (ETDEWEB)

    Bosund, M., E-mail: Markus.Bosund@tkk.fi [Department of Micro and Nanosciences, Helsinki University of Technology, Tietotie 3, P.O. Box 3500, FI-02015 TKK, Espoo (Finland); Mizohata, K. [The Division of Materials Physics, Department of Physics, University of Helsinki (Finland); Hakkarainen, T. [Department of Micro and Nanosciences, Helsinki University of Technology, Tietotie 3, P.O. Box 3500, FI-02015 TKK, Espoo (Finland); Putkonen, M. [Beneq Oy, P.O. Box 262, FI-01511 Vantaa (Finland); Soederlund, M.; Honkanen, S.; Lipsanen, H. [Department of Micro and Nanosciences, Helsinki University of Technology, Tietotie 3, P.O. Box 3500, FI-02015 TKK, Espoo (Finland)

    2009-11-15

    Yb{sub 2}O{sub 3} thin films were grown onto Si(1 0 0) and glass substrates by atomic layer deposition using Yb(thd){sub 3} and ozone precursors. Self saturating growth appeared when the growth temperature was between 300 and 350 deg. C. Polycrystalline BCC structure with (2 2 2), (4 0 0), (4 1 1), (4 4 0), (6 1 1) and (6 2 2) orientations was observed using X-ray diffraction measurements with lattice constant a{sub 0}=10.4 A. The mass density for the films grown at 300 and 350 {sup o} C was found to be 8.9 and 9.0 g/cm{sup 3}, respectively. The film roughness increased with growth temperature from 0.9 (at 300 deg. C) to 1.3 nm (350 deg. C). Elastic recoil detection analysis revealed that the Yb/O ratio of the films grown at 350 deg. C was 0.63 and the films contained 1.1% hydrogen, 0.7% carbon and 0.08% nitrogen impurities. The refractive index of the film was about 1.9 at near-IR wavelength.

  10. Standing and sitting adlayers in atomic layer deposition of ZnO

    International Nuclear Information System (INIS)

    The extent of reactivity of diethyl zinc (DEZ) with a hydroxylated surface during atomic layer deposition (ALD) of ZnO using DEZ and water is measured. Two adlayer configurations of DEZ are possible. The “standing” adlayer releases one ethyl group from DEZ. The “sitting” adlayer releases both ethyl groups, thus forming a Zn bridge between two O anions. Density functional theory calculations suggest the sitting configuration is more stable than the standing configuration by 790 meV. In situ quadrupole mass spectroscopy of by-product ethane generated in ALD half cycles indicate that ∼1.56 OH sites react with a DEZ molecule resulting in 71.6% of sitting sites. A simple simulation of a “ball-and-stick” DEZ molecule randomly collapsing on a neighboring site remarkably captures this adlayer behavior. It is concluded that DEZ fraction sitting is a competitive process of a standing DEZ molecule collapsing onto an available neighboring hydroxyl site, as sites vie for occupancy via adsorption and surface diffusion

  11. Spectroscopic characterization of ZrO2 thin films grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Zirconium dioxide films grown by atomic layer deposition from ZrCl4 and H2O at substrate temperatures of 500-870 K were characterized using spectroscopic methods. A significant influence of the phase composition on absorption and photoluminescence spectra was observed. The band-gap energies determined from absorption spectra of films with monoclinic structure grown at 670-870 K ranged from 5.25 to 5.28 eV. Low-temperature (10 K) photoexcitation of these films resulted in a non-elementary emission band with the maximum at 4.25-4.35 eV, tentatively assigned to the radiative decay of self-trapped excitons. The low-energy edges of the excitation spectra coincided with the edges of intrinsic absorption. A film that was grown at 500 K and contained tetragonal ZrO2 with large amounts of impurities had an absorption edge at 5.26 eV and wide emission band at 3.0 eV, which could be excited at as low photon energy as 4.9 eV. (author)

  12. Fluidized-bed atomic layer deposition reactor for the synthesis of core-shell nanoparticles

    International Nuclear Information System (INIS)

    The design of a fluidized bed atomic layer deposition (ALD) reactor is described in detail. The reactor consists of three parts that have all been placed in one protective cabinet: precursor dosing, reactor, and residual gas treatment section. In the precursor dosing section, the chemicals needed for the ALD reaction are injected into the carrier gas using different methods for different precursors. The reactor section is designed in such a way that a homogeneous fluidized bed can be obtained with a constant, actively controlled, reactor pressure. Furthermore, no filters are required inside the reactor chamber, minimizing the risk of pressure increase due to fouling. The residual gas treatment section consists of a decomposition furnace to remove residual precursor and a particle filter and is installed to protect the pump. In order to demonstrate the performance of the reactor, SiO2 particles have been coated with TiO2 using tetrakis-dimethylamino titanium (TDMAT) and H2O as precursors. Experiments with varying pulse times show that saturated growth can be obtained with TDMAT pulse times larger than 600 s. Analysis of the powder with High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) and energy dispersive X-ray spectroscopy confirmed that after 50 cycles, all SiO2 particles were coated with a 1.6 nm homogenous shell of TiO2

  13. Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis–catalysis testing tool

    International Nuclear Information System (INIS)

    An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10−3 to 1 bar and 300–1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al2O3 overcoats, and evaluation of catalyst propylene hydrogenation activity

  14. Macroporous p-GaP Photocathodes Prepared by Anodic Etching and Atomic Layer Deposition Doping.

    Science.gov (United States)

    Lee, Sudarat; Bielinski, Ashley R; Fahrenkrug, Eli; Dasgupta, Neil P; Maldonado, Stephen

    2016-06-29

    P-type macroporous gallium phosphide (GaP) photoelectrodes have been prepared by anodic etching of an undoped, intrinsically n-type GaP(100) wafer and followed by drive-in doping with Zn from conformal ZnO films prepared by atomic layer deposition (ALD). Specifically, 30 nm ALD ZnO films were coated on GaP macroporous films and then annealed at T = 650 °C for various times to diffuse Zn in GaP. Under 100 mW cm(-2) white light illumination, the resulting Zn-doped macroporous GaP consistently exhibit strong cathodic photocurrent when measured in aqueous electrolyte containing methyl viologen. Wavelength-dependent photoresponse measurements of the Zn-doped macroporous GaP revealed enhanced collection efficiency at wavelengths longer than 460 nm, indicating that the ALD doping step rendered the entire material p-type and imparted the ability to sustain a strong internal electric field that preferentially drove photogenerated electrons to the GaP/electrolyte interface. Collectively, this work presents a doping strategy with a potentially high degree of controllability for high-aspect ratio III-V materials, where the ZnO ALD film is a practical dopant source for Zn. PMID:27254534

  15. Plasma-Enhanced Atomic Layer Deposition of Silicon Nitride Using a Novel Silylamine Precursor.

    Science.gov (United States)

    Park, Jae-Min; Jang, Se Jin; Yusup, Luchana L; Lee, Won-Jun; Lee, Sang-Ick

    2016-08-17

    We report the plasma-enhanced atomic layer deposition (PEALD) of silicon nitride thin film using a silylamine compound as the silicon precursor. A series of silylamine compounds were designed by replacing SiH3 groups in trisilylamine by dimethylaminomethylsilyl or trimethylsilyl groups to obtain sufficient thermal stability. The silylamine compounds were synthesized through redistribution, amino-substitution, lithiation, and silylation reactions. Among them, bis(dimethylaminomethylsilyl)trimethylsilyl amine (C9H29N3Si3, DTDN2-H2) was selected as the silicon precursor because of the lowest bond dissociation energy and sufficient vapor pressures. The energies for adsorption and reaction of DTDN2-H2 with the silicon nitride surface were also calculated by density functional theory. PEALD silicon nitride thin films were prepared using DTDN2-H2 and N2 plasma. The PEALD process window was between 250 and 400 °C with a growth rate of 0.36 Å/cycle. The best film quality was obtained at 400 °C with a RF power of 100 W. The PEALD film prepared showed good bottom and sidewall coverages of ∼80% and ∼73%, respectively, on a trench-patterned wafer with an aspect ratio of 5.5. PMID:27447839

  16. Sub-5 nm nanostructures fabricated by atomic layer deposition using a carbon nanotube template

    Science.gov (United States)

    Woo, Ju Yeon; Han, Hyo; Kim, Ji Weon; Lee, Seung-Mo; Ha, Jeong Sook; Shim, Joon Hyung; Han, Chang-Soo

    2016-07-01

    The fabrication of nanostructures having diameters of sub-5 nm is very a important issue for bottom-up nanofabrication of nanoscale devices. In this work, we report a highly controllable method to create sub-5 nm nano-trenches and nanowires by combining area-selective atomic layer deposition (ALD) with single-walled carbon nanotubes (SWNTs) as templates. Alumina nano-trenches having a depth of 2.6 ∼ 3.0 nm and SiO2 nano-trenches having a depth of 1.9 ∼ 2.2 nm fully guided by the SWNTs have been formed on SiO2/Si substrate. Through infilling ZnO material by ALD in alumina nano-trenches, well-defined ZnO nanowires having a thickness of 3.1 ∼ 3.3 nm have been fabricated. In order to improve the electrical properties of ZnO nanowires, as-fabricated ZnO nanowires by ALD were annealed at 350 °C in air for 60 min. As a result, we successfully demonstrated that as-synthesized ZnO nanowire using a specific template can be made for various high-density resistive components in the nanoelectronics industry.

  17. In situ measurement of fixed charge evolution at silicon surfaces during atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Ling; Watt, Morgan R.; Strandwitz, Nicholas C., E-mail: strand@lehigh.edu [Department of Materials Science and Engineering and Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, Pennsylvania 18015 (United States)

    2015-02-09

    Interfacial fixed charge or interfacial dipoles are present at many semiconductor-dielectric interfaces and have important effects upon device behavior, yet the chemical origins of these electrostatic phenomena are not fully understood. We report the measurement of changes in Si channel conduction in situ during atomic layer deposition (ALD) of aluminum oxide using trimethylaluminum and water to probe changes in surface electrostatics. Current-voltage data were acquired continually before, during, and after the self-limiting chemical reactions that result in film growth. Our measurements indicated an increase in conductance on p-type samples with p{sup +} ohmic contacts and a decrease in conductance on analogous n-type samples. Further, p{sup +} contacted samples with n-type channels exhibited an increase in measured current and n{sup +} contacted p-type samples exhibited a decrease in current under applied voltage. Device physics simulations, where a fixed surface charge was parameterized on the channel surface, connect the surface charge to changes in current-voltage behavior. The simulations and analogous analytical relationships for near-surface conductance were used to explain the experimental results. Specifically, the changes in current-voltage behavior can be attributed to the formation of a fixed negative charge or the modification of a surface dipole upon chemisorption of trimethylaluminum. These measurements allow for the observation of fixed charge or dipole formation during ALD and provide further insight into the electrostatic behavior at semiconductor-dielectric interfaces during film nucleation.

  18. Sub-5 nm nanostructures fabricated by atomic layer deposition using a carbon nanotube template.

    Science.gov (United States)

    Woo, Ju Yeon; Han, Hyo; Kim, Ji Weon; Lee, Seung-Mo; Ha, Jeong Sook; Shim, Joon Hyung; Han, Chang-Soo

    2016-07-01

    The fabrication of nanostructures having diameters of sub-5 nm is very a important issue for bottom-up nanofabrication of nanoscale devices. In this work, we report a highly controllable method to create sub-5 nm nano-trenches and nanowires by combining area-selective atomic layer deposition (ALD) with single-walled carbon nanotubes (SWNTs) as templates. Alumina nano-trenches having a depth of 2.6 ∼ 3.0 nm and SiO2 nano-trenches having a depth of 1.9 ∼ 2.2 nm fully guided by the SWNTs have been formed on SiO2/Si substrate. Through infilling ZnO material by ALD in alumina nano-trenches, well-defined ZnO nanowires having a thickness of 3.1 ∼ 3.3 nm have been fabricated. In order to improve the electrical properties of ZnO nanowires, as-fabricated ZnO nanowires by ALD were annealed at 350 °C in air for 60 min. As a result, we successfully demonstrated that as-synthesized ZnO nanowire using a specific template can be made for various high-density resistive components in the nanoelectronics industry. PMID:27188268

  19. Fabrication of metallic single electron transistors featuring plasma enhanced atomic layer deposition of tunnel barriers

    Science.gov (United States)

    Karbasian, Golnaz

    The continuing increase of the device density in integrated circuits (ICs) gives rise to the high level of power that is dissipated per unit area and consequently a high temperature in the circuits. Since temperature affects the performance and reliability of the circuits, minimization of the energy consumption in logic devices is now the center of attention. According to the International Technology Roadmaps for Semiconductors (ITRS), single electron transistors (SETs) hold the promise of achieving the lowest power of any known logic device, as low as 1x10-18 J per switching event. Moreover, SETs are the most sensitive electrometers to date, and are capable of detecting a fraction of an electron charge. Despite their low power consumption and high sensitivity for charge detection, room temperature operation of these devices is quite challenging mainly due to lithographical constraints in fabricating structures with the required dimensions of less than 10 nm. Silicon based SETs have been reported to operate at room temperature. However, they all suffer from significant variation in batch-to-batch performance, low fabrication yield, and temperature-dependent tunnel barrier height. In this project, we explored the fabrication of SETs featuring metal-insulator-metal (MIM) tunnel junctions. While Si-based SETs suffer from undesirable effect of dopants that result in irregularities in the device behavior, in metal-based SETs the device components (tunnel barrier, island, and the leads) are well-defined. Therefore, metal SETs are potentially more predictable in behavior, making them easier to incorporate into circuits, and easier to check against theoretical models. Here, the proposed fabrication method takes advantage of unique properties of chemical mechanical polishing (CMP) and plasma enhanced atomic layer deposition (PEALD). Chemical mechanical polishing provides a path for tuning the dimensions of the tunnel junctions, surpassing the limits imposed by electron beam

  20. Electroless Cu deposition on atomic layer deposited Ru as novel seed formation process in through-Si vias

    International Nuclear Information System (INIS)

    High aspect ratio through Si vias (φ 2 μm, depth 30 μm) have been filled completely by Cu electroplating using an electroless deposited Cu seed layer. The electroless Cu deposition was carried out on ALD–Ru; the time transient of the mixed potential on Ru showed a catalyst type of behavior. The ELD–Cu, which was deposited inside TSVs along their sidewalls, was defect free and worked as a seed layer for electrodeposition of Cu to fill the structure. With a conventional method, such as PVD–Cu, it is challenging to deposit a seed in such structures. The adhesion strength of this ELD–Cu film on ALD–Ru was measured to be >100 MPa. These coupon-scale results show the feasibility of electroless deposition in TSV processing

  1. Atomic layer deposition on polymer fibers and fabrics for multifunctional and electronic textiles

    Energy Technology Data Exchange (ETDEWEB)

    Brozena, Alexandra H.; Oldham, Christopher J.; Parsons, Gregory N., E-mail: gnp@ncsu.edu [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905 (United States)

    2016-01-15

    Textile materials, including woven cotton, polymer knit fabrics, and synthetic nonwoven fiber mats, are being explored as low-cost, flexible, and light-weight platforms for wearable electronic sensing, communication, energy generation, and storage. The natural porosity and high surface area in textiles is also useful for new applications in environmental protection, chemical decontamination, pharmaceutical and chemical manufacturing, catalytic support, tissue regeneration, and others. These applications raise opportunities for new chemistries, chemical processes, biological coupling, and nanodevice systems that can readily combine with textile manufacturing to create new “multifunctional” fabrics. Atomic layer deposition (ALD) has a unique ability to form highly uniform and conformal thin films at low processing temperature on nonuniform high aspect ratio surfaces. Recent research shows how ALD can coat, modify, and otherwise improve polymer fibers and textiles by incorporating new materials for viable electronic and other multifunctional capabilities. This article provides a current overview of the understanding of ALD coating and modification of textiles, including current capabilities and outstanding problems, with the goal of providing a starting point for further research and advances in this field. After a brief introduction to textile materials and current textile treatment methods, the authors discuss unique properties of ALD-coated textiles, followed by a review of recent electronic and multifunctional textiles that use ALD coatings either as direct functional components or as critical nucleation layers for active materials integration. The article concludes with possible future directions for ALD on textiles, including the challenges in materials, manufacturing, and manufacturing integration that must be overcome for ALD to reach its full potential in electronic and other emerging multifunctional textile systems.

  2. Atomic layer deposition on polymer fibers and fabrics for multifunctional and electronic textiles

    International Nuclear Information System (INIS)

    Textile materials, including woven cotton, polymer knit fabrics, and synthetic nonwoven fiber mats, are being explored as low-cost, flexible, and light-weight platforms for wearable electronic sensing, communication, energy generation, and storage. The natural porosity and high surface area in textiles is also useful for new applications in environmental protection, chemical decontamination, pharmaceutical and chemical manufacturing, catalytic support, tissue regeneration, and others. These applications raise opportunities for new chemistries, chemical processes, biological coupling, and nanodevice systems that can readily combine with textile manufacturing to create new “multifunctional” fabrics. Atomic layer deposition (ALD) has a unique ability to form highly uniform and conformal thin films at low processing temperature on nonuniform high aspect ratio surfaces. Recent research shows how ALD can coat, modify, and otherwise improve polymer fibers and textiles by incorporating new materials for viable electronic and other multifunctional capabilities. This article provides a current overview of the understanding of ALD coating and modification of textiles, including current capabilities and outstanding problems, with the goal of providing a starting point for further research and advances in this field. After a brief introduction to textile materials and current textile treatment methods, the authors discuss unique properties of ALD-coated textiles, followed by a review of recent electronic and multifunctional textiles that use ALD coatings either as direct functional components or as critical nucleation layers for active materials integration. The article concludes with possible future directions for ALD on textiles, including the challenges in materials, manufacturing, and manufacturing integration that must be overcome for ALD to reach its full potential in electronic and other emerging multifunctional textile systems

  3. Resistive switching in HfO2-based atomic layer deposition grown metal–insulator–metal structures

    International Nuclear Information System (INIS)

    Highlights: • We have prepared Pt/HfO2/TiN MIM structures with very thin HfO2 films. • HfO2 films were prepared by thermal, ozone and plasma assisted atomic layer deposition. • Stable bipolar resistive switching characteristics were obtained. • Forming voltage scales with the HfO2 film thickness. • 104 consecutive resistive switching operations were attained in ms pulsed regime without degradation. - Abstract: We prepared Pt/HfO2/TiN metal–insulator–metal structures for resistive switching experiments. The HfO2 films were prepared by thermal, ozone and plasma assisted atomic layer deposition. The deposition techniques yielded HfO2 films that were conducive to stable and reproducible bipolar resistive switching. We observed that the forming voltage scaled with the HfO2 film thickness. The structures did not show degradation after 104 consecutive resistive switching operations in a millisecond pulsed regime

  4. Application of three-dimensionally area-selective atomic layer deposition for selectively coating the vertical surfaces of standing nanopillars

    Science.gov (United States)

    Dong, Wenjing; Zhang, Kenan; Zhang, Yun; Wei, Tiaoxing; Sun, Yan; Chen, Xin; Dai, Ning

    2014-01-01

    We describe a strategy for selectively coating the vertical surfaces of standing nanopillars using area-selective atomic layer deposition (ALD). Hydrophobic self-assembled monolayers (SAMs) are utilised to selectively inhibit the coating of oxides on the modified horizontal regions to ensure that only the vertical surfaces of vertical standing nanorods are coated using ALD processes. This method makes it possible to fabricate vertical nanodevices using a simple process of depositing oxide layer on a vertical surface, and can also be applied to the area-selective surface passivation of other standing structures. PMID:24662775

  5. Role of low-energy ion irradiation in the formation of an aluminum germanate layer on a germanium substrate by radical-enhanced atomic layer deposition

    International Nuclear Information System (INIS)

    Radical-enhanced atomic layer deposition uses oxygen radicals generated by a remote microwave-induced plasma as an oxidant to change the surface reactions of the alternately supplied trimethylaluminum precursor and oxygen radicals on a Ge substrate, which leads to the spontaneous formation of an aluminum germanate layer. In this paper, the effects that low-energy ions, supplied from a remote microwave plasma to the substrate along with the oxygen radicals, have on the surface reactions were studied. From a comparative study of aluminum oxide deposition under controlled ion flux irradiation on the deposition surface, it was found that the ions enhance the formation of the aluminum germanate layer. The plasma potential measured at the substrate position by the Langmuir probe method was 5.4 V. Assuming that the kinetic energy of ions arriving at the substrate surface is comparable to that gained by this plasma potential, such ions have sufficient energy to induce exchange reactions of surface-adsorbed Al atoms with the underlying Ge atoms without causing significant damage to the substrate. This ion-induced exchange reaction between Al and Ge atoms is inferred to be the background kinetics of the aluminum germanate formation by radical-enhanced atomic layer deposition

  6. Role of low-energy ion irradiation in the formation of an aluminum germanate layer on a germanium substrate by radical-enhanced atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Yukio, E-mail: y-fukuda@rs.suwa.tus.ac.jp; Yamada, Daichi; Yokohira, Tomoya; Yanachi, Kosei [Tokyo University of Science, Suwa, 5000-1 Toyohira, Chino, Nagano 391-0292 (Japan); Yamamoto, Chiaya; Yoo, Byeonghak; Sato, Tetsuya [University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511 (Japan); Yamanaka, Junji [University of Yamanashi, 7-32 Miyamae, Kofu, Yamanashi 400-8511 (Japan); Takamatsu, Toshiyuki [SST Inc., 989-6 Shimadadai, Yachiyo, Chiba 276-0004 (Japan); Okamoto, Hiroshi [Hirosaki University, 3 Bunkyo, Hirosaki 036-8561 (Japan)

    2016-03-15

    Radical-enhanced atomic layer deposition uses oxygen radicals generated by a remote microwave-induced plasma as an oxidant to change the surface reactions of the alternately supplied trimethylaluminum precursor and oxygen radicals on a Ge substrate, which leads to the spontaneous formation of an aluminum germanate layer. In this paper, the effects that low-energy ions, supplied from a remote microwave plasma to the substrate along with the oxygen radicals, have on the surface reactions were studied. From a comparative study of aluminum oxide deposition under controlled ion flux irradiation on the deposition surface, it was found that the ions enhance the formation of the aluminum germanate layer. The plasma potential measured at the substrate position by the Langmuir probe method was 5.4 V. Assuming that the kinetic energy of ions arriving at the substrate surface is comparable to that gained by this plasma potential, such ions have sufficient energy to induce exchange reactions of surface-adsorbed Al atoms with the underlying Ge atoms without causing significant damage to the substrate. This ion-induced exchange reaction between Al and Ge atoms is inferred to be the background kinetics of the aluminum germanate formation by radical-enhanced atomic layer deposition.

  7. Atomic layer deposition: a key technology for the controlled growth of oxide thin films for advanced applications

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD), also referred to as atomic layer epitaxy (ALE), was originally developed to process thin film electroluminescent structures for flat panel displays, which include as core components also insulating oxide layers such as alumina and aluminium titanium oxide. Another early application of oxide ALD was the processing of overlayers for catalysts. More recently, a major breakthrough for the ALD technology is the use of oxide thin films in microelectronics as gate and dynamic random access memory capacitor dielectrics. Besides giving a brief introduction to the ALD/ALE technology, the paper will address the present status of depositing binary and more complex (i.e. perovskite-type) metal oxides emphasizing precursor chemistry. (author)

  8. Atomic layer deposited lithium aluminum oxide: (In)dependency of film properties from pulsing sequence

    Energy Technology Data Exchange (ETDEWEB)

    Miikkulainen, Ville, E-mail: ville.miikkulainen@helsinki.fi; Nilsen, Ola; Fjellvåg, Helmer [Centre for Materials Science and Nanotechnology (SMN), Department of Chemistry, University of Oslo, P.O. Box 1126 Blindern, NO-0318 Oslo (Norway); Li, Han; King, Sean W. [Intel Corporation, 5200 NE Elam Young Parkway, Hillsboro, Oregon 97124 (United States); Laitinen, Mikko; Sajavaara, Timo [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)

    2015-01-01

    Atomic layer deposition (ALD) holds markedly high potential of becoming the enabling method for achieving the three-dimensional all-solid-state thin-film lithium ion battery (LiB). One of the most crucial components in such a battery is the electrolyte that needs to hold both low electronic conductivity and at least fair lithium ion conductivity being at the same time pinhole free. To obtain these desired properties in an electrolyte film, one necessarily has to have a good control over the elemental composition of the deposited material. The present study reports on the properties of ALD lithium aluminum oxide (Li{sub x}Al{sub y}O{sub z}) thin films. In addition to LiB electrolyte applications, Li{sub x}Al{sub y}O{sub z} is also a candidate low dielectric constant (low-k) etch stop and diffusion barrier material in nanoelectronics applications. The Li{sub x}Al{sub y}O{sub z} films were deposited employing trimethylaluminum-O{sub 3} and lithium tert-butoxide-H{sub 2}O for Al{sub 2}O{sub 3} and Li{sub 2}O/LiOH, respectively. The composition was aimed to be controlled by varying the pulsing ratio of those two binary oxide ALD cycles. The films were characterized by several methods for composition, crystallinity and phase, electrical properties, hardness, porosity, and chemical environment. Regardless of the applied pulsing ratio of Al{sub 2}O{sub 3} and Li{sub 2}O/LiOH, all the studied ALD Li{sub x}Al{sub y}O{sub z} films of 200 and 400 nm in thickness were polycrystalline in the orthorhombic β-LiAlO{sub 2} phase and also very similar to each other with respect to composition and other studied properties. The results are discussed in the context of both fundamental ALD chemistry and applicability of the films as thin-film LiB electrolytes and low-k etch stop and diffusion barriers.

  9. Luminescence properties of lanthanide and ytterbium lanthanide titanate thin films grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Lanthanide based luminescent materials are highly suitable as down conversion materials in combination with a UV-absorbing host material. The authors have used TiO2 as the UV-absorbing host material and investigated the energy transfer between TiO2 and 11 different lanthanide ions, Ln3+ (Ln = La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) in thin films grown by atomic layer deposition. They have also investigated the possibility to improve the overall energy transfer from TiO2 to Yb3+ with a second Ln3+, in order to enhance down conversion. The films were grown at a substrate temperature of 300 °C, using the Ln(thd)3/O3 (thd = 2,2,6,6-tetramethyl-3,5-heptanedione) and TiCl4/H2O precursor pairs. The focus of the work is to explore the energy transfer from TiO2 to Ln3+ ions, and the energy transfer between Ln3+ and Yb3+ ions, which could lead to efficient down conversion. The samples have been characterized by x-ray diffraction, x-ray fluorescence, spectroscopic ellipsometry, and photoluminescence. All films were amorphous as deposited, and the samples have been annealed at 600, 800, and 1000 °C in order to investigate the correlation between the crystallinity and luminescence. The lanthanum titanium oxide samples showed a weak and broad emission centered at 540 nm, which was absent in all the other samples, indicating energy transfer from TiO2 to Ln3+ in all other lanthanide samples. In the amorphous phase, all samples, apart from La, Tb, and Tm, showed a typical f-f emission when excited by a 325 nm HeCd laser. None of the samples showed any luminescence after annealing at 1000 °C due to the formation of Ln2Ti2O7. Samples containing Nd, Sm, and Eu show a change in emission spectrum when annealed at 800 °C compared to the as-deposited samples, indicating that the smaller lanthanides crystallize in a different manner than the larger lanthanides. Energy transfer from Ln3+ to Yb3+ was observed neither in the amorphous or annealed samples. On the

  10. Atomic layer deposition of cobalt carbide films and their magnetic properties using propanol as a reducing agent

    Science.gov (United States)

    Sarr, Mouhamadou; Bahlawane, Naoufal; Arl, Didier; Dossot, Manuel; McRae, Edward; Lenoble, Damien

    2016-08-01

    The investigation of highly conformal thin films using Atomic Layer Deposition (ALD) is driven by a variety of applications in modern technologies. In particular, the emergence of 3D memory device architectures requires conformal materials with tuneable magnetic properties. Here, nanocomposites of carbon, cobalt and cobalt carbide are deposited by ALD using cobalt acetylacetonate with propanol as a reducing agent. Films were grown by varying the ALD deposition parameters including deposition temperature and propanol exposure time. The morphology, the chemical composition and the crystalline structure of the cobalt carbide film were investigated. Vibrating Sample Magnetometer (VSM) measurements revealed magnetic hysteresis loops with a coercivity reaching 500 Oe and a maximal saturation magnetization of 0.9 T with a grain size less than 15 nm. Magnetic properties are shown to be tuneable by adjusting the deposition parameters that significantly affect the microstructure and the composition of the deposited films.

  11. Oxygen vacancy defect engineering using atomic layer deposited HfAlOx in multi-layered gate stack

    Science.gov (United States)

    Bhuyian, M. N.; Sengupta, R.; Vurikiti, P.; Misra, D.

    2016-05-01

    This work evaluates the defects in high quality atomic layer deposited (ALD) HfAlOx with extremely low Al (HfO2, the V+ type defects with a defect activation energy of Ea ˜ 0.2 eV modify to V2+ type to Ea ˜ 0.1 eV with reference to the Si conduction band. When devices were stressed in the gate injection mode for 1000 s, more V+ type defects are generated and Ea reverts back to ˜0.2 eV. Since Al has a less number of valence electrons than do Hf, the change in the co-ordination number due to Al incorporation seems to contribute to the defect level modifications. Additionally, the stress induced leakage current behavior observed at 20 °C and at 125 °C demonstrates that the addition of Al in HfO2 contributed to suppressed trap generation process. This further supports the defect engineering model as reduced flat-band voltage shifts were observed at 20 °C and at 125 °C.

  12. Reduced interface recombination in Cu2ZnSnS4 solar cells with atomic layer deposition Zn1-xSnxO buffer layers

    OpenAIRE

    Platzer-Björkman, Charlotte; Frisk, Christoper; Larsen, Jes; Ericson, Tove; Li, Shuyi; Scragg, Jonathan; Keller, Jan; Larsson, Fredrik; Törndahl, Tobias

    2015-01-01

    Cu2ZnSnS4 (CZTS) solar cells typically include a CdS buffer layer in between the CZTS and ZnO front contact. For sulfide CZTS, with a bandgap around 1.5 eV, the band alignment between CZTS and CdS is not ideal ("cliff-like"), which enhances interface recombination. In this work, we show how a Zn1-xSnxOy (ZTO) buffer layer can replace CdS, resulting in improved open circuit voltages (V-oc) for CZTS devices. The ZTO is deposited by atomic layer deposition (ALD), with a process previously develo...

  13. Low-temperature atomic layer deposited Al2O3 thin film on layer structure cathode for enhanced cycleability in lithium-ion batteries

    International Nuclear Information System (INIS)

    The deposition of Al2O3 on LiCoO2 electrodes using a low-temperature atomic layer deposition has been investigated. Scanning electron microscopy confirms that Al2O3 films can be homogeneously deposited on LiCoO2 particles of porous electrodes at 120 deg. C. The results of X-ray photoelectron spectroscopy show that the Al2O3 preferentially deposits on the LiCoO2. Furthermore, the results of cycling stability tests show that the cells with Al2O3-coated LiCoO2 electrodes have enhanced performance.

  14. Study on the behavior of atomic layer deposition coatings on a nickel substrate at high temperature

    Science.gov (United States)

    Sohrabi Baba Heidary, Damoon; Randall, Clive A.

    2016-06-01

    Although many techniques have been applied to protect nickel (Ni) alloys from oxidation at intermediate and high temperatures, the potential of atomic layer deposition (ALD) coatings has not been fully explored. In this paper, the application of ALD coatings (HfO2, Al2O3, SnO2, and ZnO) on Ni foils has been evaluated by electrical characterization and transmission electron microscopy analyses in order to assess their merit to increase Ni oxidation resistance; particular consideration was given to preserving Ni electrical conductivity at high temperatures. The results suggested that as long as the temperature was below 850 °C, the ALD coatings provided a physical barrier between outside oxygen and Ni metal and hindered the oxygen diffusion. It was illustrated that the barrier power of ALD coatings depends on their robustness, thicknesses, and heating rate. Among the tested ALD coatings, Al2O3 showed the maximum protection below 900 °C. However, above that temperature, the ALD coatings dissolved in the Ni substrate. As a result, they could not offer any physical barrier. The dissolution of ALD coatings doped on the NiO film, formed on the top of the Ni foils. As found by the electron energy loss spectroscopy (EELS), this doping affected the electronic transport process, through manipulating the Ni3+/Ni2+ ratio in the NiO films and the chance of polaron hopping. It was demonstrated that by using the ZnO coating, one would be able to decrease the electrical resistance of Ni foils by two orders of magnitude after exposure to 1020 °C for 4 min. In contrast, the Al2O3 coating increased the resistance of the uncoated foil by one order of magnitude, mainly due to the decrease in the ratio of Ni3+/Ni2+.

  15. Rutile-structured TiO{sub 2} deposited by plasma enhanced atomic layer deposition using tetrakis(dimethylamino)titanium precursor on in-situ oxidized Ru electrode

    Energy Technology Data Exchange (ETDEWEB)

    Pointet, John; Gonon, Patrice; Latu-Romain, Lawrence; Bsiesy, Ahmad, E-mail: Ahmad.Bsiesy@cea.fr; Vallée, Christophe [Microelectronics Technology Laboratory (LTM), Joseph Fourier University (UJF) and French National Center for Scientific Research - CNRS, CEA – LETI MINATEC, 17 Avenue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2014-01-15

    In this work, tetrakis(dimethylamino)titanium precursor as well as in-situ oxidized ruthenium bottom electrode were used to grow rutile-structured titanium dioxide thin layers by plasma enhanced atomic layer deposition. Metal–insulator–metal capacitors have been elaborated in order to study the electrical properties of the device. It is shown that this process leads to devices exhibiting excellent results in terms of dielectric constant and leakage current.

  16. Engineering the mechanical properties of ultrabarrier films grown by atomic layer deposition for the encapsulation of printed electronics

    International Nuclear Information System (INIS)

    Direct deposition of barrier films by atomic layer deposition (ALD) onto printed electronics presents a promising method for packaging devices. Films made by ALD have been shown to possess desired ultrabarrier properties, but face challenges when directly grown onto surfaces with varying composition and topography. Challenges include differing nucleation and growth rates across the surface, stress concentrations from topography and coefficient of thermal expansion mismatch, elastic constant mismatch, and particle contamination that may impact the performance of the ALD barrier. In such cases, a polymer smoothing layer may be needed to coat the surface prior to ALD barrier film deposition. We present the impact of architecture on the performance of aluminum oxide (Al2O3)/hafnium oxide (HfO2) ALD nanolaminate barrier films deposited on fluorinated polymer layer using an optical calcium (Ca) test under damp heat. It is found that with increasing polymer thickness, the barrier films with residual tensile stress are prone to cracking resulting in rapid failure of the Ca sensor at 50 °C/85% relative humidity. Inserting a SiNx layer with residual compressive stress between the polymer and ALD layers is found to prevent cracking over a range of polymer thicknesses with more than 95% of the Ca sensor remaining after 500 h of testing. These results suggest that controlling mechanical properties and film architecture play an important role in the performance of direct deposited ALD barriers

  17. Engineering the mechanical properties of ultrabarrier films grown by atomic layer deposition for the encapsulation of printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Bulusu, A.; Singh, A.; Kim, H. [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Wang, C. Y.; Dindar, A.; Fuentes-Hernandez, C.; Kippelen, B. [School of Electrical and Computer Engineering, Georgia Institute of Technology, and Center for Organic Photonics and Electronics, Atlanta, Georgia 30332 (United States); Cullen, D. [Oak Ridge National Laboratory, P.O. Box 2008 MS-6064, Oak Ridge, Tennessee 37831 (United States); Graham, S., E-mail: sgraham@gatech.edu [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Oak Ridge National Laboratory, P.O. Box 2008 MS-6064, Oak Ridge, Tennessee 37831 (United States)

    2015-08-28

    Direct deposition of barrier films by atomic layer deposition (ALD) onto printed electronics presents a promising method for packaging devices. Films made by ALD have been shown to possess desired ultrabarrier properties, but face challenges when directly grown onto surfaces with varying composition and topography. Challenges include differing nucleation and growth rates across the surface, stress concentrations from topography and coefficient of thermal expansion mismatch, elastic constant mismatch, and particle contamination that may impact the performance of the ALD barrier. In such cases, a polymer smoothing layer may be needed to coat the surface prior to ALD barrier film deposition. We present the impact of architecture on the performance of aluminum oxide (Al{sub 2}O{sub 3})/hafnium oxide (HfO{sub 2}) ALD nanolaminate barrier films deposited on fluorinated polymer layer using an optical calcium (Ca) test under damp heat. It is found that with increasing polymer thickness, the barrier films with residual tensile stress are prone to cracking resulting in rapid failure of the Ca sensor at 50 °C/85% relative humidity. Inserting a SiN{sub x} layer with residual compressive stress between the polymer and ALD layers is found to prevent cracking over a range of polymer thicknesses with more than 95% of the Ca sensor remaining after 500 h of testing. These results suggest that controlling mechanical properties and film architecture play an important role in the performance of direct deposited ALD barriers.

  18. Waterless TiO2 atomic layer deposition using titanium tetrachloride and titanium tetraisopropoxide

    International Nuclear Information System (INIS)

    The surface chemistry for TiO2 atomic layer deposition (ALD) typically utilizes water or other oxidants that can oxidize underlying substrates such as magnetic disks or semiconductors. To avoid this oxidation, waterless or oxidant-free surface chemistry can be used that involves titanium halides and titanium alkoxides. In this study, waterless TiO2 ALD was accomplished using titanium tetrachloride (TiCl4) and titanium tetraisopropoxide (TTIP). In situ transmission Fourier transform infrared (FTIR) studies were employed to study the surface species and the reactions during waterless TiO2 ALD. At low temperatures between 125 and 225  °C, the FTIR absorbance spectra revealed that the isopropoxide species remained on the surface after TTIP exposures. The TiCl4 exposures then removed the isopropoxide species and deposited additional titanium species. At high temperatures between 250 and 300  °C, the isopropoxide species were converted to hydroxyl species by β-hydride elimination. The observation of propene gaseous reaction product by quadrupole mass spectrometry (QMS) confirmed the β-hydride elimination reaction pathway. The TiCl4 exposures then easily reacted with the hydroxyl species. QMS studies also observed the 2-chloropropane and HCl gaseous reaction products and monitored the self-limiting nature of the TTIP reaction. Additional studies examined the waterless TiO2 ALD growth at low and high temperature. Quartz crystal microbalance measurements observed growth rates of ∼3 ng/cm2 at a low temperature of 150  °C. Much higher growth rates of ∼15 ng/cm2 were measured at a higher temperature of 250  °C under similar reaction conditions. X-ray reflectivity analysis measured a growth rate of 0.55 ± 0.05 Å/cycle at 250  °C. X-ray photoelectron depth-profile studies showed that the TiO2 films contained low Cl concentrations 2 ALD process using TiCl4 and TTIP should be valuable to prevent substrate oxidation during TiO2 ALD on oxygen

  19. Waterless TiO{sub 2} atomic layer deposition using titanium tetrachloride and titanium tetraisopropoxide

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Virginia R.; Cavanagh, Andrew S.; Abdulagatov, Aziz I. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215 (United States); Gibbs, Zachary M. [Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309-0424 (United States); George, Steven M., E-mail: Steven.George@Colorado.Edu [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215 and Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309-0427. (United States)

    2014-01-15

    The surface chemistry for TiO{sub 2} atomic layer deposition (ALD) typically utilizes water or other oxidants that can oxidize underlying substrates such as magnetic disks or semiconductors. To avoid this oxidation, waterless or oxidant-free surface chemistry can be used that involves titanium halides and titanium alkoxides. In this study, waterless TiO{sub 2} ALD was accomplished using titanium tetrachloride (TiCl{sub 4}) and titanium tetraisopropoxide (TTIP). In situ transmission Fourier transform infrared (FTIR) studies were employed to study the surface species and the reactions during waterless TiO{sub 2} ALD. At low temperatures between 125 and 225  °C, the FTIR absorbance spectra revealed that the isopropoxide species remained on the surface after TTIP exposures. The TiCl{sub 4} exposures then removed the isopropoxide species and deposited additional titanium species. At high temperatures between 250 and 300  °C, the isopropoxide species were converted to hydroxyl species by β-hydride elimination. The observation of propene gaseous reaction product by quadrupole mass spectrometry (QMS) confirmed the β-hydride elimination reaction pathway. The TiCl{sub 4} exposures then easily reacted with the hydroxyl species. QMS studies also observed the 2-chloropropane and HCl gaseous reaction products and monitored the self-limiting nature of the TTIP reaction. Additional studies examined the waterless TiO{sub 2} ALD growth at low and high temperature. Quartz crystal microbalance measurements observed growth rates of ∼3 ng/cm{sup 2} at a low temperature of 150  °C. Much higher growth rates of ∼15 ng/cm{sup 2} were measured at a higher temperature of 250  °C under similar reaction conditions. X-ray reflectivity analysis measured a growth rate of 0.55 ± 0.05 Å/cycle at 250  °C. X-ray photoelectron depth-profile studies showed that the TiO{sub 2} films contained low Cl concentrations <1 at. %. This waterless TiO{sub 2} ALD process

  20. Photoluminescence properties of Bi/Al-codoped silica optical fiber based on atomic layer deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Jianxiang, E-mail: wenjx@shu.edu.cn [Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, Shanghai 200072 (China); Wang, Jie; Dong, Yanhua; Chen, Na [Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, Shanghai 200072 (China); Luo, Yanhua; Peng, Gang-ding [Photonics & Optical Communications, School of Electrical Engineering & Telecommunications, University of New South Wales, Sydney 2052, NSW (Australia); Pang, Fufei; Chen, Zhenyi [Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, Shanghai 200072 (China); Wang, Tingyun, E-mail: tywang@mail.shu.edu.cn [Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, Shanghai 200072 (China)

    2015-09-15

    Highlights: • We report on a new fabrication method of producing Bi/Al-codoped silica optical fibers. • There are obvious Bi-type ions absorption peaks at 520, 700 and 800 nm. • The fluorescence peaks are 1130 and 1145 nm with 489 and 705 nm excitations, respectively. • Their fluorescence lifetimes are 701 and 721 μs, respectively. • And then there are obvious fluorescence bands in 600–850 and 900–1650 nm with 532 nm pump exciting. • There is a maximum fluorescence intensity peak at 1120 nm, and its full wave at half maximum (FWHM) is approximately 180 nm. • These may mainly result from the interaction between Bi and Al ions. • The Bi/Al-codoped silica optical fibers would be used in high power or broadly tunable laser sources, and optical fiber amplifier in the optical communication fields. - Abstract: The Bi/Al-codoped silica optical fibers are fabricated by atomic layer deposition (ALD) doping technique combing with conventional modified chemical vapor deposition (MCVD) process. Bi{sub 2}O{sub 3} and Al{sub 2}O{sub 3} are induced into silica optical fiber core layer by ALD technique, with Bis (2,2,6,6-tetra-methyl-3,5-heptanedionato) Bismuth(III) (Bi(thd){sub 3}) and H{sub 2}O as Bi and O precursors, and with Al(CH{sub 3}){sub 3} (TMA) as Al precursor, respectively. The structure features and optical properties of Bi/Al-codoped silica optical fibers are investigated. Bi{sub 2}O{sub 3} stoichiometry is confirmed by X-ray photoelectron spectroscopy (XPS). The valence state of Bi element is +3. Concentration distribution of Si, Ge and O elements is approximately 24–33, 9 and 66 mol%, respectively, in fiber preform core and cladding layer region. Bi and Al ions have been also slightly doped approximately 150–180 and 350–750 ppm in fiber preform core, respectively. Refractive index difference of the Bi/Al-codoped fiber is approximately 0.58% using optical fiber refractive index profiler analyzer. There are obvious Bi-type ions absorption

  1. Photoluminescence properties of Bi/Al-codoped silica optical fiber based on atomic layer deposition method

    International Nuclear Information System (INIS)

    Highlights: • We report on a new fabrication method of producing Bi/Al-codoped silica optical fibers. • There are obvious Bi-type ions absorption peaks at 520, 700 and 800 nm. • The fluorescence peaks are 1130 and 1145 nm with 489 and 705 nm excitations, respectively. • Their fluorescence lifetimes are 701 and 721 μs, respectively. • And then there are obvious fluorescence bands in 600–850 and 900–1650 nm with 532 nm pump exciting. • There is a maximum fluorescence intensity peak at 1120 nm, and its full wave at half maximum (FWHM) is approximately 180 nm. • These may mainly result from the interaction between Bi and Al ions. • The Bi/Al-codoped silica optical fibers would be used in high power or broadly tunable laser sources, and optical fiber amplifier in the optical communication fields. - Abstract: The Bi/Al-codoped silica optical fibers are fabricated by atomic layer deposition (ALD) doping technique combing with conventional modified chemical vapor deposition (MCVD) process. Bi2O3 and Al2O3 are induced into silica optical fiber core layer by ALD technique, with Bis (2,2,6,6-tetra-methyl-3,5-heptanedionato) Bismuth(III) (Bi(thd)3) and H2O as Bi and O precursors, and with Al(CH3)3 (TMA) as Al precursor, respectively. The structure features and optical properties of Bi/Al-codoped silica optical fibers are investigated. Bi2O3 stoichiometry is confirmed by X-ray photoelectron spectroscopy (XPS). The valence state of Bi element is +3. Concentration distribution of Si, Ge and O elements is approximately 24–33, 9 and 66 mol%, respectively, in fiber preform core and cladding layer region. Bi and Al ions have been also slightly doped approximately 150–180 and 350–750 ppm in fiber preform core, respectively. Refractive index difference of the Bi/Al-codoped fiber is approximately 0.58% using optical fiber refractive index profiler analyzer. There are obvious Bi-type ions absorption peaks at 520, 700 and 800 nm. The fluorescence peaks are at

  2. Enhancement of the electrical properties of silver nanowire transparent conductive electrodes by atomic layer deposition coating with zinc oxide

    Science.gov (United States)

    Pham, Anh-Tuan; Nguyen, Xuan-Quang; Tran, Duc-Huy; Phan, Vu Ngoc; Duong, Thanh-Tung; Nguyen, Duy-Cuong

    2016-08-01

    Transparent conductive electrodes for applications in optoelectronic devices such as solar cells and light-emitting diodes are important components and require low sheet resistance and high transmittance. Herein, we report an enhancement of the electrical properties of silver (Ag) nanowire networks by coating with zinc oxide using the atomic layer deposition technique. A strong decrease in the sheet resistance of Ag nanowires, namely from 20–40 Ω/□ to 7–15 Ω/□, was observed after coating with ZnO. Ag nanowire electrodes coated with 200-cycle ZnO by atomic layer deposition show the best quality, with a sheet resistance of 11 Ω/□ and transmittance of 75%.

  3. Impacts of Thermal Atomic Layer-Deposited AlN Passivation Layer on GaN-on-Si High Electron Mobility Transistors.

    Science.gov (United States)

    Zhao, Sheng-Xun; Liu, Xiao-Yong; Zhang, Lin-Qing; Huang, Hong-Fan; Shi, Jin-Shan; Wang, Peng-Fei

    2016-12-01

    Thermal atomic layer deposition (ALD)-grown AlN passivation layer is applied on AlGaN/GaN-on-Si HEMT, and the impacts on drive current and leakage current are investigated. The thermal ALD-grown 30-nm amorphous AlN results in a suppressed off-state leakage; however, its drive current is unchanged. It was also observed by nano-beam diffraction method that thermal ALD-amorphous AlN layer barely enhanced the polarization. On the other hand, the plasma-enhanced chemical vapor deposition (PECVD)-deposited SiN layer enhanced the polarization and resulted in an improved drive current. The capacitance-voltage (C-V) measurement also indicates that thermal ALD passivation results in a better interface quality compared with the SiN passivation. PMID:26964559

  4. Effect of Pretreatment of TaN Substrates on Atomic Layer Deposition Growth of Ru Thin Films

    Institute of Scientific and Technical Information of China (English)

    ZHOU Mi; CHEN Tao; TAN Jing-Jing; RU Guo-Ping; JIANG Yu-Long; LIU Ran; QU Xin-Ping

    2007-01-01

    The polycrystalline ruthenium films are grown on TaN substrates by atomic layer deposition (ALD) using bis(cyclopentadienyl) ruthenium [RuCp2] and oxygen as ruthenium precursor and reactant respectively at a deposition temperature of 330℃. The low-energy Ar ion bombardment and Ru pre-deposition are performed to the underlying TaN substrates before ALD process in order to improve the Ru nucleation. X-ray diffraction,X-ray photoelectron spectroscopy, canning electron microscopy and atomic force microscopy are carried out to characterize the properties of ALD Ru films.The results show that the nucleation density of Ru films with Ar+ bombardment to the underlying TaN substrates is much higher than that of the ones without any pretreatment. The possible reasons are discussed.

  5. Fibrous Containment for Improved Laboratory Handling and Uniform Nanocoating of Milligram Quantities of Carbon Nanotubes by Atomic Layer Deposition

    OpenAIRE

    Devine, Christina K.; Oldham, Christopher J.; Jur, Jesse S.; Gong, Bo; Parsons, Gregory N.

    2011-01-01

    The presence of nanostructured materials in the work place is bringing attention to the importance of safe practices for nanomaterial handling. We explored novel fiber containment methods to improve the handling of carbon nanotube (CNT) powders in the laboratory, while simultaneously allowing highly uniform and controlled atomic layer deposition (ALD) coatings on the nanotubes, down to less than 4 nm on some CNT materials. Moreover, the procedure yields uniform coatings on milligram quantitie...

  6. Microscratch testing method for systematic evaluation of the adhesion of atomic layer deposited thin films on silicon

    OpenAIRE

    Kilpi, Lauri; Ylivaara, Oili M. E.; Vaajoki, Antti; Malm, Jari; Sintonen, Sakari; Tuominen, Marko; Puurunen, Riikka L.; Ronkainen, Helena

    2016-01-01

    The scratch test method is widely used for adhesion evaluation of thin films and coatings. Usual critical load criteria designed for scratch testing of coatings were not applicable to thin atomic layer deposition (ALD) films on silicon wafers. Thus, the bases for critical load evaluation were established and the critical loads suitable for ALD coating adhesion evaluation on silicon wafers were determined in this paper as LCSi1, LCSi2, LCALD1, and LCALD2, representing the failure p...

  7. Luminescence properties of lanthanide and ytterbium lanthanide titanate thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Per-Anders, E-mail: p.a.hansen@kjemi.uio.no; Fjellvåg, Helmer; Nilsen, Ola [Department of Chemistry, Centre for Materials Science and Nanotechnology, University of Oslo, Sem Sælandsvei 26, 0371 Oslo (Norway); Finstad, Terje G. [Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, Sem Sælandsvei 24, 0371 Oslo (Norway)

    2016-01-15

    Lanthanide based luminescent materials are highly suitable as down conversion materials in combination with a UV-absorbing host material. The authors have used TiO{sub 2} as the UV-absorbing host material and investigated the energy transfer between TiO{sub 2} and 11 different lanthanide ions, Ln{sup 3+} (Ln = La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) in thin films grown by atomic layer deposition. They have also investigated the possibility to improve the overall energy transfer from TiO{sub 2} to Yb{sup 3+} with a second Ln{sup 3+}, in order to enhance down conversion. The films were grown at a substrate temperature of 300 °C, using the Ln(thd){sub 3}/O{sub 3} (thd = 2,2,6,6-tetramethyl-3,5-heptanedione) and TiCl{sub 4}/H{sub 2}O precursor pairs. The focus of the work is to explore the energy transfer from TiO{sub 2} to Ln{sup 3+} ions, and the energy transfer between Ln{sup 3+} and Yb{sup 3+} ions, which could lead to efficient down conversion. The samples have been characterized by x-ray diffraction, x-ray fluorescence, spectroscopic ellipsometry, and photoluminescence. All films were amorphous as deposited, and the samples have been annealed at 600, 800, and 1000 °C in order to investigate the correlation between the crystallinity and luminescence. The lanthanum titanium oxide samples showed a weak and broad emission centered at 540 nm, which was absent in all the other samples, indicating energy transfer from TiO{sub 2} to Ln{sup 3+} in all other lanthanide samples. In the amorphous phase, all samples, apart from La, Tb, and Tm, showed a typical f-f emission when excited by a 325 nm HeCd laser. None of the samples showed any luminescence after annealing at 1000 °C due to the formation of Ln{sub 2}Ti{sub 2}O{sub 7}. Samples containing Nd, Sm, and Eu show a change in emission spectrum when annealed at 800 °C compared to the as-deposited samples, indicating that the smaller lanthanides crystallize in a different manner than the larger

  8. CMOS compatible strategy based on selective atomic layer deposition of a hard mask for transferring block copolymer lithography patterns

    Energy Technology Data Exchange (ETDEWEB)

    Gay, G; Grampeix, H; Martin, F; Jalaguier, E; De Salvo, B [CEA LETI MINATEC, 17 rue des Martyrs, 38054 Grenoble (France); Baron, T; Agraffeil, C; Salhi, B; Chevolleau, T; Cunge, G; Tortai, J-H, E-mail: guillaume.gay@cea.fr, E-mail: thierry.baron@cea.fr [CNRS-LTM, 17 rue des Martyrs, 38054 Grenoble (France)

    2010-10-29

    A generic, CMOS compatible strategy for transferring a block copolymer template to a semiconductor substrate is demonstrated. An aluminum oxide (Al{sub 2}O{sub 3}) hard mask is selectively deposited by atomic layer deposition in an organized array of holes obtained in a PS matrix via PS-b-PMMA self-assembly. The Al{sub 2}O{sub 3} nanodots act as a highly resistant mask to plasma etching, and are used to pattern high aspect ratio (>10) silicon nanowires and nanopillars.

  9. Precise Nanoscale Surface Modification and Coating of Macroscale Objects: Open-Environment in Loco Atomic Layer Deposition on an Automobile.

    Science.gov (United States)

    Mousa, Moataz Bellah M; Oldham, Christopher J; Parsons, Gregory N

    2015-09-01

    The fundamental chemical reaction conditions that define atomic layer deposition (ALD) can be achieved in an open environment on a macroscale surface too large and complex for typical laboratory reactor-based ALD. We describe the concept of in loco ALD using conventional modulated reactant flow through a surface-mounted "ALD delivery head" to form a precise nanoscale Al2O3 film on the window of a parked automobile. Analysis confirms that the processes eliminated ambient water contamination and met other conditions that define ALD growth. Using this tool, we demonstrate open-ambient patterned deposition, metal corrosion protection, and polymer surface modification. PMID:26270083

  10. Atomic layer deposited second order nonlinear optical metamaterial for back-end integration with CMOS-compatible nanophotonic circuitry

    CERN Document Server

    Clemmen, StÉphane; Solano, Eduardo; Dendooven, Jolien; Koskinen, Kalle; Kauranen, Martti; Brainis, Edouard; Detavernier, Christophe; Baets, Roel

    2015-01-01

    We report the fabrication of artificial unidimensional crystals exhibiting an effective bulk second-order nonlinearity. The crystals are created by cycling atomic layer deposition of three dielectric materials such that the resulting metamaterial is non-centrosymmetric in the direction of the deposition. Characterization of the structures by second-harmonic generation Maker-fringe measurements shows that the main component of their nonlinear susceptibility tensor is about 5 pm/V which is comparable to well-established materials and more than an order of magnitude greater than reported for a similar crystal [1-Alloatti et al, arXiv:1504.00101[cond-mat.mtrl- sci

  11. Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al2O3-films

    Directory of Open Access Journals (Sweden)

    Jörg Haeberle

    2013-11-01

    Full Text Available We report on results on the preparation of thin (2O3 films on silicon substrates using thermal atomic layer deposition (T-ALD and plasma enhanced atomic layer deposition (PE-ALD in the SENTECH SI ALD LL system. The T-ALD Al2O3 layers were deposited at 200 °C, for the PE-ALD films we varied the substrate temperature range between room temperature (rt and 200 °C. We show data from spectroscopic ellipsometry (thickness, refractive index, growth rate over 4” wafers and correlate them to X-ray photoelectron spectroscopy (XPS results. The 200 °C T-ALD and PE-ALD processes yield films with similar refractive indices and with oxygen to aluminum elemental ratios very close to the stoichiometric value of 1.5. However, in both also fragments of the precursor are integrated into the film. The PE-ALD films show an increased growth rate and lower carbon contaminations. Reducing the deposition temperature down to rt leads to a higher content of carbon and CH-species. We also find a decrease of the refractive index and of the oxygen to aluminum elemental ratio as well as an increase of the growth rate whereas the homogeneity of the film growth is not influenced significantly. Initial state energy shifts in all PE-ALD samples are observed which we attribute to a net negative charge within the films.

  12. Electrical and mechanical stability of aluminum-doped ZnO films grown on flexible substrates by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luka, G., E-mail: gluka@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Witkowski, B.S.; Wachnicki, L.; Jakiela, R. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Virt, I.S. [University of Rzeszow, Rzeszow (Poland); Drohobych Ivan Franko State Pedagogical University, Drohobych (Ukraine); Andrzejczuk, M.; Lewandowska, M. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Godlewski, M. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszynski University, Warsaw (Poland)

    2014-08-01

    Highlights: • Transparent and conductive ZnO:Al films were grown by atomic layer deposition. • The films were grown on flexible substrates at low growth temperatures (110–140 °C). • So-obtained films have low resistivities, of the order of 10{sup −3} Ω cm. • Bending tests indicated a critical bending radius of ≈1.2 cm. • Possible sources of the film resistivity changes upon bending are proposed. - Abstract: Aluminum-doped zinc oxide (AZO) films were grown on polyethylene terephthalate (PET) substrates by atomic layer deposition (ALD) at low deposition temperatures (110–140 °C). The films have low resistivities, ∼10{sup −3} Ω cm, and high transparency (∼90%) in the visible range. Bending tests indicated a critical bending radius of ≈1.2 cm, below which the resistivity changes became irreversible. The films deposited on PET with additional buffer layer are more stable upon bending and temperature changes.

  13. Comparison of dimethylzinc and diethylzinc as precursors for monocrystalline zinc oxide grown by atomic layer deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Wachnicki, L.; Lukasiewicz, M.; Witkowski, B.; Krajewski, T.; Luka, G.; Kopalko, K.; Minikayev, R.; Przezdziecka, E.; Domagala, J.Z.; Guziewicz, E. [Polish Academy of Sciences, Institute of Physics, Warszawa (Poland); Godlewski, M. [Polish Academy of Sciences, Institute of Physics, Warszawa (Poland); Department of Mathematics and Natural Sciences, College of Science, Warszawa (Poland)

    2010-07-15

    The new trend in semiconductor technology is search of new materials, which could replace silicon in specialized applications. One of them is zinc oxide (ZnO), a II-VI semiconductor. In this work we show how to obtain at relatively low temperature monocrystalline layers of ZnO using atomic layer deposition (ALD) method with reactive dimethylzinc (DMZn) and diethylzinc (DEZn) precursors. ZnO films were deposited on gallium nitride substrates at 300 C. We compare the results obtained for these two organic zinc precursors. High resolution X-ray diffraction analysis proves that our ZnO layers are monocrystalline with FWHM of (00.2) peak 250 arcsec for DEZn and 335 arcsec for DMZn precursors. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  14. Ultrathin Coating of Confined Pt Nanocatalysts by Atomic Layer Deposition for Enhanced Catalytic Performance in Hydrogenation Reactions.

    Science.gov (United States)

    Wang, Meihua; Gao, Zhe; Zhang, Bin; Yang, Huimin; Qiao, Yan; Chen, Shuai; Ge, Huibin; Zhang, Jiankang; Qin, Yong

    2016-06-13

    Metal-support interfaces play a prominent role in heterogeneous catalysis. However, tailoring the metal-support interfaces to realize full utilization remains a major challenge. In this work, we propose a graceful strategy to maximize the metal-oxide interfaces by coating confined nanoparticles with an ultrathin oxide layer. This is achieved by sequential deposition of ultrathin Al2 O3 coats, Pt, and a thick Al2 O3 layer on carbon nanocoils templates by atomic layer deposition (ALD), followed by removal of the templates. Compared with the Pt catalysts confined in Al2 O3 nanotubes without the ultrathin coats, the ultrathin coated samples have larger Pt-Al2 O3 interfaces. The maximized interfaces significantly improve the activity and the protecting Al2 O3 nanotubes retain the stability for hydrogenation reactions of 4-nitrophenol. We believe that applying ALD ultrathin coats on confined catalysts is a promising way to achieve enhanced performance for other catalysts. PMID:27061428

  15. Electron Cyclotron Resonance Plasma-Assisted Atomic Layer Deposition of Amorphous Al2O3 Thin Films

    International Nuclear Information System (INIS)

    Without extra heating, Al2O3 thin films were deposited on a hydrogen-terminated Si substrate etched in hydrofluoric acid by using a self-built electron cyclotron resonance (ECR) plasma-assisted atomic layer deposition (ALD) device with Al(CH3)3 (trimethylaluminum; TMA) and O2 used as precursor and oxidant, respectively. During the deposition process, Ar was introduced as a carrier and purging gas. The chemical composition and microstructure of the as-deposited Al2O3 films were characterized by using X-ray diffraction (XRD), an X-ray photoelectric spectroscope (XPS), a scanning electron microscope (SEM), an atomic force microscope (AFM) and a high-resolution transmission electron microscope (HRTEM). It achieved a growth rate of 0.24 nm/cycle, which is much higher than that deposited by thermal ALD. It was found that the smooth surface thin film was amorphous alumina, and an interfacial layer formed with a thickness of ca. 2 nm was observed between the Al2O3 film and substrate Si by HRTEM. We conclude that ECR plasma-assisted ALD can grow Al2O3 films with an excellent quality at a high growth rate at ambient temperature.

  16. Spatial atomic layer deposition: Performance of low temperature H2O and O3 oxidant chemistry for flexible electronics encapsulation

    International Nuclear Information System (INIS)

    Water and oxygen were compared as oxidizing agents for the Al2O3 atomic layer deposition process using spatial atomic layer deposition reactor. The influence of the precursor dose on the deposition rate and refractive index, which was used as a proxy for film density, was measured as a function of residence time, defined as the time which the moving substrate spent within one precursor gas zone. The effect of temperature on the growth characteristics was also measured. The water-based process gave faster deposition rates and higher refractive indices but the ozone process allowed deposition to take place at lower temperatures while still maintaining good film quality. In general, processes based on both oxidation chemistries were able to produce excellent moisture barrier films with water vapor transmission rate levels of 10−4 g/m2 day measured at 38 °C and 90% of relative humidity on polyethylene naphthalate substrates. However, the best result of <5 × 10−5 was obtained at 100 °C process temperature with water as precursor

  17. Supportless Platinum Nanotubes Array by Atomic Layer Deposition as PEM Fuel Cell Electrode

    International Nuclear Information System (INIS)

    Highlights: • A simple process for the fabrication of Pt nanotubes arrays has been developed. • The nanotubes array is stuck on a Nafion membrane and is coated by thin Nafion film. • Demonstration of the Pt nanotubes array MEA towards ORR in half-cell. - Abstract: This work reports the fabrication and the test of a novel type of electrode for polymer electrolyte fuel cells, based on an array of oriented and self-supported platinum nanotubes. The dense array of nanotubes is produced by coating the surface of a porous Anodized Aluminum Oxide template by Pt using the Atomic Layer Deposition technique. The nanotubes have a length of around 2 μm, an external diameter of around 180 nm and 20 nm thick Pt walls. As a consequence the tubes are stiff and self-standing with no need for a supporting structure. The array of nanotubes has a density of approximately 109 tubes cm−2 and is stuck onto a Nafion® membrane with excellent adhesion. The electrochemical response of the platinum nanotubes array electrode is investigated by means of half-cell tests and it is compared with the response of a conventional electrode based on a Pt/C dispersion. The nanotubes array shows excellent surface utilization and gas accessibility. The surface specific activity of the nanotubes array towards oxygen reduction reaction is comparable to the one of the conventional electrode: 37 μA cmPt−2 vs 28 μA cmPt−2 of the Pt/C dispersion. Conversely, the mass activity still remains low: 5.5 A/gPt vs 15 A/gPt of the Pt/C dispersion, therefore future actions to decrease the Pt loading and increase the mass activity are outlined. The scale-up of this prototype of supportless nanotubes array electrode from half–cell to fuel cell size is also demonstrated, opening the way to its test under real operating conditions

  18. Atomic Layer-by-Layer Deposition of Pt on Pd Nanocubes for Catalysts with Enhanced Activity and Durability toward Oxygen Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Shuifen; Choi, Sang; Lu, Ning; Roling, Luke T.; Herron, Jeffrey A.; Zhang, Lei; Park, Jinho; Wang, Jinguo; Kim, Moon J.; Xie, Zhaoxiong; Mavrikakis, Manos; Xia, Younan

    2014-06-11

    An effective strategy for reducing the Pt content while retaining the activity of a Pt-based catalyst is to deposit the Pt atoms as ultrathin skins of only a few atomic layers thick on nanoscale substrates made of another metal. During deposition, however, the Pt atoms often take an island growth mode because of a strong bonding between Pt atoms. Here we report a versatile route to the conformal deposition of Pt as uniform, ultrathin shells on Pd nanocubes in a solution phase. The introduction of the Pt precursor at a relatively slow rate and high temperature allowed the deposited Pt atoms to spread across the entire surface of a Pd nanocube to generate a uniform shell. The thickness of the Pt shell could be controlled from one to six atomic layers by varying the amount of Pt precursor added into the system. Compared to a commercial Pt/C catalyst, the Pd@PnL (n = 1-6) core-shell nanocubes showed enhancements in specific activity and durability toward the oxygen reduction reaction (ORR). Density functional theory (DFT) calculations on model (100) surfaces suggest that the enhancement in specific activity can be attributed to the weakening of OH binding through ligand and strain effects, which, in turn, increases the rate of OH hydrogenation. A volcano-type relationship between the ORR specific activity and the number of Pt atomic layers was derived, in good agreement with the experimental results. Both theoretical and experimental studies indicate that the ORR specific activity was maximized for the catalysts based on Pd@Pt2-3L nanocubes. Because of the reduction in Pt content used and the enhancement in specific activity, the Pd@Pt1L nanocubes showed a Pt mass activity with almost three-fold enhancement relative to the Pt/C catalyst.

  19. Morphology, composition and electrical properties of SnO2:Cl thin films grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Chlorine doped SnO2 thin films were prepared using atomic layer deposition at temperatures between 300 and 450 °C using SnCl4 and H2O as the reactants. Composition, structure, surface morphology, and electrical properties of the as-deposited films were examined. Results showed that the as-deposited SnO2 films all exhibited rutile structure with [O]/[Sn] ratios between 1.35 and 1.40. The electrical conductivity was found independent on [O]/[Sn] ratio but dependent on chlorine doping concentration, grain size, and surface morphology. The 300 °C-deposited film performed a higher electrical conductivity of 315 S/cm due to its higher chlorine doping level, larger grain size, and smoother film surface. The existence of Sn2+ oxidation state was demonstrated to minimize the effects of chlorine on raising the electrical conductivity of films

  20. Gas sensing properties of very thin TiO2 films prepared by atomic layer deposition (ALD)

    International Nuclear Information System (INIS)

    Very thin titanium dioxide (TiO2) films of less than 10 nm were deposited by atomic layer deposition (ALD) in order to study their gas sensing properties. Applying the quartz crystal microbalance (QCM) method, prototype structures with the TiO2 ALD deposited thin films were tested for sensitivity to NO2. Although being very thin, the films were sensitive at room temperature and could register low concentrations as 50-100 ppm. The sorption is fully reversible and the films seem to be capable to detect for long term. These initial results for very thin ALD deposited TiO2 films give a promising approach for producing gas sensors working at room temperature on a fast, simple and cost-effective technology

  1. Atomic Layer Deposited MoS2 as a Carbon and Binder Free Anode in Li-ion Battery

    International Nuclear Information System (INIS)

    Molybdenum sulfide is deposited by atomic layer deposition (ALD) using molybdenum hexacarbonyl and hydrogen sulfide. Film growth is studied using in-situ quartz crystal microbalance, ex-situ X-ray reflectivity and ellipsometry. Deposition chemistry is further investigated with in-situ Fourier transform infrared spectroscopy. Self-limiting nature of the reaction is observed, typical of ALD. Saturated growth rate of 2.5 Å per cycle at 170 °C is obtained. As-deposited films are found amorphous in nature. As-grown films are tested as lithium-ion battery anode under half cell configuration. Electrochemical charge-discharge measurements demonstrate a stable cyclic performance with good capacity retention. Discharge capacity of 851 mAh g−1 is obtained after 50 cycles which corresponds to 77% of capacity retention of the initial capacity

  2. The uniformity of Al distribution in aluminum-doped zinc oxide films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luka, G., E-mail: gluka@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Wachnicki, L.; Witkowski, B.S.; Krajewski, T.A.; Jakiela, R.; Guziewicz, E. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Godlewski, M. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszynski University, Warsaw (Poland)

    2011-02-25

    We investigated the aluminum distribution in aluminum-doped zinc oxide films grown by atomic layer deposition. Surface morphology, structure, composition and electrical properties of obtained films were studied. For the aluminum content less than 2 at.%, a periodicity of Al distribution along the layer depth was observed. This periodicity diminished significantly after annealing the samples in nitrogen atmosphere at 300 deg. C. For the Al content higher than 2 at.%, its distribution in ZnO:Al films was uniform within the depth measurement accuracy of {approx}5-10 nm.

  3. Efficient, air-stable colloidal quantum dot solar cells encapsulated using atomic layer deposition of a nanolaminate barrier

    KAUST Repository

    Ip, Alexander H.

    2013-12-23

    Atomic layer deposition was used to encapsulate colloidal quantum dot solar cells. A nanolaminate layer consisting of alternating alumina and zirconia films provided a robust gas permeation barrier which prevented device performance degradation over a period of multiple weeks. Unencapsulated cells stored in ambient and nitrogen environments demonstrated significant performance losses over the same period. The encapsulated cell also exhibited stable performance under constant simulated solar illumination without filtration of harsh ultraviolet photons. This monolithically integrated thin film encapsulation method is promising for roll-to-roll processed high efficiency nanocrystal solar cells. © 2013 AIP Publishing LLC.

  4. Effect of corona pre-treatment on the performance of gas barrier layers applied by atomic layer deposition onto polymer-coated paperboard

    International Nuclear Information System (INIS)

    The effect of corona pre-treatment on the performance of Al2O3 and SiO2 gas barrier layers applied by atomic layer deposition onto polymer-coated paperboards was studied. Both polyethylene and polylactide coated paperboards were corona treated prior to ALD. Corona treatment increased surface energies of the paperboard substrates, and this effect was still observed after several days. Al2O3 and SiO2 films were grown on top of the polymer coatings at temperature of 100 deg. C using the atomic layer deposition (ALD) technique. For SiO2 depositions a new precursor, bis(diethylamido) silane, was used. The positive effect of the corona pre-treatment on the barrier properties of the polymer-coated paperboards with the ALD-grown layers was more significant with polyethylene coated paperboard and with thin deposited layers (shorter ALD process). SiO2 performed similarly to Al2O3 with the PE coated board when it comes to the oxygen barrier, while the performance of SiO2 with the biopolymer-coated board was more moderate. The effect of corona pre-treatment was negligible or even negative with the biopolymer-coated board. The ALD film growth and the effect of corona treatment on different substrates require further investigation.

  5. Electroless copper on refractory and noble metal substrates with an ultra-thin plasma-assisted atomic layer deposited palladium layer

    International Nuclear Information System (INIS)

    Electroless Cu was investigated on refractory metal, W and TaN X, and Ir noble metal substrates with a plasma-assisted atomic layer deposited palladium layer for the potential back-end-of-the-line (BEOL) metallization of advanced integrated devices. The sodium and potassium-free Cu electroless bath consisted of: ethylenediamine tetraacetic acid (EDTA) as a chelating agent, glyoxylic acid as a reducing agent, and additional chemicals such as polyethylene glycol, 2,2'-dipyridine and RE-610 as surfactant, stabilizer and wetting agent respectively. The growth and chemical characterization of the Cu films was carried out with a field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), and Rutherford backscattering spectrometry (RBS). Group VIII metals such as Pt, Pd, etc., are stable in the electroless bath and catalytic towards the oxidation of glyoxylic acid and therefore work well for the electroless deposition of Cu. From RBS analysis, the amount of carbon and oxygen in Cu films were less than 1-3%. The Cu films were electroless deposited at 45-50 deg. C on patterned tantalum nitride with plasma-assisted atomic layer deposited (PA-ALD) Pd as a catalytic layer. Electroless Cu trench fill was successful with ultrasonic vibration, RE-610, and lowering the temperature to 45-50 deg. C on TaN X with the PA-ALD Pd catalytic layer

  6. Filling performance and electrical characteristics of Al2O3 films deposited by atomic layer deposition for through-silicon via applications

    International Nuclear Information System (INIS)

    We have evaluated the conformality and electrical properties of Al2O3 films deposited by atomic layer deposition at temperatures below 300 °C for through-silicon via (TSV) applications. Al2O3 films were able to be conformally deposited on the scallops of 50-μm-wide, 100-μm-deep TSV at the temperature range between 200 and 300 °C. The median breakdown fields of the metal–insulator–metal device with 30-nm-thick Al2O3 layer were above 6 MV/cm for the films deposited at 250 and 300 °C, while that at 200 °C was inferior due to residual carbon impurities in the oxide layer. - Highlights: • Filling performance and electrical properties of Al2O3 films were evaluated. • Al2O3 films were conformally deposited on the scallops of through-silicon via holes. • The median breakdown field of 30-nm-thick Al2O3 layer was above 6 MV/cm. • The Al2O3 film deposited at 200 °C was inferior due to the residual carbon impurities. • Al2O3 films showed a promise as the dielectric for through-silicon via application

  7. Properties of plasma-enhanced atomic layer deposited TiCx films as a diffusion barrier for Cu metallization

    International Nuclear Information System (INIS)

    TiCx films were grown on thermally grown SiO2 substrate by atomic layer deposition (ALD) using tetrakis–neopentyl–titanium [Ti(CH2C(CH3)3)4, TiNp4, Np = neopentyl, CH2C(CH3)3] and direct plasma of H2 as a reactant at the substrate temperature ranging from 200 to 400 °C. A narrow ALD temperature window from 275 to 300 °C was shown and a growth rate of 0.054 nm/cycle at the ALD temperature window was obtained. The ALD-TiCx films formed nanocrystalline structure with rock-salt phase that was confirmed by X-ray diffractometry and transmission electronic microscopy (TEM) analysis. Its resistivity was dependent on the microstructure features characterized by grain size and crystallinity as well as its density, which could be controlled by varying the deposition temperature. Resistivity of ~ 600 μΩ cm was obtained at the deposition temperature 300 °C where is in the ALD temperature window, by optimizing deposition condition. In this study, a performance of very thin ALD-TiCx (6 nm) as a diffusion barrier for Cu interconnects was evaluated. The results showed that the structure of Cu (80 nm)/ALD-TiCx (6 nm)/Si was stable after annealing at 600 °C for 30 min. Cross-sectional view TEM analysis combined with energy-dispersive spectroscopy revealed that ALD-TiCx diffusion barrier failed by the diffusion of Cu through the thin barrier layer into Si at 650 °C without interfacial reactions between the layers. - Highlights: • Atomic layer deposition (ALD) of TiCx using a metallorganic precursor. • The growth rate of 0.054 nm/cycle. • ALD temperature window between 275 and 300 °C. • Evaluation as a diffusion barrier against Cu

  8. Ionic properties of ultrathin yttria-stabilized zirconia thin films fabricated by atomic layer deposition with water, oxygen, and ozone

    International Nuclear Information System (INIS)

    We compared the ionic properties of yttria-stabilized zirconia (YSZ) thin films prepared by atomic layer deposition (ALD) using various oxidants including water, oxygen, and ozone. Cross-plane conductivity measurements were performed at low temperature (50 °C) and high temperature (450 °C) using AC impedance spectroscopy. As a result, we have confirmed that the conductivity of ALD YSZ films below 300 °C is greater by several orders of magnitude compared to the nano-scale YSZ thin films synthesized by other conventional techniques. Among the ALD YSZ samples, ALD YSZ fabricated using water showed the highest conductivity while ALD YSZ fabricated using ozone showed the lowest. We have analyzed this result in relation with grain morphology characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), and the chemical binding states measured by X-ray photoelectron spectroscopy (XPS). - Highlights: • YSZ is prepared by atomic layer deposition (ALD) with H2O, O2, and O3 as oxidants. • Grain size of ALD YSZ membranes deposited using H2O is the smallest. • Conductivity of ALD YSZ made with H2O shows the highest value below 300 °C. • Conductivity trends coincide with the hydroxyl group content measured by XPS

  9. Ionic properties of ultrathin yttria-stabilized zirconia thin films fabricated by atomic layer deposition with water, oxygen, and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Keun; Jang, Dong Young; Kim, Jun Woo [School of Mechanical Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); Bae, Kiho [School of Mechanical Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology (KIST), Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Shim, Joon Hyung, E-mail: shimm@korea.ac.kr [School of Mechanical Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of)

    2015-08-31

    We compared the ionic properties of yttria-stabilized zirconia (YSZ) thin films prepared by atomic layer deposition (ALD) using various oxidants including water, oxygen, and ozone. Cross-plane conductivity measurements were performed at low temperature (50 °C) and high temperature (450 °C) using AC impedance spectroscopy. As a result, we have confirmed that the conductivity of ALD YSZ films below 300 °C is greater by several orders of magnitude compared to the nano-scale YSZ thin films synthesized by other conventional techniques. Among the ALD YSZ samples, ALD YSZ fabricated using water showed the highest conductivity while ALD YSZ fabricated using ozone showed the lowest. We have analyzed this result in relation with grain morphology characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), and the chemical binding states measured by X-ray photoelectron spectroscopy (XPS). - Highlights: • YSZ is prepared by atomic layer deposition (ALD) with H{sub 2}O, O{sub 2}, and O{sub 3} as oxidants. • Grain size of ALD YSZ membranes deposited using H{sub 2}O is the smallest. • Conductivity of ALD YSZ made with H{sub 2}O shows the highest value below 300 °C. • Conductivity trends coincide with the hydroxyl group content measured by XPS.

  10. Integration of atomic layer deposition CeO2 thin films with functional complex oxides and 3D patterns

    International Nuclear Information System (INIS)

    We present a low-temperature, < 300 °C, ex-situ integration of atomic layer deposition (ALD) ultrathin CeO2 layers (3 to 5 unit cells) with chemical solution deposited La0.7Sr0.3MnO3 (LSMO) functional complex oxides for multilayer growth without jeopardizing the morphology, microstructure and physical properties of the functional oxide layer. We have also extended this procedure to pulsed laser deposited YBa2Cu3O7 (YBCO) thin films. Scanning force microscopy, X-ray diffraction, aberration corrected scanning transmission electron microscopy and macroscopic magnetic measurements were used to evaluate the quality of the perovskite films before and after the ALD process. By means of microcontact printing and ALD we have prepared CeO2 patterns using an ozone-robust photoresist that will avoid the use of hazardous lithography processes directly on the device components. These bilayers, CeO2/LSMO and CeO2/YBCO, are foreseen to have special interest for resistive switching phenomena in resistive random-access memory. - Highlights: • Integration of atomic layer deposition (ALD) CeO2 layers on functional complex oxides • Resistive switching is identified in CeO2/La0.7Sr0.3MnO3 and CeO2/YBa2Cu3O7 bilayers. • Study of the robustness of organic polymers for area-selective ALD • Combination of ALD and micro-contact printing to obtain 3D patterns of CeO2

  11. Atomic layer deposition TiO{sub 2} coated porous silicon surface: Structural characterization and morphological features

    Energy Technology Data Exchange (ETDEWEB)

    Iatsunskyi, Igor, E-mail: igoyat@amu.edu.pl [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska str., 61-614, Poznan (Poland); Department of Experimental Physics, Odessa National I.I. Mechnikov University, 42, Pastera str., 65023 Odessa (Ukraine); Jancelewicz, Mariusz; Nowaczyk, Grzegorz [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska str., 61-614, Poznan (Poland); Kempiński, Mateusz [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska str., 61-614, Poznan (Poland); Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poland (Poland); Peplińska, Barbara [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska str., 61-614, Poznan (Poland); Department of Macromolecular Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland); Jarek, Marcin; Załęski, Karol [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska str., 61-614, Poznan (Poland); Jurga, Stefan [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska str., 61-614, Poznan (Poland); Department of Macromolecular Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland); Smyntyna, Valentyn [Department of Experimental Physics, Odessa National I.I. Mechnikov University, 42, Pastera str., 65023 Odessa (Ukraine)

    2015-08-31

    TiO{sub 2} thin films were grown on highly-doped p-Si (100) macro- and mesoporous structures by atomic layer deposition (ALD) using TiCl{sub 4} and deionized water as precursors at 300 °C. The crystalline structure, chemical composition, and morphology of the deposited films and initial silicon nanostructures were investigated by scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy and X-ray diffraction (XRD). The mean size of TiO{sub 2} crystallites was determined by TEM, XRD and Raman spectroscopy. It was shown that the mean crystallite size and the crystallinity of the TiO{sub 2} are influenced dramatically by the morphology of the porous silicon, with the mesoporous silicon resulting in a much finer grain size and amorphous structure than the macroporous silicon having a partially crystal anatase phase. A simple model of the ALD layer growth inside the pores was presented. - Highlights: • The morphology and chemical composition of TiO{sub 2} and porous Si were established. • The approximate size of TiO{sub 2} nanocrystals was estimated. • The model of the atomic layer deposition coating in the porous Si was presented.

  12. Relation of lifetime to surface passivation for atomic-layer-deposited Al2O3 on crystalline silicon solar cell

    International Nuclear Information System (INIS)

    Highlights: • We investigated the relation of potassium contamination on Si solar wafer to lifetime. • We deposited Al2O3 layer by atomic layer deposition (ALD) on Si solar wafer after several cleaning process. • Potassium can be left on Si surface by incomplete cleaning process and degrade the Al2O3 passivation quality. - Abstract: We investigated the relation of potassium contamination on a crystalline silicon (c-Si) surface after potassium hydroxide (KOH) etching to the lifetime of the c-Si solar cell. Alkaline solution was employed for saw damage removal (SDR), texturing, and planarization of a textured c-Si solar wafer prior to atomic layer deposition (ALD) Al2O3 growth. In the solar-cell manufacturing process, ALD Al2O3 passivation is utilized to obtain higher conversion efficiency. ALD Al2O3 shows excellent surface passivation, though minority carrier lifetime varies with cleaning conditions. In the present study, we investigated the relation of potassium contamination to lifetime in solar-cell processing. The results showed that the potassium-contaminated samples, due to incomplete cleaning of KOH, had a short lifetime, thus establishing that residual potassium can degrade Al2O3 surface passivation

  13. Low-Temperature Process for Atomic Layer Chemical Vapor Deposition of an Al2O3 Passivation Layer for Organic Photovoltaic Cells.

    Science.gov (United States)

    Kim, Hoonbae; Lee, Jihye; Sohn, Sunyoung; Jung, Donggeun

    2016-05-01

    Flexible organic photovoltaic (OPV) cells have drawn extensive attention due to their light weight, cost efficiency, portability, and so on. However, OPV cells degrade quickly due to organic damage by water vapor or oxygen penetration when the devices are driven in the atmosphere without a passivation layer. In order to prevent damage due to water vapor or oxygen permeation into the devices, passivation layers have been introduced through methods such as sputtering, plasma enhanced chemical vapor deposition, and atomic layer chemical vapor deposition (ALCVD). In this work, the structural and chemical properties of Al2O3 films, deposited via ALCVD at relatively low temperatures of 109 degrees C, 200 degrees C, and 300 degrees C, are analyzed. In our experiment, trimethylaluminum (TMA) and H2O were used as precursors for Al2O3 film deposition via ALCVD. All of the Al2O3 films showed very smooth, featureless surfaces without notable defects. However, we found that the plastic flexible substrate of an OPV device passivated with 300 degrees C deposition temperature was partially bended and melted, indicating that passivation layers for OPV cells on plastic flexible substrates need to be formed at temperatures lower than 300 degrees C. The OPV cells on plastic flexible substrates were passivated by the Al2O3 film deposited at the temperature of 109 degrees C. Thereafter, the photovoltaic properties of passivated OPV cells were investigated as a function of exposure time under the atmosphere. PMID:27483916

  14. Formation of Micro- and Nanostructures on the Nanotitanium Surface by Chemical Etching and Deposition of Titania Films by Atomic Layer Deposition (ALD

    Directory of Open Access Journals (Sweden)

    Denis V. Nazarov

    2015-12-01

    Full Text Available In this study, an integrated approach was used for the preparation of a nanotitanium-based bioactive material. The integrated approach included three methods: severe plastic deformation (SPD, chemical etching and atomic layer deposition (ALD. For the first time, it was experimentally shown that the nature of the etching medium (acidic or basic Piranha solutions and the etching time have a significant qualitative impact on the nanotitanium surface structure both at the nano- and microscale. The etched samples were coated with crystalline biocompatible TiO2 films with a thickness of 20 nm by Atomic Layer Deposition (ALD. Comparative study of the adhesive and spreading properties of human osteoblasts MG-63 has demonstrated that presence of nano- and microscale structures and crystalline titanium oxide on the surface of nanotitanium improve bioactive properties of the material.

  15. TiO{sub 2} anatase films obtained by direct liquid injection atomic layer deposition at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Avril, L., E-mail: ludovic.avril@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Reymond-Laruinaz, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Decams, J.M. [Annealsys, rue de la Vieille Poste, 34055 Montpellier Cedex 1 (France); Bruyère, S.; Potin, V.; Lucas, M.C. Marco de; Imhoff, L. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France)

    2014-01-01

    TiO{sub 2} thin films were grown by direct liquid injection atomic layer deposition (DLI-ALD) with infrared rapid thermal heating using titanium tetraisopropoxide and water as precursors. This titanium tetraisopropoxide/water process exhibited a growth rate of 0.018 nm/cycle in a self-limited ALD growth mode at 280 °C. Scanning electron microscopy and atomic force microscopy analyses have shown a smooth surface with a low roughness. XPS results demonstrated that the films were pure and close to the TiO{sub 2} stoichiometric composition in depth. Raman spectroscopy revealed that the films were crystallized to the anatase structure in the as-deposited state at low temperature without necessity of high temperature annealing. Results obtained demonstrate that the liquid injection ALD is an efficient method of elaborating titanium oxide films using titanium tetraisopropoxide as precursor.

  16. Ternary semiconductor compounds CuInS2 (CIS) thin films synthesized by electrochemical atomic layer deposition (EC-ALD)

    International Nuclear Information System (INIS)

    In this paper the formation and characterization of the I-III-VI2 semiconductor compound CuInS2 (CIS) on gold substrate at room temperature by electrochemical atomic layer deposition (EC-ALD) method are reported. Optimum deposition potentials for each element are determined using cyclic voltammetry (CV) technique and Amperometric I-t method is used to prepare the semiconductor compound. These thin films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FT-IR). XRD results indicate that the CIS thin films have a (1 1 2) preferred orientation. The XPS analyses of the films reveal that Cu, In and S are present in an atomic ratio of approximately 1:1:2. And their semiconductor band gaps are found to be 1.50 eV by FT-IR.

  17. Electrochemical properties of Atomic layer deposition processed CeO2 as a protective layer for the molten carbonate fuel cell cathode

    International Nuclear Information System (INIS)

    Highlights: • Nano-structured CeO2-coated Ni by Atomic Layer Deposition, crystalline as-deposited. • Progressive transformation into a complex surface stable in molten carbonates. • Lower Ni solubility with CeO2 protective coating. • Feasibility of CeO2 coating in Molten Carbonate Fuel Cell cathode conditions. - Abstract: In order to increase the lifetime and performance of the molten carbonate fuel cell, it is compulsory to control the corrosion and dissolution of the state of the art porous nickel oxide cathode. A protective coating constituted by more stable oxides appears to be the best approach. Previous research on CeO2 coatings obtained by DC reactive magnetron sputtering to protect the Molten carbonate fuel cell cathode gave promising results but it was necessary to improve the coating adhesion. In this paper Atomic Layer Deposition, producing high quality, homogeneous and conformal layers, was used to obtain thin layers of CeO2 (20 nm and 120 nm) deposited over porous nickel. CeO2-Ni coated samples were tested as cathodes in Li2CO3-K2CO3 (62-38 mol %) eutectic mixture under standard cathode atmosphere (CO2/air 30:70 vol. %). Structural and morphological characterizations of the nickel coated cathode before and after electrochemical tests in the molten carbonate melt are reported together with the Open Circuit Potential evolution all over 230 h for both the bare porous nickel and the CeO2-coated samples

  18. Barrier properties of plastic films coated with an Al2O3 layer by roll-to-toll atomic layer deposition

    International Nuclear Information System (INIS)

    Thin (30–40 nm) and highly uniform Al2O3 coatings have been deposited at relatively low temperature of 100 °C onto various polymeric materials employing the atomic layer deposition (ALD) technique, both batch and roll-to-roll (R2R) mode. The applications for ALD have long been limited those feasible for batch processing. The work demonstrates that R2R ALD can deposit thin films with properties that are comparable to the film properties fabricated by in batch. This accelerates considerably the commercialization of many products, such as flexible, printed electronics, organic light-emitting diode lighting, third generation thin film photovoltaic devices, high energy density thin film batteries, smart textiles, organic sensors, organic/recyclable packaging materials, and flexible displays, to name a few. - Highlights: • Thin and uniform Al2O3 coatings have been deposited onto polymers materials. • Batch and roll-to-roll (R2R) atomic layer deposition (ALD) have been employed. • Deposition with either process improved the barrier properties. • Sensitivity of coated films to defects affects barrier obtained with R2R ALD

  19. Barrier properties of plastic films coated with an Al{sub 2}O{sub 3} layer by roll-to-toll atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hirvikorpi, Terhi, E-mail: Terhi.Hirvikorpi@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Laine, Risto, E-mail: Risto.Laine@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Vähä-Nissi, Mika, E-mail: Mika.Vaha-Nissi@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kilpi, Väinö, E-mail: Vaino.Kilpi@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Salo, Erkki, E-mail: Erkki.Salo@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Li, Wei-Min, E-mail: Wei-Min.Li@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Lindfors, Sven, E-mail: Sven.Lindfors@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Vartiainen, Jari, E-mail: Jari.Vartiainen@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kenttä, Eija, E-mail: Eija.Kentta@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Nikkola, Juha, E-mail: Juha.Nikkola@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1300, FI-33101 Tampere (Finland); Harlin, Ali, E-mail: Ali.Harlin@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kostamo, Juhana, E-mail: Juhana.Kostamo@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland)

    2014-01-01

    Thin (30–40 nm) and highly uniform Al{sub 2}O{sub 3} coatings have been deposited at relatively low temperature of 100 °C onto various polymeric materials employing the atomic layer deposition (ALD) technique, both batch and roll-to-roll (R2R) mode. The applications for ALD have long been limited those feasible for batch processing. The work demonstrates that R2R ALD can deposit thin films with properties that are comparable to the film properties fabricated by in batch. This accelerates considerably the commercialization of many products, such as flexible, printed electronics, organic light-emitting diode lighting, third generation thin film photovoltaic devices, high energy density thin film batteries, smart textiles, organic sensors, organic/recyclable packaging materials, and flexible displays, to name a few. - Highlights: • Thin and uniform Al{sub 2}O{sub 3} coatings have been deposited onto polymers materials. • Batch and roll-to-roll (R2R) atomic layer deposition (ALD) have been employed. • Deposition with either process improved the barrier properties. • Sensitivity of coated films to defects affects barrier obtained with R2R ALD.

  20. Electrowetting properties of atomic layer deposited Al{sub 2}O{sub 3} decorated silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Rajkumar, K.; Rajavel, K. [Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu (India); Cameron, D. C. [ASTRaL, Lappeenranta University of Technology, Mikkeli (Finland); current address Miktech Oy, Mikkeli (Finland); Mangalaraj, D. [Department of NanoScience and Technology, Bharathiar University, Coimbatore, Tamil Nadu (India); Rajendrakumar, R. T., E-mail: buc@edu.in [Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu (India); Department of NanoScience and Technology, Bharathiar University, Coimbatore, Tamil Nadu (India)

    2015-06-24

    This paper reports the electrowetting properties of liquid droplet on superhydrophobic silicon nanowires with Atomic layer deposited (ALD) Al{sub 2}O{sub 3} as dielectric layer. Silicon wafer were etched by metal assisted wet chemical etching with silver as catalyst. ALD Al{sub 2}O{sub 3} films of 10nm thickness were conformally deposited over silicon nanowires. Al{sub 2}O{sub 3} dielectric film coated silicon nanowires was chemically modified with Trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane to make it superhydrophobic(SHP). The contact angle was measured and all the samples exhibited superhydrophobic nature with maximum contact angles of 163° and a minimum contact angle hysteresis of 6°. Electrowetting induced a maximum reversible decrease of the contact angle of 20°at 150V in air.

  1. Epitaxial growth of zinc oxide by the method of atomic layer deposition on SiC/Si substrates

    Science.gov (United States)

    Kukushkin, S. A.; Osipov, A. V.; Romanychev, A. I.

    2016-07-01

    For the first time, zinc oxide epitaxial films on silicon were grown by the method of atomic layer deposition at a temperature T = 250°C. In order to avoid a chemical reaction between silicon and zinc oxide (at the growth temperature, the rate constant of the reaction is of the order of 1022), a high-quality silicon carbide buffer layer with a thickness of ~50 nm was preliminarily synthesized by the chemical substitution of atoms on the silicon surface. The zinc oxide films were grown on n- and p-type Si(100) wafers. The ellipsometric, Raman, electron diffraction, and trace element analyses showed that the ZnO films are epitaxial.

  2. Atomic layer deposition of Al2O3 for single electron transistors utilizing Pt oxidation and reduction

    International Nuclear Information System (INIS)

    This work describes the fabrication of single electron transistors using electron beam lithography and atomic layer deposition to form nanoscale tunnel transparent junctions of alumina (Al2O3) on platinum nanowires using either water or ozone as the oxygen precursor and trimethylaluminum as the aluminum precursor. Using room temperature, low frequency conductance measurements between the source and drain, it was found that devices fabricated using water had higher conductance than devices fabricated with ozone. Subsequent annealing caused both water- and ozone-based devices to increase in conductance by more than 2 orders of magnitude. Furthermore, comparison of devices at low temperatures (∼4 K) showed that annealed devices displayed much closer to the ideal behavior (i.e., constant differential conductance) outside of the Coulomb blockade region and that untreated devices showed nonlinear behavior outside of the Coulomb blockade region (i.e., an increase in differential conductance with source-drain voltage bias). Transmission electron microscopy cross-sectional images showed that annealing did not significantly change device geometry, but energy dispersive x-ray spectroscopy showed an unusually large amount of oxygen in the bottom platinum layer. This suggests that the atomic layer deposition process results in the formation of a thin platinum surface oxide, which either decomposes or is reduced during the anneal step, resulting in a tunnel barrier without the in-series native oxide contribution. Furthermore, the difference between ozone- and water-based devices suggests that ozone promotes atomic layer deposition nucleation by oxidizing the surface but that water relies on physisorption of the precursors. To test this theory, devices were exposed to forming gas at room temperature, which also reduces platinum oxide, and a decrease in resistance was observed, as expected

  3. Stability of 8-hydroxyquinoline aluminum films encapsulated by a single Al{sub 2}O{sub 3} barrier deposited by low temperature atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Maindron, Tony, E-mail: tony.maindron@cea.fr [CEA-LETI, MINATEC Campus, LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Simon, Jean-Yves; Viasnoff, Emilie [CEA-LETI, MINATEC Campus, LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Lafond, Dominique [CEA-LETI, MINATEC Campus, LETI/DTSI/SCMC/, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France)

    2012-09-30

    100 nm thick 8-AlQ{sub 3} films deposited onto silicon wafers have been encapsulated by mean of low temperature atomic layer deposition of Al{sub 2}O{sub 3} (20 nm). Investigation of the film evolution under storage test as harsh as 65 Degree-Sign C/85% RH has been investigated up to {approx} 1000 h and no severe degradation could be noticed. The results have been compared to raw AlQ{sub 3} films which deteriorate far faster in the same conditions. For that purpose, fluorescence measurements and atomic force microscopy have been used to monitor the film evolution while transmission electron microscopy has been used to image the interface between AlQ{sub 3} and Al{sub 2}O{sub 3}. This concept of bilayer AlQ{sub 3}/Al{sub 2}O{sub 3} barrier films has finally been tested as an encapsulation barrier onto an organic light-emitting diode. - Highlights: Black-Right-Pointing-Pointer Thin Al{sub 2}O{sub 3} films have been deposited by atomic layer deposition onto organic films. Black-Right-Pointing-Pointer AlQ{sub 3}/Al{sub 2}O{sub 3}-encapsulated organic light-emitting diodes show long-term stability. Black-Right-Pointing-Pointer Unencapsulated reference AlQ{sub 3} films degrade much faster.

  4. On the physical and chemical details of alumina atomic layer deposition: A combined experimental and numerical approach

    International Nuclear Information System (INIS)

    Alumina thin film is typically studied as a model atomic layer deposition (ALD) process due to its high dielectric constant, high thermal stability, and good adhesion on various wafer surfaces. Despite extensive applications of alumina ALD in microelectronics industries, details on the physical and chemical processes are not yet well understood. ALD experiments are not able to shed adequate light on the detailed information regarding the transient ALD process. Most of current numerical approaches lack detailed surface reaction mechanisms, and their results are not well correlated with experimental observations. In this paper, the authors present a combined experimental and numerical study on the details of flow and surface reactions in alumina ALD using trimethylaluminum and water as precursors. Results obtained from experiments and simulations are compared and correlated. By experiments, growth rate on five samples under different deposition conditions is characterized. The deposition rate from numerical simulation agrees well with the experimental results. Details of precursor distributions in a full cycle of ALD are studied numerically to bridge between experimental observations and simulations. The 3D transient numerical model adopts surface reaction kinetics and mechanisms based on atomic-level studies to investigate the surface deposition process. Surface deposition is shown as a strictly self-limited process in our numerical studies. ALD is a complex strong-coupled fluid, thermal and chemical process, which is not only heavily dependent on the chemical kinetics and surface conditions but also on the flow and material distributions

  5. Single phase ZnO submicrotubes as a replica of electrospun polymer fiber template by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gyeong-Man, E-mail: gmkim@ceit.es [CEIT and TECNUN, University of Navarra, Paseo de Mikeletegi 48, 20009 Donostia-San Sebastian (Spain); Lee, Seung-Mo [Nano-Mechanical Systems Research Division, Korea Institute of Machinery and Materials (KIMM), 156 Gajungbukno, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Knez, Mato [Nanomaterials Group, CIC nanoGUNE, Tolosa Hiribidea 76, E-20018 Donostia-San Sebastian (Spain); Simon, Paul [Max-Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden (Germany)

    2014-07-01

    Free-standing and highly interconnected ZnO tubes consisting of nanostructured single phase grains are fabricated by atomic layer deposition (ALD) combined with the electrospinning technique. Hereby, electrospun poly(vinyl pyrrolidone) fiber mat is used as a soft template for coating with zinc oxide. The deposition is conducted onto the template at 70 °C by using diethylzinc and water as ALD precursors. The crystal structure, microstructure and optical properties of the ZnO deposited layers are studied in detail by transmission electron microscopy and X-ray diffraction before and after calcination. After calcination in air at 500 °C for 4 h the morphology of the wedge-like grains transforms into platelet-like structures with lattice parameters similar to those of the standard bulk polycrystalline ZnO. The resulting nanostructured ZnO tubes exhibit unique optical properties, which arose from the quantum-confinement of ZnO thin films prepared by ALD. The measured band gap energies for both the as-deposited and the calcined ZnO films are much lower than that of bulk ZnO or the single crystalline ZnO. Furthermore, the ultraviolet light is completely absorbed in both cases. The self-supported free-standing polycrystalline ZnO tubes can be easily handled and are bearing high potential for future applications related to catalysis, electronics, photonics, sensing, medicine and controlled drug release. - Highlights: • ZnO tubes were replicated from the electrospun fibers by atomic layer deposition. • ZnO tubes exhibited unique optical properties from their quantum-confinement. • Band gap energies for ZnO films are much lower than for single crystalline ZnO. • Ultraviolet light is completely absorbed by ZnO tubes. • Such self-supported ZnO tubes can be reclaimed for use in future applications.

  6. Atomic layer deposition precursor step repetition and surface plasma pretreatment influence on semiconductor–insulator–semiconductor heterojunction solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Talkenberg, Florian, E-mail: florian.talkenberg@ipht-jena.de; Illhardt, Stefan; Schmidl, Gabriele; Schleusener, Alexander; Sivakov, Vladimir [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745 Jena (Germany); Radnóczi, György Zoltán; Pécz, Béla [Centre for Energy Research, Institute of Technical Physics and Materials Science, Konkoly-Thege Miklós u. 29-33, H-1121 Budapest (Hungary); Dikhanbayev, Kadyrjan; Mussabek, Gauhar [Department of Physics and Engineering, al-Farabi Kazakh National University, 71 al-Farabi Ave., 050040 Almaty (Kazakhstan); Gudovskikh, Alexander [Nanotechnology Research and Education Centre, St. Petersburg Academic University, Russian Academy of Sciences, Hlopina Str. 8/3, 194021 St. Petersburg (Russian Federation)

    2015-07-15

    Semiconductor–insulator–semiconductor heterojunction solar cells were prepared using atomic layer deposition (ALD) technique. The silicon surface was treated with oxygen and hydrogen plasma in different orders before dielectric layer deposition. A plasma-enhanced ALD process was applied to deposit dielectric Al{sub 2}O{sub 3} on the plasma pretreated n-type Si(100) substrate. Aluminum doped zinc oxide (Al:ZnO or AZO) was deposited by thermal ALD and serves as transparent conductive oxide. Based on transmission electron microscopy studies the presence of thin silicon oxide (SiO{sub x}) layer was detected at the Si/Al{sub 2}O{sub 3} interface. The SiO{sub x} formation depends on the initial growth behavior of Al{sub 2}O{sub 3} and has significant influence on solar cell parameters. The authors demonstrate that a hydrogen plasma pretreatment and a precursor dose step repetition of a single precursor improve the initial growth behavior of Al{sub 2}O{sub 3} and avoid the SiO{sub x} generation. Furthermore, it improves the solar cell performance, which indicates a change of the Si/Al{sub 2}O{sub 3} interface states.

  7. Atomic layer deposition precursor step repetition and surface plasma pretreatment influence on semiconductor–insulator–semiconductor heterojunction solar cell

    International Nuclear Information System (INIS)

    Semiconductor–insulator–semiconductor heterojunction solar cells were prepared using atomic layer deposition (ALD) technique. The silicon surface was treated with oxygen and hydrogen plasma in different orders before dielectric layer deposition. A plasma-enhanced ALD process was applied to deposit dielectric Al2O3 on the plasma pretreated n-type Si(100) substrate. Aluminum doped zinc oxide (Al:ZnO or AZO) was deposited by thermal ALD and serves as transparent conductive oxide. Based on transmission electron microscopy studies the presence of thin silicon oxide (SiOx) layer was detected at the Si/Al2O3 interface. The SiOx formation depends on the initial growth behavior of Al2O3 and has significant influence on solar cell parameters. The authors demonstrate that a hydrogen plasma pretreatment and a precursor dose step repetition of a single precursor improve the initial growth behavior of Al2O3 and avoid the SiOx generation. Furthermore, it improves the solar cell performance, which indicates a change of the Si/Al2O3 interface states

  8. Surface passivation of nano-textured fluorescent SiC by atomic layer deposited TiO2

    Science.gov (United States)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas; Fadil, Ahmed; Syväjärvi, Mikael; Petersen, Paul Michael; Ou, Haiyan

    2016-07-01

    Nano-textured surfaces have played a key role in optoelectronic materials to enhance the light extraction efficiency. In this work, morphology and optical properties of nano-textured SiC covered with atomic layer deposited (ALD) TiO2 were investigated. In order to obtain a high quality surface for TiO2 deposition, a three-step cleaning procedure was introduced after RIE etching. The morphology of anatase TiO2 indicates that the nano-textured substrate has a much higher surface nucleated grain density than a flat substrate at the beginning of the deposition process. The corresponding reflectance increases with TiO2 thickness due to increased surface diffuse reflection. The passivation effect of ALD TiO2 thin film on the nano-textured fluorescent 6H-SiC sample was also investigated and a PL intensity improvement of 8.05% was obtained due to the surface passivation.

  9. Characteristics and properties of metal aluminum thin films prepared by electron cyclotron resonance plasma-assisted atomic layer deposition technology

    Institute of Scientific and Technical Information of China (English)

    Xiong Yu-Qing; Li Xing-Cun; Chen Qiang; Lei Wen-Wen; Zhao Qiao; Sang Li-Jun; Liu Zhong-Wei; Wang Zheng-Duo; Yang Li-Zhen

    2012-01-01

    Metal aluminum (Al) thin films are prepared by 2450 MHz electron cyclotron resonance plasma-assisted atomic layer deposition on glass and p-Si substrates using trimethylaluminum as the precursor and hydrogen as the reductive gas.We focus our attention on the plasma source for the thin-film preparation and annealing of the as-deposited films relative to the surface square resistivity.The square resistivity of as-deposited Al films is greatly reduced after annealing and almost reaches the value of bulk metal.Through chemical and structural analysis,we conclude that the square resistivity is determined by neither the contaminant concentration nor the surface morphology,but by both the crystallinity and crystal size in this process.

  10. Plasma-Enhanced Atomic Layer Deposition (PEALD of TiN using the Organic Precursor Tetrakis(ethylmethylamidoTitanium (TEMAT

    Directory of Open Access Journals (Sweden)

    Chen Z.X.

    2016-01-01

    Full Text Available This paper presents the plasma-enhanced atomic layer deposition (PEALD of titanium nitride (TiN using the organic precursor tetrakis(ethylmethylamidotitanium (TEMAT, with remote ammonia (NH3 plasma as reactant gas. This work investigates the impact of substrate temperature, from 150-350°C, and plasma times, from 5-30s, on deposition rate, resistivity, carbon content, N/Ti ratio and film density. The lowest resistivity of ~ 250 μΩ.cm was achieved at substrate temperatures 300-350°C and plasma time of 20s. At low substrate temperatures, although deposition was possible, carbon concentration was found to be higher, which thus affects film resistivity and density.

  11. Ru-decorated Pt nanoparticles on N-doped multi-walled carbon nanotubes by atomic layer deposition for direct methanol fuel cells

    DEFF Research Database (Denmark)

    Johansson, Anne-Charlotte Elisabeth Birgitta; Yang, R.B.; Haugshøj, K.B.;

    2013-01-01

    We present atomic layer deposition (ALD) as a new method for the preparation of highly dispersed Ru-decorated Pt nanoparticles for use as catalyst in direct methanol fuel cells (DMFCs). The nanoparticles were deposited onto N-doped multi-walled carbon nanotubes (MWCNTs) at 250 °C using trimethyl...... controlled size and composition can be deposited, with up-scaling prospects....

  12. Probing the Structure and Chemistry of Perylenetetracarboxylic Dianhydride on Graphene Before and After Atomic Layer Deposition of Alumina.

    Science.gov (United States)

    Johns, James E; Karmel, Hunter J; Alaboson, Justice M P; Hersam, Mark C

    2012-07-11

    The superlative electronic properties of graphene suggest its use as the foundation of next generation integrated circuits. However, this application requires precise control of the interface between graphene and other materials, especially the metal oxides that are commonly used as gate dielectrics. Towards that end, organic seeding layers have been empirically shown to seed ultrathin dielectric growth on graphene via atomic layer deposition (ALD), although the underlying chemical mechanisms and structural details of the molecule/dielectric interface remain unknown. Here, confocal resonance Raman spectroscopy is employed to quantify the structure and chemistry of monolayers of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on graphene before and after deposition of alumina with the ALD precursors trimethyl aluminum (TMA) and water. Photoluminescence measurements provide further insight into the details of the growth mechanism, including the transition between layer-by-layer growth and island formation. Overall, these results reveal that PTCDA is not consumed during ALD, thereby preserving a well-defined and passivating organic interface between graphene and deposited dielectric thin films. PMID:22905282

  13. Atomic/Molecular Layer Deposition of Lithium Terephthalate Thin Films as High Rate Capability Li-Ion Battery Anodes.

    Science.gov (United States)

    Nisula, Mikko; Karppinen, Maarit

    2016-02-10

    We demonstrate the fabrication of high-quality electrochemically active organic lithium electrode thin films by the currently strongly emerging combined atomic/molecular layer deposition (ALD/MLD) technique using lithium terephthalate, a recently found anode material for lithium-ion battery (LIB), as a proof-of-the-concept material. Our deposition process for Li-terephthalate is shown to well comply with the basic principles of ALD-type growth including the sequential self-saturated surface reactions, a necessity when aiming at micro-LIB devices with three-dimensional architectures. The as-deposited films are found crystalline across the deposition temperature range of 200-280 °C, which is a trait highly desired for an electrode material but rather unusual for hybrid inorganic-organic thin films. Excellent rate capability is ascertained for the Li-terephthalate films with no conductive additives required. The electrode performance can be further enhanced by depositing a thin protective LiPON solid-state electrolyte layer on top of Li-terephthalate; this yields highly stable structures with capacity retention of over 97% after 200 charge/discharge cycles at 3.2 C. PMID:26812433

  14. Seeding Atomic Layer Deposition of High-k Dielectrics on Epitaxial Graphene with Organic Self-assembled Monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Alaboson, Justice M. P.; Wang, Qing Hua; Emery, J.D.; Lipson, Albert L; Bedzyk, M.J.; Elam, Jeffrey W.; Pellin, Michael J.; Hersam, Mark C.

    2011-06-28

    The development of high-performance graphene-based nanoelectronics requires the integration of ultrathin and pinhole-free high-k dielectric films with graphene at the wafer scale. Here, we demonstrate that self-assembled monolayers of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) act as effective organic seeding layers for atomic layer deposition (ALD) of HfO₂ and Al₂O₃ on epitaxial graphene on SiC(0001). The PTCDA is deposited via sublimation in ultrahigh vacuum and shown to be highly ordered with low defect density by molecular-resolution scanning tunneling microscopy. Whereas identical ALD conditions lead to incomplete and rough dielectric deposition on bare graphene, the chemical functionality provided by the PTCDA seeding layer yields highly uniform and conformal films. The morphology and chemistry of the dielectric films are characterized by atomic force microscopy, ellipsometry, cross-sectional scanning electron microscopy, and X-ray photoelectron spectroscopy, while high-resolution X-ray reflectivity measurements indicate that the underlying graphene remains intact following ALD. Using the PTCDA seeding layer, metal-oxide-graphene capacitors fabricated with a 3 nm Al₂O₃ and 10 nm HfO₂ dielectric stack show high capacitance values of ~700 nF/cm² and low leakage currents of ~5 × 10{sup –9} A/cm² at 1 V applied bias. These results demonstrate the viability of sublimated organic self-assembled monolayers as seeding layers for high-k dielectric films in graphene-based nanoelectronics.

  15. Seeding atomic layer deposition of high-k dielectrics on epitaxial graphene with organic self-assembled monolayers.

    Science.gov (United States)

    Alaboson, Justice M P; Wang, Qing Hua; Emery, Jonathan D; Lipson, Albert L; Bedzyk, Michael J; Elam, Jeffrey W; Pellin, Michael J; Hersam, Mark C

    2011-06-28

    The development of high-performance graphene-based nanoelectronics requires the integration of ultrathin and pinhole-free high-k dielectric films with graphene at the wafer scale. Here, we demonstrate that self-assembled monolayers of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) act as effective organic seeding layers for atomic layer deposition (ALD) of HfO(2) and Al(2)O(3) on epitaxial graphene on SiC(0001). The PTCDA is deposited via sublimation in ultrahigh vacuum and shown to be highly ordered with low defect density by molecular-resolution scanning tunneling microscopy. Whereas identical ALD conditions lead to incomplete and rough dielectric deposition on bare graphene, the chemical functionality provided by the PTCDA seeding layer yields highly uniform and conformal films. The morphology and chemistry of the dielectric films are characterized by atomic force microscopy, ellipsometry, cross-sectional scanning electron microscopy, and X-ray photoelectron spectroscopy, while high-resolution X-ray reflectivity measurements indicate that the underlying graphene remains intact following ALD. Using the PTCDA seeding layer, metal-oxide-graphene capacitors fabricated with a 3 nm Al(2)O(3) and 10 nm HfO(2) dielectric stack show high capacitance values of ∼700 nF/cm(2) and low leakage currents of ∼5 × 10(-9) A/cm(2) at 1 V applied bias. These results demonstrate the viability of sublimated organic self-assembled monolayers as seeding layers for high-k dielectric films in graphene-based nanoelectronics. PMID:21553842

  16. Impact of morphological defects on the electrical breakdown of ultra thin atomic layer deposition processed Al{sub 2}O{sub 3} layers

    Energy Technology Data Exchange (ETDEWEB)

    Spahr, Holger; Bülow, Tim; Nowak, Christine; Hirschberg, Felix; Reinker, Johannes; Hamwi, Sami; Johannes, Hans-Hermann, E-mail: h2.johannes@ihf.tu-bs.de; Kowalsky, Wolfgang

    2013-05-01

    We report on the continuous increase of the breakdown electric field, also known as disruptive strength, of an ultra thin layer based on Al{sub 2}O{sub 3} prepared by low temperature atomic layer deposition (ALD) by reducing its thickness down to 3 nm. By measuring the disruptive strength for lower thicknesses, we demonstrate that these observations are in agreement with recent reports. Furthermore we detected an increase within the disruptive strength towards lower thicknesses together with a rise of the pin hole density. The pin holes, originating from an inhomogeneous growth of the dielectric and referred to as morphological defects and current conducting paths, are detected by Cu electroplating and result in a lower permittivity of the dielectric. As a conclusion, the dielectric breakdown of thin, low temperature ALD processed Al{sub 2}O{sub 3} layers does not seem to be negatively influenced by the increase of the pin hole density. Thus, the increase of the disruptive strength is either due to the morphological defects in the form of pin holes or a material phenomenon that is not affected by its nanoporous structure. - Highlights: • Defects in atomic layer deposited Al{sub 2}O{sub 3} films detected by Cu electroplating • Defect density rises as layer thickness decreases. • Relative permittivity decreases at lower layer thicknesses. • Despite of increasing defect density, breakdown electric field increases. • Defect density not correlated to those defects supporting electrical breakdown.

  17. On adsorption of aluminium and methyl groups on silica for TMA/H2O process in atomic layer deposition of aluminium oxide nano layers

    Indian Academy of Sciences (India)

    Anu Philip; K Rajeev Kumar

    2010-04-01

    A detailed chemisorption mechanism is proposed for the atomic layer deposition (ALD) of aluminium oxide nano layers using trimethyl aluminum (TMA) and water as precursors. Six possible chemisorption mechanisms, complete ligand exchange, partial ligand exchange, simple dissociation, complete dissociation via ligand exchange, complete dissociation and association, are proposed and related parameters like ligand to metal ratio (L/M), concentrations of metal atoms and methyl groups adsorbed are calculated and compared against reported values. The maximum number of methyl groups that can get attached on the surface is calculated in a different way which yields a more realistic value of 6.25 per nm2 substrate area. The dependence of the number of metal atoms adsorbed on OH concentration is explained clearly. It is proposed that a combination of complete ligand exchange and complete dissociation is the most probable chemisorption mechanism taking place at various OH concentrations.

  18. Improved photo-stability of silicon nanobelt arrays by atomic layer deposition for efficient photocatalytic hydrogen evolution

    Science.gov (United States)

    Bao, Xiao-Qing; Liu, Lifeng

    2014-12-01

    Silicon nanostructures have recently drawn great interest for use as photocathodes to produce hydrogen through water photoelectrolysis. Despite the high photocurrent observed, nanostructured Si photocathodes usually exhibit poor photo-stability in aqueous solution and rapidly deactivate. Herein, we report that by coating a thin titania protection layer using atomic layer deposition (ALD), the photo-stability of silicon nanobelt arrays fabricated by metal assisted chemical etching can be markedly improved. The photocurrent loss of the silicon nanobelt array photoelectrode coated with a 3 nm titania layer is found to be much lower than that of the electrode without a titania coating. We also demonstrate that the 3 nm titania coated Si nanobelt arrays can sustain more than twelve hours without a significant loss in photocurrent under operation conditions before it eventually fails. The possible failure mechanism is preliminarily investigated.

  19. Atomic Layer Deposition-Confined Nonstoichiometric TiO2 Nanocrystals with Tunneling Effects for Solar Driven Hydrogen Evolution.

    Science.gov (United States)

    Zhang, Peng; Tachikawa, Takashi; Fujitsuka, Mamoru; Majima, Tetsuro

    2016-04-01

    Ti(3+) self-doped TiO2 nanocrystals (TNCs) confined with controllable atomic layer deposition (ALD) amorphous layers were developed to provide a novel model of metal-insulator-semiconductor (MIS) photocatalysts for hydrogen generation in the ultraviolet to near-infrared region. Photoexcitation of optimized MIS nanostructures consisting of a metal cocatalyst (Pt), electron tunneling layer (ALD TiO2), and photoactive nonstoichiometric core (Ti(3+)-doped TNC) exhibited efficient hydrogen generation (52 μmol h(-1)·g(-1)), good reusability (16 h), and long-term stability (>7 d). The charge-transfer dynamics were examined using transient absorption spectroscopy to clarify the relationship between the photocatalytic activity and the tunneling effect. Our strategies highlight defect engineering in fabricating MIS photocatalysts with improved charge separation and tailored solar energy conversion properties. PMID:26963920

  20. Electrical Characteristics of TiO(2-x)/TiO2 Resistive Switching Memory Fabricated by Atomic Layer Deposition.

    Science.gov (United States)

    Heo, Kwan-Jun; Kim, Won-You; Kim, Sung-Jin

    2016-06-01

    The rewritable low-power operated nonvolatile resistive random access memory device composed of Al(top)/TiO(2-x)/TiO2/Al(bottom) are demonstrated. The active component, the TiO2 layer of the device, is fabricated by atomic layer deposition. The oxygen vacancy TiO(2-x)/TiO2 layer annealed at 600 degrees C using rapid thermal annealing and it was proven to be in the rutile phase by X-ray diffraction analysis. The device exhibits nonvolatile memory behavior consistent with resistive switching properties, demonstrates an ON/OFF ratio of approximately 1,000:1, requires range of low voltage less than 0.4 V, and is still operational more than 120 times. PMID:27427707

  1. Atomic layer deposition of environmentally benign SnTiO{sub x} as a potential ferroelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Siliang; Selvaraj, Sathees Kannan [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Choi, Yoon-Young; Hong, Seungbum [Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Nakhmanson, Serge M. [Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Takoudis, Christos G., E-mail: takoudis@uic.edu [Department of Bioengineering and Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States)

    2016-01-15

    Inspired by the need to discover environmentally friendly, lead-free ferroelectric materials, here the authors report the atomic layer deposition of tin titanate (SnTiO{sub x}) aiming to obtain the theoretically predicted perovskite structure that possesses ferroelectricity. In order to establish the growth conditions and probe the film structure and ferroelectric behavior, the authors grew SnTiO{sub x} films on the commonly used Si(100) substrate. Thin films of SnTiO{sub x} have been successfully grown at a deposition temperature of 200 °C, with a Sn/Ti atomic layer deposition (ALD) cycle ratio of 2:3 and postdeposition heat treatments under different conditions. X-ray photoelectron spectroscopy revealed excellent composition tunability of ALD. X-ray diffraction spectra suggested anatase phase for all films annealed at 650 and 350 °C, with peak positions shifted toward lower 2-theta angles indicating enlarged unit cell volume. The film annealed in O{sub 2} at 350 °C exhibited piezoresponse amplitude and phase hysteresis loops, indicative of the existence of switchable polarization.

  2. Highly ordered freestanding titanium oxide nanotube arrays using Si-containing block copolymer lithography and atomic layer deposition

    International Nuclear Information System (INIS)

    Highly ordered freestanding TiO2 nanotube arrays with atomic layer control of wall thickness were fabricated using an organic–inorganic hybrid nanoporous template and atomic layer deposition (ALD). The hybrid nanoporous template with a high-aspect-ratio cylindrical nanopore array can be readily fabricated by pattern transfer from a thin silicon-containing block copolymer film into a thick cross-linked organic polymer layer. The template exhibited excellent thermal stability and thus allowed the high-temperature ALD process to conformally deposit TiO2 thin films on the inner surface of cylindrical nanopores. The ultrafine thickness tunability of the ALD process made it possible to develop TiO2 nanotubes with various wall thicknesses. After the template was removed using a dry etch followed by calcination, vertically aligned and highly crystalline anatase TiO2 nanotube arrays were produced without collapse or bundling. We also fabricated the highly uniform freestanding arrays of multi-component nanotubes composed of TiO2/Al2O3/TiO2 nanolaminate and Ti–Al–O mixed-phase films with precisely controlled thickness and composition. (paper)

  3. Reaction Mechanism Underlying Atomic Layer Deposition of Antimony Telluride Thin Films.

    Science.gov (United States)

    Han, Byeol; Kim, Yu-Jin; Park, Jae-Min; Yusup, Luchana L; Ishii, Hana; Lansalot-Matras, Clement; Lee, Won-Jun

    2016-05-01

    The mechanism underlying the deposition of SbTe films by alternating exposures to Sb(NMe2)3 and Te(GeMe3)2 was investigated. Sb(NMe2)3 and Te(GeMe3)2 were selected because they have very high vapor pressure and are free of Si, Cl, and O atoms in the molecules. The mechanism of deposition was proposed by density functional theory (DFT) calculation and was verified by in-situ quartz crystal microbalance (QCM) analysis. DFT calculation expected the ligand-exchange reactions between the Sb and Te precursors to form Me2NGeMe3 as the byproduct. QCM analysis indicated that a single -NMe2 group in Sb(NMe2)3 reacts with -TeGeMe3 on the surface to form an Sb2Te3 film, and that a small fraction of Sb is incorporated into the film by the thermal decomposition of Sb(NMe2)3. The Te(GeMe3)2 molecules were thermally stable up to 120 degrees C, while the Sb(NMe2)3 molecules decomposed at temperatures of 60 degrees C and higher. Sb-rich SbTe films with different Sb contents were prepared by controlling the partial decomposition of Sb(NMe2)3 molecules, which was enhanced by increasing the pulse time of the precursor. PMID:27483847

  4. Indium oxide thin film prepared by low temperature atomic layer deposition using liquid precursors and ozone oxidant

    Energy Technology Data Exchange (ETDEWEB)

    Maeng, W.J. [Department of Materials Science and Engineering, University of Wisconsin Madison, Madison, WI 53706 (United States); Choi, Dong-Won [Division of Materials Science and Engineering, 222 Wangsimni-ro, Seongdong-gu, Hanyang University, Seoul, 133-719 (Korea, Republic of); Park, Jozeph, E-mail: jozeph.park@gmail.com [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Park, Jin-Seong, E-mail: jsparklime@hanyang.ac.kr [Division of Materials Science and Engineering, 222 Wangsimni-ro, Seongdong-gu, Hanyang University, Seoul, 133-719 (Korea, Republic of)

    2015-11-15

    Transparent conducting Indium oxide (InO{sub x}) thin films were deposited by atomic layer deposition at low deposition temperatures below 100 °C. For the comparative study with liquid precursors in low temperature thermal ALD, diethyl[1,1,1-trimethyl-N-(trimethylsilyl)silanaminato]-Indium, [3-(dimethylamino-kN)propyl-kC]dimethyl-Indium, and triethyl indium (TEIn) were used as the In precursors. Ozone was used as the oxidant for all precursors. InO{sub x} films grown using the three precursors all exhibit relatively low electrical resistivity below 10{sup −3} Ω cm at temperatures above 150 °C. Below 100 °C, the lowest resistivity (2 × 10{sup −3} Ω cm) was observed in the films grown with TEIn. The electrical, structural and optical properties were systematically investigated as functions of the deposition temperature and precursors. - Highlights: • InO{sub x} thin films were deposited by ALD at extremely low deposition temperatures below 100 °C. • InO{sub x} films exhibit relatively low electrical resistivity below 10{sup −3} Ω cm at temperatures above 150 °C. • Ozone stimulate the chemical reactions to yield dense indium oxide films at low temperatures.

  5. Indium oxide thin film prepared by low temperature atomic layer deposition using liquid precursors and ozone oxidant

    International Nuclear Information System (INIS)

    Transparent conducting Indium oxide (InOx) thin films were deposited by atomic layer deposition at low deposition temperatures below 100 °C. For the comparative study with liquid precursors in low temperature thermal ALD, diethyl[1,1,1-trimethyl-N-(trimethylsilyl)silanaminato]-Indium, [3-(dimethylamino-kN)propyl-kC]dimethyl-Indium, and triethyl indium (TEIn) were used as the In precursors. Ozone was used as the oxidant for all precursors. InOx films grown using the three precursors all exhibit relatively low electrical resistivity below 10−3 Ω cm at temperatures above 150 °C. Below 100 °C, the lowest resistivity (2 × 10−3 Ω cm) was observed in the films grown with TEIn. The electrical, structural and optical properties were systematically investigated as functions of the deposition temperature and precursors. - Highlights: • InOx thin films were deposited by ALD at extremely low deposition temperatures below 100 °C. • InOx films exhibit relatively low electrical resistivity below 10−3 Ω cm at temperatures above 150 °C. • Ozone stimulate the chemical reactions to yield dense indium oxide films at low temperatures

  6. Atomic-layer chemical-vapor-deposition of TiN thin films on Si(100) and Si(111)

    CERN Document Server

    Kim, Y S; Kim, Y D; Kim, W M

    2000-01-01

    An atomic-layer chemical vapor deposition (AL-CVD) system was used to deposit TiN thin films on Si(100) and Si(111) substrates by cyclic exposures of TiCl sub 4 and NH sub 3. The growth rate was measured by using the number of deposition cycles, and the physical properties were compared with those of TiN films grown by using conventional deposition methods. To investigate the growth mechanism, we suggest a growth model for TiN n order to calculate the growth rate per cycle with a Cerius program. The results of the calculation with the model were compared with the experimental values for the TiN film deposited using the AL-CVD method. The stoichiometry of the TiN film was examined by using Auger electron spectroscopy, and the chlorine and the oxygen impurities were examined. The x-ray diffraction and the transmission electron microscopy results for the TiN film exhibited a strong (200) peak and a randomly oriented columnar microstructure. The electrical resistivity was found to decrease with increasing deposit...

  7. Epitaxial strontium titanate films grown by atomic layer deposition on SrTiO3-buffered Si(001) substrates

    International Nuclear Information System (INIS)

    Epitaxial strontium titanate (STO) films have been grown by atomic layer deposition (ALD) on Si(001) substrates with a thin STO buffer layer grown by molecular beam epitaxy (MBE). Four unit cells of STO grown by MBE serve as the surface template for ALD growth. The STO films grown by ALD are crystalline as-deposited with minimal, if any, amorphous SiOx layer at the STO-Si interface. The growth of STO was achieved using bis(triisopropylcyclopentadienyl)-strontium, titanium tetraisopropoxide, and water as the coreactants at a substrate temperature of 250 °C. In situ x-ray photoelectron spectroscopy (XPS) analysis revealed that the ALD process did not induce additional Si–O bonding at the STO-Si interface. Postdeposition XPS analysis also revealed sporadic carbon incorporation in the as-deposited films. However, annealing at a temperature of 250 °C for 30 min in moderate to high vacuum (10−6–10−9 Torr) removed the carbon species. Higher annealing temperatures (>275 °C) gave rise to a small increase in Si–O bonding, as indicated by XPS, but no reduced Ti species were observed. X-ray diffraction revealed that the as-deposited STO films were c-axis oriented and fully crystalline. A rocking curve around the STO(002) reflection gave a full width at half maximum of 0.30° ± 0.06° for film thicknesses ranging from 5 to 25 nm. Cross-sectional transmission electron microscopy revealed that the STO films were continuous with conformal growth to the substrate and smooth interfaces between the ALD- and MBE-grown STO. Overall, the results indicate that thick, crystalline STO can be grown on Si(001) substrates by ALD with minimal formation of an amorphous SiOx layer using a four-unit-cell STO buffer layer grown by MBE to serve as the surface template.

  8. Tunnel spin injection into graphene using Al2O3 barrier grown by atomic layer deposition on functionalized graphene surface

    OpenAIRE

    Yamaguchi, Takehiro; Masubuchi, Satoru; Iguchi, Kazuyuki; Moriya, Rai; Machida, Tomoki

    2011-01-01

    We demonstrate electrical tunnel spin injection from a ferromagnet to graphene through a high-quality Al2O3 grown by atomic layer deposition (ALD). The graphene surface is functionalized with a self-assembled monolayer of 3,4,9,10-perylene tetracarboxylic acid (PTCA) to promote adhesion and growth of Al2O3 with a smooth surface. Using this composite tunnel barrier of ALD-Al2O3 and PTCA, a spin injection signal of 30 ohm has been observed from non-local magnetoresistance measurements at 45 K, ...

  9. 570 mV photovoltage, stabilized n-Si/CoO_x heterojunction photoanodes fabricated using atomic layer deposition

    OpenAIRE

    Zhou, Xinghao; Liu, Rui; Sun, Ke; Papadantonakis, Kimberly M.; Brunschwig, Bruce S.; Lewis, Nathan S.

    2016-01-01

    Heterojunction photoanodes, consisting of n-type crystalline Si(100) substrates coated with a thin ∼50 nm film of cobalt oxide fabricated using atomic-layer deposition (ALD), exhibited photocurrent-onset potentials of −205 ± 20 mV relative to the formal potential for the oxygen-evolution reaction (OER), ideal regenerative solar-to-O_2(g) conversion efficiencies of 1.42 ± 0.20%, and operated continuously for over 100 days (∼2500 h) in 1.0 M KOH(aq) under simulated solar illumination. The ALD C...

  10. Energy band alignment of atomic layer deposited HfO2 on epitaxial (110)Ge grown by molecular beam epitaxy

    OpenAIRE

    Hudait, Mantu K.; Zhu, Y.; Maurya, Deepam; Priya, Shashank

    2013-01-01

    The band alignment properties of atomic layer HfO2 film deposited on epitaxial (110)Ge, grown by molecular beam epitaxy, was investigated using x-ray photoelectron spectroscopy. The cross-sectional transmission electron microscopy exhibited a sharp interface between the (110)Ge epilayer and the HfO2 film. The measured valence band offset value of HfO2 relative to (110)Ge was 2.28 +/- 0.05 eV. The extracted conduction band offset value was 2.66 +/- 0.1 eV using the bandgaps of HfO2 of 5.61 eV ...

  11. Quartz crystal microbalance study of tungsten atomic layer deposition using WF6 and Si2H6

    International Nuclear Information System (INIS)

    The atomic layer deposition (ALD) of tungsten can be accomplished using sequential exposures of WF6 and Si2H6 (disilane). In this paper, W ALD is explored using in situ quartz crystal microbalance (QCM) measurements as a function of the reactant exposure and deposition temperature. The QCM measurements revealed that the WF6 reaction is self-limiting. In contrast, W ALD growth rates exhibited a slow and continual increase for disilane exposures > 4 x 104 L. The W ALD growth rate was also weakly temperature-dependent with an activation energy of 1.5 ± 0.1 kcal/mol at T 275 deg. C. The QCM results and previous Auger results for W ALD yield the relationship between the silicon coverage deposited during the Si2H6 exposure and the tungsten coverage deposited during the WF6 exposure. The W/Si atomic ratio of ∼ 1:1 is consistent with earlier Auger investigations of the surface chemistry during W ALD at 200 deg. C. The QCM measurements are also consistent with silicon coverages of 1.7-2.1 monolayers after the Si2H6 exposures. These high silicon coverages are believed to result by silylene insertion from Si2H6 into surface Si-H bonds

  12. Theoretical modeling and experimental observations of the atomic layer deposition of SrO using a cyclopentadienyl Sr precursor

    Science.gov (United States)

    Fredrickson, Kurt D.; McDaniel, Martin D.; Slepko, Alex; Ekerdt, John G.; Demkov, Alexander A.

    2016-08-01

    First-principle calculations are used to model the adsorption and hydration of strontium bis(cyclopentadienyl) [Sr(Cp)2] on TiO2-terminated strontium titanate, SrTiO3 (STO), for the deposition of strontium oxide, SrO, by atomic layer deposition (ALD). The Sr(Cp)2 precursor is shown to adsorb on the TiO2-terminated surface, with the Sr atom assuming essentially the bulk position in STO. The C-Sr bonds are weaker than in the free molecule, with a Ti atom at the surface bonding to one of the C atoms in the cyclopentadienyl rings. The surface does not need to be hydrogenated for precursor adsorption. The calculations are compared with experimental observations for a related Sr cyclopentadienyl precursor, strontium bis(triisopropylcyclopentadienyl) [Sr(iPr3Cp)2], adsorbed on TiO2-terminated STO. High-resolution x-ray photoelectron spectroscopy and low-energy ion scattering spectroscopy show adsorption of the Sr precursor on the TiO2-terminated STO after a single precursor dose. This study suggests that ALD growth from the strontium precursors featuring cyclopentadienyl ligands, such as Sr(Cp)2, may initiate film growth on non-hydroxylated surfaces.

  13. X-ray scattering of calcite thin films deposited by atomic layer deposition: Studies in air and in calcite saturated water solution

    International Nuclear Information System (INIS)

    Carbonates are one of the most abundant groups of minerals in earth systems and are important in many geological settings and industrial processes. Calcite (CaCO3) thin films produced by atomic layer deposition offer a method to evaluate the surficial properties of carbonates as well as interactions at the carbonate–fluid interface. Using synchrotron X-ray reflectivity and X-ray diffraction, these films are observed to be porous, polycrystalline, and have crystallites oriented with the major (104) calcite cleavage plane parallel to the surface of the z-cut single crystal quartz substrate. An Al2O3 buffer layer, present between quartz and the calcite film, does not affect the as-deposited film, but does influence how the films reorganize in contact with fluid. Without a buffer layer, calcite reorients its crystallites to have populations of (006) and (030) parallel to the substrate, while those with an Al2O3 buffer layer become more amorphous. Amorphous films may represent an analog to amorphous calcium carbonate and provide insights into that material's thermophysical behavior. Due to a higher percentage of pore spaces available for fluid infiltration, films deposited at higher temperature make the calcite thin films more susceptible to amorphization. These films are chemically similar, but structurally dissimilar to bulk natural calcite. Nevertheless, they can be a complementary system to traditional single crystal X-ray surface scattering studies on carbonates, particularly for important but less common minerals, to evaluate mineral–fluid interfacial interactions. - Highlights: • Atomic layer deposition (ALD) used to produce calcite films. • Calcite film orientation and crystallinity depend on ALD parameters. • ALD calcite films can be both crystalline and amorphous. • Interaction of water with films can re-orient or amorphize the films. • ALD calcite films may be useful to study carbonate–fluid interfacial interactions

  14. Surface atoms core-level shifts in single crystal GaAs surfaces: Interactions with trimethylaluminum and water prepared by atomic layer deposition

    International Nuclear Information System (INIS)

    The surface As/Ga atoms 3d core-level spectra of the atomically clean GaAs(1 1 1)A-2 × 2, GaAs(0 0 1)-2 × 4, and GaAs(0 0 1)-4 × 6 surfaces were firstly presented using high-resolution synchrotron radiation photoemission as a probe. The technique clearly explicates behaviors of the As atoms in different surface reconstruction. For GaAs(1 1 1)A-2 × 2, the surface As sits in the same plane as the Ga atoms. As to the GaAs(0 0 1)-2 × 4 surface, the As–As dimers dominate the surface layer, while for GaAs(001)-4 × 6, the As existed in two forms, the As in the As–Ga dimer and the 3-fold coordinated As. Next, we present a microscopic view of in situ atomic layer deposition (ALD) of Al2O3 on GaAs taking the two (0 0 1) surfaces as examples. The precursors were trimethylaluminum (TMA) and water. TMA could exist in either a chemisorbed or physisorbed form, depending on the charge environment of the associated surface atoms. The subsequent water purge resulted in both adsorbed forms being etched off or transformed the physisorbed TMA into the As-O-Al(CH3)2 configuration. We found that the ALD process rendered the precursors partially and selectively in forming bonds with the surface atoms without disturbing the atoms in the subsurface layer. Upon annealing, the interfacial bonding was dominated with the As-Al as well as Ga-O bonds.

  15. Passivation of pigment-grade TiO2 particles by nanothick atomic layer deposited SiO2 films

    International Nuclear Information System (INIS)

    Pigment-grade TiO2 particles were passivated using nanothick insulating films fabricated by atomic layer deposition (ALD). Conformal SiO2 and Al2O3 layers were coated onto anatase and rutile powders in a fluidized bed reactor. SiO2 films were deposited using tris-dimethylaminosilane (TDMAS) and H2O2 at 500 deg. C. Trimethylaluminum and water were used as precursors for Al2O3 ALD at 177 deg. C. The photocatalytic activity of anatase pigment-grade TiO2 was decreased by 98% after the deposition of 2 nm SiO2 films. H2SO4 digest tests were performed to exhibit the pinhole-free nature of the coatings and the TiO2 digest rate was 40 times faster for uncoated TiO2 than SiO2 coated over a 24 h period. Mass spectrometry was used to monitor reaction progress and allowed for dosing time optimization. These results demonstrate that the TDMAS-H2O2 chemistry can deposit high quality, fully dense SiO2 films on high radius of curvature substrates. Particle ALD is a viable passivation method for pigment-grade TiO2 particles

  16. Integration of atomic layer deposited high-k dielectrics on GaSb via hydrogen plasma exposure

    Directory of Open Access Journals (Sweden)

    Laura B. Ruppalt

    2014-12-01

    Full Text Available In this letter we report the efficacy of a hydrogen plasma pretreatment for integrating atomic layer deposited (ALD high-k dielectric stacks with device-quality p-type GaSb(001 epitaxial layers. Molecular beam eptiaxy-grown GaSb surfaces were subjected to a 30 minute H2/Ar plasma treatment and subsequently removed to air. High-k HfO2 and Al2O3/HfO2 bilayer insulating films were then deposited via ALD and samples were processed into standard metal-oxide-semiconductor (MOS capacitors. The quality of the semiconductor/dielectric interface was probed by current-voltage and variable-frequency admittance measurements. Measurement results indicate that the H2-plamsa pretreatment leads to a low density of interface states nearly independent of the deposited dielectric material, suggesting that pre-deposition H2-plasma exposure, coupled with ALD of high-k dielectrics, may provide an effective means for achieving high-quality GaSb MOS structures for advanced Sb-based digital and analog electronics.

  17. Atomic layer deposition-Sequential self-limiting surface reactions for advanced catalyst "bottom-up" synthesis

    Science.gov (United States)

    Lu, Junling; Elam, Jeffrey W.; Stair, Peter C.

    2016-06-01

    Catalyst synthesis with precise control over the structure of catalytic active sites at the atomic level is of essential importance for the scientific understanding of reaction mechanisms and for rational design of advanced catalysts with high performance. Such precise control is achievable using atomic layer deposition (ALD). ALD is similar to chemical vapor deposition (CVD), except that the deposition is split into a sequence of two self-limiting surface reactions between gaseous precursor molecules and a substrate. The unique self-limiting feature of ALD allows conformal deposition of catalytic materials on a high surface area catalyst support at the atomic level. The deposited catalytic materials can be precisely constructed on the support by varying the number and type of ALD cycles. As an alternative to the wet-chemistry based conventional methods, ALD provides a cycle-by-cycle "bottom-up" approach for nanostructuring supported catalysts with near atomic precision. In this review, we summarize recent attempts to synthesize supported catalysts with ALD. Nucleation and growth of metals by ALD on oxides and carbon materials for precise synthesis of supported monometallic catalyst are reviewed. The capability of achieving precise control over the particle size of monometallic nanoparticles by ALD is emphasized. The resulting metal catalysts with high dispersions and uniformity often show comparable or remarkably higher activity than those prepared by conventional methods. For supported bimetallic catalyst synthesis, we summarize the strategies for controlling the deposition of the secondary metal selectively on the primary metal nanoparticle but not on the support to exclude monometallic formation. As a review of the surface chemistry and growth behavior of metal ALD on metal surfaces, we demonstrate the ways to precisely tune size, composition and structure of bimetallic metal nanoparticles. The cycle-by-cycle "bottom up" construction of bimetallic (or multiple

  18. Atomic layer deposition of ruthenium (Ru) thin films using ethylbenzen-cyclohexadiene Ru(0) as a seed layer for copper metallization

    Energy Technology Data Exchange (ETDEWEB)

    Yeo, Seungmin; Choi, Sang-Hyeok; Park, Ji-Yoon [School of Materials Science and Engineering, Yeungnam University, 214–1, Dae-dong, Gyeongsan-City, South Korea, 712–749 (Korea, Republic of); Kim, Soo-Hyun, E-mail: soohyun@ynu.ac.kr [School of Materials Science and Engineering, Yeungnam University, 214–1, Dae-dong, Gyeongsan-City, South Korea, 712–749 (Korea, Republic of); Cheon, Taehoon [Center for Core Research Facilities, Daegu Gyeongbuk Institute of Science and Technology, Sang-ri, Hyeonpung-myeon, Dalseong-gun, Daegu (Korea, Republic of); Lim, Byoung-Yong; Kim, Sunjung [School of Materials Science and Engineering, University of Ulsan, Mugeo-dong, Nam-gu, Ulsan 680–749 (Korea, Republic of)

    2013-11-01

    Ruthenium (Ru) thin films were grown on thermally-grown SiO{sub 2} substrates using atomic layer deposition (ALD) by a sequential supply of (ethylbenzene)(1,3-cyclohexadiene)Ru(0) (EBCHDRu, C{sub 14}H{sub 18}Ru), and molecular oxygen (O{sub 2}) at deposition temperatures ranging from 140 to 350 °C. A self-limiting film growth was confirmed at the deposition temperature of 225 °C and the growth rate was 0.1 nm/cycle on the SiO{sub 2} substrate with a negligible number of incubation cycles (approximately 2 cycles). Plan-view transmission electron microscopy analysis showed that nucleation was started after only 3 ALD cycles and the maximum nuclei density of 1.43 × 10{sup 12}/cm{sup 2} was obtained after 5 ALD cycles. A continuous Ru film with a thickness of ∼ 4 nm was formed after 40 ALD cycles. The film resistivity was decreased with increasing deposition temperature, which was closely related to its crystallinity, microstructure, and density, and the minimum resistivity of ∼ 14 μΩ-cm was obtained at the deposition temperature of 310 °C. The step coverage was approximately 100% at trench (aspect ratio: 4.5) with the top opening size of ∼ 25 nm. Finally, the ALD-Ru film was evaluated in terms of its performance as a seed layer for Cu electroplating. - Highlights: • Atomic layer deposition (ALD) of Ru using a zero metal valence precursor. • The growth rate of 0.1 nm/cycle and negligible incubation cycle. • Excellent step coverage at 25 nm trench (aspect ratio: 4.5). • Electroplating of Cu on a 5-nm-thick ALD-Ru film.

  19. Development of electrostatic supercapacitors by atomic layer deposition on nanoporous anodic aluminium oxides for energy harvesting applications

    Directory of Open Access Journals (Sweden)

    Lucia eIglesias

    2015-03-01

    Full Text Available Nanomaterials can provide innovative solutions for solving the usual energy harvesting and storage drawbacks that take place in conventional energy storage devices based on batteries or electrolytic capacitors, because they are not fully capable for attending the fast energy demands and high power densities required in many of present applications. Here, we report on the development and characterization of novel electrostatic supercapacitors made by conformal Atomic Layer Deposition on the high open surface of nanoporous anodic alumina membranes employed as templates. The structure of the designed electrostatic supercapacitor prototype consists of successive layers of Aluminium doped Zinc Oxide, as the bottom and top electrodes, together Al2O3 as the intermediate dielectric layer. The conformality of the deposited conductive and dielectric layers, together with their composition and crystalline structure have been checked by XRD and electron microscopy techniques. Impedance measurements performed for the optimized electrostatic supercapacitor device give a high capacitance value of 200 µF/cm2 at the frequency of 40 Hz, which confirms the theoretical estimations for such kind of prototypes, and the leakage current reaches values around of 1.8 mA/cm2 at 1 V. The high capacitance value achieved by the supercapacitor prototype together its small size turns these devices in outstanding candidates for using in energy harvesting and storage applications.

  20. Enhanced Performance of Nanowire-Based All-TiO2 Solar Cells using Subnanometer-Thick Atomic Layer Deposited ZnO Embedded Layer

    International Nuclear Information System (INIS)

    In this paper, the effect of angstrom-thick atomic layer deposited (ALD) ZnO embedded layer on photovoltaic (PV) performance of Nanowire-Based All-TiO2 solar cells has been systematically investigated. Our results indicate that by varying the thickness of ZnO layer the efficiency of the solar cell can be significantly changed. It is shown that the efficiency has its maximum for optimal thickness of 1 ALD cycle in which this ultrathin ZnO layer improves device performance through passivation of surface traps without hampering injection efficiency of photogenerated electrons. The mechanisms contributing to this unprecedented change in PV performance of the cell have been scrutinized and discussed

  1. Efficient solar photocatalytic activity of TiO2 coated nano-porous silicon by atomic layer deposition

    Science.gov (United States)

    Sampath, Sridhar; Maydannik, Philipp; Ivanova, Tatiana; Shestakova, Marina; Homola, Tomáš; Bryukvin, Anton; Sillanpää, Mika; Nagumothu, Rameshbabu; Alagan, Viswanathan

    2016-09-01

    In the present study, TiO2 coated nano-porous silicon (TiO2/PS) was prepared by atomic layer deposition (ALD) whereas porous silicon was prepared by stain etching method for efficient solar photocatalytic activity. TiO2/PS was characterized by FESEM, AFM, XRD, XPS and DRS UV-vis spectrophotometer. Absorbance spectrum revealed that TiO2/PS absorbs complete solar light with wave length range of 300 nm-800 nm and most importantly, it absorbs stronger visible light than UV light. The reason for efficient solar light absorption of TiO2/PS is that nanostructured TiO2 layer absorbs UV light and nano-porous silicon layer absorbs visible light which is transparent to TiO2 layer. The amount of visible light absorption of TiO2/PS directly increases with increase of silicon etching time. The effect of silicon etching time of TiO2/PS on solar photocatalytic activity was investigated towards methylene blue dye degradation. Layer by layer solar absorption mechanism was used to explain the enhanced photocatalytic activity of TiO2/PS solar absorber. According to this, the photo-generated electrons of porous silicon will be effectively injected into TiO2 via hetero junction interface which leads to efficient charge separation even though porous silicon is not participating in any redox reactions in direct.

  2. Room temperature plasma enhanced atomic layer deposition for TiO{sub 2} and WO{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Alexander; Schnabel, Hans-Dieter, E-mail: Hans.Dieter.Schnabel@fh-zwickau.de; Reinhold, Ullrich; Rauer, Sebastian; Neidhardt, Andreas [Department of Physical Engineering and Informatics, University of Applied Science, Westsächsische Hochschule Zwickau, Dr.-Friedrichs-Ring 2a, 08056 Zwíckau (Germany)

    2016-01-15

    This paper presents a study on plasma enhanced atomic layer deposition (ALD) of TiO{sub 2} and WO{sub 3} films on silicon substrates. At low temperatures, ALD processes, which are not feasible at high temperatures, could be possible. For example, temperatures at 180 °C and above allow no WO{sub 3} ALD process with WF{sub 6} as a precursor because etching processes hinder film growth. Further low temperature deposition techniques are needed to coat temperature sensitive materials. For the deposition, WF{sub 6} and TiCl{sub 4} are used as metal precursors and O{sub 2} and H{sub 2}O as oxygen sources. The depositions were accomplished in the temperature range of 30 °C up to 180 °C for both metal oxides. Spectroscopic ellipsometry, x-ray reflection, and grazing incidence diffraction were used to investigate the deposited ALD thin films. Film growth, density, crystallinity, and roughness are discussed as functions of temperature after ensuring the ALD requirement of self-saturating adsorption. Growth rates and measured material properties are in good agreement with literature data.

  3. Study of atomic layer deposition of indium oxy-sulfide films for Cu(In,Ga)Se2 solar cells

    International Nuclear Information System (INIS)

    This paper explores the growth mechanism of plasma enhanced atomic layer deposition of In2(S,O)3 films. The films were deposited using indium acetylacetonate (In(acac)3), hydrogen sulfide (H2S) and Ar/O2 plasma as oxygen precursor. The films were characterized using X-ray reflectometry, spectrophotometry, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. To understand the growth mechanism and especially the interactions between Ar/O2 plasma and In2(S,O)3 growing film, in-situ analyses were performed using quadrupole mass spectrometry. In-situ qualitative analysis revealed good correlation between the species detected in vapor phase and thin film properties. High concentrations of atomic and molecular oxygen were measured in the vapor phase during O2 plasma pulses. Significant decrease of these species could be observed by varying the plasma power from 2600 to 300 W, while the optical band gap remained at high values (> 2.6 eV). The analysis of the O2-free/Ar plasma process showed that some of these oxygen species originate either from the indium precursor or from the substrate surface. This study explains the high oxygen content of the films, and allows us to reduce and control it. Generally, this report provides keys to understand the effect of plasma reactivity for the elaboration of oxide based materials. - Highlights: • In2(S,O)3 films were synthesized by plasma enhanced atomic layer deposition. • Growth mechanism was studied via gas phase analysis by Quadrupole Mass Spectrometry. • Good correlation between the vapor phase species and thin films properties was observed. • The film compositions and band gaps can be controlled by varying the plasma power

  4. Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

    Energy Technology Data Exchange (ETDEWEB)

    Hoye, Robert L. Z., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk; MacManus-Driscoll, Judith L., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Muñoz-Rojas, David [LMGP, University Grenoble-Alpes, CNRS, F-3800 Grenoble (France); Nelson, Shelby F. [Kodak Research Laboratories, Eastman Kodak Company, Rochester, New York 14650 (United States); Illiberi, Andrea; Poodt, Paul [Holst Centre/TNO Thin Film Technology, Eindhoven, 5656 AE (Netherlands); Roozeboom, Fred [Holst Centre/TNO Thin Film Technology, Eindhoven, 5656 AE (Netherlands); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB (Netherlands)

    2015-04-01

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-SALD technology will enable the commercial processing of thin films over large areas on a sheet-to-sheet and roll-to-roll basis, with new reactor designs emerging for flexible plastic and paper electronics.

  5. Enhanced Dry Reforming of Methane on Ni and Ni-Pt Catalysts Synthesized by Atomic Layer Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Troy D.; Montemore, Matthew M.; Lubers, Alia M.; Ellis, Lucas D.; Weimer, Alan; Falconer, John L.; Medlin, James W.

    2015-02-25

    Atomic layer deposition (ALD) was used to deposit Ni and Pt on alumina supports to form monometallic and bimetallic catalysts with initial particle sizes of 1–2.4 nm. The ALD catalysts were more active (per mass of metal) than catalysts prepared by incipient wetness (IW) for dry reforming of methane (DRM), and they did not form carbon whiskers during reaction due to their sufficiently small size. Catalysts modified by Pt ALD had higher rates of reaction per mass of metal and inhibited coking, whereas NiPt catalysts synthesized by IW still formed carbon whiskers. Temperature-programmed reduction of Ni catalysts modified by Pt ALD indicated the presence of bimetallic interaction. Density functional theory calculations suggested that under reaction conditions, the NiPt surfaces form Ni-terminated surfaces that are associated with higher DRM rates (due to their C and O adsorption energies, as well as the CO formation and CH4 dissociation energies).

  6. Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

    International Nuclear Information System (INIS)

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-SALD technology will enable the commercial processing of thin films over large areas on a sheet-to-sheet and roll-to-roll basis, with new reactor designs emerging for flexible plastic and paper electronics

  7. A modular reactor design for in situ synchrotron x-ray investigation of atomic layer deposition processes

    Energy Technology Data Exchange (ETDEWEB)

    Klug, Jeffrey A., E-mail: jklug@anl.gov; Emery, Jonathan D.; Martinson, Alex B. F.; Proslier, Thomas, E-mail: prolier@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Weimer, Matthew S. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Yanguas-Gil, Angel; Elam, Jeffrey W. [Energy Systems Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Seifert, Sönke; Schlepütz, Christian M. [X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Hock, Adam S. [Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Chemical Science and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2015-11-15

    Synchrotron characterization techniques provide some of the most powerful tools for the study of film structure and chemistry. The brilliance and tunability of the Advanced Photon Source allow access to scattering and spectroscopic techniques unavailable with in-house laboratory setups and provide the opportunity to probe various atomic layer deposition (ALD) processes in situ starting at the very first deposition cycle. Here, we present the design and implementation of a portable ALD instrument which possesses a modular reactor scheme that enables simple experimental switchover between various beamlines and characterization techniques. As first examples, we present in situ results for (1) X-ray surface scattering and reflectivity measurements of epitaxial ZnO ALD on sapphire, (2) grazing-incidence small angle scattering of MnO nucleation on silicon, and (3) grazing-incidence X-ray absorption spectroscopy of nucleation-regime Er{sub 2}O{sub 3} ALD on amorphous ALD alumina and single crystalline sapphire.

  8. A modular reactor design for in situ synchrotron X-ray investigation of atomic layer deposition processes

    Energy Technology Data Exchange (ETDEWEB)

    Klug, Jeffrey A.; Weimer, Matthew S.; Emery, Jonathan D.; Yanguas-Gil, Angel; Seifert, Sonke; Schleputz, Christian M.; Martinson, Alex B. F.; Elam, Jeffrey W.; Hock, Adam S.; Proslier, Thomas

    2015-11-01

    Synchrotron characterization techniques provide some of the most powerful tools for the study of film structure and chemistry. The brilliance and tunability of the Advanced Photon Source allow access to scattering and spectroscopic techniques unavailable with in-house laboratory setups and provide the opportunity to probe various atomic layer deposition (ALD) processes in situ starting at the very first deposition cycle. Here, we present the design and implementation of a portable ALD instrument which possesses a modular reactor scheme that enables simple experimental switchover between various beamlines and characterization techniques. As first examples, we present \\textit{in situ} results for 1.) X-ray surface scattering and reflectivity measurements of epitaxial ZnO ALD on sapphire, 2.) grazing-incidence small angle scattering of MnO nucleation on silicon, and 3.) grazing-incidence X-ray absorption spectroscopy of nucleation-regime Er2O3 ALD on amorphous ALD alumina and single crystalline sapphire.

  9. A modular reactor design for in situ synchrotron x-ray investigation of atomic layer deposition processes

    Science.gov (United States)

    Klug, Jeffrey A.; Weimer, Matthew S.; Emery, Jonathan D.; Yanguas-Gil, Angel; Seifert, Sönke; Schlepütz, Christian M.; Martinson, Alex B. F.; Elam, Jeffrey W.; Hock, Adam S.; Proslier, Thomas

    2015-11-01

    Synchrotron characterization techniques provide some of the most powerful tools for the study of film structure and chemistry. The brilliance and tunability of the Advanced Photon Source allow access to scattering and spectroscopic techniques unavailable with in-house laboratory setups and provide the opportunity to probe various atomic layer deposition (ALD) processes in situ starting at the very first deposition cycle. Here, we present the design and implementation of a portable ALD instrument which possesses a modular reactor scheme that enables simple experimental switchover between various beamlines and characterization techniques. As first examples, we present in situ results for (1) X-ray surface scattering and reflectivity measurements of epitaxial ZnO ALD on sapphire, (2) grazing-incidence small angle scattering of MnO nucleation on silicon, and (3) grazing-incidence X-ray absorption spectroscopy of nucleation-regime Er2O3 ALD on amorphous ALD alumina and single crystalline sapphire.

  10. A modular reactor design for in situ synchrotron x-ray investigation of atomic layer deposition processes

    International Nuclear Information System (INIS)

    Synchrotron characterization techniques provide some of the most powerful tools for the study of film structure and chemistry. The brilliance and tunability of the Advanced Photon Source allow access to scattering and spectroscopic techniques unavailable with in-house laboratory setups and provide the opportunity to probe various atomic layer deposition (ALD) processes in situ starting at the very first deposition cycle. Here, we present the design and implementation of a portable ALD instrument which possesses a modular reactor scheme that enables simple experimental switchover between various beamlines and characterization techniques. As first examples, we present in situ results for (1) X-ray surface scattering and reflectivity measurements of epitaxial ZnO ALD on sapphire, (2) grazing-incidence small angle scattering of MnO nucleation on silicon, and (3) grazing-incidence X-ray absorption spectroscopy of nucleation-regime Er2O3 ALD on amorphous ALD alumina and single crystalline sapphire

  11. Structural, electrical and optical characterization of Ti-doped ZnO films grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Highlights: • Ti-doped ZnO films were deposited using atomic layer deposition. • Increase in a-axis orientation with Ti content. • Lowest resistivity of 1.8 × 10−3 Ω cm at 1.7 cat% Ti. • Increase in mobility with small amount of Ti doping. • Burstein–Moss-shift observed with increasing Ti concentration. - Abstract: Thin films of Ti-doped ZnO (TZO) have been deposited using Atomic Layer Deposition (ALD) achieving highly conductive materials with resistivities down to 1.8 × 10−3 Ω cm at 1.7 cat% Ti doping, with a maximum dopant efficiency of 31%. The high conductivity and doping efficiency suggests a good distribution of dopants, otherwise a common challenge for doping by ALD. The charge mobility for Ti concentrations below 1.2 cat% was higher than for pure ZnO. The texture of the films changed from a predominantly c-axis to a-axis orientation with increasing Ti concentration, while the lattice parameters remained unaltered. The TZO films were highly transparent with an absorbance in the visible range of less than 2% for 200 nm films. The band gap increased with Ti content from 3.28 eV for pure ZnO to 3.67 eV for 5.9 cat% Ti, attributed to the Burstein Moss effect. The index of refraction varied with the Ti content showing a minimum of 1.90 for 1.7 cat% Ti

  12. Growth of controllable ZnO film by atomic layer deposition technique via inductively coupled plasma treatment

    International Nuclear Information System (INIS)

    An inductively coupled plasma technique (ICP), namely, remote-plasma treatment was introduced to ionize the water molecules as the precursor for the deposition of ZnO film via the atomic layer deposition processes. Compared with the H2O gas as the precursor for the ALD growth, the ionized water molecules can provide a lesser energy to uniformly stabilize oxidization processes, resulting in a better film quality with a higher resistivity owing to less formation of intrinsic defects at a lower growth temperature. The relationship between resistivity and formation mechanisms have been discussed and investigated through analyses of atomic force microscopy, photonluminescence, and absorption spectra, respectively. Findings indicate that the steric hindrance of the ligands plays an important rule for the ALD-ZnO film sample with the ICP treatment while the limited number of bonding sites will be dominant for the ALD-ZnO film without the ICP treatment owing to decreasing of the reactive sites via the ligand-exchange reaction during the dissociation process. Finally, the enhanced aspect-ratio into the anodic aluminum oxide with the better improved uniform coating of ZnO layer after the ICP treatment was demonstrated, providing an important information for a promising application in electronics based on ZnO ALD films.

  13. Simulation of nucleation and growth of atomic layer deposition phosphorus for doping of advanced FinFETs

    International Nuclear Information System (INIS)

    Simulations for the nucleation and growth of phosphorus films were carried out using density functional theory. The surface was represented by a Si9H12 truncated cluster surface model with 2 × 1-reconstructured (100) Si-OH terminations for the initial reaction sites. Chemistries included phosphorous halides (PF3, PCl3, and PBr3) and disilane (Si2H6). Atomic layer deposition (ALD) reaction sequences were illustrated with three-dimensional molecular models using sequential PF3 and Si2H6 reactions and featuring SiFH3 as a byproduct. Exothermic reaction pathways were developed for both nucleation and growth for a Si-OH surface. Energetically favorable reactions for the deposition of four phosphorus atoms including lateral P–P bonding were simulated. This paper suggests energetically favorable thermodynamic reactions for the growth of elemental phosphorus on (100) silicon. Phosphorus layers made by ALD are an option for doping advanced fin field-effect transistors (FinFETs). Phosphorus may be thermally diffused into the silicon or recoil knocked in; simulations of the recoil profile of phosphorus into a FinFET surface are illustrated

  14. Simulation of nucleation and growth of atomic layer deposition phosphorus for doping of advanced FinFETs

    Energy Technology Data Exchange (ETDEWEB)

    Seide