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Sample records for silicon nitride based

  1. Process for producing silicon nitride based articles of high fracture toughness and strength

    Science.gov (United States)

    Huckabee, M.; Buljan, S.T.; Neil, J.T.

    1991-09-10

    A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12 m[sup 2]/g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

  2. Silicon nitride nanosieve membrane

    NARCIS (Netherlands)

    Tong, D.H.; Jansen, Henricus V.; Gadgil, V.J.; Bostan, C.G.; Berenschot, Johan W.; van Rijn, C.J.M.; Elwenspoek, Michael Curt

    2004-01-01

    An array of very uniform cylindrical nanopores with a pore diameter as small as 25 nm has been fabricated in an ultrathin micromachined silicon nitride membrane using focused ion beam (FIB) etching. The pore size of this nanosieve membrane was further reduced to below 10 nm by coating it with

  3. Atomic oxygen effects on boron nitride and silicon nitride: A comparison of ground based and space flight data

    Science.gov (United States)

    Cross, J. B.; Lan, E. H.; Smith, C. A.; Whatley, W. J.

    1990-01-01

    The effects of atomic oxygen on boron nitride (BN) and silicon nitride (Si3N4) were evaluated in a low Earth orbit (LEO) flight experiment and in a ground based simulation facility. In both the inflight and ground based experiments, these materials were coated on thin (approx. 250A) silver films, and the electrical resistance of the silver was measured in situ to detect any penetration of atomic oxygen through the BN and Si3N4 materials. In the presence of atomic oxygen, silver oxidizes to form silver oxide, which has a much higher electrical resistance than pure silver. Permeation of atomic oxygen through BN, as indicated by an increase in the electrical resistance of the silver underneath, was observed in both the inflight and ground based experiments. In contrast, no permeation of atomic oxygen through Si3N4 was observed in either the inflight or ground based experiments. The ground based results show good qualitative correlation with the LEO flight results, indicating that ground based facilities such as the one at Los Alamos National Lab can reproduce space flight data from LEO.

  4. Waveguide silicon nitride grating coupler

    Science.gov (United States)

    Litvik, Jan; Dolnak, Ivan; Dado, Milan

    2016-12-01

    Grating couplers are one of the most used elements for coupling of light between optical fibers and photonic integrated components. Silicon-on-insulator platform provides strong confinement of light and allows high integration. In this work, using simulations we have designed a broadband silicon nitride surface grating coupler. The Fourier-eigenmode expansion and finite difference time domain methods are utilized in design optimization of grating coupler structure. The fully, single etch step grating coupler is based on a standard silicon-on-insulator wafer with 0.55 μm waveguide Si3N4 layer. The optimized structure at 1550 nm wavelength yields a peak coupling efficiency -2.6635 dB (54.16%) with a 1-dB bandwidth up to 80 nm. It is promising way for low-cost fabrication using complementary metal-oxide- semiconductor fabrication process.

  5. Characteristics of thin-film transistors based on silicon nitride passivation by excimer laser direct patterning

    International Nuclear Information System (INIS)

    Chen, Chao-Nan; Huang, Jung-Jie

    2013-01-01

    This study explored the removal of silicon nitride using KrF laser ablation technology with a high threshold fluence of 990 mJ/cm 2 . This technology was used for contact hole patterning to fabricate SiN x -passivation-based amorphous-silicon thin films in a transistor device. Compared to the photolithography process, laser direct patterning using KrF laser ablation technology can reduce the number of process steps by at least three. Experimental results showed that the mobility and threshold voltages of thin film transistors patterned using the laser process were 0.16 cm 2 /V-sec and 0.2 V, respectively. The device performance and the test results of gate voltage stress reliability demonstrated that laser direct patterning is a promising alternative to photolithography in the panel manufacturing of thin-film transistors for liquid crystal displays. - Highlights: ► KrF laser ablation technology is used to remove silicon nitride. ► A simple method for direct patterning contact-hole in thin-film-transistor device. ► Laser technology reduced processing by at least three steps

  6. Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength

    Science.gov (United States)

    Huckabee, M.L.; Buljan, S.T.; Neil, J.T.

    1991-09-17

    A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength are disclosed. The powder mixture includes (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12m[sup 2]g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder. No Drawings

  7. Vertical integration of high-Q silicon nitride microresonators into silicon-on-insulator platform.

    Science.gov (United States)

    Li, Qing; Eftekhar, Ali A; Sodagar, Majid; Xia, Zhixuan; Atabaki, Amir H; Adibi, Ali

    2013-07-29

    We demonstrate a vertical integration of high-Q silicon nitride microresonators into the silicon-on-insulator platform for applications at the telecommunication wavelengths. Low-loss silicon nitride films with a thickness of 400 nm are successfully grown, enabling compact silicon nitride microresonators with ultra-high intrinsic Qs (~ 6 × 10(6) for 60 μm radius and ~ 2 × 10(7) for 240 μm radius). The coupling between the silicon nitride microresonator and the underneath silicon waveguide is based on evanescent coupling with silicon dioxide as buffer. Selective coupling to a desired radial mode of the silicon nitride microresonator is also achievable using a pulley coupling scheme. In this work, a 60-μm-radius silicon nitride microresonator has been successfully integrated into the silicon-on-insulator platform, showing a single-mode operation with an intrinsic Q of 2 × 10(6).

  8. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    International Nuclear Information System (INIS)

    Shuleiko, D V; Ilin, A S

    2016-01-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

  9. Reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Porz, F.

    1982-10-01

    Reaction-bonded silicon nitride (RBSN) has been characterized. The oxidation behaviour in air up to 1500 0 C and 3000 h and the effects of static and cyclic oxidation on room-temperature strength have been studied. (orig./IHOE) [de

  10. Bio-functionalization of silicon nitride-based piezo-resistive ...

    Indian Academy of Sciences (India)

    Methods of bio-functionalize silicon nitride involve process steps to ... substance in applications such as clinical analysis, environmental control and industrial pro- ... anisms could be optical (measure the deflection), or measurement of a change in ... point of care (PoC), and the instrumentation involved is quite sophisticated.

  11. Silicon nitride-fabrication, forming and properties

    International Nuclear Information System (INIS)

    Yehezkel, O.

    1983-01-01

    This article, which is a literature survey of the recent years, includes description of several methods for the formation of silicone nitride, and five methods of forming: Reaction-bonded silicon nitride, sintering, hot pressing, hot isostatic pressing and chemical vapour deposition. Herein are also included data about mechanical and physical properties of silicon nitride and the relationship between the forming method and the properties. (author)

  12. On-chip photonic microsystem for optical signal processing based on silicon and silicon nitride platforms

    Science.gov (United States)

    Li, Yu; Li, Jiachen; Yu, Hongchen; Yu, Hai; Chen, Hongwei; Yang, Sigang; Chen, Minghua

    2018-04-01

    The explosive growth of data centers, cloud computing and various smart devices is limited by the current state of microelectronics, both in terms of speed and heat generation. Benefiting from the large bandwidth, promising low power consumption and passive calculation capability, experts believe that the integrated photonics-based signal processing and transmission technologies can break the bottleneck of microelectronics technology. In recent years, integrated photonics has become increasingly reliable and access to the advanced fabrication process has been offered by various foundries. In this paper, we review our recent works on the integrated optical signal processing system. We study three different kinds of on-chip signal processors and use these devices to build microsystems for the fields of microwave photonics, optical communications and spectrum sensing. The microwave photonics front receiver was demonstrated with a signal processing range of a full-band (L-band to W-band). A fully integrated microwave photonics transceiver without the on-chip laser was realized on silicon photonics covering the signal frequency of up 10 GHz. An all-optical orthogonal frequency division multiplexing (OFDM) de-multiplier was also demonstrated and used for an OFDM communication system with the rate of 64 Gbps. Finally, we show our work on the monolithic integrated spectrometer with a high resolution of about 20 pm at the central wavelength of 1550 nm. These proposed on-chip signal processing systems potential applications in the fields of radar, 5G wireless communication, wearable devices and optical access networks.

  13. Analysis of the effective thermoelastic properties and stress fields in silicon nitride based on EBSD data

    Czech Academy of Sciences Publication Activity Database

    Othmani, Y.; Böhlke, T.; Lube, T.; Fellmeth, A.; Chlup, Zdeněk; Colonna, F.; Hashibon, A.

    2016-01-01

    Roč. 36, č. 5 (2016), s. 1109-1125 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 EU Projects: European Commission(XE) 263476 Institutional support: RVO:68081723 Keywords : Silicon nitride * EBSD data * Hashin-Shtrikman bounds * Finite element analysis Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass Impact factor: 3.411, year: 2016

  14. Analytical and Experimental Evaluation of Joining Silicon Carbide to Silicon Carbide and Silicon Nitride to Silicon Nitride for Advanced Heat Engine Applications Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.

    1994-01-01

    Techniques were developed to produce reliable silicon nitride to silicon nitride (NCX-5101) curved joins which were used to manufacture spin test specimens as a proof of concept to simulate parts such as a simple rotor. Specimens were machined from the curved joins to measure the following properties of the join interlayer: tensile strength, shear strength, 22 C flexure strength and 1370 C flexure strength. In parallel, extensive silicon nitride tensile creep evaluation of planar butt joins provided a sufficient data base to develop models with accurate predictive capability for different geometries. Analytical models applied satisfactorily to the silicon nitride joins were Norton's Law for creep strain, a modified Norton's Law internal variable model and the Monkman-Grant relationship for failure modeling. The Theta Projection method was less successful. Attempts were also made to develop planar butt joins of siliconized silicon carbide (NT230).

  15. Suppression of interfacial voids formation during silane (SiH4)-based silicon oxide bonding with a thin silicon nitride capping layer

    Science.gov (United States)

    Lee, Kwang Hong; Bao, Shuyu; Wang, Yue; Fitzgerald, Eugene A.; Seng Tan, Chuan

    2018-01-01

    The material properties and bonding behavior of silane-based silicon oxide layers deposited by plasma-enhanced chemical vapor deposition were investigated. Fourier transform infrared spectroscopy was employed to determine the chemical composition of the silicon oxide films. The incorporation of hydroxyl (-OH) groups and moisture absorption demonstrates a strong correlation with the storage duration for both as-deposited and annealed silicon oxide films. It is observed that moisture absorption is prevalent in the silane-based silicon oxide film due to its porous nature. The incorporation of -OH groups and moisture absorption in the silicon oxide films increase with the storage time (even in clean-room environments) for both as-deposited and annealed silicon oxide films. Due to silanol condensation and silicon oxidation reactions that take place at the bonding interface and in the bulk silicon, hydrogen (a byproduct of these reactions) is released and diffused towards the bonding interface. The trapped hydrogen forms voids over time. Additionally, the absorbed moisture could evaporate during the post-bond annealing of the bonded wafer pair. As a consequence, defects, such as voids, form at the bonding interface. To address the problem, a thin silicon nitride capping film was deposited on the silicon oxide layer before bonding to serve as a diffusion barrier to prevent moisture absorption and incorporation of -OH groups from the ambient. This process results in defect-free bonded wafers.

  16. Fusion bonding of silicon nitride surfaces

    DEFF Research Database (Denmark)

    Reck, Kasper; Østergaard, Christian; Thomsen, Erik Vilain

    2011-01-01

    While silicon nitride surfaces are widely used in many micro electrical mechanical system devices, e.g. for chemical passivation, electrical isolation or environmental protection, studies on fusion bonding of two silicon nitride surfaces (Si3N4–Si3N4 bonding) are very few and highly application...

  17. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    Science.gov (United States)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  18. Silicon-Nitride-based Integrated Optofluidic Biochemical Sensors using a Coupled-Resonator Optical Waveguide

    Directory of Open Access Journals (Sweden)

    Jiawei eWANG

    2015-04-01

    Full Text Available Silicon nitride (SiN is a promising material platform for integrating photonic components and microfluidic channels on a chip for label-free, optical biochemical sensing applications in the visible to near-infrared wavelengths. The chip-scale SiN-based optofluidic sensors can be compact due to a relatively high refractive index contrast between SiN and the fluidic medium, and low-cost due to the complementary metal-oxide-semiconductor (CMOS-compatible fabrication process. Here, we demonstrate SiN-based integrated optofluidic biochemical sensors using a coupled-resonator optical waveguide (CROW in the visible wavelengths. The working principle is based on imaging in the far field the out-of-plane elastic-light-scattering patterns of the CROW sensor at a fixed probe wavelength. We correlate the imaged pattern with reference patterns at the CROW eigenstates. Our sensing algorithm maps the correlation coefficients of the imaged pattern with a library of calibrated correlation coefficients to extract a minute change in the cladding refractive index. Given a calibrated CROW, our sensing mechanism in the spatial domain only requires a fixed-wavelength laser in the visible wavelengths as a light source, with the probe wavelength located within the CROW transmission band, and a silicon digital charge-coupled device (CCD / CMOS camera for recording the light scattering patterns. This is in sharp contrast with the conventional optical microcavity-based sensing methods that impose a strict requirement of spectral alignment with a high-quality cavity resonance using a wavelength-tunable laser. Our experimental results using a SiN CROW sensor with eight coupled microrings in the 680nm wavelength reveal a cladding refractive index change of ~1.3 × 10^-4 refractive index unit (RIU, with an average sensitivity of ~281 ± 271 RIU-1 and a noise-equivalent detection limit (NEDL of 1.8 ×10^-8 RIU ~ 1.0 ×10^-4 RIU across the CROW bandwidth of ~1 nm.

  19. Prototype of a silicon nitride ceramic-based miniplate osteofixation system for the midface.

    Science.gov (United States)

    Neumann, Andreas; Unkel, Claus; Werry, Christoph; Herborn, Christoh U; Maier, Horst R; Ragoss, Christian; Jahnke, Klaus

    2006-06-01

    The favorable properties of silicon nitride (Si3N4) ceramics, such as high mean strength level and fracture toughness, suggest biomedical use as an implant material. Minor reservations about the biocompatibility of Si3N4 ceramics were cleared up by previous in vitro and in vivo investigations. A Si3N4 prototype minifixation system was manufactured and implanted for osteosynthesis of artificial frontal bone defects in 3 minipigs. After 3 months, histological sections, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans were obtained. Finite element modeling (FEM) was used to simulate stresses and strains on Si3N4 miniplates and screws to calculate survival probabilities. Si3N4 miniplates and screws showed satisfying intraoperative workability. There was no implant loss, displacement, or fracture. Bone healing was complete in all animals. The formation of new bone was observed in direct contact to the implants. The implants showed no artifacts on CT and MRI scanning. FEM simulation confirmed the mechanical reliability of the screws, whereas simulated plate geometries regarding pullout forces at maximum load showed limited safety in a bending situation. Si3N4 ceramics show a good biocompatibility outcome both in vitro and in vivo. In ENT surgery, this ceramic may serve as a biomaterial for osteosynthesis (eg, of the midface including reconstruction the floor of the orbit and the skull base). To our knowledge, this is the first introduction of a ceramic-based miniplate-osteofixation system. Advantages compared with titanium are no risk of implantation to bone with mucosal attachment, no need for explantation, and no interference with radiologic imaging. Disadvantages include the impossibility of individual bending of the miniplates.

  20. Nitride-based Quantum-Confined Structures for Ultraviolet-Visible Optical Devices on Silicon Substrates

    KAUST Repository

    Janjua, Bilal

    2017-04-01

    III–V nitride quantum-confined structures embedded in nanowires (NWs), also known as quantum-disks-in-nanowires (Qdisks-in-NWs), have recently emerged as a new class of nanoscale materials exhibiting outstanding properties for optoelectronic devices and systems. It is promising for circumventing the technology limitation of existing planar epitaxy devices, which are bounded by the lattice-, crystal-structure-, and thermal- matching conditions. This work presents significant advances in the growth of good quality GaN, InGaN and AlGaN Qdisks-in-NWs based on careful optimization of the growth parameters, coupled with a meticulous layer structure and active region design. The NWs were grown, catalyst-free, using plasma assisted molecular beam epitaxy (PAMBE) on silicon (Si) substrates. A 2-step growth scheme was developed to achieve high areal density, dislocation free and vertically aligned NWs on Ti/Si substrates. Numerical modeling of the NWs structures, using the nextnano3 software, showed reduced polarization fields, and, in the presence of Qdisks, exhibited improved quantum-confinement; thus contributing to high carrier radiative-recombination rates. As a result, based on the growth and device structure optimization, the technologically challenging orange and yellow NWs light emitting devices (LEDs) targeting the ‘green-yellow’ gap were demonstrated on scalable, foundry compatible, and low-cost Ti coated Si substrates. The NWs work was also extended to LEDs emitting in the ultraviolet (UV) range with niche applications in environmental cleaning, UV-curing, medicine, and lighting. In this work, we used a Ti (100 nm) interlayer and Qdisks to achieve good quality AlGaN based UV-A (320 - 400 nm) device. To address the issue of UV-absorbing polymer, used in the planarization process, we developed a pendeo-epitaxy technique, for achieving an ultra-thin coalescence of the top p-GaN contact layer, for a self-planarized Qdisks-in-NWs UV-B (280 – 320 nm) LED grown

  1. Towards a high performing UV-A sensor based on Silicon Carbide and hydrogenated Silicon Nitride absorbing layers

    International Nuclear Information System (INIS)

    Mazzillo, M.; Renna, L.; Costa, N.; Badalà, P.; Sciuto, A.; Mannino, G.

    2016-01-01

    Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. The sun is our primary natural source of UV radiation. The strength of the sun's ultraviolet radiation is expressed as Solar UV Index (UVI). UV-A (320–400 nm) and UV-B (290–320 nm) rays mostly contribute to UVI. UV-B is typically the most destructive form of UV radiation because it has enough energy to cause photochemical damage to cellular DNA. Also overexposure to UV-A rays, although these are less energetic than UV-B photons, has been associated with toughening of the skin, suppression of the immune system, and cataract formation. The use of preventive measures to decrease sunlight UV radiation absorption is fundamental to reduce acute and irreversible health diseases to skin, eyes and immune system. In this perspective UV sensors able to monitor in a monolithic and compact chip the UV Index and relative UV-A and UV-B components of solar spectrum can play a relevant role for prevention, especially in view of the integration of these detectors in close at hand portable devices. Here we present the preliminary results obtained on our UV-A sensor technology based on the use of hydrogenated Silicon Nitride (SiN:H) thin passivating layers deposited on the surface of thin continuous metal film Ni 2 Si/4H-SiC Schottky detectors, already used for UV-Index monitoring. The first UV-A detector prototypes exhibit a very low leakage current density of about 0.2 pA/mm 2 and a peak responsivity value of 0.027 A/W at 330 nm, both measured at 0V bias.

  2. Compressive creep of silicon nitride

    International Nuclear Information System (INIS)

    Silva, C.R.M. da; Melo, F.C.L. de; Cairo, C.A.; Piorino Neto, F.

    1990-01-01

    Silicon nitride samples were formed by pressureless sintering process, using neodymium oxide and a mixture of neodymium oxide and yttrio oxide as sintering aids. The short term compressive creep behaviour was evaluated over a stress range of 50-300 MPa and temperature range 1200 - 1350 0 C. Post-sintering heat treatments in nitrogen with a stepwise decremental variation of temperature were performed in some samples and microstructural analysis by X-ray diffraction and transmission electron microscopy showed that the secondary crystalline phase which form from the remnant glass are dependent upon composition and percentage of aditives. Stress exponent values near to unity were obtained for materials with low glass content suggesting grain boundary diffusion accommodation processes. Cavitation will thereby become prevalent with increase in stress, temperature and decrease in the degree of crystallization of the grain boundary phase. (author) [pt

  3. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim

    2000-01-01

    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bu...

  4. Preparation of aluminum nitride-silicon carbide nanocomposite powder by the nitridation of aluminum silicon carbide

    NARCIS (Netherlands)

    Itatani, K.; Tsukamoto, R.; Delsing, A.C.A.; Hintzen, H.T.J.M.; Okada, I.

    2002-01-01

    Aluminum nitride (AlN)-silicon carbide (SiC) nanocomposite powders were prepared by the nitridation of aluminum-silicon carbide (Al4SiC4) with the specific surface area of 15.5 m2·g-1. The powders nitrided at and above 1400°C for 3 h contained the 2H-phases which consisted of AlN-rich and SiC-rich

  5. Analysis of the properties of silicon nitride based ceramic (Si_3N_4) cutting tool using different addictive

    International Nuclear Information System (INIS)

    Pereira, Joaquim Lopes; Souza, Jose Vitor Candido de; Raymundo, Emerson Augusto; Silva, Oliverio Macedo Moreira

    2013-01-01

    The constant search for new materials is part of the scientific and technological development of the industries. Ceramic been presenting important developments in terms of scientific and technological development, highlighting the predominance of covalent ceramics, which has important applications where abrasion resistance and hardness are required. Between covalent materials, several research papers in search of property improvements and cost reduction. However the production of ceramics of silicon nitride (Si_3N_4) with a reduced cost is possible only if used methods and different additives. The aim of this work is the development of compositions based on silicon nitride (Si_3N_4) using different additives such as Y_2O_3, CeO_2, Al_2O_3 , and CTR_2O_3 in varying amounts. For the development of ceramics, the mixtures were homogenized, dried, compacted and sintered using the sintering process of 1850°C for 1 hour, with a heating rate of 25°C/min. The characterizations were performed as a function of relative density by Archimedes method, the mass loss measured before and after sintering, phase analysis by X-ray diffraction, microstructure by scanning electron microscopy (SEM), and hardness and fracture toughness indentation method. The results showed relative density 97-98, Vickers hardness 17-19 GPa, fracture toughness from 5.6 to 6.8 MPa.m"1"/"2. The different phases were obtained depending on the types of additives used. The obtained results are promising for tribological applications. (author)

  6. Realization of an ultra-compact polarization beam splitter using asymmetric MMI based on silicon nitride / silicon-on-insulator platform.

    Science.gov (United States)

    Sun, Xiao; Aitchison, J Stewart; Mojahedi, Mo

    2017-04-03

    We have experimentally demonstrated a compact polarization beam splitter (PBS) based on the silicon nitride/silicon-on-insulator platform using the recently proposed augmented-low-index-guiding (ALIG) waveguide structure. The two orthogonal polarizations are split in an asymmetric multimode interference (MMI) section, which was 1.6 μm wide and 4.8 μm long. The device works well over the entire C-band wavelength range and has a measured low insertion loss of less than 1 dB. The polarization extinction ratio at the Bar Port is approximately 17 dB and at the Cross Port is approximately 25 dB. The design of the device is robust and has a good fabrication tolerance.

  7. Design and fabrication of ultrathin silicon-nitride membranes for use in UV-visible airgap-based MEMS optical filters

    International Nuclear Information System (INIS)

    Ghaderi, Mohammadamir; Wolffenbuttel, Reinoud F.

    2016-01-01

    MEMS-based airgap optical filters are composed of quarter-wave thick high-index dielectric membranes that are separated by airgaps. The main challenge in the fabrication of these filters is the intertwined optical and mechanical requirements. The thickness of the layers decreases with design wavelength, which makes the optical performance in the UV more susceptible to fabrication tolerances, such as thickness and composition of the deposited layers, while the ability to sustain a certain level of residual stress by the structural strength becomes more critical. Silicon-nitride has a comparatively high Young's modulus and good optical properties, which makes it a suitable candidate as the membrane material. However, both the mechanical and optical properties in a silicon-nitride film strongly depend on the specifics of the deposition process. A design trade-off is required between the mechanical strength and the index of refraction, by tuning the silicon content in the silicon-nitride film. However, also the benefit of a high index of refraction in a silicon-rich film should be weighed against the increased UV optical absorption. This work presents the design, fabrication, and preliminary characterization of one and three quarter-wave thick silicon-nitride membranes with a one-quarter airgap and designed to give a spectral reflectance at 400 nm. The PECVD silicon-nitride layers were initially characterized, and the data was used for the optical and mechanical design of the airgap filters. A CMOS compatible process based on polysilicon sacrificial layers was used for the fabrication of the membranes. Optical characterization results are presented. (paper)

  8. Cavitation contributes substantially to tensile creep in silicon nitride

    International Nuclear Information System (INIS)

    Luecke, W.E.; Wiederhorn, S.M.; Hockey, B.J.; Krause, R.F. Jr.; Long, G.G.

    1995-01-01

    During tensile creep of a hot isostatically pressed (HIPed) silicon nitride, the volume fraction of cavities increases linearly with strain; these cavities produce nearly all of the measured strain. In contrast, compressive creep in the same stress and temperature range produces very little cavitation. A stress exponent that increases with stress (var-epsilon ∝ σ n , 2 < n < 7) characterizes the tensile creep response, while the compressive creep response exhibits a stress dependence of unity. Furthermore, under the same stress and temperature, the material creeps nearly 100 times faster in tension than in compression. Transmission electron microscopy (TEM) indicates that the cavities formed during tensile creep occur in pockets of residual crystalline silicate phase located at silicon nitride multigrain junctions. Small-angle X-ray scattering (SAXS) from crept material quantifies the size distribution of cavities observed in TEM and demonstrates that cavity addition, rather than cavity growth, dominates the cavitation process. These observations are in accord with a model for creep based on the deformation of granular materials in which the microstructure must dilate for individual grains t slide past one another. During tensile creep the silicon nitride grains remain rigid; cavitation in the multigrain junctions allows the silicate to flow from cavities to surrounding silicate pockets, allowing the dilation of the microstructure and deformation of the material. Silicon nitride grain boundary sliding accommodates this expansion and leads to extension of the specimen. In compression, where cavitation is suppressed, deformation occurs by solution-reprecipitation of silicon nitride

  9. Evanescent field phase shifting in a silicon nitride waveguide using a coupled silicon slab

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup; Oxenløwe, Leif Katsuo; Green, William M. J.

    2015-01-01

    An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration....

  10. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz. 1 m and 25 m, and a sintered silicon carbide (SSiC) are reported. The RIF experiments were conducted using a Vicker's ...

  11. A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon-Gallium-Nitride Slot Waveguide Structures.

    Science.gov (United States)

    Malka, Dror; Danan, Yossef; Ramon, Yehonatan; Zalevsky, Zeev

    2016-06-25

    In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI) coupler in a silicon (Si)-gallium nitride (GaN) slot waveguide structure is presented-to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM). Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530-1565 nm) into four output ports with low insertion losses (0.07 dB).

  12. Silicon nitride photonics: from visible to mid-infrared wavelengths

    Science.gov (United States)

    Micó, Gloria; Bru, Luis A.; Pastor, Daniel; Doménech, David; Fernández, Juan; Sánchez, Ana; Cirera, Josep M.; Domínguez, Carlos; Muñoz, Pascual

    2018-02-01

    Silicon nitride has received a lot of attention during the last ten years, for applications such as bio-photonics, tele/datacom, optical signal processing and sensing. In this paper, firstly an updated review of the state of the art of silicon nitride photonics integration platforms will be provided. Secondly, our developments on a moderate confinement Si3N4 platform in the near-infrared will be presented. Finally, our steps towards establishing a Si3N4 based platform for broadband operation spanning from visible to mid-infrared wavelengths will be introduced.

  13. Microstructure and mechanical properties of silicon nitride structural ceramics of silicon nitride

    International Nuclear Information System (INIS)

    Strohaecker, T.R.; Nobrega, M.C.S.

    1989-01-01

    The utilization of direct evaluation technic of tenacity for fracturing by hardness impact in silicon nitride ceramics is described. The microstructure were analysied, by Scanning Electron Microscopy, equiped with a microanalysis acessory by X ray energy dispersion. The difference between the values of K IC measure for two silicon nitride ceramics is discussed, in function of the microstructures and the fracture surfaces of the samples studied. (C.G.C.) [pt

  14. Silicon oxide nanoimprint stamp fabrication by edge lithography reinforced with silicon nitride

    NARCIS (Netherlands)

    Zhao, Yiping; Berenschot, Johan W.; de Boer, Meint J.; Jansen, Henricus V.; Tas, Niels Roelof; Huskens, Jurriaan; Elwenspoek, Michael Curt

    2007-01-01

    The fabrication of silicon oxide nanoimprint stamp employing edge lithography in combination with silicon nitride deposition is presented. The fabrication process is based on conventional photolithography an weg etching methods. Nanoridges with width dimension of sub-20 nm were fabricated by edge

  15. Fabrication of a silicon oxide stamp by edge lithography reinforced with silicon nitride for nanoimprint lithography

    NARCIS (Netherlands)

    Zhao, Yiping; Berenschot, Johan W.; de Boer, M.; de Boer, Meint J.; Jansen, Henricus V.; Tas, Niels Roelof; Huskens, Jurriaan; Elwenspoek, Michael Curt

    2008-01-01

    The fabrication of a stamp reinforced with silicon nitride is presented for its use in nanoimprint lithography. The fabrication process is based on edge lithography using conventional optical lithography and wet anisotropic etching of 110 silicon wafers. SiO2 nano-ridges of 20 nm in width were

  16. Covalent biofunctionalization of silicon nitride surfaces

    NARCIS (Netherlands)

    Arafat, A.; Giesbers, M.; Rosso, M.; Sudhölter, E.J.R.; Schroën, C.G.P.H.; White, R.G.; Li Yang,; Linford, M.R.; Zuilhof, H.

    2007-01-01

    Covalently attached organic monolayers on etched silicon nitride (SixN4; x 3) surfaces were prepared by reaction of SixN4-coated wafers with neat or solutions of 1-alkenes and 1-alkynes in refluxing mesitylene. The surface modification was monitored by measurement of the static water contact angle,

  17. Colloidal characterization of silicon nitride and silicon carbide

    Science.gov (United States)

    Feke, Donald L.

    1986-01-01

    The colloidal behavior of aqueous ceramic slips strongly affects the forming and sintering behavior and the ultimate mechanical strength of the final ceramic product. The colloidal behavior of these materials, which is dominated by electrical interactions between the particles, is complex due to the strong interaction of the solids with the processing fluids. A surface titration methodology, modified to account for this interaction, was developed and used to provide fundamental insights into the interfacial chemistry of these systems. Various powder pretreatment strategies were explored to differentiate between true surface chemistry and artifacts due to exposure history. The colloidal behavior of both silicon nitride and carbide is dominated by silanol groups on the powder surfaces. However, the colloid chemistry of silicon nitride is apparently influenced by an additional amine group. With the proper powder treatments, silicon nitride and carbide powder can be made to appear colloidally equivalent. The impact of these results on processing control will be discussed.

  18. 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).

  19. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Unknown

    carbide ceramics. A K MUKHOPADHYAY. Central Glass and Ceramic Research Institute, Kolkata 700 032, India. Abstract. Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz.

  20. Ion beam induces nitridation of silicon

    International Nuclear Information System (INIS)

    Petravic, M.; Williams, J.S.; Conway, M.

    1998-01-01

    High dose ion bombardment of silicon with reactive species, such as oxygen and nitrogen, has attracted considerable interest due to possible applications of beam-induced chemical compounds with silicon. For example, high energy oxygen bombardment of Si is now routinely used to form buried oxide layers for device purposes, the so called SIMOX structures. On the other hand, Si nitrides, formed by low energy ( 100 keV) nitrogen beam bombardment of Si, are attractive as oxidation barriers or gate insulators, primarily due to the low diffusivity of many species in Si nitrides. However, little data exists on silicon nitride formation during bombardment and its angle dependence, in particular for N 2 + bombardment in the 10 keV range, which is of interest for analytical techniques such as SIMS. In SIMS, low energy oxygen ions are more commonly used as bombarding species, as oxygen provides stable ion yields and enhances the positive secondary ion yield. Therefore, a large body of data can be found in the literature on oxide formation during low energy oxygen bombardment. Nitrogen bombardment of Si may cause similar effects to oxygen bombardment, as nitrogen and oxygen have similar masses and ranges in Si, show similar sputtering effects and both have the ability to form chemical compounds with Si. In this work we explore this possibility in some detail. We compare oxide and nitride formation during oxygen and nitrogen ion bombardment of Si under similar conditions. Despite the expected similar behaviour, some large differences in compound formation were found. These differences are explained in terms of different atomic diffusivities in oxides and nitrides, film structural differences and thermodynamic properties. (author)

  1. Silicon Nitride Antireflection Coatings for Photovoltaic Cells

    Science.gov (United States)

    Johnson, C.; Wydeven, T.; Donohoe, K.

    1984-01-01

    Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

  2. Bonding silicon nitride using glass-ceramic

    International Nuclear Information System (INIS)

    Dobedoe, R.S.

    1995-01-01

    Silicon nitride has been successfully bonded to itself using magnesium-aluminosilicate glass and glass-ceramic. For some samples, bonding was achieved using a diffusion bonder, but in other instances, following an initial degassing hold, higher temperatures were used in a nitrogen atmosphere with no applied load. For diffusion bonding, a small applied pressure at a temperature below which crystallisation occurs resulted in intimate contact. At slightly higher temperatures, the extent of the reaction at the interface and the microstructure of the glass-ceramic joint was highly sensitive to the bonding temperature. Bonding in a nitrogen atmosphere resulted in a solution-reprecipitation reaction. A thin layer of glass produced a ''dry'', glass-free joint, whilst a thicker layer resulted in a continuous glassy join across the interface. The chromium silicide impurities within the silicon nitride react with the nucleating agent in the glass ceramic, which may lead to difficulty in producing a fine glass-ceramic microstructure. Slightly lower temperatures in nitrogen resulted in a polycrystalline join but the interfacial contact was poor. It is hoped that one of the bonds produced may be developed to eventually form part of a graded joint between silicon nitride and a high temperature nickel alloy. (orig.)

  3. Wide wavelength range tunable one-dimensional silicon nitride nano-grating guided mode resonance filter based on azimuthal rotation

    Directory of Open Access Journals (Sweden)

    Ryoji Yukino

    2017-01-01

    Full Text Available We describe wavelength tuning in a one dimensional (1D silicon nitride nano-grating guided mode resonance (GMR structure under conical mounting configuration of the device. When the GMR structure is rotated about the axis perpendicular to the surface of the device (azimuthal rotation for light incident at oblique angles, the conditions for resonance are different than for conventional GMR structures under classical mounting. These resonance conditions enable tuning of the GMR peak position over a wide range of wavelengths. We experimental demonstrate tuning over a range of 375 nm between 500 nm˜875 nm. We present a theoretical model to explain the resonance conditions observed in our experiments and predict the peak positions with show excellent agreement with experiments. Our method for tuning wavelengths is simpler and more efficient than conventional procedures that employ variations in the design parameters of structures or conical mounting of two-dimensional (2D GMR structures and enables a single 1D GMR device to function as a high efficiency wavelength filter over a wide range of wavelengths. We expect tunable filters based on this technique to be applicable in a wide range of fields including astronomy and biomedical imaging.

  4. The Effect of Polymer Char on Nitridation Kinetics of Silicon

    Science.gov (United States)

    Chan, Rickmond C.; Bhatt, Ramakrishna T.

    1994-01-01

    Effects of polymer char on nitridation kinetics of attrition milled silicon powder have been investigated from 1200 to 1350 C. Results indicate that at and above 1250 C, the silicon compacts containing 3.5 wt percent polymer char were fully converted to Si3N4 after 24 hr exposure in nitrogen. In contrast, the silicon compacts without polymer char could not be fully converted to Si3N4 at 1350 C under similar exposure conditions. At 1250 and 1350 C, the silicon compacts with polymer char showed faster nitridation kinetics than those without the polymer char. As the polymer char content is increased, the amount of SiC in the nitrided material is also increased. By adding small amounts (approx. 2.5 wt percent) of NiO, the silicon compacts containing polymer char can be completely nitrided at 1200 C. The probable mechanism for the accelerated nitridation of silicon containing polymer char is discussed.

  5. Four-Wave Mixing in Silicon-Rich Nitride Waveguides

    DEFF Research Database (Denmark)

    Mitrovic, Miranda; Guan, Xiaowei; Ji, Hua

    2015-01-01

    We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss.......We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss....

  6. Compositional analysis of silicon oxide/silicon nitride thin films

    Directory of Open Access Journals (Sweden)

    Meziani Samir

    2016-06-01

    Full Text Available Hydrogen, amorphous silicon nitride (SiNx:H abbreviated SiNx films were grown on multicrystalline silicon (mc-Si substrate by plasma enhanced chemical vapour deposition (PECVD in parallel configuration using NH3/SiH4 gas mixtures. The mc-Si wafers were taken from the same column of Si cast ingot. After the deposition process, the layers were oxidized (thermal oxidation in dry oxygen ambient environment at 950 °C to get oxide/nitride (ON structure. Secondary ion mass spectroscopy (SIMS, Rutherford backscattering spectroscopy (RBS, Auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX were employed for analyzing quantitatively the chemical composition and stoichiometry in the oxide-nitride stacked films. The effect of annealing temperature on the chemical composition of ON structure has been investigated. Some species, O, N, Si were redistributed in this structure during the thermal oxidation of SiNx. Indeed, oxygen diffused to the nitride layer into Si2O2N during dry oxidation.

  7. Fabrication of functional structures on thin silicon nitride membranes

    NARCIS (Netherlands)

    Ekkels, P.; Tjerkstra, R.W.; Krijnen, Gijsbertus J.M.; Berenschot, Johan W.; Brugger, J.P.; Elwenspoek, Michael Curt

    A process to fabricate functional polysilicon structures above large (4×4 mm2) thin (200 nm), very flat LPCVD silicon rich nitride membranes was developed. Key features of this fabrication process are the use of low-stress LPCVD silicon nitride, sacrificial layer etching, and minimization of

  8. Niobium nitride Josephson junctions with silicon and germanium barriers

    International Nuclear Information System (INIS)

    Cukauskas, E.J.; Carter, W.L.

    1988-01-01

    Niobium nitride based junctions with silicon, germanium, and composite silicon/germanium barriers were fabricated and characterized for several barrier compositions. The current-voltage characteristics were analyzed at several temperatures using the Simmons model and numerical integration of the WKB approximation for the average barrier height and effective thickness. The zero voltage conductance was measured from 1.5 K to 300 K and compared to the Mott hopping conductivity model and the Stratton tunneling temperature dependence. Conductivity followed Mott conductivity at temperatures above 60 K for junctions with less than 100 angstrom thick barriers

  9. High temperature corrosion of silicon carbide and silicon nitride in the presence of chloride compound

    International Nuclear Information System (INIS)

    McNallan, M.

    1993-01-01

    Silicon carbide and silicon nitride are resistant to oxidation because a protective silicon dioxide films on their surfaces in most oxidizing environments. Chloride compounds can attack the surface in two ways: 1) chlorine can attack the silicon directly to form a volatile silicon chloride compound or 2) alkali compounds combined with the chlorine can be transported to the surface where they flux the silica layer by forming stable alkali silicates. Alkali halides have enough vapor pressure that a sufficient quantity of alkali species to cause accelerated corrosion can be transported to the ceramic surface without the formation of a chloride deposit. When silicon carbide is attacked simultaneously by chlorine and oxygen, the corrosion products include both volatile and condensed spices. Silicon nitride is much more resistance to this type of attack than silicon carbide. Silicon based ceramics are exposed to oxidizing gases in the presence of alkali chloride vapors, the rate of corrosion is controlled primarily by the driving force for the formation of alkali silicate, which can be quantified as the activity of the alkali oxide in equilibrium with the corrosive gas mixture. In a gas mixture containing a fixed partial pressure of KCl, the rate of corrosion is accelerated by increasing the concentration of water vapor and inhibited by increasing the concentration of HCl. Similar results have been obtained for mixtures containing other alkalis and halogens. (Orig./A.B.)

  10. Method of production of hollow silicon nitride articles

    International Nuclear Information System (INIS)

    Parr, N.L.; Brown, R.L.

    1971-01-01

    The hollow articles prepared according to the invention have a high density, exhibit no internal stresses and correspond to high demands of tolerance and surface quality. One obtains these by flame spraying silicon powder on a pre-heated form designed with separating agent - e.g. NaCl. After removing the form, the silicon is nitridated to silicon nitride by heating in N 2 or in an atmosphere of ammonia. This process can be interrupted if the article is also to be mechanically processed, and then the nitridation can be completed. (Hoe/LH) [de

  11. A review of oxide, silicon nitride, and silicon carbide brazing

    International Nuclear Information System (INIS)

    Santella, M.L.; Moorhead, A.J.

    1987-01-01

    There is growing interest in using ceramics for structural applications, many of which require the fabrication of components with complicated shapes. Normal ceramic processing methods restrict the shapes into which these materials can be produced, but ceramic joining technology can be used to overcome many of these limitations, and also offers the possibility for improving the reliability of ceramic components. One method of joining ceramics is by brazing. The metallic alloys used for bonding must wet and adhere to the ceramic surfaces without excessive reaction. Alumina, partially stabilized zirconia, and silicon nitride have high ionic character to their chemical bonds and are difficult to wet. Alloys for brazing these materials must be formulated to overcome this problem. Silicon carbide, which has some metallic characteristics, reacts excessively with many alloys, and forms joints of low mechanical strength. The brazing characteristics of these three types of ceramics, and residual stresses in ceramic-to-metal joints are briefly discussed

  12. Hybrid Coupling of Laser Light sources to Silicon (Oxy)Nitride Based Waveguides

    NARCIS (Netherlands)

    Krijger, A.J.T. de; Bekman, H.H.P.T.

    1997-01-01

    An efficient method was developed to couple a diode laser to a high contrast waveguides. The laserdiodes were mounted with sub-micron precision using a thermocompression mounting technique. An AlGaAs (λ = 850 nm) laserdiode was coupled to a SiON based slab waveguide (efficiency η EQ 25 - 30%) and to

  13. Nitride-based Quantum-Confined Structures for Ultraviolet-Visible Optical Devices on Silicon Substrates

    KAUST Repository

    Janjua, Bilal

    2017-01-01

    quality GaN, InGaN and AlGaN Qdisks-in-NWs based on careful optimization of the growth parameters, coupled with a meticulous layer structure and active region design. The NWs were grown, catalyst-free, using plasma assisted molecular beam epitaxy (PAMBE

  14. High temperature mechanical performance of a hot isostatically pressed silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, A.A.; Ferber, M.K.; Jenkins, M.G.; Lin, C.K.J. [and others

    1996-01-01

    Silicon nitride ceramics are an attractive material of choice for designers and manufacturers of advanced gas turbine engine components for many reasons. These materials typically have potentially high temperatures of usefulness (up to 1400{degrees}C), are chemically inert, have a relatively low specific gravity (important for inertial effects), and are good thermal conductors (i.e., resistant to thermal shock). In order for manufacturers to take advantage of these inherent properties of silicon nitride, the high-temperature mechanical performance of the material must first be characterized. The mechanical response of silicon nitride to static, dynamic, and cyclic conditions at elevated temperatures, along with reliable and representative data, is critical information that gas turbine engine designers and manufacturers require for the confident insertion of silicon nitride components into gas turbine engines. This final report describes the high-temperature mechanical characterization and analyses that were conducted on a candidate structural silicon nitride ceramic. The high-temperature strength, static fatigue (creep rupture), and dynamic and cyclic fatigue performance were characterized. The efforts put forth were part of Work Breakdown Structure Subelement 3.2.1, {open_quotes}Rotor Data Base Generation.{close_quotes} PY6 is comparable to other hot isostatically pressed (HIPed) silicon nitrides currently being considered for advanced gas turbine engine applications.

  15. A superhydrophobic chip based on SU-8 photoresist pillars suspended on a silicon nitride membrane

    KAUST Repository

    Marinaro, Giovanni; Accardo, Angelo; De Angelis, Francesco; Dane, Thomas; Weinhausen, Britta; Burghammer, Manfred; Riekel, Christian

    2014-01-01

    We developed a new generation of superhydrophobic chips optimized for probing ultrasmall sample quantities by X-ray scattering and fluorescence techniques. The chips are based on thin Si3N4 membranes with a tailored pattern of SU-8 photoresist pillars. Indeed, aqueous solution droplets can be evaporated and concentrated at predefined positions using a non-periodic pillar pattern. We demonstrated quantitatively the deposition and aggregation of gold glyconanoparticles from the evaporation of a nanomolar droplet in a small spot by raster X-ray nanofluorescence. Further, raster nanocrystallography of biological objects such as rod-like tobacco mosaic virus nanoparticles reveals crystalline macro-domain formation composed of highly oriented nanorods. © 2014 the Partner Organisations.

  16. A superhydrophobic chip based on SU-8 photoresist pillars suspended on a silicon nitride membrane

    KAUST Repository

    Marinaro, Giovanni

    2014-07-28

    We developed a new generation of superhydrophobic chips optimized for probing ultrasmall sample quantities by X-ray scattering and fluorescence techniques. The chips are based on thin Si3N4 membranes with a tailored pattern of SU-8 photoresist pillars. Indeed, aqueous solution droplets can be evaporated and concentrated at predefined positions using a non-periodic pillar pattern. We demonstrated quantitatively the deposition and aggregation of gold glyconanoparticles from the evaporation of a nanomolar droplet in a small spot by raster X-ray nanofluorescence. Further, raster nanocrystallography of biological objects such as rod-like tobacco mosaic virus nanoparticles reveals crystalline macro-domain formation composed of highly oriented nanorods. © 2014 the Partner Organisations.

  17. Optimization of time–temperature schedule for nitridation of silicon ...

    Indian Academy of Sciences (India)

    pact was optimized by kinetic study of the reaction, 3Si + 2N2 = Si3N4 at four different temperatures (1250°C,. 1300°C, 1350°C and 1400°C). ... Reaction sintered silicon nitride; nitridation; reaction kinetics. 1. Introduction. Formation of ..... cation of silica layer resulted in active oxidation of silicon at high temperature to ...

  18. Tensile creep behavior in an advanced silicon nitride

    International Nuclear Information System (INIS)

    Lofaj, F.

    2000-01-01

    Tensile creep behavior and changes in the microstructure of the advanced silicon nitride, SN 88M, were studied at temperatures from 1250 to 1400 C to reveal the creep resistance and lifetime-controlling processes. Assuming power law dependence of the minimum strain rate on stress, stress exponents from 6 to 8 and an apparent activation energy of 780 kJ/mol were obtained. Extensive electron microscopy observations revealed significant changes in the crystalline secondary phases and creep damage development. Creep damage was classified in two groups: 'inter-granular' defects in the amorphous boundary phases, and 'intra-granular' defects in silicon nitride grains. The inter-granular defects involved multigrain junction cavities, two-grain junction cavities, microcracks and cracks. The intra-granular defects included broken large grains, small symmetrical and asymmetrical cavities, and crack-like intragranular cavities. Cavities are generated continuously during the whole deformation starting from the threshold strain of ∝0.1%, and they contribute linearly to the tensile strain. Cavities produce more than 90% of the total tensile strain, and it is concluded that cavitation is the main creep mechanism in silicon nitride ceramics. The multigrain junction cavities are considered to be the most important for generating new volume and producing tensile strain. The Luecke and Wiederhorn (L and W) creep model, based on cavitation at multigrain junctions according to an exponential law, was proven to correspond to the stress dependence of the minimum strain rate. A qualitative model based on the L and W model was suggested and expanded to include intragranular cavitation. The basic mechanisms involve a repeating of the sequence grain boundary sliding (GBS) => cavitation at multigrain junctions => viscous flow and dissolution-precipitation. (orig.)

  19. Broadband wavelength conversion in hydrogenated amorphous silicon waveguide with silicon nitride layer

    Science.gov (United States)

    Wang, Jiang; Li, Yongfang; Wang, Zhaolu; Han, Jing; Huang, Nan; Liu, Hongjun

    2018-01-01

    Broadband wavelength conversion based on degenerate four-wave mixing is theoretically investigated in a hydrogenated amorphous silicon (a-Si:H) waveguide with silicon nitride inter-cladding layer (a-Si:HN). We have found that enhancement of the non-linear effect of a-Si:H waveguide nitride intermediate layer facilitates broadband wavelength conversion. Conversion bandwidth of 490 nm and conversion efficiency of 11.4 dB were achieved in a numerical simulation of a 4 mm-long a-Si:HN waveguide under 1.55 μm continuous wave pumping. This broadband continuous-wave wavelength converter has potential applications in photonic networks, a type of readily manufactured low-cost highly integrated optical circuits.

  20. Optical property of silicon quantum dots embedded in silicon nitride by thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Baek Hyun, E-mail: bhkim@andrew.cmu.ed [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United Sates (United States); Davis, Robert F. [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United Sates (United States); Park, Seong-Ju [Nanophotonic Semiconductors Laboratory, Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712 (Korea, Republic of)

    2010-01-01

    We present the effects on the thermal annealing of silicon quantum dots (Si QDs) embedded in silicon nitride. The improved photoluminescence (PL) intensities and the red-shifted PL spectra were obtained with annealing treatment in the range of 700 to 1000 {sup o}C. The shifts of PL spectra were attributed to the increase in the size of Si QDs. The improvement of the PL intensities was also attributed to the reduction of point defects at Si QD/silicon nitride interface and in the silicon nitride due to hydrogen passivation effects.

  1. The atomic and electronic structure of amorphous silicon nitride

    International Nuclear Information System (INIS)

    Alvarez, F.; Valladares, A.A.

    2002-01-01

    Using a novel approach to the ab initio generation of random networks we constructed two nearly stoichiometric samples of amorphous silicon nitride with the same content x= 1.29. The two 64-atom periodically-continued cubic diamond-like cells contain 28 silicons and 36 nitrogens randomly substituted, and were amorphized with a 6 f s time step by heating them to just below their melting temperature with a Harris-functional based, molecular dynamics code in the LDA approximation. The averaged total radial distribution function (RDF) obtained is compared with some existing Tersoff-like potential simulations and with experiment; ours agree with experiment. All the partial radial features are calculated and the composition of the second peak also agrees with experiment. The electronic structure is calculated and the optical gaps obtained using both a HOMO-LUMO approach and the Tauc-like procedure developed recently that gives reasonable gaps. (Author)

  2. Gelcasting of SiC/Si for preparation of silicon nitride bonded silicon carbide

    International Nuclear Information System (INIS)

    Xie, Z.P.; Tsinghua University, Beijing,; Cheng, Y.B.; Lu, J.W.; Huang, Y.

    2000-01-01

    In the present paper, gelcasting of aqueous slurry with coarse silicon carbide(1mm) and fine silicon particles was investigated to fabricate silicon nitride bonded silicon carbide materials. Through the examination of influence of different polyelectrolytes on the Zeta potential and viscosity of silicon and silicon carbide suspensions, a stable SiC/Si suspension with 60 vol% solid loading could be prepared by using polyelectrolyte of D3005 and sodium alginate. Gelation of this suspension can complete in 10-30 min at 60-80 deg C after cast into mold. After demolded, the wet green body can be dried directly in furnace and the green strength will develop during drying. Complex shape parts with near net size were prepared by the process. Effects of the debindering process on nitridation and density of silicon nitride bonded silicon carbide were also examined. Copyright (2000) The Australian Ceramic Society

  3. Preparation and properties of bisphenol-F based boron-phenolic resin/modified silicon nitride composites and their usage as binders for grinding wheels

    International Nuclear Information System (INIS)

    Lin, Chun-Te; Lee, Hsun-Tsing; Chen, Jem-Kun

    2015-01-01

    Highlights: • Bisphenol-F based boron-phenolic resins (B-BPF) with B−O bonds were synthesized. • The modified silicon nitride (m-SiN) was well dispersed and adhered in the B-BPF. • B-BPF/m-SiN composites have good thermal resistance and mechanical properties. • The grinding wheels bound by B-BPF/m-SiN have excellent grinding quality. - Abstract: In this study, phenolic resins based on bisphenol-F (BPF) were synthesized. Besides, ammonium borate was added in the synthesis process of BPF to form the bisphenol-F based boron-phenolic resins (B-BPF). The glass transition temperature, thermal resistance, flexural strength and hardness of B-BPF are respectively higher than those of BPF. This is due to the presence of new cross-link B−O bonds in the B-BPF. In addition, the 3-aminopropyltriethoxysilane modified silicon nitride powders (m-SiN) were fully mixed with B-BPF to form the B-BPF/m-SiN composites. The thermal resistance and mechanical properties of the B-BPF/m-SiN are promoted by the well-dispersed and well-adhered m-SiN in these novel polymer/ceramics composites. The results of grinding experiments indicate that the grinding wheels bound by the B-BPF/m-SiN have better grinding quality than those bound by the BPF. Thus the B-BPF/m-SiN composites are better binding media than the BPF resins

  4. Second-harmonic generation in substoichiometric silicon nitride layers

    Science.gov (United States)

    Pecora, Emanuele; Capretti, Antonio; Miano, Giovanni; Dal Negro, Luca

    2013-03-01

    Harmonic generation in optical circuits offers the possibility to integrate wavelength converters, light amplifiers, lasers, and multiple optical signal processing devices with electronic components. Bulk silicon has a negligible second-order nonlinear optical susceptibility owing to its crystal centrosymmetry. Silicon nitride has its place in the microelectronic industry as an insulator and chemical barrier. In this work, we propose to take advantage of silicon excess in silicon nitride to increase the Second Harmonic Generation (SHG) efficiency. Thin films have been grown by reactive magnetron sputtering and their nonlinear optical properties have been studied by femtosecond pumping over a wide range of excitation wavelengths, silicon nitride stoichiometry and thermal processes. We demonstrate SHG in the visible range (375 - 450 nm) using a tunable 150 fs Ti:sapphire laser, and we optimize the SH emission at a silicon excess of 46 at.% demonstrating a maximum SHG efficiency of 4x10-6 in optimized films. Polarization properties, generation efficiency, and the second order nonlinear optical susceptibility are measured for all the investigated samples and discussed in terms of an effective theoretical model. Our findings show that the large nonlinear optical response demonstrated in optimized Si-rich silicon nitride materials can be utilized for the engineering of nonlinear optical functions and devices on a Si chip.

  5. Memory characteristics of silicon nitride with silicon nanocrystals as a charge trapping layer of nonvolatile memory devices

    International Nuclear Information System (INIS)

    Choi, Sangmoo; Yang, Hyundeok; Chang, Man; Baek, Sungkweon; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

    2005-01-01

    Silicon nitride with silicon nanocrystals formed by low-energy silicon plasma immersion ion implantation has been investigated as a charge trapping layer of a polycrystalline silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. Compared with the control sample without silicon nanocrystals, silicon nitride with silicon nanocrystals provides excellent memory characteristics, such as larger width of capacitance-voltage hysteresis, higher program/erase speed, and lower charge loss rate at elevated temperature. These improved memory characteristics are derived by incorporation of silicon nanocrystals into the charge trapping layer as additional accessible charge traps with a deeper effective trap energy level

  6. Origin of interfacial charging in irradiated silicon nitride capacitors

    International Nuclear Information System (INIS)

    Hughes, R.C.

    1984-01-01

    Many experiments show that when metal-silicon nitride-silicon dioxide-silicon (MNOS) devices are irradiated in short circuit, a large interfacial charge builds up near the nitride-SiO 2 -Si interface. This effect cannot be explained by simple models of radiation-induced conductivity of the nitride, but it is reported here that inclusion of carrier diffusion and recombination in the photoconductivity equations can predict the observed behavior. Numerical solutions on a computer are required, however, when these complications are added. The simulations account for the magnitude and radiation dose dependence of the results, as well as the occurrence of a steady state during the irradiation. The location of the excess trapped charge near the interface is also predicted, along with the large number of new traps which must be introduced to influence the steady-state charge distribution

  7. Nano-ridge fabrication by local oxidation of silicon edges with silicon nitride as a mask

    NARCIS (Netherlands)

    Haneveld, J.; Berenschot, Johan W.; Maury, P.A.; Jansen, Henricus V.

    2005-01-01

    A method to fabricate nano-ridges over a full wafer is presented. The fabrication method uses local oxidation of silicon, with silicon nitride as a mask, and wet anisotropic etching of silicon. The realized structures are 7-20 nm wide, 40-100 nm high and centimeters long. All dimensions are easily

  8. Alternative Liquid Fuel Effects on Cooled Silicon Nitride Marine Gas Turbine Airfoils

    Energy Technology Data Exchange (ETDEWEB)

    Holowczak, J.

    2002-03-01

    With prior support from the Office of Naval Research, DARPA, and U.S. Department of Energy, United Technologies is developing and engine environment testing what we believe to be the first internally cooled silicon nitride ceramic turbine vane in the United States. The vanes are being developed for the FT8, an aeroderivative stationary/marine gas turbine. The current effort resulted in further manufacturing and development and prototyping by two U.S. based gas turbine grade silicon nitride component manufacturers, preliminary development of both alumina, and YTRIA based environmental barrier coatings (EBC's) and testing or ceramic vanes with an EBC coating.

  9. Enhanced Electroluminescence from Silicon Quantum Dots Embedded in Silicon Nitride Thin Films Coupled with Gold Nanoparticles in Light Emitting Devices

    Directory of Open Access Journals (Sweden)

    Ana Luz Muñoz-Rosas

    2018-03-01

    Full Text Available Nowadays, the use of plasmonic metal layers to improve the photonic emission characteristics of several semiconductor quantum dots is a booming tool. In this work, we report the use of silicon quantum dots (SiQDs embedded in a silicon nitride thin film coupled with an ultra-thin gold film (AuNPs to fabricate light emitting devices. We used the remote plasma enhanced chemical vapor deposition technique (RPECVD in order to grow two types of silicon nitride thin films. One with an almost stoichiometric composition, acting as non-radiative spacer; the other one, with a silicon excess in its chemical composition, which causes the formation of silicon quantum dots imbibed in the silicon nitride thin film. The ultra-thin gold film was deposited by the direct current (DC-sputtering technique, and an aluminum doped zinc oxide thin film (AZO which was deposited by means of ultrasonic spray pyrolysis, plays the role of the ohmic metal-like electrode. We found that there is a maximum electroluminescence (EL enhancement when the appropriate AuNPs-spacer-SiQDs configuration is used. This EL is achieved at a moderate turn-on voltage of 11 V, and the EL enhancement is around four times bigger than the photoluminescence (PL enhancement of the same AuNPs-spacer-SiQDs configuration. From our experimental results, we surmise that EL enhancement may indeed be due to a plasmonic coupling. This kind of silicon-based LEDs has the potential for technology transfer.

  10. Modelling structure and properties of amorphous silicon boron nitride ceramics

    Directory of Open Access Journals (Sweden)

    Johann Christian Schön

    2011-06-01

    Full Text Available Silicon boron nitride is the parent compound of a new class of high-temperature stable amorphous ceramics constituted of silicon, boron, nitrogen, and carbon, featuring a set of properties that is without precedent, and represents a prototypical random network based on chemical bonds of predominantly covalent character. In contrast to many other amorphous materials of technological interest, a-Si3B3N7 is not produced via glass formation, i.e. by quenching from a melt, the reason being that the binary components, BN and Si3N4, melt incongruently under standard conditions. Neither has it been possible to employ sintering of μm-size powders consisting of binary nitrides BN and Si3N4. Instead, one employs the so-called sol-gel route starting from single component precursors such as TADB ((SiCl3NH(BCl2. In order to determine the atomic structure of this material, it has proven necessary to simulate the actual synthesis route.Many of the exciting properties of these ceramics are closely connected to the details of their amorphous structure. To clarify this structure, it is necessary to employ not only experimental probes on many length scales (X-ray, neutron- and electron scattering; complex NMR experiments; IR- and Raman scattering, but also theoretical approaches. These address the actual synthesis route to a-Si3B3N7, the structural properties, the elastic and vibrational properties, aging and coarsening behaviour, thermal conductivity and the metastable phase diagram both for a-Si3B3N7 and possible silicon boron nitride phases with compositions different from Si3N4: BN = 1 : 3. Here, we present a short comprehensive overview over the insights gained using molecular dynamics and Monte Carlo simulations to explore the energy landscape of a-Si3B3N7, model the actual synthesis route and compute static and transport properties of a-Si3BN7.

  11. The oxidation of titanium nitride- and silicon nitride-coated stainless steel in carbon dioxide environments

    International Nuclear Information System (INIS)

    Mitchell, D.R.G.; Stott, F.H.

    1992-01-01

    A study has been undertaken into the effects of thin titanium nitride and silicon nitride coatings, deposited by physical vapour deposition and chemical vapour deposition processes, on the oxidation resistance of 321 stainless steel in a simulated advanced gas-cooled reactor carbon dioxide environment for long periods at 550 o C and 700 o C under thermal-cycling conditions. The uncoated steel contains sufficient chromium to develop a slow-growing chromium-rich oxide layer at these temperatures, particularly if the surfaces have been machine-abraded. Failure of this layer in service allows formation of less protective iron oxide-rich scales. The presence of a thin (3-4 μm) titanium nitride coating is not very effective in increasing the oxidation resistance since the ensuing titanium oxide scale is not a good barrier to diffusion. Even at 550 o C, iron oxide-rich nodules are able to develop following relatively rapid oxidation and breakdown of the coating. At 700 o C, the coated specimens oxidize at relatively similar rates to the uncoated steel. A thin silicon nitride coating gives improved oxidation resistance, with both the coating and its slow-growing oxide being relatively electrically insulating. The particular silicon nitride coating studied here was susceptible to spallation on thermal cycling, due to an inherently weak coating/substrate interface. (Author)

  12. Damage initiation and evolution in silicon nitride under\

    Czech Academy of Sciences Publication Activity Database

    Raga, R.; Khader, I.; Chlup, Zdeněk; Kailer, A.

    360-361, AUG (2016), s. 147-159 ISSN 0043-1648 EU Projects: European Commission(XE) 263476 - ROLICER Institutional support: RVO:68081723 Keywords : Silicon nitride * Rollingcontactfatigue * Subsurface damage Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.531, year: 2016

  13. Hardness and thermal stability of cubic silicon nitride

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Kragh, Flemming; Frost, D. J.

    2001-01-01

    The hardness and thermal stability of cubic spinel silicon nitride (c-Si3N4), synthesized under high-pressure and high-temperature conditions, have been studied by microindentation measurements, and x-ray powder diffraction and scanning electron microscopy, respectively The phase at ambient...

  14. TXRF analysis of trace metals in thin silicon nitride films

    International Nuclear Information System (INIS)

    Vereecke, G.; Arnauts, S.; Verstraeten, K.; Schaekers, M.; Heyrts, M.M.

    2000-01-01

    As critical dimensions of integrated circuits continue to decrease, high dielectric constant materials such as silicon nitride are being considered to replace silicon dioxide in capacitors and transistors. The achievement of low levels of metal contamination in these layers is critical for high performance and reliability. Existing methods of quantitative analysis of trace metals in silicon nitride require high amounts of sample (from about 0.1 to 1 g, compared to a mass of 0.2 mg for a 2 nm thick film on a 8'' silicon wafer), and involve digestion steps not applicable to films on wafers or non-standard techniques such as neutron activation analysis. A novel approach has recently been developed to analyze trace metals in thin films with analytical techniques currently used in the semiconductor industry. Sample preparation consists of three steps: (1) decomposition of the silicon nitride matrix by moist HF condensed at the wafer surface to form ammonium fluosilicate. (2) vaporization of the fluosilicate by a short heat treatment at 300 o C. (3) collection of contaminants by scanning the wafer surface with a solution droplet (VPD-DSC procedure). The determination of trace metals is performed by drying the droplet on the wafer and by analyzing the residue by TXRF, as it offers the advantages of multi-elemental analysis with no dilution of the sample. The lower limits of detection for metals in 2 nm thick films on 8'' silicon wafers range from about 10 to 200 ng/g. The present study will focus on the matrix effects and the possible loss of analyte associated with the evaporation of the fluosilicate salt, in relation with the accuracy and the reproducibility of the method. The benefits of using an internal standard will be assessed. Results will be presented from both model samples (ammonium fluoride contaminated with metallic salts) and real samples (silicon nitride films from a production tool). (author)

  15. Amorphous silicon rich silicon nitride optical waveguides for high density integrated optics

    DEFF Research Database (Denmark)

    Philipp, Hugh T.; Andersen, Karin Nordström; Svendsen, Winnie Edith

    2004-01-01

    Amorphous silicon rich silicon nitride optical waveguides clad in silica are presented as a high-index contrast platform for high density integrated optics. Performance of different cross-sectional geometries have been measured and are presented with regards to bending loss and insertion loss...

  16. Modification of silicon nitride and silicon carbide surfaces for food and biosensor applications

    NARCIS (Netherlands)

    Rosso, M.

    2009-01-01

    Silicon-rich silicon nitride (SixN4, x > 3) is a robust insulating material widely used for the coating of microdevices: its high chemical and mechanical inertness make it a material of choice for the reinforcement of fragile microstructures (e.g. suspended microcantilevers, micro-fabricated

  17. Thin film silicon on silicon nitride for radiation hardened dielectrically isolated MISFET's

    International Nuclear Information System (INIS)

    Neamen, D.; Shedd, W.; Buchanan, B.

    1975-01-01

    The permanent ionizing radiation effects resulting from charge trapping in a silicon nitride isolation dielectric have been determined for a total ionizing dose up to 10 7 rads (Si). Junction FET's, whose active channel region is directly adjacent to the silicon-silicon nitride interface, were used to measure the effects of the radiation induced charge trapping in the Si 3 N 4 isolation dielectric. The JFET saturation current and channel conductance versus junction gate voltage and substrate voltage were characterized as a function of the total ionizing radiation dose. The experimental results on the Si 3 N 4 are compared to results on similar devices with SiO 2 dielectric isolation. The ramifications of using the silicon nitride for fabricating radiation hardened dielectrically isolated MIS devices are discussed

  18. Annealing temperature dependence of photoluminescent characteristics of silicon nanocrystals embedded in silicon-rich silicon nitride films grown by PECVD

    International Nuclear Information System (INIS)

    Chao, D.S.; Liang, J.H.

    2013-01-01

    Recently, light emission from silicon nanostructures has gained great interest due to its promising potential of realizing silicon-based optoelectronic applications. In this study, luminescent silicon nanocrystals (Si–NCs) were in situ synthesized in silicon-rich silicon nitride (SRSN) films grown by plasma-enhanced chemical vapor deposition (PECVD). SRSN films with various excess silicon contents were deposited by adjusting SiH 4 flow rate to 100 and 200 sccm and keeping NH 3 one at 40 sccm, and followed by furnace annealing (FA) treatments at 600, 850 and 1100 °C for 1 h. The effects of excess silicon content and post-annealing temperature on optical properties of Si–NCs were investigated by photoluminescence (PL) and Fourier transform infrared spectroscopy (FTIR). The origins of two groups of PL peaks found in this study can be attributed to defect-related interface states and quantum confinement effects (QCE). Defect-related interface states lead to the photon energy levels almost kept constant at about 3.4 eV, while QCE results in visible and tunable PL emission in the spectral range of yellow and blue light which depends on excess silicon content and post-annealing temperature. In addition, PL intensity was also demonstrated to be highly correlative to the excess silicon content and post-annealing temperature due to its corresponding effects on size, density, crystallinity, and surface passivation of Si–NCs. Considering the trade-off between surface passivation and structural properties of Si–NCs, an optimal post-annealing temperature of 600 °C was suggested to maximize the PL intensity of the SRSN films

  19. Analytical and experimental evaluation of joining silicon carbide to silicon carbide and silicon nitride to silicon nitride for advanced heat engine applications Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.; Vartabedian, A.M.; Wade, J.A.; White, C.S. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.

    1994-10-01

    The purpose of joining, Phase 2 was to develop joining technologies for HIP`ed Si{sub 3}N{sub 4} with 4wt% Y{sub 2}O{sub 3} (NCX-5101) and for a siliconized SiC (NT230) for various geometries including: butt joins, curved joins and shaft to disk joins. In addition, more extensive mechanical characterization of silicon nitride joins to enhance the predictive capabilities of the analytical/numerical models for structural components in advanced heat engines was provided. Mechanical evaluation were performed by: flexure strength at 22 C and 1,370 C, stress rupture at 1,370 C, high temperature creep, 22 C tensile testing and spin tests. While the silicon nitride joins were produced with sufficient integrity for many applications, the lower join strength would limit its use in the more severe structural applications. Thus, the silicon carbide join quality was deemed unsatisfactory to advance to more complex, curved geometries. The silicon carbide joining methods covered within this contract, although not entirely successful, have emphasized the need to focus future efforts upon ways to obtain a homogeneous, well sintered parent/join interface prior to siliconization. In conclusion, the improved definition of the silicon carbide joining problem obtained by efforts during this contract have provided avenues for future work that could successfully obtain heat engine quality joins.

  20. Thermodynamics of silicon nitridation - Effect of hydrogen

    Science.gov (United States)

    Shaw, N. J.; Zeleznik, F. J.

    1982-01-01

    Equilibrium compositions for the nitridization of Si were calculated to detect the effectiveness of H2 in removal of the oxide film and in increasing the concentration of SiO and reducing the proportions of O2. Gibbs free energy for the formation of SiN2O was computed above 1685 K, and at lower temperatures. The thermodynamic properties of SiN2O2 were then considered from 1000-3000 K, taking into account the known thermodynamic data for 39 molecular combinations of the Si, Ni, and O. The gases formed were assumed ideal mixtures with pure phase condensed species. The mole fractions were obtained for a system of SiO2 with each Si particle covered with a thin layer of SiO2 before nitridation, and a system in which the nitriding atmosphere had access to the Si. The presence of H2 was determined to enhance the removal of NiO2 in the first system, decrease the partial pressure of O2, increase the partial pressures of SiO, Si, H2O, NH3, and SiH4, while its effects were negligible in the Si system.

  1. High-rate silicon nitride deposition for photovoltaics : from fundamentals to industrial application

    NARCIS (Netherlands)

    Kessels, W.M.M.; Oever, van den P.J.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Sanden, van de M.C.M.

    2005-01-01

    The development of a novel plasma technique for high rate (> 1 nm/s) silicon nitride deposition for multifunctional antireflection coatings on crystalline silicon solar cells is described. The research has involved the analysis of the structural and optical properties of the silicon nitride films as

  2. High-rate silicon nitride deposition for photovoltaics : from fundamentals to industrial application

    NARCIS (Netherlands)

    Kessels, W.M.M.; Oever, van den P.J.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Sanden, van de M.C.M.

    2004-01-01

    The development of a novel plasma technique for high rate (> 1 nm/s) silicon nitride deposition for multifunctional antireflection coatings on crystalline silicon solar cells is described. The research has involved the analysis of the structural and optical properties of the silicon nitride films as

  3. Some new aspects of microstructural development during sintering of silicon nitride

    International Nuclear Information System (INIS)

    Feuer, H.; Woetting, G.; Gugel, E.

    1994-01-01

    The mechanical properties of silicon nitride ceramics strongly depend on their microstructure. However, there is still a lively discussion about the parameters controlling the microstructural development. The current research was stimulated by the observation that a bimodal grain-size distribution in dense silicon nitride has a very beneficial effect on the mechanical properties, especially on the fracture toughness. This paper is focused on the relationship between the α-β-transformation and the densification of silicon nitride powders with different characteristics and sintering additives. Effects of β-grains originally present in the silicon nitride powder, of added β-silicon nitride seeds and of β-crystals formed by the α/β-transformation on the resulting microstructure and on the properties are discussed. The results are summarised in a model describing prerequisites and processing conditions, which are necessary to achieve a bimodal microstructure, i. e. a self-reinforced silicon nitride ceramic. (orig.)

  4. Silicon Nitride Photonic Integration Platforms for Visible, Near-Infrared and Mid-Infrared Applications

    Science.gov (United States)

    Micó, Gloria; Pastor, Daniel; Pérez, Daniel; Doménech, José David; Fernández, Juan; Baños, Rocío; Alemany, Rubén; Sánchez, Ana M.; Cirera, Josep M.; Mas, Roser

    2017-01-01

    Silicon nitride photonics is on the rise owing to the broadband nature of the material, allowing applications of biophotonics, tele/datacom, optical signal processing and sensing, from visible, through near to mid-infrared wavelengths. In this paper, a review of the state of the art of silicon nitride strip waveguide platforms is provided, alongside the experimental results on the development of a versatile 300 nm guiding film height silicon nitride platform. PMID:28895906

  5. SONOS memories with embedded silicon nanocrystals in nitride

    International Nuclear Information System (INIS)

    Liu, Mei-Chun; Chiang, Tsung-Yu; Chao, Tien-Sheng; Kuo, Po-Yi; Lei, Tan-Fu; Chou, Ming-Hong; Wu, Yi-Hong; Cheng, Ching-Hwa; Liu, Sheng-Hsien; Yang, Wen-Luh; You, Hsin-Chiang

    2008-01-01

    We have successfully demonstrated SONOS memories with embedded Si-NCs in silicon nitride. This new structure exhibits excellent characteristics in terms of larger memory windows and longer retention time compared to control devices. Using the same thickness 2.5 nm of the bottom tunneling oxide, we found that N 2 O is better than O 2 oxide. Retention property is improved when the thickness of N 2 O is increased to 3.0 nm

  6. Corrosion of silicon nitride in high temperature alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Liyan, E-mail: liyan.qiu@cnl.ca; Guzonas, Dave A.; Qian, Jing

    2016-08-01

    The corrosion of silicon nitride (Si{sub 3}N{sub 4}) in alkaline solutions was studied at temperatures from 60 to 300 °C. Si{sub 3}N{sub 4} experienced significant corrosion above 100 °C. The release rates of silicon and nitrogen follow zero order reaction kinetics and increase with increasing temperature. The molar ratio of dissolved silicon and nitrogen species in the high temperature solutions is the same as that in the solid phase (congruent dissolution). The activation energy for silicon and nitrogen release rates is 75 kJ/mol which agrees well with that of silica dissolution. At 300 °C, the release of aluminum is observed and follows first order reaction kinetics while other minor constituents including Ti and Y are highly enriched on the corrosion films due to the low solubility of their oxides.

  7. Optical and passivating properties of hydrogenated amorphous silicon nitride deposited by plasma enhanced chemical vapour deposition for application on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wight, Daniel Nilsen

    2008-07-01

    Within this thesis, several important subjects related to the use of amorphous silicon nitride made by plasma enhanced chemical vapour deposition as an anti-reflective coating on silicon solar cells are presented. The first part of the thesis covers optical simulations to optimise single and double layer anti-reflective coatings with respect to optical performance when situated on a silicon solar cell. The second part investigates the relationship between important physical properties of silicon nitride films when deposited under different conditions. The optical simulations were either based on minimising the reflectance off a silicon nitride/silicon wafer stack or maximising the transmittance through the silicon nitride into the silicon wafer. The former method allowed consideration of the reflectance off the back surface of the wafer, which occurs typically at wavelengths above 1000 nm due to the transparency of silicon at these wavelengths. However, this method does not take into consideration the absorption occurring in the silicon nitride, which is negligible at low refractive indexes but quite significant when the refractive index increases above 2.1. For high-index silicon nitride films, the latter method is more accurate as it considers both reflectance and absorbance in the film to calculate the transmittance into the Si wafer. Both methods reach similar values for film thickness and refractive index for optimised single layer anti-reflective coatings, due to the negligible absorption occurring in these films. For double layer coatings, though, the reflectance based simulations overestimated the optimum refractive index for the bottom layer, which would have lead to excessive absorption if applied to real anti-reflective coatings. The experimental study on physical properties for silicon nitride films deposited under varying conditions concentrated on the estimation of properties important for its applications, such as optical properties, passivation

  8. Hydrogen diffusion between plasma-deposited silicon nitride-polyimide polymer interfaces

    International Nuclear Information System (INIS)

    Nguyen, S.V.; Kerbaugh, M.

    1988-01-01

    This paper reports a nuclear reaction analysis (NRA) for hydrogen technique used to analyze the hydrogen concentration near plasma enhanced chemical vapor deposition (PECVD) silicon nitride-polyimide interfaces at various nitride-deposition and polyimide-polymer-curing temperatures. The CF 4 + O 2 (8% O 2 ) plasma-etch-rate variation of PECVD silicon nitride films deposited on polyimide appeared to correlate well with the variation of hydrogen-depth profiles in the nitride films. The NRA data indicate that hydrogen-depth-profile fluctuation in the nitride films is due to hydrogen diffusion between the nitride-polyimide interfaces during deposition. Annealing treatment of polyimide films in a hydrogen atmosphere prior to the nitride film deposition tends to enhance the hydrogen-depth-profile uniformity in the nitride films, and thus substantially reduces or eliminates variation in the nitride plasma-etch rate

  9. Frequency effects and properties of plasma deposited fluorinated silicon nitride

    International Nuclear Information System (INIS)

    Chang, C.; Flamm, D.L.; Ibbotson, D.E.; Mucha, J.A.

    1988-01-01

    The properties of low-hydrogen, fluorinated plasma-enhanced chemical vapor deposition (PECVD) silicon nitride films grown using NF 3 /SiH 4 /N 2 feed mixtures in 200 kHz and 14 MHz discharges were compared. High-energy ion bombardment at 200 kHz is expected to enhance surface diffusion and chemical reconstruction. Compared to fluorinated silicon nitride deposited at 14 MHz under otherwise comparable conditions, the 200 kHz films had a lower Si--H bond concentration (approx. 21 cm -3 ), lower total hydrogen content (5--8 x 10 21 cm -3 ), better resistance to oxidation, lower compressive stress (-0.7 to -1.5 Gdyne/cm), and higher density (3.1 g/cm 3 ). The dielectric constant of better low-frequency Class I films was constant to 500 MHz, while that of high-frequency films fell up to 15% between 100 Hz and 10 MHz. The absorption edges of low-frequency PECVD fluorinated silicon nitride films were between 5.0 and 6.1 eV, which compare with 4.4 to 5.6 eV for the high-excitation frequency fluorinated material and 3 to 4 eV for conventional PECVD nitride. However high-frequency films may have fewer trap centers and a lower dielectric constant. 14 MHz p-SiN:F films grown with NH 3 as an auxiliary nitrogen source showed absorption edges similar to low-frequency material grown from NF 3 /SiH 4 /N 2 , but they have substantially more N--H bonding. The dielectric constant and absorption edge of these films were comparable to those of low-frequency p-SiN:F from NF 3 /SiH 4 /N 2

  10. Thermogravimetric analysis of silicon carbide-silicon nitride fibers at ambient to 1000 C in air

    Science.gov (United States)

    Daniels, J. G.; Ledbetter, F. E., III; Clemons, J. M.; Penn, B. G.

    1984-01-01

    Thermogravimetric analysis of silicon carbide-silicon nitride fibers was carried out at ambient to 1000 C in air. The weight loss over this temperature range was negligible. In addition, the oxidative stability at high temperature for a short period of time was determined. Fibers heated at 1000 C in air for fifteen minutes showed negligible weight loss (i.e., less than 1 percent).

  11. Increased carrier lifetimes in epitaxial silicon layers on buried silicon nitride produced by ion implantation

    International Nuclear Information System (INIS)

    Skorupa, W.; Kreissig, U.; Hensel, E.; Bartsch, H.

    1984-01-01

    Carrier lifetimes were measured in epitaxial silicon layers deposited on buried silicon nitride produced by high-dose nitrogen implantation at 330 keV. The values were in the range 20-200 μs. The results are remarkable taking into account the high density of crystal defects in the epitaxial layers. Comparing with other SOI technologies the measured lifetimes are higher by 1-2 orders of magnitude. (author)

  12. Bioactive silicon nitride: A new therapeutic material for osteoarthropathy

    Science.gov (United States)

    Pezzotti, Giuseppe; Marin, Elia; Adachi, Tetsuya; Rondinella, Alfredo; Boschetto, Francesco; Zhu, Wenliang; Sugano, Nobuhiko; Bock, Ryan M.; McEntire, Bryan; Bal, Sonny B.

    2017-03-01

    While the reciprocity between bioceramics and living cells is complex, it is principally governed by the implant’s surface chemistry. Consequently, a deeper understanding of the chemical interactions of bioceramics with living tissue could ultimately lead to new therapeutic strategies. However, the physical and chemical principles that govern these interactions remain unclear. The intricacies of this biological synergy are explored within this paper by examining the peculiar surface chemistry of a relatively new bioceramic, silicon nitride (Si3N4). Building upon prior research, this paper aims at obtaining new insights into the biological interactions between Si3N4 and living cells, as a consequence of the off-stoichiometric chemical nature of its surface at the nanometer scale. We show here yet unveiled details of surface chemistry and, based on these new data, formulate a model on how, ultimately, Si3N4 influences cellular signal transduction functions and differentiation mechanisms. In other words, we interpret its reciprocity with living cells in chemical terms. These new findings suggest that Si3N4 might provide unique new medicinal therapies and effective remedies for various bone or joint maladies and diseases.

  13. High efficiency nitride based phosphores for white LEDs

    NARCIS (Netherlands)

    Li, Yuan Qiang; Hintzen, H.T.J.M.

    2008-01-01

    In this overview paper, novel rare-earth doped silicon nitride based phosphors for white LEDs applications have been demonstrated. The luminescence properties of orange-red-emitting phosphors (M2Si5N8:Eu2+) and green-to-yellow emitting phosphors (MSi2N2O2:Eu2+, M = Ca, Sr, Ba) are discussed in

  14. Linear and nonlinear characterization of low-stress high-confinement silicon-rich nitride waveguides.

    Science.gov (United States)

    Krückel, Clemens J; Fülöp, Attila; Klintberg, Thomas; Bengtsson, Jörgen; Andrekson, Peter A; Torres-Company, Víctor

    2015-10-05

    In this paper we introduce a low-stress silicon enriched nitride platform that has potential for nonlinear and highly integrated optics. The manufacturing process of this platform is CMOS compatible and the increased silicon content allows tensile stress reduction and crack free layer growth of 700 nm. Additional benefits of the silicon enriched nitride is a measured nonlinear Kerr coefficient n(2) of 1.4·10(-18) m(2)/W (5 times higher than stoichiometric silicon nitride) and a refractive index of 2.1 at 1550 nm that enables high optical field confinement allowing high intensity nonlinear optics and light guidance even with small bending radii. We analyze the waveguide loss (∼1 dB/cm) in a spectrally resolved fashion and include scattering loss simulations based on waveguide surface roughness measurements. Detailed simulations show the possibility for fine dispersion and nonlinear engineering. In nonlinear experiments we present continuous-wave wavelength conversion and demonstrate that the material does not show nonlinear absorption effects. Finally, we demonstrate microfabrication of resonators with high Q-factors (∼10(5)).

  15. Thermo-Optic Characterization of Silicon Nitride Resonators for Cryogenic Photonic Circuits

    NARCIS (Netherlands)

    Elshaari, A.W.A.; Esmaeil Zadeh, I.; Jöns, K.D.; Zwiller, Val

    2016-01-01

    In this paper, we characterize the Thermo-optic properties of silicon nitride ring resonators between 18 and 300 K. The Thermo-optic coefficients of the silicon nitride core and the oxide cladding are measured by studying the temperature dependence of the resonance wavelengths. The resonant modes

  16. Dispersion engineering of thick high-Q silicon nitride ring-resonators via atomic layer deposition.

    Science.gov (United States)

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

    2012-12-03

    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. Both, magnitude and bandwidth of anomalous dispersion can be significantly increased. The 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.

  17. Hydrogen concentration profiles and chemical bonding in silicon nitride

    International Nuclear Information System (INIS)

    Peercy, P.S.; Stein, H.J.; Doyle, B.L.; Picraux, S.T.

    1978-01-01

    The complementary technique of nuclear reaction analysis and infrared absorption were used to study the concentration profile and chemical bonding of hydrogen in silicon nitride for different preparation and annealing conditions. Silicon nitride prepared by chemical vapor deposition from ammonia-silane mixtures is shown to have hydrogen concentrations of 8.1 and 6.5 at.% for deposition temperatures of 750 and 900 0 C, respectively. Plasma deposition at 300 0 C from these gases results in hydrogen concentrations of approximately 22 at.%. Comparison of nuclear reaction analysis and infrared absorption measurements after isothermal annealing shows that all of the hydrogen retained in the films remains bonded to either silicon or nitrogen and that hydrogen release from the material on annealing is governed by various trap energies involving at least two N-H and one Si-H trap. Reasonable estimates of the hydrogen release rates can be made from the effective diffusion coefficient obtained from measurements of hydrogen migration in hydrogen implanted and annealed films

  18. Influence of the initial grain size of silicon on microstructure and mechanical properties of reaction-sintered silicon nitride

    International Nuclear Information System (INIS)

    Heinrich, J.

    1977-01-01

    The influence of the initial grain size of the silicon powder on the microstructure and the resulting mechanical properties are studied. The smaller the grain size of the silicon powders used, the higher will be the degree of reaction at the beginning of the nitridation reaction and the higher the amount of α-modification in the fully nitridated samples. Moreover, the nitrification time can be considerably shortened when fine-grained silicon powders ( [de

  19. Evaluation of silicon nitride as a substrate for culture of PC12 cells: an interfacial model for functional studies in neurons.

    Directory of Open Access Journals (Sweden)

    Johan Jaime Medina Benavente

    Full Text Available Silicon nitride is a biocompatible material that is currently used as an interfacial surface between cells and large-scale integration devices incorporating ion-sensitive field-effect transistor technology. Here, we investigated whether a poly-L-lysine coated silicon nitride surface is suitable for the culture of PC12 cells, which are widely used as a model for neural differentiation, and we characterized their interaction based on cell behavior when seeded on the tested material. The coated surface was first examined in terms of wettability and topography using contact angle measurements and atomic force microscopy and then, conditioned silicon nitride surface was used as the substrate for the study of PC12 cell culture properties. We found that coating silicon nitride with poly-L-lysine increased surface hydrophilicity and that exposing this coated surface to an extracellular aqueous environment gradually decreased its roughness. When PC12 cells were cultured on a coated silicon nitride surface, adhesion and spreading were facilitated, and the cells showed enhanced morphological differentiation compared to those cultured on a plastic culture dish. A bromodeoxyuridine assay demonstrated that, on the coated silicon nitride surface, higher proportions of cells left the cell cycle, remained in a quiescent state and had longer survival times. Therefore, our study of the interaction of the silicon nitride surface with PC12 cells provides important information for the production of devices that need to have optimal cell culture-supporting properties in order to be used in the study of neuronal functions.

  20. Combination of silicon nitride and porous silicon induced optoelectronic features enhancement of multicrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rabha, Mohamed Ben; Dimassi, Wissem; Gaidi, Mounir; Ezzaouia, Hatem; Bessais, Brahim [Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia)

    2011-06-15

    The effects of antireflection (ARC) and surface passivation films on optoelectronic features of multicrystalline silicon (mc-Si) were investigated in order to perform high efficiency solar cells. A double layer consisting of Plasma Enhanced Chemical Vapor Deposition (PECVD) of silicon nitride (SiN{sub x}) on porous silicon (PS) was achieved on mc-Si surfaces. It was found that this treatment decreases the total surface reflectivity from about 25% to around 6% in the 450-1100 nm wavelength range. As a result, the effective minority carrier diffusion length, estimated from the Laser-beam-induced current (LBIC) method, was found to increase from 312 {mu}m for PS-treated cells to about 798 {mu}m for SiN{sub x}/PS-treated ones. The deposition of SiN{sub x} was found to impressively enhance the minority carrier diffusion length probably due to hydrogen passivation of surface, grain boundaries and bulk defects. Fourier Transform Infrared Spectroscopy (FTIR) shows that the vibration modes of the highly suitable passivating Si-H bonds exhibit frequency shifts toward higher wavenumber, depending on the x ratio of the introduced N atoms neighbors. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, David, E-mail: caballero@unistra.fr [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); University of Barcelona, Department of Electronics, C/ Marti i Franques 1, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain); Martinez, Elena [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain); Bausells, Joan [Centre Nacional de Microelectronica (CNM-IMB), CSIC, Campus UAB, 08193 Bellaterra (Spain); Errachid, Abdelhamid, E-mail: abdelhamid.errachid-el-salhi@univ-lyon1.fr [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); Universite Claude Bernard - Lyon 1, LSA - UMR 5180, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Samitier, Josep [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); University of Barcelona, Department of Electronics, C/ Marti i Franques 1, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer An impedimetric label-free immunosensor was developed for the specific detection of human serum albumin proteins. Black-Right-Pointing-Pointer Anti-HSA antibodies were covalently immobilized on silicon nitride surfaces using a direct functionalization methodology. Black-Right-Pointing-Pointer Silicon nitride offers multiple advantages compared to other common materials. Black-Right-Pointing-Pointer The proposed sensor has high sensitivity and good selectivity for the detection of HSA proteins. - Abstract: In this work we report the fabrication and characterization of a label-free impedimetric immunosensor based on a silicon nitride (Si{sub 3}N{sub 4}) surface for the specific detection of human serum albumin (HSA) proteins. Silicon nitride provides several advantages compared with other materials commonly used, such as gold, and in particular in solid-state physics for electronic-based biosensors. However, few Si{sub 3}N{sub 4}-based biosensors have been developed; the lack of an efficient and direct protocol for the integration of biological elements with silicon-based substrates is still one of its the main drawbacks. Here, we use a direct functionalization method for the direct covalent binding of monoclonal anti-HSA antibodies on an aldehyde-functionalized Si-p/SiO{sub 2}/Si{sub 3}N{sub 4} structure. This methodology, in contrast with most of the protocols reported in literature, requires less chemical reagents, it is less time-consuming and it does not need any chemical activation. The detection capability of the immunosensor was tested by performing non-faradaic electrochemical impedance spectroscopy (EIS) measurements for the specific detection of HSA proteins. Protein concentrations within the linear range of 10{sup -13}-10{sup -7} M were detected, showing a sensitivity of 0.128 {Omega} {mu}M{sup -1} and a limit of detection of 10{sup -14} M. The specificity of the sensor was also addressed by studying the

  2. Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface

    International Nuclear Information System (INIS)

    Caballero, David; Martinez, Elena; Bausells, Joan; Errachid, Abdelhamid; Samitier, Josep

    2012-01-01

    Highlights: ► An impedimetric label-free immunosensor was developed for the specific detection of human serum albumin proteins. ► Anti-HSA antibodies were covalently immobilized on silicon nitride surfaces using a direct functionalization methodology. ► Silicon nitride offers multiple advantages compared to other common materials. ► The proposed sensor has high sensitivity and good selectivity for the detection of HSA proteins. - Abstract: In this work we report the fabrication and characterization of a label-free impedimetric immunosensor based on a silicon nitride (Si 3 N 4 ) surface for the specific detection of human serum albumin (HSA) proteins. Silicon nitride provides several advantages compared with other materials commonly used, such as gold, and in particular in solid-state physics for electronic-based biosensors. However, few Si 3 N 4 -based biosensors have been developed; the lack of an efficient and direct protocol for the integration of biological elements with silicon-based substrates is still one of its the main drawbacks. Here, we use a direct functionalization method for the direct covalent binding of monoclonal anti-HSA antibodies on an aldehyde-functionalized Si-p/SiO 2 /Si 3 N 4 structure. This methodology, in contrast with most of the protocols reported in literature, requires less chemical reagents, it is less time-consuming and it does not need any chemical activation. The detection capability of the immunosensor was tested by performing non-faradaic electrochemical impedance spectroscopy (EIS) measurements for the specific detection of HSA proteins. Protein concentrations within the linear range of 10 −13 –10 −7 M were detected, showing a sensitivity of 0.128 Ω μM −1 and a limit of detection of 10 −14 M. The specificity of the sensor was also addressed by studying the interferences with a similar protein, bovine serum albumin. The results obtained show that the antibodies were efficiently immobilized and the proteins

  3. Hydrogenated amorphous silicon nitride photonic crystals for improved-performance surface electromagnetic wave biosensors.

    Science.gov (United States)

    Sinibaldi, Alberto; Descrovi, Emiliano; Giorgis, Fabrizio; Dominici, Lorenzo; Ballarini, Mirko; Mandracci, Pietro; Danz, Norbert; Michelotti, Francesco

    2012-10-01

    We exploit the properties of surface electromagnetic waves propagating at the surface of finite one dimensional photonic crystals to improve the performance of optical biosensors with respect to the standard surface plasmon resonance approach. We demonstrate that the hydrogenated amorphous silicon nitride technology is a versatile platform for fabricating one dimensional photonic crystals with any desirable design and operating in a wide wavelength range, from the visible to the near infrared. We prepared sensors based on photonic crystals sustaining either guided modes or surface electromagnetic waves, also known as Bloch surface waves. We carried out for the first time a direct experimental comparison of their sensitivity and figure of merit with surface plasmon polaritons on metal layers, by making use of a commercial surface plasmon resonance instrument that was slightly adapted for the experiments. Our measurements demonstrate that the Bloch surface waves on silicon nitride photonic crystals outperform surface plasmon polaritons by a factor 1.3 in terms of figure of merit.

  4. Nanostructured silicon nitride from wheat and rice husks

    Energy Technology Data Exchange (ETDEWEB)

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Wollmershauser, J. A.; Feng, C. R. [Materials Science and Component Technology Directorate, Naval Research Laboratory, Washington, D.C. 20375 (United States)

    2016-04-07

    Nanoparticles, submicron-diameter tubes, and rods of Si{sub 3}N{sub 4} were synthesized from the thermal treatment of wheat and rice husks at temperatures at and above 1300 °C in a nitrogen atmosphere. The whole pattern Rietveld analysis of the observed diffraction data from treatments at 1300 °C showed the formation of only hexagonal α-phase of Si{sub 3}N{sub 4} with an R-factor of 1%, whereas samples treated at 1400 °C and above showed both α- and β-phases with an R-factor of 2%. Transmission electron microscopy showed the presence of tubes, rods, and nanoparticles of Si{sub 3}N{sub 4}. In a two-step process, where pure SiC was produced first from rice or wheat husk in an argon atmosphere and subsequently treated in a nitrogen atmosphere at 1450 °C, a nanostructured composite material having α- and β-phases of Si{sub 3}N{sub 4} combined with cubic phase of SiC was formed. The thermodynamics of the formation of silicon nitride is discussed in terms of the solid state reaction between organic matter (silica content), which is inherently present in the wheat and rice husks, with the nitrogen from the furnace atmosphere. Nanostructures of silicon nitride formed by a single direct reaction or their composites with SiC formed in a two-step process of agricultural byproducts provide an uncomplicated sustainable synthesis route for silicon nitride used in mechanical, biotechnology, and electro-optic nanotechnology applications.

  5. Surface Area, and Oxidation Effects on Nitridation Kinetics of Silicon Powder Compacts

    Science.gov (United States)

    Bhatt, R. T.; Palczer, A. R.

    1998-01-01

    Commercially available silicon powders were wet-attrition-milled from 2 to 48 hr to achieve surface areas (SA's) ranging from 1.3 to 70 sq m/g. The surface area effects on the nitridation kinetics of silicon powder compacts were determined at 1250 or 1350 C for 4 hr. In addition, the influence of nitridation environment, and preoxidation on nitridation kinetics of a silicon powder of high surface area (approximately equals 63 sq m/g) was investigated. As the surface area increased, so did the percentage nitridation after 4 hr in N2 at 1250 or 1350 C. Silicon powders of high surface area (greater than 40 sq m/g) can be nitrided to greater than 70% at 1250 C in 4 hr. The nitridation kinetics of the high-surface-area powder compacts were significantly delayed by preoxidation treatment. Conversely, the nitridation environment had no significant influence on the nitridation kinetics of the same powder. Impurities present in the starting powder, and those accumulated during attrition milling, appeared to react with the silica layer on the surface of silicon particles to form a molten silicate layer, which provided a path for rapid diffusion of nitrogen and enhanced the nitridation kinetics of high surface area silicon powder.

  6. An Annotated Bibliography on Silicon Nitride for Structural Applications

    Science.gov (United States)

    1977-03-01

    annotated in this bibliography with each entry under the name of the specific author. 16. Canteloup, J., and Mocellin , A., "Synthesis of...thinning. Oxidation of the SJ3N4 grains started at the grain boundaries. 81. Torre, J. P., and Mocellin , A., "On the Existence of Si-AI-O-N Solid...Torre, J. P., and Mocellin , A., "Some Effects of Al and O2 on the Nitridation of Silicon Compacts", J. Mater. Sei., 11., 1725-1733(1976). Highest final

  7. Elastic properties of silicon nitride ceramics reinforced with graphene nanofillers

    Czech Academy of Sciences Publication Activity Database

    Seiner, Hanuš; Ramírez, C.; Koller, M.; Sedlák, Petr; Landa, Michal; Miranzo, P.; Belmonte, M.; Osendí, M. I.

    2015-01-01

    Roč. 87, December (2015), s. 675-680 ISSN 0264-1275 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61388998 Keywords : multilayer graphene * graphene oxide (GO) * silicon nitride * elastic constants * elastic modulus * shear modulus Subject RIV: JI - Composite Materials Impact factor: 3.997, year: 2015 http://www.sciencedirect.com/science/article/pii/S0264127515302938/pdfft?md5=571e00fd7f976e9b66ed789ae2a868b2&pid=1-s2.0-S0264127515302938-main.pdf

  8. Quality factor improvement of silicon nitride micro string resonators

    DEFF Research Database (Denmark)

    Schmid, Silvan; Malm, Bjarke; Boisen, Anja

    2011-01-01

    Resonant micro and nano strings are of interest for sensor applications due to their extraordinary high quality factors, low mass and tunable resonant frequency. It has been found that the quality factor of strings is usually limited by clamping loss. In this work, clamping loss has been addressed...... by varying the clamping design and string geometry. We present silicon nitride micro strings with quality factors (Q) of up to 4 million in high vacuum achieved by minimizing clamping loss. For applications such as for chemical sensing, strings need to vibrate at atmospheric pressure. Maximal quality factor...

  9. Ultra-compact silicon nitride grating coupler for microscopy systems

    OpenAIRE

    Zhu, Yunpeng; Wang, Jie; Xie, Weiqiang; Tian, Bin; Li, Yanlu; Brainis, Edouard; Jiao, Yuqing; Van Thourhout, Dries

    2017-01-01

    Grating couplers have been widely used for coupling light between photonic chips and optical fibers. For various quantum-optics and bio-optics experiments, on the other hand, there is a need to achieve good light coupling between photonic chips and microscopy systems. Here, we propose an ultra-compact silicon nitride (SiN) grating coupler optimized for coupling light from a waveguide to a microscopy system. The grating coupler is about 4 by 2 mu m(2) in size and a 116 nm 1 dB bandwidth can be...

  10. Oxidation Protection of Porous Reaction-Bonded Silicon Nitride

    Science.gov (United States)

    Fox, D. S.

    1994-01-01

    Oxidation kinetics of both as-fabricated and coated reaction-bonded silicon nitride (RBSN) were studied at 900 and 1000 C with thermogravimetry. Uncoated RBSN exhibited internal oxidation and parabolic kinetics. An amorphous Si-C-O coating provided the greatest degree of protection to oxygen, with a small linear weight loss observed. Linear weight gains were measured on samples with an amorphous Si-N-C coating. Chemically vapor deposited (CVD) Si3N4 coated RBSN exhibited parabolic kinetics, and the coating cracked severely. A continuous-SiC-fiber-reinforced RBSN composite was also coated with the Si-C-O material, but no substantial oxidation protection was observed.

  11. Single-layer graphene on silicon nitride micromembrane resonators

    DEFF Research Database (Denmark)

    Schmid, Silvan; Bagci, Tolga; Zeuthen, Emil

    2014-01-01

    Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect...... for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling...

  12. Compressibility and thermal expansion of cubic silicon nitride

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lindelov, H.; Gerward, Leif

    2002-01-01

    The compressibility and thermal expansion of the cubic silicon nitride (c-Si3N4) phase have been investigated by performing in situ x-ray powder-diffraction measurements using synchrotron radiation, complemented with computer simulations by means of first-principles calculations. The bulk...... compressibility of the c-Si3N4 phase originates from the average of both Si-N tetrahedral and octahedral compressibilities where the octahedral polyhedra are less compressible than the tetrahedral ones. The origin of the unit cell expansion is revealed to be due to the increase of the octahedral Si-N and N-N bond...

  13. Polar and Nonpolar Gallium Nitride and Zinc Oxide based thin film heterostructures Integrated with Sapphire and Silicon

    Science.gov (United States)

    Gupta, Pranav

    This dissertation work explores the understanding of the relaxation and integration of polar and non-polar of GaN and ZnO thin films with Sapphire and silicon substrates. Strain management and epitaxial analysis has been performed on wurtzitic GaN(0001) thin films grown on c-Sapphire and wurtzitic non-polar a-plane GaN(11-20) thin films grown on r-plane Sapphire (10-12) by remote plasma atomic nitrogen source assisted UHV Pulsed Laser Deposition process. It has been established that high-quality 2-dimensional c-axis GaN(0001) nucleation layers can be grown on c-Sapphire by PLD process at growth temperatures as low as ˜650°C. Whereas the c-axis GaN on c-sapphire has biaxially negative misfit, the crystalline anisotropy of the a-plane GaN films on r-Sapphire results in compressive and tensile misfits in the two major orthogonal directions. The measured strains have been analyzed in detail by X-ray, Raman spectroscopy and TEM. Strain relaxation in GaN(0001)/Sapphire thin film heterostructure has been explained by the principle of domain matched epitaxial growth in large planar misfit system and has been demonstrated by TEM study. An attempt has been made to qualitatively understand the minimization of free energy of the system from the strain perspective. Analysis has been presented to quantify the strain components responsible for the compressive strain observed in the GaN(0001) thin films on c-axis Sapphire substrates. It was also observed that gallium rich deposition conditions in PLD process lead to smoother nucleation layers because of higher ad-atom mobility of gallium. We demonstrate near strain relaxed epitaxial (0001) GaN thin films grown on (111) Si substrates using TiN as intermediate buffer layer by remote nitrogen plasma assisted UHV pulsed laser deposition (PLD). Because of large misfits between the TiN/GaN and TiN/Si systems the TIN buffer layer growth occurs via nucleation of interfacial dislocations under domain matching epitaxy paradigm. X-ray and

  14. High Temperature Corrosion of Silicon Carbide and Silicon Nitride in Water Vapor

    Science.gov (United States)

    Opila, E. J.; Robinson, Raymond C.; Cuy, Michael D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Silicon carbide (SiC) and silicon nitride (Si3N4) are proposed for applications in high temperature combustion environments containing water vapor. Both SiC and Si3N4 react with water vapor to form a silica (SiO2) scale. It is therefore important to understand the durability of SiC, Si3N4 and SiO2 in water vapor. Thermogravimetric analyses, furnace exposures and burner rig results were obtained for these materials in water vapor at temperatures between 1100 and 1450 C and water vapor partial pressures ranging from 0.1 to 3.1 atm. First, the oxidation of SiC and Si3N4 in water vapor is considered. The parabolic kinetic rate law, rate dependence on water vapor partial pressure, and oxidation mechanism are discussed. Second, the volatilization of silica to form Si(OH)4(g) is examined. Mass spectrometric results, the linear kinetic rate law and a volatilization model based on diffusion through a gas boundary layer are discussed. Finally, the combined oxidation and volatilization reactions, which occur when SiC or Si3N4 are exposed in a water vapor-containing environment, are presented. Both experimental evidence and a model for the paralinear kinetic rate law are shown for these simultaneous oxidation and volatilization reactions.

  15. Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Kirill O. Bugaev

    2012-01-01

    Full Text Available Vibrational properties of hydrogenated silicon-rich nitride (SiN:H of various stoichiometry (0.6≤≤1.3 and hydrogenated amorphous silicon (a-Si:H films were studied using Raman spectroscopy and Fourier transform infrared spectroscopy. Furnace annealing during 5 hours in Ar ambient at 1130∘C and pulse laser annealing were applied to modify the structure of films. Surprisingly, after annealing with such high-thermal budget, according to the FTIR data, the nearly stoichiometric silicon nitride film contains hydrogen in the form of Si–H bonds. From analysis of the FTIR data of the Si–N bond vibrations, one can conclude that silicon nitride is partly crystallized. According to the Raman data a-Si:H films with hydrogen concentration 15% and lower contain mainly Si–H chemical species, and films with hydrogen concentration 30–35% contain mainly Si–H2 chemical species. Nanosecond pulse laser treatments lead to crystallization of the films and its dehydrogenization.

  16. Low-stress silicon nitride layers for MEMS applications

    Science.gov (United States)

    Iliescu, Ciprian; Wei, Jiashen; Chen, Bangtao; Ong, Poh Lam; Tay, Francis E. H.

    2006-12-01

    The paper presents two deposition methods for generation of SiN x layers with "zero" residual stress in PECVD reactors: mixed frequency and high power in high frequency mode (13.56 MHz). Traditionally, mix frequency mode is commonly used to produce low stress SiN x layers, which alternatively applies the HF and LF mode. However, due to the low deposition rate of LF mode, the combined deposition rate of mix frequency is quite small in order to produce homogenous SiN x layers. In the second method, a high power which was up to 600 W has been used, may also produce low residual stress (0-20 MPa), with higher deposition rate (250 to 350 nm/min). The higher power not only leads to higher dissociation rates of gases which results in higher deposition rates, but also brings higher N bonding in the SiN x films and higher compressive stress from higher volume expansion of SiN x films, which compensates the tensile stress and produces low residual stress. In addition, the paper investigates the influence of other important parameters which have great impact to the residual stress and deposition rates, such as reactant gases flow rate and pressure. By using the final optimized recipe, masking layer for anisotropic wet etching in KOH and silicon nitride cantilever have been successfully fabricated based on the low stress SiN x layers. Moreover, nanoporous membrane with 400nm pores has also been fabricated and tested for cell culture. By cultivating the mouse D1 mesenchymal stem cells on top of the nanoporous membrane, the results showed that mouse D1 mesenchymal stem cells were able to grow well. This shows that the nanoporous membrane can be used as the platform for interfacing with living cells to become biocapsules for biomolecular separation.

  17. Electron and ion beam degradation effects in AES analysis of silicon nitride thin films

    International Nuclear Information System (INIS)

    Fransen, F.; Vanden Berghe, R.; Vlaeminck, R.; Hinoul, M.; Remmerie, J.; Maes, H.E.

    1985-01-01

    Silicon nitride films are currently investigated by AES combined with ion profiling techniques for their stoichiometry and oxygen content. During this analysis, ion beam and primary electron effects were observed. The effect of argon ion bombardment is the preferential sputtering of nitrogen, forming 'covalent' silicon at the surface layer (AES peak at 91 eV). The electron beam irradiation results in a decrease of the covalent silicon peak, either by an electron beam annealing effect in the bulk of the silicon nitride film, or by an ionization enhanced surface diffusion process of the silicon (electromigration). By the electron beam annealing, nitrogen species are liberated in the bulk of the silicon nitride film and migrate towards the surface where they react with the covalent silicon. The ionization enhanced diffusion originates from local charging of the surface, induced by the electron beam. (author)

  18. Demonstration of slot-waveguide structures on silicon nitride / silicon oxide platform.

    Science.gov (United States)

    Barrios, C A; Sánchez, B; Gylfason, K B; Griol, A; Sohlström, H; Holgado, M; Casquel, R

    2007-05-28

    We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of <20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.

  19. Single-layer graphene on silicon nitride micromembrane resonators

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Silvan; Guillermo Villanueva, Luis; Amato, Bartolo; Boisen, Anja [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, 2800 Kongens Lyngby (Denmark); Bagci, Tolga; Zeuthen, Emil; Sørensen, Anders S.; Usami, Koji; Polzik, Eugene S. [QUANTOP, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Taylor, Jacob M. [Joint Quantum Institute/NIST, College Park, Maryland 20899 (United States); Herring, Patrick K.; Cassidy, Maja C. [School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Charles M. [Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Cheol Shin, Yong; Kong, Jing [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-02-07

    Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling of graphene covered membranes is found to be equal to a perfectly conductive membrane, without significantly adding mass, decreasing the superior mechanical quality factor or affecting the optical properties of pure SiN micromembranes. The concept of graphene-SiN resonators allows a broad range of new experiments both in applied physics and fundamental basic research, e.g., for the mechanical, electrical, or optical characterization of graphene.

  20. Optically induced paramagnetism in amorphous hydrogenated silicon nitride thin films

    International Nuclear Information System (INIS)

    Warren, W.L.; Kanicki, J.; Buchwald, W.R.; Rong, F.C.; Harmatz, M.

    1992-01-01

    This paper reports that the creation mechanisms of Si and N dangling bond defect centers in amorphous hydrogenated silicon nitride thin films by ultra-violet (UV) illumination are investigated. The creation efficiency and density of Si centers in the N-rich films are independent of illumination temperature, strongly suggesting that the creation mechanism of the spins in electronic in nature, i.e., a charge transfer mechanism. However, our results suggest that the creation of the Si dangling bond in the Si-rich films are different. Last, we find that the creation of the N dangling-bond in N-rich films can be fit to a stretched exponential time dependence, which is characteristic of dispersive charge transport

  1. The relationship of microstructure and temperature to fracture mechanics parameters in reaction bonded silicon nitride

    International Nuclear Information System (INIS)

    Jennings, H.M.; Dalgleish, B.J.; Pratt, P.L.

    1978-01-01

    The development of physical properties in reaction bonded silicon nitride has been investigated over a range of temperatures and correlated with microstructure. Fracture mechanics parameters, elastic moduli, strength and critical defect size have been determined. The nitrided microstructure is shown to be directly related to these observed properties and these basic relationships can be used to produce material with improved properties. (orig.) [de

  2. Joining and interface characterization of in situ reinforced silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Asthana, R., E-mail: asthanar@uwstout.edu [Department of Engineering and Technology, 326 FH, University of Wisconsin-Stout, Menomonie, WI 54751 (United States); Singh, M., E-mail: Mrityunjay.Singh@nasa.gov [Ohio Aerospace Institute, NASA Glenn Research Center, Cleveland, OH 44135 (United States); Martinez-Fernandez, J., E-mail: Martinez@us.es [Dpto. Física de la Materia Condensada-ICMSE, Universidad de Sevilla-CSIC, Avda. Reina Mercedes, s/n, 41012 Sevilla (Spain)

    2013-03-05

    Highlights: ► AS800 Si{sub 3}N{sub 4} brazed using oxidation-resistant, high use-temperature braze Cu-ABA. ► Interface enriched in Ti and Si but not in Y, La, and Sr (from Y{sub 2}O{sub 3}, La{sub 2}O{sub 3} and SrO). ► Rapid early-stage kinetic evident in constant layer thickness, composition with time. ► Highly textured large grains of Cu and features associated with plastic deformation. -- Abstract: Copper-base active metal interlayers were used to bond in situ reinforced silicon nitride (Honeywell AS800) at 1317 K for 5 and 30 min in vacuum. The joints were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron back scattered diffraction (EBSD), and transmission electron microscopy (TEM). A Ti-rich interaction zone (∼3.0–3.5 μm thick) formed at the Si{sub 3}N{sub 4}/braze interface. This reaction layer grew toward the inner part of the joint with a featureless microstructure, creating a strong bond. Regions of a Ti-rich phase were frequently found next to the reaction layer but surrounded by the Cu alloy. Extensive Ti and Si enrichments were noted at the interface but there was no evidence of interfacial segregation of Y, La, and Sr (from Y{sub 2}O{sub 3}, La{sub 2}O{sub 3} and SrO, added as sintering aids). The reaction layer thickness and composition did not change when brazing time increased from 5 min to 30 min suggesting rapid growth kinetics in the early stages of reaction. The joints were crack-free and showed features associated with plastic deformation, which indicated that the metal interlayer accommodated strain associated with CTE mismatch. The inner part of the joint consisted of highly textured large grains of the braze alloy.

  3. On the photon annealing of silicon-implanted gallium-nitride layers

    International Nuclear Information System (INIS)

    Seleznev, B. I.; Moskalev, G. Ya.; Fedorov, D. G.

    2016-01-01

    The conditions for the formation of ion-doped layers in gallium nitride upon the incorporation of silicon ions followed by photon annealing in the presence of silicon dioxide and nitride coatings are analyzed. The conditions of the formation of ion-doped layers with a high degree of impurity activation are established. The temperature dependences of the surface concentration and mobility of charge carriers in ion-doped GaN layers annealed at different temperatures are studied.

  4. Studies on silicon nitrides; Chikka keiso ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-31

    Sinters of silicon nitrides have excellent properties as a structural material, but their technological repercussion effect is not as much as has been expected. The cause is in insufficient understanding on the mutual relationship between microstructures and mechanical properties. Therefore, methods of controlling structures were first discussed in the studies on synthesis of high-tenacity ceramics. In order to achieve high reliability in material strength, discussions were given on means to have a structure developed with high reproducibility. Development was performed on {beta} powder which shows no abnormal grain growth and is stable at elevated temperatures. Then, quantitative evaluation was made on factors to manifest a self-compounding structure with columnar particles grown in ultrafine particles. The relationship between its chemical composition, microstructure and mechanical properties was also discussed. Particle shapes of silicon carbides and their fracture tenacity values were considered theoretically by using a drawing model. To evaluate the microstructure, it is important to determine the grain boundary composition, whereas an electric field radiation type high-performance electron microscope was developed. In discussing the fracture mechanism, a model was structured for behavior of covalent binding crystals against external stress. 164 refs., 95 figs., 10 tabs.

  5. Molecular Surveillance of Viral Processes Using Silicon Nitride Membranes

    Directory of Open Access Journals (Sweden)

    Deborah F. Kelly

    2013-03-01

    Full Text Available Here we present new applications for silicon nitride (SiN membranes to evaluate biological processes. We determined that 50-nanometer thin films of SiN produced from silicon wafers were sufficiently durable to bind active rotavirus assemblies. A direct comparison of SiN microchips with conventional carbon support films indicated that SiN performs equivalent to the traditional substrate to prepare samples for Electron Microscopy (EM imaging. Likewise, SiN films coated with Ni-NTA affinity layers concentrated rotavirus particles similarly to affinity-coated carbon films. However, affinity-coated SiN membranes outperformed glow-discharged conventional carbon films 5-fold as indicated by the number of viral particles quantified in EM images. In addition, we were able to recapitulate viral uncoating and transcription mechanisms directed onto the microchip surfaces. EM images of these processes revealed the production of RNA transcripts emerging from active rotavirus complexes. These results were confirmed by the functional incorporation of radiolabeled nucleotides into the nascent RNA transcripts. Collectively, we demonstrate new uses for SiN membranes to perform molecular surveillance on life processes in real-time.

  6. Robust Environmental Barrier Coatings for Silicon Nitride, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicon based ceramics are the leading candidates for the high temperature structural components of the advanced propulsion engines. For such applications, one key...

  7. Mechanical and tribological properties of silicon nitride films synthesized by ion beam enhanced deposition

    International Nuclear Information System (INIS)

    Chen Yuanru; Li Shizhuo; Zhang Xushou; Liu Hong; Yang Genqing; Qu Baochun

    1991-01-01

    This article describes preliminary investigations of mechanical and tribological properties of silicon nitride film formed by ion beam enhanced deposition (IBED) on GH37 (Ni-based alloys) steel. The films were synthesized by silicon vapor deposition with a rate of 1 A/s and by 40 keV nitrogen ion bombardment simultaneously. The thickness of the film was about 5000 A. X-ray photoelectron spectroscopy and infrared absorption spectroscopy revealed that a stoichiometric Si 3 N 4 film was formed. The observation of TEM showed that the IBED Si 3 N 4 film normally had an amorphous structure. However, electron diffraction patterns revealed a certain crystallinity. The mechanical and tribological properties of the films were investigated with a scratch tester, microhardness meter, and a ball-on-disc tribometer respectively. Results show that the adhesive strength between film and substrate is about 51 N, the Vickers microhardness with a load of 0.2 N is 980, the friction coefficient measured for steel against silicon nitride film ranges from 0.1 to 0.15, and the wear rate of coatings is about 6.8x10 -5 mm 3 /(mN). Finally, the relationship among thermal annealing, crystallinity and tribological characteristics of the Si 3 N 4 film is discussed. (orig.)

  8. Annealing and deposition effects of the chemical composition of silicon rich nitride

    DEFF Research Database (Denmark)

    Andersen, Karin Nordström; Svendsen, Winnie Edith; Stimpel-Lindner, T.

    2005-01-01

    Silicon-rich nitride, deposited by LPCVD, is a low stress amorphous material with a high refractive index. After deposition the silicon-rich nitride thin film is annealed at temperatures above 1100 oC to break N-H bonds, which have absorption peaks in the wavelength band important for optical...... in optical waveguides. This means that the annealing temperature must be high enough to break the N-H bonds, but no so high as to produce clusters. Therefore, the process window for an annealing step lies between 1100 and 1150 oC. The chemical composition of amorphous silicon-rich nitride has been...... investigated by Rutherford back scattering (RBS) and X-ray photoelectron spectroscopy (XPS). The influence of deposition parameters and annealing temperatures on the stoichiometry and the chemical bonds will be discussed. The origin of the clusters has been found to be silicon due to severe silicon out...

  9. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, A.T.; Baggerman, J.; Paulusse, J.M.J.; Rijn, van C.J.M.; Zuilhof, H.

    2011-01-01

    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable

  10. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, Ai T.; Baggerman, Jacob; Paulusse, Jos Marie Johannes; van Rijn, Cees J.M.; Zuilhof, Han

    2011-01-01

    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable Si−C

  11. Reaction sintering of a clay-containing silicon nitride bonded silicon carbide refractory

    International Nuclear Information System (INIS)

    Swenser, S.P.; Cheng, Y.B.

    1998-01-01

    Aspects of the reaction sequence for the reaction bonding of a cast refractory, which in the green state was composed of 79 wt-% SiC grit, 16 wt-% Si powder and 5 wt-% clay were established. As it was fired up to 1600 deg C in flowing N 2 (g), weight gains were noted and phase evolution was monitored by X-ray diffraction. However, details of the reaction sequence were not determined directly from this material because several reaction-bonding processes occurred simultaneously. Reaction features were ascertained by contrasting the weight changes and phase evolution in the refractory with those observed during reaction-bonding of (a) Si and clay without the SiC and (b) SiC and clay without the Si. In addition to silicon nitridation and the development of sialon phases by silicothermal and carbothermal reduction-nitridation processes, indirect evidence suggested that α-Si 3 N 4 formed by the carbothermal reduction-nitridation (CRN) of SiO(g). Copyright (1998) Australasian Ceramic Society

  12. Quantitative Auger depth profiling of LPCVD and PECVD silicon nitride films

    International Nuclear Information System (INIS)

    Keim, E.G.; Aite, K.

    1989-01-01

    Thin silicon nitride films (100-210 nm) with refractive indices varying from 1.90 to 2.10 were deposited on silicon substrates by low pressure chemical vapour deposition (LPCVD) and plasma enhanced chemical vapour deposition (PECVD). Rutherford backscattering spectrometry (RBS), ellipsometry, surface profiling measurements and Auger electron spectroscopy (AES) in combination with Ar + sputtering were used to characterize these films. We have found that the use of (p-p)heights of the Si LVV and N KLL Auger transitions in the first derivative of the energy distribution (dN(E)/dE) leads to an accurate determination of the silicon nitride composition in Auger depth profiles over a wide range of atomic Si/N ratios. Moreover, we have shown that the Si KLL Auger transition, generally considered to be a better probe than the low energy Si LVV Auger transition in determining the chemical composition of silicon nitride layers, leads to deviating results. (orig.)

  13. Nitride fuels irradiation performance data base

    International Nuclear Information System (INIS)

    Brozak, D.E.; Thomas, J.K.; Peddicord, K.L.

    1987-01-01

    An irradiation performance data base for nitride fuels has been developed from an extensive literature search and review that emphasized uranium nitride, but also included performance data for mixed nitrides [(U,Pu)N] and carbonitrides [(U,Pu)C,N] to increase the quantity and depth of pin data available. This work represents a very extensive effort to systematically collect and organize irradiation data for nitride-based fuels. The data base has many potential applications. First, it can facilitate parametric studies of nitride-based fuels to be performed using a wide range of pin designs and operating conditions. This should aid in the identification of important parameters and design requirements for multimegawatt and SP-100 fuel systems. Secondly, the data base can be used to evaluate fuel performance models. For detailed studies, it can serve as a guide to selecting a small group of pin specimens for extensive characterization. Finally, the data base will serve as an easily accessible and expandable source of irradiation performance information for nitride fuels

  14. Microstructural and reliability in grinding of silicon nitride

    International Nuclear Information System (INIS)

    Liu, C.-C.

    2004-01-01

    A sintered Si 3 N 4 matrix has been characterized by TEM. The film thickness distribution of Si 3 N 4 was measured by high resolution transmission electron microscopy (HREM). Surface grinding is performed on two table speeds of 0.08 and 0.25 m s -1 with different depth of cut. The ground surfaces were observed with scanning electron microscopy (SEM). The surface texture was found to have greater dependence on depth of cut and table speed. The surface roughness is improved after smaller depth of cut. The flexural strength of ground specimens were measured by four-point flexure tests. The effect of depth of cut during grinding on the flexural strength and reliability of silicon nitride is investigated. The large depth of cut of 30 μm/pass resulted in a further decreased in strength of 540 MPa and a Weibull modulus of 7.5. When the depth of cut of 5 μm/pass were subjected to the ground specimens, the average strength was increased to 670 MPa and Weibull modulus to 9.1

  15. Fabrication and properties of graphene reinforced silicon nitride composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yaping; Li, Bin, E-mail: libin@nudt.edu.cn; Zhang, Changrui; Wang, Siqing; Liu, Kun; Yang, Bei

    2015-09-17

    Silicon nitride (Si{sub 3}N{sub 4}) ceramic composites reinforced with graphene platelets (GPLs) were prepared by hot pressed sintering and pressureless sintering respectively. Adequate intermixing of the GPLs and the ceramic powders was achieved in nmethyl-pyrrolidone (NMP) under ultrasonic vibration followed by ball-milling. The microstructure and phases of the Si{sub 3}N{sub 4} ceramic composites were investigated by Field Emission Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The effects of GPLs on the composites' mechanical properties were analyzed. The results showed that GPLs were well dispersed in the Si{sub 3}N{sub 4} ceramic matrix. β-Si{sub 3}N{sub 4,} O′-sialon and GPLs were present in the hot-pressed composites while pressureless sintered composites contain β-Si{sub 3}N{sub 4}, Si, SiC and GPLs. Graphene has the potential to improve the mechanical properties of both the hot pressed and pressureless sintered composites. Toughening effect of GPLs on the pressureless sintered composites appeared more effective than that on the hot pressed composites. Toughening mechanisms, such as pull-out, crack bridging and crack deflection induced by GPLs were observed in the composites prepared by the two methods.

  16. Fabrication and properties of graphene reinforced silicon nitride composite materials

    International Nuclear Information System (INIS)

    Yang, Yaping; Li, Bin; Zhang, Changrui; Wang, Siqing; Liu, Kun; Yang, Bei

    2015-01-01

    Silicon nitride (Si 3 N 4 ) ceramic composites reinforced with graphene platelets (GPLs) were prepared by hot pressed sintering and pressureless sintering respectively. Adequate intermixing of the GPLs and the ceramic powders was achieved in nmethyl-pyrrolidone (NMP) under ultrasonic vibration followed by ball-milling. The microstructure and phases of the Si 3 N 4 ceramic composites were investigated by Field Emission Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The effects of GPLs on the composites' mechanical properties were analyzed. The results showed that GPLs were well dispersed in the Si 3 N 4 ceramic matrix. β-Si 3 N 4, O′-sialon and GPLs were present in the hot-pressed composites while pressureless sintered composites contain β-Si 3 N 4 , Si, SiC and GPLs. Graphene has the potential to improve the mechanical properties of both the hot pressed and pressureless sintered composites. Toughening effect of GPLs on the pressureless sintered composites appeared more effective than that on the hot pressed composites. Toughening mechanisms, such as pull-out, crack bridging and crack deflection induced by GPLs were observed in the composites prepared by the two methods

  17. Ag doped silicon nitride nanocomposites for embedded plasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Bayle, M.; Bonafos, C., E-mail: bonafos@cemes.fr; Benzo, P.; Benassayag, G.; Pécassou, B.; Carles, R. [CEMES-CNRS and Université de Toulouse, 29 rue J. Marvig, 31055 Toulouse, Cedex 04 (France); Khomenkova, L.; Gourbilleau, F. [CIMAP, CNRS/CEA/ENSICAEN/UCBN, 6 Boulevard Maréchal Juin, 14050 Caen, Cedex 4 (France)

    2015-09-07

    The localized surface plasmon-polariton resonance (LSPR) of noble metal nanoparticles (NPs) is widely exploited for enhanced optical spectroscopies of molecules, nonlinear optics, photothermal therapy, photovoltaics, or more recently in plasmoelectronics and photocatalysis. The LSPR frequency depends not only of the noble metal NP material, shape, and size but also of its environment, i.e., of the embedding matrix. In this paper, Ag-NPs have been fabricated by low energy ion beam synthesis in silicon nitride (SiN{sub x}) matrices. By coupling the high refractive index of SiN{sub x} to the relevant choice of dielectric thickness in a SiN{sub x}/Si bilayer for an optimum antireflective effect, a very sharp plasmonic optical interference is obtained in mid-range of the visible spectrum (2.6 eV). The diffusion barrier property of the host SiN{sub x} matrix allows for the introduction of a high amount of Ag and the formation of a high density of Ag-NPs that nucleate during the implantation process. Under specific implantation conditions, in-plane self-organization effects are obtained in this matrix that could be the result of a metastable coarsening regime.

  18. Silicon Nitride Background in Nanophotonic Waveguide Enhanced Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ashim Dhakal

    2017-02-01

    Full Text Available Recent studies have shown that evanescent Raman spectroscopy using a silicon nitride (SiN nanophotonic waveguide platform has higher signal enhancement when compared to free-space systems. However, signal-to-noise ratio from the waveguide at a low analyte concentration is constrained by the shot-noise from the background light originating from the waveguide itself. Hence, understanding the origin and properties of this waveguide background luminescence (WGBL is essential to developing mitigation strategies. Here, we identify the dominating component of the WGBL spectrum composed of a broad Raman scattering due to momentum selection-rule breaking in amorphous materials, and several peaks specific to molecules embedded in the core. We determine the maximum of the Raman scattering efficiency of the WGBL at room temperature for 785 nm excitation to be 4.5 ± 1 × 10−9 cm−1·sr−1, at a Stokes shift of 200 cm−1. This efficiency decreases monotonically for higher Stokes shifts. Additionally, we also demonstrate the use of slotted waveguides and quasi-transverse magnetic polarization as some mitigation strategies.

  19. Elasticity and inelasticity of silicon nitride/boron nitride fibrous monoliths.

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B. I.; Burenkov, Yu. A.; Kardashev, B. K.; Singh, D.; Goretta, K. C.; de Arellano-Lopez, A. R.; Energy Technology; Russian Academy of Sciences; Univer. de Sevilla

    2001-01-01

    A study is reported on the effect of temperature and elastic vibration amplitude on Young's modulus E and internal friction in Si{sub 3}N{sub 4} and BN ceramic samples and Si{sub 3}N{sub 4}/BN monoliths obtained by hot pressing of BN-coated Si{sub 3}N{sub 4} fibers. The fibers were arranged along, across, or both along and across the specimen axis. The E measurements were carried out under thermal cycling within the 20-600 C range. It was found that high-modulus silicon-nitride specimens possess a high thermal stability; the E(T) dependences obtained under heating and cooling coincide well with one another. The low-modulus BN ceramic exhibits a considerable hysteresis, thus indicating evolution of the defect structure under the action of thermoelastic (internal) stresses. Monoliths demonstrate a qualitatively similar behavior (with hysteresis). This behavior of the elastic modulus is possible under microplastic deformation initiated by internal stresses. The presence of microplastic shear in all the materials studied is supported by the character of the amplitude dependences of internal friction and the Young's modulus. The experimental data obtained are discussed in terms of a model in which the temperature dependences of the elastic modulus and their features are accounted for by both microplastic deformation and nonlinear lattice-atom vibrations, which depend on internal stresses.

  20. Final report. Fabrication of silicon carbide/silicon nitride nanocomposite materials and characterization of their performance; Herstellung von Siliciumcarbid/Siliciumnitrid-Nanocomposite-Werkstoffen und Charakterisierung ihrer Leistungsfaehigkeit. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Westerheide, R.; Woetting, G.; Schmitz, H.W.

    1998-07-01

    The presented activities were initiated by the well known publications of Niihara and Ishizaki. There, the strengthening and toughening of silicon nitride by nanoscaled silicon carbide particles are described. Both authors have used expensive powder production routes to achieve the optimum mechanical properties. However, for a commercial purpose these routes are not applicable due to their high cost and low reproducibility. The production route chosen by H.C. Starck together with CFI and the Fraunhofer-Institute is a powder synthesis based on the carbothermal reaction of silicon nitride as a low cost synthesis method. The investigations were performed for materials made from synthesis powders and other reference materials. The materials were densified with relatively high amounts of conventional sintering additives by gas pressure sintering. It is shown, that the postulated maxima of strength and fracture toughness behaviour at room temperature with maxima at about 5% to 25% nanoscaled SiC cannot be achieved. However, the mechanical high temperature material behaviour is as good as the behaviour of highly developed silicon nitride materials, which are produced by HIP or by consequent minimisation of the additive content with the well known difficulties to densify these materials. An overview will be given here on the powder production route and their specific problems, the mechanical properties, the microstructure and the possible effects of the microstructure, which result in an improvement of the creep resistance. (orig.)

  1. Application of plasma silicon nitride to crystalline thin-film silicon solar cells. Paper

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, J.; Oberbeck, L.; Rinke, T.J.; Berge, C.; Bergmann, R.B.

    2002-07-01

    We use plasma-enhanced chemical vapour deposition to deposit silicon nitride (SiN{sub x}) films at low temperature(400 C) onto the front surface of two different types of crystalline thin-film Si solar cells. The silicon nitride acts as an excellent antireflection coating on Si and provides a very high degree of electronic surface passivation over a wide range of compositions, including near-stoichiometric and Si-rich SiN{sub x}. Application of stoichiometric SiN{sub x} to non-textured thin-film cells, epitaxially grown at low temperature by ion-assisted deposition onto a monocrystalline Si substrate, results in an open-circuit voltage of 622 mV, a short-circuit current density of 26.6 mA/cm{sup 2} and an efficiency of 12.7%. It is shown that the SiN{sub x}-passivated in-situ grown n{sup +}-emitter of this cell type allows to reach open-circuit voltages of up to 667 mV. Silicon-rich SiN{sub x} is applied to the phosphorus-diffused n{sup +}-emitter of a textured thin-film cell on a glass superstrate fabricated by layer-transfer. The emitter saturation current density of these cells is only 40-64 fA/cm{sup 2}, which allows for open-circuit voltages of up to 699 mV. An impressively high open-circuit voltage of 638 mV and a short-circuit current density of 32.0 mA/cm{sup 2} are obtained for a 25 {mu}m thick SiN{sub x}-passivated, random pyramid-textured transfer cell. A transfer cell efficiency of 15.3% is independently confirmed.

  2. Elastocapillary folding of three dimensional micro-structures using water pumped through the wafer via a silicon nitride tube

    NARCIS (Netherlands)

    Legrain, A.B.H.; Berenschot, Johan W.; Sanders, Remco G.P.; Ma, Kechun; Tas, Niels Roelof; Abelmann, Leon

    2011-01-01

    In this paper we present the first investigation of a batch method for folding of threedimensional micrometer-sized silicon nitride structures by capillary forces. Silicon nitride tubes have been designed and fabricated using DRIE at the center of the planar origami patterns of the structures. Water

  3. Ab initio design of nanostructures for solar energy conversion: a case study on silicon nitride nanowire.

    Science.gov (United States)

    Pan, Hui

    2014-01-01

    Design of novel materials for efficient solar energy conversion is critical to the development of green energy technology. In this work, we present a first-principles study on the design of nanostructures for solar energy harvesting on the basis of the density functional theory. We show that the indirect band structure of bulk silicon nitride is transferred to direct bandgap in nanowire. We find that intermediate bands can be created by doping, leading to enhancement of sunlight absorption. We further show that codoping not only reduces the bandgap and introduces intermediate bands but also enhances the solubility of dopants in silicon nitride nanowires due to reduced formation energy of substitution. Importantly, the codoped nanowire is ferromagnetic, leading to the improvement of carrier mobility. The silicon nitride nanowires with direct bandgap, intermediate bands, and ferromagnetism may be applicable to solar energy harvesting.

  4. Transient and steady-state erosion of in-situ reinforced silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Karasek, K.R. [Allied Signal Research and Technology, Des Plaines, IL (United States); Whalen, P.J. [Allied Signal, Inc., Morristown, NJ (United States); Rateick, R.G. Jr. [Allied Signal Aerospace, South Bend, IN (United States); Hamilton, A.C. [Michigan Technological Univ., Houghton, MI (United States); Routbort, J.L. [Argonne National Lab., IL (United States)

    1994-10-01

    Relative to most other materials silicon nitride is very erosion resistant. However, the resulting surface flaws degrade strength - a serious concern for component designers. AlliedSignal Ceramic Components GS-44 in-situ reinforced silicon nitride was eroded in a slinger apparatus. Both transient (extremely low level) and steady-state erosion regimes were investigated. Alumina particles with effective average diameters of 140 Jim and 63 {mu}m were used at velocities of 50 m/s, 100 m/s, and 138 m/s. Biaxial tensile strength was measured. Strength decreased by about 15% after a very small erodent dosage and then remained virtually constant with further erosion. In-situ reinforcement produces R-curve behavior in which the fracture toughness increases with crack size. The effect of this is quite dramatic with strength loss being significantly less than expected for a normal silicon nitride with constant fracture toughness.

  5. Preparation and mechanical properties of carbon nanotube-silicon nitride nano-ceramic matrix composites

    Science.gov (United States)

    Tian, C. Y.; Jiang, H.

    2018-01-01

    Carbon nanotube-silicon nitride nano-ceramic matrix composites were fabricated by hot-pressing nano-sized Si3N4 powders and carbon nanotubes. The effect of CNTs on the mechanical properties of silicon nitride was researched. The phase compositions and the microstructure characteristics of the samples as well as the distribution of carbon nanotube in the silicon nitride ceramic were analyzed by X-ray diffraction and scanning electron microscope. The results show that the microstructure of composites consists mainly of α-Si3N4, β-Si3N4, Si2N2O and carbon natubes. The addition of proper amount of carbon nanotubes can improve the fracture toughness and the flexural strength, and the optimal amount of carbon nanotube are both 3wt.%. However the Vickers hardness values decrease with the increase of carbon nanotubes content.

  6. Effect of post-deposition implantation and annealing on the properties of PECVD deposited silicon nitride films

    International Nuclear Information System (INIS)

    Shams, Q.A.

    1988-01-01

    Recently it has been shown that memory-quality silicon nitride can be deposited using plasma enhanced chemical vapor deposition (PECVD). Nitrogen implantation and post-deposition annealing resulted in improved memory properties of MNOS devices. The primary objective of the work described here is the continuation of the above work. Silicon nitride films were deposited using argon as the carrier gas and evaluated in terms of memory performance as the charge-trapping layer in the metal-nitride-oxide-silicon (MNOS) capacitor structure. The bonding structure of PECVD silicon nitride was modified by annealing in different ambients at temperatures higher than the deposition temperature. Post-deposition ion implantation was used to introduce argon into the films in an attempt to influence the transfer, trapping, and emission of charge during write/erase exercising of the MNOS devices. Results show that the memory performance of PECVD silicon nitride is sensitive to the deposition parameters and post-deposition processing

  7. Silicon nitride back-end optics for biosensor applications

    Science.gov (United States)

    Romero-García, Sebastian; Merget, Florian; Zhong, Frank C.; Finkelstein, Hod; Witzens, Jeremy

    2013-05-01

    Silicon nitride (SiN) is a promising candidate material for becoming a standard high-performance solution for integrated biophotonics applications in the visible spectrum. As a key feature, its compatibility with the complementary-oxidemetal- semiconductor (CMOS) technology permits cost reduction at large manufacturing volumes that is particularly advantageous for manufacturing consumables. In this work, we show that the back-end deposition of a thin SiN film enables the large light-cladding interaction desirable for biosensing applications while the refractive index contrast of the technology (Δn ≍ 0.5) also enables a considerable level of integration with reduced waveguide bend radii. Design and experimental validation also show that several advantages are derived from the moderate SiN/SiO2 refractive index contrast, such as lower scattering losses in interconnection waveguides and relaxed tolerances to fabrication imperfections as compared to higher refractive index contrast material systems. As a drawback, a moderate refractive index contrast also makes the implementation of compact grating couplers more challenging, due to the fact that only a relatively weak scattering strength can be achieved. Thereby, the beam diffracted by the grating tends to be rather large and consequently exhibit stringent angular alignment tolerances. Here, we experimentally demonstrate how a proper design of the bottom and top cladding oxide thicknesses allows reduction of the full-width at half maximum (FWHM) and alleviates this problem. Additionally, the inclusion of a CMOS-compatible AlCu/TiN bottom reflector further decreases the FWHM and increases the coupling efficiency. Finally, we show that focusing grating designs greatly reduce the device footprint without penalizing the device metrics.

  8. Thermogravimetric analysis of silicon carbide-silicon nitride polycarbosilazane precursor during pyrolysis from ambient to 1000 C

    Science.gov (United States)

    Ledbetter, F. E., III; Daniels, J. G.; Clemons, J. M.; Hundley, N. H.; Penn, B. G.

    1984-01-01

    Thermogravimetric analysis data are presented on the unmeltable polycarbosilazane precursor of silicon carbide-silicon nitride fibers, over the room temperature-1000 C range in a nitrogen atmosphere, in order to establish the weight loss at various temperatures during the precursor's pyrolysis to the fiber material. The fibers obtained by this method are excellent candidates for use in applications where the oxidation of carbon fibers (above 400 C) renders them unsuitable.

  9. Gallium nitride-based micro-opto-electro-mechanical systems

    Science.gov (United States)

    Stonas, Andreas Robert

    Gallium Nitride and its associated alloys InGaN and AlGaN have many material properties that are highly desirable for micro-electro-mechanical systems (MEMS), and more specifically micro-opto-electro-mechanical systems (MOEMS). The group III-nitrides are tough, stiff, optically transparent, direct bandgap, chemically inert, highly piezoelectric, and capable of functioning at high temperatures. There is currently no other semiconductor system that possesses all of these properties. Taken together, these attributes make the nitrides prime candidates not only for creating new versions of existing device structures, but also for creating entirely unique devices which combine these properties in novel ways. Unfortunately, their chemical resiliency also makes the group III-nitrides extraordinarily difficult to shape into devices. In particular, until this research, no undercut etch technology existed that could controllably separate a selected part of a MEMS device from its sapphire or silicon carbide substrate. This has effectively prevented GaN-based MEMS from being developed. This dissertation describes how this fabrication obstacle was overcome by a novel etching geometry (bandgap-selective backside-illuminated photoelectochemical (BS-BIPEC) etching) and its resulting morphologies. Several gallium-nitride based MEMS devices were created, actuated, and modelled, including cantilevers and membranes. We describe in particular our pursuit of one of the many novel device elements that is possible only in this material system: a transducer that uses an externally applied strain to dynamically change the optical transition energy of a quantum well. While the device objective of a dynamically tunable quantum well was not achieved, we have demonstrated sufficient progress to believe that such a device will be possible soon. We have observed a shift (5.5meV) of quantum well transition energies in released structures, and we have created structures that can apply large biaxial

  10. Microstructure and initial growth characteristics of the low temperature microcrystalline silicon films on silicon nitride surface

    International Nuclear Information System (INIS)

    Park, Young-Bae; Rhee, Shi-Woo

    2001-01-01

    Microstructure and initial growth characteristics of the hydrogenated microcrystalline Si (μc-Si:H) films grown on hydrogenated amorphous silicon nitride (a-SiN x :H) surface at low temperature were investigated using high resolution transmission electron microscope and micro-Raman spectroscopy. With increasing the Si and Si - H contents in the SiN x :H surfaces, μc-Si crystallites, a few nanometers in size, were directly grown on amorphous nitride surfaces. It is believed that the crystallites were grown through the nucleation and phase transition from amorphous to crystal in a hydrogen-rich ambient of gas phase and growing surface. The crystallite growth characteristics on the dielectric surface were dependent on the stoichiometric (x=N/Si) ratio corresponding hydrogen bond configuration of the SiN x :H surface. Surface facetting and anisotropic growth of the Si crystallites resulted from the different growth rate on the different lattice planes of Si. No twins and stacking faults were observed in the (111) lattice planes of the Si crystallites surrounding the a-Si matrix. This atomic-scale structure was considered to be the characteristic of the low temperature crystallization of the μc-Si:H by the strain relaxation of crystallites in the a-Si:H matrix. [copyright] 2001 American Institute of Physics

  11. Process for the production of metal nitride sintered bodies and resultant silicon nitride and aluminum nitride sintered bodies

    Science.gov (United States)

    Yajima, S.; Omori, M.; Hayashi, J.; Kayano, H.; Hamano, M.

    1983-01-01

    A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and avoidance of previously known faults.

  12. Argon plasma treatment of silicon nitride (SiN) for improved antireflection coating on c-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Hemanta; Mitra, Suchismita; Saha, Hiranmay; Datta, Swapan Kumar; Banerjee, Chandan, E-mail: chandanbanerjee74@gmail.com

    2017-01-15

    Highlights: • Antireflection properties of argon plasma treated silicon nitride layer and its effect on crystalline silicon solar cell. • The reduction in reflection due to the formation of a silicon oxynitride/silicon nitride double layer. • EQE reveals a relative increase of 2.72% in J{sub sc} and 4.46% in conversion efficiency. - Abstract: Antireflection properties of argon plasma treated silicon nitride layer and its effect on crystalline silicon solar cell is presented here. Hydrogenated silicon nitride (a-SiN:H) layer has been deposited on a silicon substrate by Plasma Enhanced Chemical Vapour Deposition (PECVD) using a mixture of silane (SiH{sub 4}), ammonia (NH{sub 3}) and hydrogen (H{sub 2}) gases followed by a argon plasma treatment. Optical analysis reveals a significant reduction in reflectance after argon plasma treatment of silicon nitride layer. While FESEM shows nanostructures on the surface of the silicon nitride film, FTIR reveals a change in Si−N, Si−O and N−H bonds. On the other hand, ellipsometry shows the variation of refractive index and formation of double layer. Finally, a c-Si solar cell has been fabricated with the said anti-reflection coating. External quantum efficiency reveals a relative increase of 2.72% in the short circuit current density and 4.46% in conversion efficiency over a baseline efficiency of 16.58%.

  13. Formation of nanocrystals embedded in a silicon nitride film at a low temperature ({<=}200 deg. C)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung-Min; Kim, Tae-Hwan [Department of Nano Science and Technology, University of Seoul, Seoul 130-743 (Korea, Republic of); Hong, Wan-Shick [Department of Nano Science and Technology, University of Seoul, Seoul 130-743 (Korea, Republic of)], E-mail: wshong@uos.ac.kr

    2008-12-15

    Silicon-rich silicon nitride films with embedded silicon nanocrystals (Si NCs) were fabricated successfully on plastic substrates at a low temperature by catalytic chemical vapor deposition. A mixture of SiH{sub 4}, NH{sub 3} and H{sub 2} was used as a source gas. Formation of the silicon nanocrystals was analyzed by photoluminescence spectra and was confirmed by transmission electron microscopy. The formation of Si NCs required an H{sub 2}/SiH{sub 4} mixture ratio that was higher than four.

  14. Helium ion beam induced electron emission from insulating silicon nitride films under charging conditions

    Science.gov (United States)

    Petrov, Yu. V.; Anikeva, A. E.; Vyvenko, O. F.

    2018-06-01

    Secondary electron emission from thin silicon nitride films of different thicknesses on silicon excited by helium ions with energies from 15 to 35 keV was investigated in the helium ion microscope. Secondary electron yield measured with Everhart-Thornley detector decreased with the irradiation time because of the charging of insulating films tending to zero or reaching a non-zero value for relatively thick or thin films, respectively. The finiteness of secondary electron yield value, which was found to be proportional to electronic energy losses of the helium ion in silicon substrate, can be explained by the electron emission excited from the substrate by the helium ions. The method of measurement of secondary electron energy distribution from insulators was suggested, and secondary electron energy distribution from silicon nitride was obtained.

  15. Life prediction and mechanical reliability of NT551 silicon nitride

    Science.gov (United States)

    Andrews, Mark Jay

    The inert strength and fatigue performance of a diesel engine exhaust valve made from silicon nitride (Si3N4) ceramic were assessed. The Si3N4 characterized in this study was manufactured by Saint Gobain/Norton Industrial Ceramics and was designated as NT551. The evaluation was made utilizing a probabilistic life prediction algorithm that combined censored test specimen strength data with a Weibull distribution function and the stress field of the ceramic valve obtained from finite element analysis. The major assumptions of the life prediction algorithm are that the bulk ceramic material is isotropic and homogeneous and that the strength-limiting flaws are uniformly distributed. The results from mechanical testing indicated that NT551 was not a homogeneous ceramic and that its strength were functions of temperature, loading rate, and machining orientation. Fractographic analysis identified four different failure modes; 2 were identified as inhomogeneities that were located throughout the bulk of NT551 and were due to processing operations. The fractographic analysis concluded that the strength degradation of NT551 observed from the temperature and loading rate test parameters was due to a change of state that occurred in its secondary phase. Pristine and engine-tested valves made from NT551 were loaded to failure and the inert strengths were obtained. Fractographic analysis of the valves identified the same four failure mechanisms as found with the test specimens. The fatigue performance and the inert strength of the Si3N 4 valves were assessed from censored and uncensored test specimen strength data, respectively. The inert strength failure probability predictions were compared to the inert strength of the Si3N4 valves. The inert strength failure probability predictions were more conservative than the strength of the valves. The lack of correlation between predicted and actual valve strength was due to the nonuniform distribution of inhomogeneities present in NT

  16. TOPICAL REVIEW Textured silicon nitride: processing and anisotropic properties

    Directory of Open Access Journals (Sweden)

    Xinwen Zhu and Yoshio Sakka

    2008-01-01

    Full Text Available Textured silicon nitride (Si3N4 has been intensively studied over the past 15 years because of its use for achieving its superthermal and mechanical properties. In this review we present the fundamental aspects of the processing and anisotropic properties of textured Si3N4, with emphasis on the anisotropic and abnormal grain growth of β-Si3N4, texture structure and texture analysis, processing methods and anisotropic properties. On the basis of the texturing mechanisms, the processing methods described in this article have been classified into two types: hot-working (HW and templated grain growth (TGG. The HW method includes the hot-pressing, hot-forging and sinter-forging techniques, and the TGG method includes the cold-pressing, extrusion, tape-casting and strong magnetic field alignment techniques for β-Si3N4 seed crystals. Each processing technique is thoroughly discussed in terms of theoretical models and experimental data, including the texturing mechanisms and the factors affecting texture development. Also, methods of synthesizing the rodlike β-Si3N4 single crystals are presented. Various anisotropic properties of textured Si3 N4 and their origins are thoroughly described and discussed, such as hardness, elastic modulus, bending strength, fracture toughness, fracture energy, creep behavior, tribological and wear behavior, erosion behavior, contact damage behavior and thermal conductivity. Models are analyzed to determine the thermal anisotropy by considering the intrinsic thermal anisotropy, degree of orientation and various microstructure factors. Textured porous Si3N4 with a unique microstructure composed of oriented elongated β-Si3N4 and anisotropic pores is also described for the first time, with emphasis on its unique mechanical and thermal-mechanical properties. Moreover, as an important related material, textured α-Sialon is also reviewed, because the presence of elongated α-Sialon grains allows the production of textured

  17. Young's modulus and fracture toughness of silicon nitride ceramics at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rouxel, T. [Rennes Univ. (France). Lab. de Recherche en Mecanique Applicee

    2002-07-01

    The temperature dependencies of Young's modulus (E) and fracture toughness (K{sub 1c}) of several silicon nitride-based monolithic and composite materials, are reviewed. A transition range is observed between 1130 and 1180 C on the E(T) curves, which is systematically 150 to 200 C above the T{sub g} of oxynitride glasses of composition close to that of the intergranular glassy pockets. It is thus supposed that this transition reflects the behaviour of the interfacial glassy films. The higher the glassy phase content, the higher is the temperature sensitivity. The presence of SiC particles greatly attenuates the sensitivity. Thus, Young's modulus decreases more slowly with temperature and fracture toughness changes little up to 1300 C. The K{sub 1c} (T) curves exhibit four different stages which are discussed and interpreted on the basis of a theoretical model. (orig.)

  18. Low-loss compact multilayer silicon nitride platform for 3D photonic integrated circuits.

    Science.gov (United States)

    Shang, Kuanping; Pathak, Shibnath; Guan, Binbin; Liu, Guangyao; Yoo, S J B

    2015-08-10

    We design, fabricate, and demonstrate a silicon nitride (Si(3)N(4)) multilayer platform optimized for low-loss and compact multilayer photonic integrated circuits. The designed platform, with 200 nm thick waveguide core and 700 nm interlayer gap, is compatible for active thermal tuning and applicable to realizing compact photonic devices such as arrayed waveguide gratings (AWGs). We achieve ultra-low loss vertical couplers with 0.01 dB coupling loss, multilayer crossing loss of 0.167 dB at 90° crossing angle, 50 μm bending radius, 100 × 2 μm(2) footprint, lateral misalignment tolerance up to 400 nm, and less than -52 dB interlayer crosstalk at 1550 nm wavelength. Based on the designed platform, we demonstrate a 27 × 32 × 2 multilayer star coupler.

  19. Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials

    Science.gov (United States)

    Nikzad, Shouleh; Hoenk, Michael; Jewell, April D.; Hennessy, John J.; Carver, Alexander G.; Jones, Todd J.; Goodsall, Timothy M.; Hamden, Erika T.; Suvarna, Puneet; Bulmer, J.; Shahedipour-Sandvik, F.; Charbon, Edoardo; Padmanabhan, Preethi; Hancock, Bruce; Bell, L. Douglas

    2016-01-01

    Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100–300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness. PMID:27338399

  20. Nano-structure and tribological properties of B+ and Ti+ co-implanted silicon nitride

    International Nuclear Information System (INIS)

    Nakamura, Naoki; Noda, Katsutoshi; Yamauchi, Yukihiko

    2005-01-01

    Silicon nitride ceramics have been co-implanted with boron and titanium ions at a fluence of 2 x 10 17 ions/cm 2 and an energy of 200 keV. TEM results indicated that the boron and titanium-implanted layers were amorphized separately and titanium nitride nano-crystallites were formed in the titanium-implanted layer. XPS results indicated that the implantation profile varied a little depending on the ion implantation sequence of boron and titanium ions, with the boron implantation peak shifting to a shallower position when implanted after Ti + -implantation. Wear tests of these ion-implanted materials were carried out using a block-on-ring wear tester under non-lubricated conditions against commercially available silicon nitride materials. The specific wear rate was reduced by ion implantation and showed that the specific wear rate of Ti + -implanted sample was the lowest, followed by B + , Ti + co-implanted and B + -implanted samples

  1. Plasma-enhanced growth, composition, and refractive index of silicon oxy-nitride films

    DEFF Research Database (Denmark)

    Mattsson, Kent Erik

    1995-01-01

    Secondary ion mass spectrometry and refractive index measurements have been carried out on silicon oxy-nitride produced by plasma-enhanced chemical vapor deposition (PECVD). Nitrous oxide and ammonia were added to a constant flow of 2% silane in nitrogen, to produce oxy-nitride films with atomic...... nitrogen concentrations between 2 and 10 at. %. A simple atomic valence model is found to describe both the measured atomic concentrations and published material compositions for silicon oxy-nitride produced by PECVD. A relation between the Si–N bond concentration and the refractive index is found......-product. A model, that combine the chemical net reaction and the stoichiometric rules, is found to agree with measured deposition rates for given material compositions. Effects of annealing in a nitrogen atmosphere has been investigated for the 400 °C– 1100 °C temperature range. It is observed that PECVD oxy...

  2. Improved reaction sintered silicon nitride. [protective coatings to improve oxidation resistance

    Science.gov (United States)

    Baumgartner, H. R.

    1978-01-01

    Processing treatments were applied to as-nitrided reaction sintered silicon nitride (RSSN) with the purposes of improving strength after processing to above 350 MN/m2 and improving strength after oxidation exposure. The experimental approaches are divided into three broad classifications: sintering of surface-applied powders; impregnation of solution followed by further thermal processing; and infiltration of molten silicon and subsequent carburization or nitridation of the silicon. The impregnation of RSSN with solutions of aluminum nitrate and zirconyl chloride, followed by heating at 1400-1500 C in a nitrogen atmosphere containing silicon monoxide, improved RSSN strength and oxidation resistance. The room temperature bend strength of RSSN was increased nearly fifty percent above the untreated strength with mean absolute strengths up to 420 MN/m2. Strengths of treated samples that were measured after a 12 hour oxidation exposure in air were up to 90 percent of the original as-nitrided strength, as compared to retained strengths in the range of 35 to 60 percent for untreated RSSN after the same oxidation exposure.

  3. Size-dependent effective Young’s modulus of silicon nitride cantilevers

    NARCIS (Netherlands)

    Babaei Gavan, K.; Westra, H.J.R.; Van der Drift, E.W.J.M.; Venstra, W.J.; Van der Zant, H.S.J.

    2009-01-01

    The effective Young’s modulus of silicon nitride cantilevers is determined for thicknesses in the range of 20–684 nm by measuring resonance frequencies from thermal noise spectra. A significant deviation from the bulk value is observed for cantilevers thinner than 150 nm. To explain the observations

  4. On the intrinsic moisture permeation rate of remote microwave plasma-deposited silicon nitride layers

    NARCIS (Netherlands)

    van Assche, F. J. H.; Unnikrishnan, S.; Michels, J. J.; van Mol, A. M. B.; van de Weijer, P.; M. C. M. van de Sanden,; Creatore, M.

    2014-01-01

    We report on a low substrate temperature (110 °C) remote microwave plasma-enhanced chemical vapor deposition (PECVD) process of silicon nitride barrier layers against moisture permeation for organic light emitting diodes (OLEDs) and other moisture sensitive devices such as organic

  5. Damage progression in silicon nitride undergoing non-conforming hybrid cyclic contact

    Czech Academy of Sciences Publication Activity Database

    Raga, R.; Khader, I.; Chlup, Zdeněk; Kailer, A.

    2017-01-01

    Roč. 105, DEC (2017), s. 97-110 ISSN 0142-1123 EU Projects: European Commission(XE) 263476 - ROLICER Institutional support: RVO:68081723 Keywords : Silicon nitride * Cyclic contact fatigue * Surface and subsurface damage Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.899, year: 2016

  6. Evaluation and silicon nitride internal combustion engine components. Final report, Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Voldrich, W. [Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.

    1992-04-01

    The feasibility of silicon nitride (Si{sub 3}N{sub 4}) use in internal combustion engines was studied by testing three different components for wear resistance and lower reciprocating mass. The information obtained from these preliminary spin rig and engine tests indicates several design changes are necessary to survive high-stress engine applications. The three silicon nitride components tested were valve spring retainers, tappet rollers, and fuel pump push rod ends. Garrett Ceramic Components` gas-pressure sinterable Si{sub 3}N{sub 4} (GS-44) was used to fabricate the above components. Components were final machined from densified blanks that had been green formed by isostatic pressing of GS-44 granules. Spin rig testing of the valve spring retainers indicated that these Si{sub 3}N{sub 4} components could survive at high RPM levels (9,500) when teamed with silicon nitride valves and lower spring tension than standard titanium components. Silicon nitride tappet rollers showed no wear on roller O.D. or I.D. surfaces, steel axles and lifters; however, due to the uncrowned design of these particular rollers the cam lobes indicated wear after spin rig testing. Fuel pump push rod ends were successful at reducing wear on the cam lobe and rod end when tested on spin rigs and in real-world race applications.

  7. Covalent functionalization of silicon nitride surfaces for anti-biofouling and bioselective capture

    NARCIS (Netherlands)

    Nguyen, A.T.

    2011-01-01

    Microsieves – microengineered membranes – have been introduced in microfiltration technology as a new generation of inorganic membranes. The thin membranes are made of silicon nitride (SixN4), which gives the membranes outstanding features, such as chemical inertness and high mechanical

  8. Near-field optical microscope using a silicon-nitride probe

    NARCIS (Netherlands)

    van Hulst, N.F.; Moers, M.H.P.; Moers, M.H.P.; Noordman, O.F.J.; Noordman, O.F.J.; Tack, R.G.; Segerink, Franciscus B.; Bölger, B.; Bölger, B.

    1993-01-01

    Operation of an alternative near-field optical microscope is presented. The microscope uses a microfabricated silicon- nitride probe with integrated cantilever, as originally developed for force microscopy. The cantilever allows routine close contact near-field imaging o­n arbitrary surfaces without

  9. Processing development for ceramic structural components: the influence of a presintering of silicon on the final properties of reaction bonded silicon nitride. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-01

    The influence of a presintering of silicon on the final properties of reaction bonded silicon nitride has been studied using scanning electron and optical microscopy, x-ray diffraction analysis, 4 pt. bend test, and mecury intrusion porosimetry. It has been shown that presintering at 1050/sup 0/C will not affect the final nitrided properties. At 1200/sup 0/C, the oxide layer is removed, promoting the formation of B-phase silicon nitride. Presintering at 1200/sup 0/C also results in compact weight loss due to the volatilization of silicon, and the formation of large pores which severely reduce nitrided strength. The development of the structure of sintered silicon compacts appears to involve a temperature gradient, with greater sintering observed near the surface.

  10. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Science.gov (United States)

    Gajos, Katarzyna; Budkowski, Andrzej; Tsialla, Zoi; Petrou, Panagiota; Awsiuk, Kamil; Dąbczyński, Paweł; Bernasik, Andrzej; Rysz, Jakub; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios

    2017-07-01

    Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si3N4-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si3N4 surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency increases with the printing probe concentration.

  11. Light-induced enhancement of the minority carrier lifetime in boron-doped Czochralski silicon passivated by doped silicon nitride

    International Nuclear Information System (INIS)

    Wang, Hongzhe; Chen, Chao; Pan, Miao; Sun, Yiling; Yang, Xi

    2015-01-01

    Graphical abstract: - Highlights: • The phosphorus-doped SiN x with negative fixed charge was deposited by PECVD. • The increase of lifetime was observed on P-doped SiN x passivated Si under illumination. • The enhancement of lifetime was caused by the increase of negative fixed charges. - Abstract: This study reports a doubling of the effective minority carrier lifetime under light soaking conditions, observed in a boron-doped p-type Czochralski grown silicon wafer passivated by a phosphorus-doped silicon nitride thin film. The analysis of capacitance–voltage curves revealed that the fixed charge in this phosphorus-doped silicon nitride film was negative, which was unlike the well-known positive fixed charges observed in traditional undoped silicon nitride. The analysis results revealed that the enhancement phenomenon of minority carrier lifetime was caused by the abrupt increase in the density of negative fixed charge (from 7.2 × 10 11 to 1.2 × 10 12 cm −2 ) after light soaking.

  12. Fabrication of novel AFM probe with high-aspect-ratio ultra-sharp three-face silicon nitride tips

    NARCIS (Netherlands)

    Vermeer, Rolf; Berenschot, Johan W.; Sarajlic, Edin; Tas, Niels Roelof; Jansen, Henricus V.

    In this paper we present the wafer-scale fabrication of molded AFM probes with high aspect ratio ultra-sharp three-plane silicon nitride tips. Using $\\langle$111$\\rangle$ silicon wafers a dedicated process is developed to fabricate molds in the silicon wafer that have a flat triangular bottom

  13. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Energy Technology Data Exchange (ETDEWEB)

    Gajos, Katarzyna, E-mail: katarzyna.gajos@doctoral.uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Budkowski, Andrzej [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Tsialla, Zoi; Petrou, Panagiota [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Awsiuk, Kamil; Dąbczyński, Paweł [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Bernasik, Andrzej [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Rysz, Jakub [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Misiakos, Konstantinos; Raptis, Ioannis [Department of Microelectronics, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Kakabakos, Sotirios [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece)

    2017-07-15

    Highlights: • Contact pin-printing of overlapping probe spots and spotting by hand are compared. • Contact pin-printing favors probe immobilization with two-fold higher surface density. • Incomplete monolayer develops to bilayer as printing solution concentration increases. • Blocking molecules complete probe monolayer but reduce probe bilayer. • Surface immunoreaction increases with probe concentration in printing solution. - Abstract: Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si{sub 3}N{sub 4}-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si{sub 3}N{sub 4} surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency

  14. Growth of gallium nitride based devices on silicon(001) substrates by metalorganic vapor phase epitaxy; Wachstum von Galliumnitrid-basierten Bauelementen auf Silizium(001)-Substraten mittels metallorganischer Gasphasenepitaxie

    Energy Technology Data Exchange (ETDEWEB)

    Reiher, Fabian

    2009-02-25

    The main topic of this thesis is to investigate GaN-based layer systems grown by metalorganic vapor phase epitaxy on Si(001) substrates. A temperature shift up to 45 K is measured for a complete device structure on a 2-inch silicon substrate. By using a 40 nm thin LT-AlN-seed layer (680 C), the GaN crystallites on Si(001) substrates are almost oriented with their GaN(10 anti 12)-planes parallel to the Si(001)-plane. A four-fold azimuthal symmetry occurs for these layers, with the GaN[10 anti 11]-direction is aligned parallel to one of the four equivalent left angle 110 right angle -directions, respectively. However, a mono-crystalline and fully coalesced GaN-layer with this crystallographic orientation could not yet been obtained. If a deposition temperature of more than 1100 C is used for the AlN-seed layer, solely the GaN[0001]- growth direction of crystallites occurs in the main GaN layer on Si(001) substrates. These c-axis oriented GaN columns feature two opposite azimuthal alignments that are rotated by 90 with respect to each other and with GaN[11 anti 20] parallel Si[110] and GaN[10 anti 10] parallel Si[110], respectively. By using 4 off-oriented substrates towards the Si[110]-direction, one certain azimuthal texture component can be selected. The critical value of the miscut angle corresponds to theoretical calculations predicting the occurrence of atomic double steps on the Si(001) surface. The achieved crystallographic quality of the GaN layers on Si(001) is characterized by having a tilt of FWHM=0.27 and a twist of FWHM=0.8 of the crystallites, determined by X-ray diffraction. A completely crack-free, up to 2.5 {mu}m thick, and mono-crystalline GaN-template can be realized on Si(001), integrating 4 or 5 LT-AlN-interlayers in the GaN buffer structure. Based on this structure, the first successful implementation of an (InGaN/GaN)-LED on Si(001) is achieved. Furthermore, the possible fabrication of GaN-based FET-structures is demonstrated with a fully

  15. Gallium nitride heterostructures on 3D structured silicon.

    Science.gov (United States)

    Fündling, Sönke; Sökmen, Unsal; Peiner, Erwin; Weimann, Thomas; Hinze, Peter; Jahn, Uwe; Trampert, Achim; Riechert, Henning; Bakin, Andrey; Wehmann, Hergo-Heinrich; Waag, Andreas

    2008-10-08

    We investigated GaN-based heterostructures grown on three-dimensionally patterned Si(111) substrates by metal organic vapour phase epitaxy, with the goal of fabricating well controlled high quality, defect reduced GaN-based nanoLEDs. The high aspect ratios of such pillars minimize the influence of the lattice mismatched substrate and improve the material quality. In contrast to other approaches, we employed deep etched silicon substrates to achieve a controlled pillar growth. For that a special low temperature inductively coupled plasma etching process has been developed. InGaN/GaN multi-quantum-well structures have been incorporated into the pillars. We found a pronounced dependence of the morphology of the GaN structures on the size and pitch of the pillars. Spatially resolved optical properties of the structures are analysed by cathodoluminescence.

  16. Gallium nitride heterostructures on 3D structured silicon

    Energy Technology Data Exchange (ETDEWEB)

    Fuendling, Soenke; Soekmen, Uensal; Peiner, Erwin; Bakin, Andrey; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Weimann, Thomas; Hinze, Peter [Physikalisch Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Jahn, Uwe; Trampert, Achim; Riechert, Henning [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)], E-mail: s.fuendling@tu-bs.de

    2008-10-08

    We investigated GaN-based heterostructures grown on three-dimensionally patterned Si(111) substrates by metal organic vapour phase epitaxy, with the goal of fabricating well controlled high quality, defect reduced GaN-based nanoLEDs. The high aspect ratios of such pillars minimize the influence of the lattice mismatched substrate and improve the material quality. In contrast to other approaches, we employed deep etched silicon substrates to achieve a controlled pillar growth. For that a special low temperature inductively coupled plasma etching process has been developed. InGaN/GaN multi-quantum-well structures have been incorporated into the pillars. We found a pronounced dependence of the morphology of the GaN structures on the size and pitch of the pillars. Spatially resolved optical properties of the structures are analysed by cathodoluminescence.

  17. Rolling-element fatigue life of silicon nitride balls. [as compared to that of steel, ceramic, and cermet materials

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.

    1974-01-01

    The five-ball fatigue tester was used to evaluate silicon nitride as a rolling-element bearing material. Results indicate that hot-pressed silicon nitride running against steel may be expected to yield fatigue lives comparable to or greater than those of bearing quality steel running against steel at stress levels typical rolling-element bearing application. The fatigue life of hot-pressed silicon nitride is considerably greater than that of any ceramic or cermet tested. Computer analysis indicates that there is no improvement in the lives of 120-mm-bore angular--contact ball bearings of the same geometry operating at DN values from 2 to 4 million where hot-pressed silicon nitride balls are used in place of steel balls.

  18. Study of the main parameters involved in carbothermal reduction reaction of silica aiming to obtain silicon nitride powder

    International Nuclear Information System (INIS)

    Rocha, J.C. da; Greca, M.C.

    1989-01-01

    The influence of main parameters involved in the method of silicon nitride attainment by carbothermal reduction of silica followed by nitridation were studied in isothermal experiments of fine powder mixtures of silica and graphite in a nitrogen gas flow. The time, temperature, rate C/SiO 2 and flow of nitrogen were varied since they are the main parameters involved in this kind of reaction. The products of reaction were analysed by X-ray diffraction to identify the crystalline phases and as a result was obtained the nucleation of silicon nitride phase. Meanwhile, corroborating prior results, we verified to be difficult the progress of the reaction and the inhibition of formation of silicon carbide phase, the last one being associated to the formation of silicon nitride phase due to thermodynamic matters [pt

  19. Heterogeneous integration of lithium niobate and silicon nitride waveguides for wafer-scale photonic integrated circuits on silicon.

    Science.gov (United States)

    Chang, Lin; Pfeiffer, Martin H P; Volet, Nicolas; Zervas, Michael; Peters, Jon D; Manganelli, Costanza L; Stanton, Eric J; Li, Yifei; Kippenberg, Tobias J; Bowers, John E

    2017-02-15

    An ideal photonic integrated circuit for nonlinear photonic applications requires high optical nonlinearities and low loss. This work demonstrates a heterogeneous platform by bonding lithium niobate (LN) thin films onto a silicon nitride (Si3N4) waveguide layer on silicon. It not only provides large second- and third-order nonlinear coefficients, but also shows low propagation loss in both the Si3N4 and the LN-Si3N4 waveguides. The tapers enable low-loss-mode transitions between these two waveguides. This platform is essential for various on-chip applications, e.g., modulators, frequency conversions, and quantum communications.

  20. Structure analysis of aluminium silicon manganese nitride precipitates formed in grain-oriented electrical steels

    International Nuclear Information System (INIS)

    Bernier, Nicolas; Xhoffer, Chris; Van De Putte, Tom; Galceran, Montserrat; Godet, Stéphane

    2013-01-01

    We report a detailed structural and chemical characterisation of aluminium silicon manganese nitrides that act as grain growth inhibitors in industrially processed grain-oriented (GO) electrical steels. The compounds are characterised using energy dispersive X-ray spectrometry (EDX) and energy filtered transmission electron microscopy (EFTEM), while their crystal structures are analysed using X-ray diffraction (XRD) and TEM in electron diffraction (ED), dark-field, high-resolution and automated crystallographic orientation mapping (ACOM) modes. The chemical bonding character is determined using electron energy loss spectroscopy (EELS). Despite the wide variation in composition, all the precipitates exhibit a hexagonal close-packed (h.c.p.) crystal structure and lattice parameters of aluminium nitride. The EDX measurement of ∼ 900 stoichiometrically different precipitates indicates intermediate structures between pure aluminium nitride and pure silicon manganese nitride, with a constant Si/Mn atomic ratio of ∼ 4. It is demonstrated that aluminium and silicon are interchangeably precipitated with the same local arrangement, while both Mn 2+ and Mn 3+ are incorporated in the h.c.p. silicon nitride interstitial sites. The oxidation of the silicon manganese nitrides most likely originates from the incorporation of oxygen during the decarburisation annealing process, thus creating extended planar defects such as stacking faults and inversion domain boundaries. The chemical composition of the inhibitors may be written as (AlN) x (SiMn 0.25 N y O z ) 1−x with x ranging from 0 to 1. - Highlights: • We study the structure of (Al,Si,Mn)N inhibitors in grain oriented electrical steels. • Inhibitors have the hexagonal close-packed symmetry with lattice parameters of AlN. • Inhibitors are intermediate structures between pure AlN and (Si,Mn)N with Si/Mn ∼ 4. • Al and Si share the same local arrangement; Mn is incorporated in both Mn 2+ and Mn 3+ . • Oxygen

  1. Spin transport, magnetoresistance, and electrically detected magnetic resonance in amorphous hydrogenated silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Mutch, Michael J. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Lenahan, Patrick M. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States)

    2016-08-08

    We report on a study of spin transport via electrically detected magnetic resonance (EDMR) and near-zero field magnetoresistance (MR) in silicon nitride films. Silicon nitrides have long been important materials in solid state electronics. Although electronic transport in these materials is not well understood, electron paramagnetic resonance studies have identified a single dominating paramagnetic defect and have also provided physical and chemical descriptions of the defects, called K centers. Our EDMR and MR measurements clearly link the near-zero field MR response to the K centers and also indicate that K center energy levels are approximately 3.1 eV above the a-SiN:H valence band edge. In addition, our results suggest an approach for the study of defect mediated spin-transport in inorganic amorphous insulators via variable electric field and variable frequency EDMR and MR which may be widely applicable.

  2. Laser-assisted turning of components made of silicon-nitride ceramics

    International Nuclear Information System (INIS)

    Klocke, F.; Bausch, S.

    2001-01-01

    The manufacture of high-precision parts made of silicon-nitride ceramic, such as roller bearing rings or valves, currently involves finishing in the form of time and cost intensive grinding operations. This has resulted in demands for the development of more efficient machining techniques and for the subsequent provision of these within a manufacturing environment. A prototype of a precision lathe with an integrated high power diode laser for laser-assisted turning has been developed at the Fraunhofer IPT in close co-operation with industrial partners. When the workpiece is heated continuously by the laser, the resultant localized material softening enables the ceramic to be machined using a defined cutting edge. The application of this technique allows complex silicon nitride ceramic parts with surface qualities of up to R a = 0.3 μm to be produced considerably more flexibly than before, with no requirement for cooling lubricant. (author)

  3. Practical application of silicon nitride ceramics for sliding parts of rotary engine

    International Nuclear Information System (INIS)

    Ueki, M.; Sato, Y.; Fukuda, K.

    1994-01-01

    Research on ceramic substitutes for the apex seals of the rotary engine have been carrying out. The aim of the substitution of apex seals, the development of high strength silicon nitride ceramics, and the application of the ceramic to the apex seals are described. The properties of silicon nitride ceramics used as apex seals in rotary engines for racing cars are presented. The apex seals were recovered from the rotary engines of racing cars in the 1989 and 1990 Le Mans 24-hour Grand Prix races, and the damage of the seals was investigated and analyzed in detail. One problem was the adhesion to the seals of the hardened chromium plating detached from the inside surface of the rotor housing. The adhesion of chromium caused the fine cracking and subsequent chipping of the apex seals. (orig.)

  4. Application of Silicon Nitride (Si3N4 Ceramics in Ball Bearing

    Directory of Open Access Journals (Sweden)

    Wijianto Wijianto

    2016-08-01

    operation up to 1000°C, greater thermal shock resistance, lower density and low thermal expansion. This properties gives some benefit for ball bearing material such as higher running speed, reduce vibration of the shaft, will improve the life time and maintenance cost, lower heat generated, less energy consumption, lower wear rate, reducing noise level and reduce of using lubricant. The sintering methods are used to produce ball bearing from silicon nitride. Some techniques can be applied to increase ceramics strength which are reduce porosity, reduce grain size, reduce surface flaw and proof stressing. The surface finishing of the ceramic bearing is very important because silicon nitride as a brittle material, its strength is limited to the flaw sizes especially the flaw at the surface.

  5. Ultra-thin alumina and silicon nitride MEMS fabricated membranes for the electron multiplication

    Science.gov (United States)

    Prodanović, V.; Chan, H. W.; Graaf, H. V. D.; Sarro, P. M.

    2018-04-01

    In this paper we demonstrate the fabrication of large arrays of ultrathin freestanding membranes (tynodes) for application in a timed photon counter (TiPC), a novel photomultiplier for single electron detection. Low pressure chemical vapour deposited silicon nitride (Si x N y ) and atomic layer deposited alumina (Al2O3) with thicknesses down to only 5 nm are employed for the membrane fabrication. Detailed characterization of structural, mechanical and chemical properties of the utilized films is carried out for different process conditions and thicknesses. Furthermore, the performance of the tynodes is investigated in terms of secondary electron emission, a fundamental attribute that determines their applicability in TiPC. Studied features and presented fabrication methods may be of interest for other MEMS application of alumina and silicon nitride as well, in particular where strong ultra-thin membranes are required.

  6. Effects of plasma-deposited silicon nitride passivation on the radiation hardness of CMOS integrated circuits

    International Nuclear Information System (INIS)

    Clement, J.J.

    1980-01-01

    The use of plasma-deposited silicon nitride as a final passivation over metal-gate CMOS integrated circuits degrades the radiation hardness of these devices. The hardness degradation is manifested by increased radiation-induced threshold voltage shifts caused principally by the charging of new interface states and, to a lesser extent, by the trapping of holes created upon exposure to ionizing radiation. The threshold voltage shifts are a strong function of the deposition temperature, and show very little dependence on thickness for films deposited at 300 0 C. There is some correlation between the threshold voltage shifts and the hydrogen content of the PECVD silicon nitride films used as the final passivation layer as a function of deposition temperature. The mechanism by which the hydrogen contained in these films may react with the Si/SiO 2 interface is not clear at this point

  7. Microencapsulation of silicon nitride particles with yttria and yttria-alumina precursors

    International Nuclear Information System (INIS)

    Garg, A.K.; De Jonghe, L.C.

    1990-01-01

    Procedures are described to deposit uniform layers of yttria and yttria-alumina precursors on fine powders and whiskers of silicon nitride. The coatings were produced by aging at elevated temperatures aqueous systems containing the silicon nitride core particles, yttrium and aluminum nitrates, and urea. Optimum concentrations of the core particles, in relation to the reactants, were established to promote surface deposition of the oxide precursors. Polymeric dispersants were used effectively to prevent agglomeration of the solids during the microencapsulation process. The morphology of the powders was characterized using scanning and transmission electron microscopy. The mechanisms for the formation of the coated layers are discussed. A description is provided that allows qualitative assessment of the experimental factors that determine microencapsulation by a slurry method

  8. Synthesis and characterization of nano silicon and titanium nitride ...

    Indian Academy of Sciences (India)

    The characterization techniques indicated ... Scalable synthesis; microwave plasma; chemical synthesis; nanoparticles. 1. Introduction ... used but very few methods are available to produce silicon and titanium ... current (A). (m3/h). 1. Si. 2.1.

  9. Strength evaluation test of pressureless-sintered silicon nitride at room temperature

    Science.gov (United States)

    Matsusue, K.; Takahara, K.; Hashimoto, R.

    1984-01-01

    In order to study strength characteristics at room temperature and the strength evaluating method of ceramic materials, the following tests were conducted on pressureless sintered silicon nitride specimens: bending tests, the three tensile tests of rectangular plates, holed plates, and notched plates, and spin tests of centrally holed disks. The relationship between the mean strength of specimens and the effective volume of specimens are examined using Weibull's theory. The effect of surface grinding on the strength of specimens is discussed.

  10. The Effects of Thermal Cycling on Gallium Nitride and Silicon Carbide Semiconductor Devices for Aerospace Use

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad

    2012-01-01

    Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These Include radiation, extreme temperatures, thermal cycling, to name a few. Preliminary data obtained on new Gallium Nitride and Silicon Carbide power devices under exposure to radiation followed by long term thermal cycling are presented. This work was done in collaboration with GSFC and JPL in support of the NASA Electronic Parts and Packaging (NEPP) Program

  11. Effect of hot isostatic pressing on reaction-bonded silicon nitride

    Science.gov (United States)

    Watson, G. K.; Moore, T. J.; Millard, M. L.

    1984-01-01

    Specimens of nearly theoretical density have been obtained through the isostatic hot pressing of reaction-bonded silicon nitride under 138 MPa of pressure for two hours at 1850, 1950, and 2050 C. An amorphous phase that is introduced by the hot isostatic pressing partly accounts for the fact that while room temperature flexural strength more than doubles, the 1200 C flexural strength increases significantly only after pressing at 2050 C.

  12. Highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles

    Science.gov (United States)

    Huang, Yuewang; Zhao, Qiancheng; Sharac, Nicholas; Ragan, Regina; Boyraz, Ozdal

    2015-05-01

    We demonstrate the fabrication of a highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles for plasmonic enhancement. The average enhancement effect is evaluated by measuring the spectral broadening effect caused by self-phase-modulation. The nonlinear refractive index n2 was measured to be 7.0917×10-19 m2/W for a waveguide whose Wopen is 5 μm. Several waveguides at different locations on one wafer were measured in order to take the randomness of the nanoparticle distribution into consideration. The largest enhancement is measured to be as high as 10 times. Fabrication of this waveguide started with a MEMS grade photomask. By using conventional optical lithography, the wide linewidth was transferred to a wafer. Then the wafer was etched anisotropically by potassium hydroxide (KOH) to engrave trapezoidal trenches with an angle of 54.7º. Side wall roughness was mitigated by KOH etching and thermal oxidation that was used to generate a buffer layer for silicon nitride waveguide. The guiding material silicon nitride was then deposited by low pressure chemical vapor deposition. The waveguide was then patterned with a chemical template, with 20 nm gold particles being chemically attached to the functionalized poly(methyl methacrylate) domains. Since the particles attached only to the PMMA domains, they were confined to localized regions, therefore forcing the nanoparticles into clusters of various numbers and geometries. Experiments reveal that the waveguide has negligible nonlinear absorption loss, and its nonlinear refractive index can be greatly enhanced by gold nano clusters. The silicon nitride trench waveguide has large nonlinear refractive index, rendering itself promising for nonlinear applications.

  13. Rf-plasma synthesis of nanosize silicon carbide and nitride. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Buss, R.J.

    1997-02-01

    A pulsed rf plasma technique is capable of generating ceramic particles of 10 manometer dimension. Experiments using silane/ammonia and trimethylchlorosilane/hydrogen gas mixtures show that both silicon nitride and silicon carbide powders can be synthesized with control of the average particle diameter from 7 to 200 nm. Large size dispersion and much agglomeration appear characteristic of the method, in contrast to results reported by another research group. The as produced powders have a high hydrogen content and are air and moisture sensitive. Post-plasma treatment in a controlled atmosphere at elevated temperature (800{degrees}C) eliminates the hydrogen and stabilizes the powder with respect to oxidation or hydrolysis.

  14. Mechanics of silicon nitride thin-film stressors on a transistor-like geometry

    Directory of Open Access Journals (Sweden)

    S. Reboh

    2013-10-01

    Full Text Available To understand the behavior of silicon nitride capping etch stopping layer stressors in nanoscale microelectronics devices, a simplified structure mimicking typical transistor geometries was studied. Elastic strains in the silicon substrate were mapped using dark-field electron holography. The results were interpreted with the aid of finite element method modeling. We show, in a counterintuitive sense, that the stresses developed by the film in the vertical sections around the transistor gate can reach much higher values than the full sheet reference. This is an important insight for advanced technology nodes where the vertical contribution of such liners is predominant over the horizontal part.

  15. Fracture toughness of silicon nitride thin films of different thicknesses as measured by bulge tests

    International Nuclear Information System (INIS)

    Merle, B.; Goeken, M.

    2011-01-01

    A bulge test setup was used to determine the fracture toughness of amorphous low-pressure chemical vapor deposited (LPCVD) silicon nitride films with various thicknesses in the range 40-108 nm. A crack-like slit was milled in the center of each free-standing film with a focused ion beam, and the membrane was deformed in the bulge test until failure occurred. The fracture toughness K IC was calculated from the pre-crack length and the stress at failure. It is shown that the membrane is in a transition state between pure plane-stress and plane-strain which, however, had a negligible influence on the measurement of the fracture toughness, because of the high brittleness of silicon nitride and its low Young's modulus over yield strength ratio. The fracture toughness K IC was found to be constant at 6.3 ± 0.4 MPa m 1/2 over the whole thickness range studied, which compares well with bulk values. This means that the fracture toughness, like the Young's modulus, is a size-independent quantity for LPCVD silicon nitride. This presumably holds true for all amorphous brittle ceramic materials.

  16. Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

    KAUST Repository

    Yang, Xinbo

    2018-04-19

    Minimizing carrier recombination at contact regions by using carrier‐selective contact materials, instead of heavily doping the silicon, has attracted considerable attention for high‐efficiency, low‐cost crystalline silicon (c‐Si) solar cells. A novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties to the silicon surface, due to their small conduction band offset and large valence band offset. Thin TaNx interlayers provide moderate passivation of the silicon surfaces while simultaneously allowing a low contact resistivity to n‐type silicon. A power conversion efficiency (PCE) of over 20% is demonstrated with c‐Si solar cells featuring a simple full‐area electron‐selective TaNx contact, which significantly improves the fill factor and the open circuit voltage (Voc) and hence provides the higher PCE. The work opens up the possibility of using metal nitrides, instead of metal oxides, as carrier‐selective contacts or electron transport layers for photovoltaic devices.

  17. Formation of Mach angle profiles during wet etching of silica and silicon nitride materials

    Energy Technology Data Exchange (ETDEWEB)

    Ghulinyan, M., E-mail: ghulinyan@fbk.eu [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy); Bernard, M.; Bartali, R. [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy); Deptartment of Physics, University of Trento, I-38123 Povo (Italy); Pucker, G. [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy)

    2015-12-30

    Highlights: • Photoresist adhesion induces the formation of complex etch profiles in dielectrics. • Hydrofluoric acid etching of silica glass and silicon nitride materials was studied. • The phenomenon has been modeled in analogy with sonic boom propagation. • The material etch rate and resist adhesion/erosion define the final profile. - Abstract: In integrated circuit technology peeling of masking photoresist films is a major drawback during the long-timed wet etching of materials. It causes an undesired film underetching, which is often accompanied by a formation of complex etch profiles. Here we report on a detailed study of wedge-shaped profile formation in a series of silicon oxide, silicon oxynitride and silicon nitride materials during wet etching in a buffered hydrofluoric acid (BHF) solution. The shape of etched profiles reflects the time-dependent adhesion properties of the photoresist to a particular material and can be perfectly circular, purely linear or a combination of both, separated by a knee feature. Starting from a formal analogy between the sonic boom propagation and the wet underetching process, we model the wedge formation mechanism analytically. This model predicts the final form of the profile as a function of time and fits the experimental data perfectly. We discuss how this knowledge can be extended to the design and the realization of optical components such as highly efficient etch-less vertical tapers for passive silicon photonics.

  18. Nitriding behavior of Ni and Ni-based binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fonovic, Matej

    2015-01-15

    Gaseous nitriding is a prominent thermochemical surface treatment process which can improve various properties of metallic materials such as mechanical, tribological and/or corrosion properties. This process is predominantly performed by applying NH{sub 3}+H{sub 2} containing gas atmospheres serving as the nitrogen donating medium at temperatures between 673 K and 873 K (400 C and 600 C). NH{sub 3} decomposes at the surface of the metallic specimen and nitrogen diffuses into the surface adjacent region of the specimen whereas hydrogen remains in the gas atmosphere. One of the most important parameters characterizing a gaseous nitriding process is the so-called nitriding potential (r{sub N}) which determines the chemical potential of nitrogen provided by the gas phase. The nitriding potential is defined as r{sub N} = p{sub NH{sub 3}}/p{sub H{sub 2}{sup 3/2}} where p{sub NH{sub 3}} and p{sub H{sub 2}} are the partial pressures of the NH{sub 3} and H{sub 2} in the nitriding atmosphere. In contrast with nitriding of α-Fe where the nitriding potential is usually in the range between 0.01 and 1 atm{sup -1/2}, nitriding of Ni and Ni-based alloys requires employing nitriding potentials higher than 100 atm{sup -1/2} and even up to ∞ (nitriding in pure NH{sub 3} atmosphere). This behavior is compatible with decreased thermodynamic stability of the 3d-metal nitrides with increasing atomic number. Depending on the nitriding conditions (temperature, nitriding potential and treatment time), different phases are formed at the surface of the Ni-based alloys. By applying very high nitriding potential, formation of hexagonal Ni{sub 3}N at the surface of the specimen (known as external nitriding) leads to the development of a compound layer, which may improve tribological properties. Underneath the Ni{sub 3}N compound layer, two possibilities exist: (i) alloying element precipitation within the nitrided zone (known as internal nitriding) and/or (ii) development of metastable and

  19. Mid-infrared frequency comb via coherent dispersive wave generation in silicon nitride nanophotonic waveguides

    Science.gov (United States)

    Guo, Hairun; Herkommer, Clemens; Billat, Adrien; Grassani, Davide; Zhang, Chuankun; Pfeiffer, Martin H. P.; Weng, Wenle; Brès, Camille-Sophie; Kippenberg, Tobias J.

    2018-06-01

    Mid-infrared optical frequency combs are of significant interest for molecular spectroscopy due to the large absorption of molecular vibrational modes on the one hand, and the ability to implement superior comb-based spectroscopic modalities with increased speed, sensitivity and precision on the other hand. Here, we demonstrate a simple, yet effective, method for the direct generation of mid-infrared optical frequency combs in the region from 2.5 to 4.0 μm (that is, 2,500-4,000 cm-1), covering a large fraction of the functional group region, from a conventional and compact erbium-fibre-based femtosecond laser in the telecommunication band (that is, 1.55 μm). The wavelength conversion is based on dispersive wave generation within the supercontinuum process in an unprecedented large-cross-section silicon nitride (Si3N4) waveguide with the dispersion lithographically engineered. The long-wavelength dispersive wave can perform as a mid-infrared frequency comb, whose coherence is demonstrated via optical heterodyne measurements. Such an approach can be considered as an alternative option to mid-infrared frequency comb generation. Moreover, it has the potential to realize compact dual-comb spectrometers. The generated combs also have a fine teeth-spacing, making them suitable for gas-phase analysis.

  20. Deformation and wear of pyramidal, silicon-nitride AFM tips scanning micrometre-size features in contact mode

    NARCIS (Netherlands)

    Bloo, M.; Haitjema, H.; Pril, W.O.

    1999-01-01

    An experimental study was carried out, in order to investigate the deformation and wear taking place on pyramidal silicon-nitride AFM tips. The study focuses on the contact mode scanning of silicon features of micrometre-size. First the deformation and the mechanisms of wear of the tip during

  1. Damage-free laser patterning of silicon nitride on textured crystalline silicon using an amorphous silicon etch mask for Ni/Cu plated silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bailly, Mark S., E-mail: mbailly@asu.edu; Karas, Joseph; Jain, Harsh; Dauksher, William J.; Bowden, Stuart

    2016-08-01

    We investigate the optimization of laser ablation with a femtosecond laser for direct and indirect removal of SiN{sub x} on alkaline textured c-Si. Our proposed resist-free indirect removal process uses an a-Si:H etch mask and is demonstrated to have a drastically improved surface quality of the laser processed areas when compared to our direct removal process. Scanning electron microscope images of ablated sites show the existence of substantial surface defects for the standard direct removal process, and the reduction of those defects with our proposed process. Opening of SiN{sub x} and SiO{sub x} passivating layers with laser ablation is a promising alternative to the standard screen print and fire process for making contact to Si solar cells. The potential for small contacts from laser openings of dielectrics coupled with the selective deposition of metal from light induced plating allows for high-aspect-ratio metal contacts for front grid metallization. The minimization of defects generated in this process would serve to enhance the performance of the device and provides the motivation for our work. - Highlights: • Direct laser removal of silicon nitride (SiN{sub x}) damages textured silicon. • Direct laser removal of amorphous silicon (a-Si) does not damage textured silicon. • a-Si can be used as a laser patterned etch mask for SiN{sub x}. • Chemically patterned SiN{sub x} sites allow for Ni/Cu plating.

  2. High-Responsivity Graphene-Boron Nitride Photodetector and Autocorrelator in a Silicon Photonic Integrated Circuit.

    Science.gov (United States)

    Shiue, Ren-Jye; Gao, Yuanda; Wang, Yifei; Peng, Cheng; Robertson, Alexander D; Efetov, Dmitri K; Assefa, Solomon; Koppens, Frank H L; Hone, James; Englund, Dirk

    2015-11-11

    Graphene and other two-dimensional (2D) materials have emerged as promising materials for broadband and ultrafast photodetection and optical modulation. These optoelectronic capabilities can augment complementary metal-oxide-semiconductor (CMOS) devices for high-speed and low-power optical interconnects. Here, we demonstrate an on-chip ultrafast photodetector based on a two-dimensional heterostructure consisting of high-quality graphene encapsulated in hexagonal boron nitride. Coupled to the optical mode of a silicon waveguide, this 2D heterostructure-based photodetector exhibits a maximum responsivity of 0.36 A/W and high-speed operation with a 3 dB cutoff at 42 GHz. From photocurrent measurements as a function of the top-gate and source-drain voltages, we conclude that the photoresponse is consistent with hot electron mediated effects. At moderate peak powers above 50 mW, we observe a saturating photocurrent consistent with the mechanisms of electron-phonon supercollision cooling. This nonlinear photoresponse enables optical on-chip autocorrelation measurements with picosecond-scale timing resolution and exceptionally low peak powers.

  3. Effects of Interface Coating and Nitride Enhancing Additive on Properties of Hi-Nicalon SiC Fiber Reinforced Reaction-Bonded Silicon Nitride Composites

    Science.gov (United States)

    Bhatt, Ramakrishana T.; Hull, David R.; Eldridge, Jeffrey I.; Babuder, Raymond

    2000-01-01

    Strong and tough Hi-Nicalon SiC fiber reinforced reaction-bonded silicon nitride matrix composites (SiC/ RBSN) have been fabricated by the fiber lay-up approach. Commercially available uncoated and PBN, PBN/Si-rich PBN, and BN/SiC coated SiC Hi-Nicalon fiber tows were used as reinforcement. The composites contained approximately 24 vol % of aligned 14 micron diameter SiC fibers in a porous RBSN matrix. Both one- and two-dimensional composites were characterized. The effects of interface coating composition, and the nitridation enhancing additive, NiO, on the room temperature physical, tensile, and interfacial shear strength properties of SiC/RBSN matrix composites were evaluated. Results indicate that for all three coated fibers, the thickness of the coatings decreased from the outer periphery to the interior of the tows, and that from 10 to 30 percent of the fibers were not covered with the interface coating. In the uncoated regions, chemical reaction between the NiO additive and the SiC fiber occurs causing degradation of tensile properties of the composites. Among the three interface coating combinations investigated, the BN/SiC coated Hi-Nicalon SiC fiber reinforced RBSN matrix composite showed the least amount of uncoated regions and reasonably uniform interface coating thickness. The matrix cracking stress in SiC/RBSN composites was predicted using a fracture mechanics based crack bridging model.

  4. Joining and Integration of Silicon Nitride Ceramics for Aerospace and Energy Systems

    Science.gov (United States)

    Singh, M.; Asthana, R.

    2009-01-01

    Light-weight, creep-resistant silicon nitride ceramics possess excellent high-temperature strength and are projected to significantly raise engine efficiency and performance when used as turbine components in the next-generation turbo-shaft engines without the extensive cooling that is needed for metallic parts. One key aspect of Si3N4 utilization in such applications is its joining response to diverse materials. In an ongoing research program, the joining and integration of Si3N4 ceramics with metallic, ceramic, and composite materials using braze interlayers with the liquidus temperature in the range 750-1240C is being explored. In this paper, the self-joining behavior of Kyocera Si3N4 and St. Gobain Si3N4 using a ductile Cu-based active braze (Cu-ABA) containing Ti will be presented. Joint microstructure, composition, hardness, and strength as revealed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Knoop microhardness test, and offset compression shear test will be presented. Additionally, microstructure, composition, and joint strength of Si3N4/Inconel 625 joints made using Cu-ABA, will be presented. The results will be discussed with reference to the role of chemical reactions, wetting behavior, and residual stresses in joints.

  5. Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film.

    Science.gov (United States)

    Nishiyama, Hidetoshi; Suga, Mitsuo; Ogura, Toshihiko; Maruyama, Yuusuke; Koizumi, Mitsuru; Mio, Kazuhiro; Kitamura, Shinichi; Sato, Chikara

    2010-03-01

    Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry. (c) 2010 Elsevier Inc. All rights reserved.

  6. Structural impact on the eigenenergy renormalization for carbon and silicon allotropes and boron nitride polymorphs

    Science.gov (United States)

    Tutchton, Roxanne; Marchbanks, Christopher; Wu, Zhigang

    2018-05-01

    The phonon-induced renormalization of electronic band structures is investigated through first-principles calculations based on the density functional perturbation theory for nine materials with various crystal symmetries. Our results demonstrate that the magnitude of the zero-point renormalization (ZPR) of the electronic band structure is dependent on both crystal structure and material composition. We have performed analysis of the electron-phonon-coupling-induced renormalization for two silicon (Si) allotropes, three carbon (C) allotropes, and four boron nitride (BN) polymorphs. Phonon dispersions of each material were computed, and our analysis indicates that materials with optical phonons at higher maximum frequencies, such as graphite and hexagonal BN, have larger absolute ZPRs, with the exception of graphene, which has a considerably smaller ZPR despite having phonon frequencies in the same range as graphite. Depending on the structure and material, renormalizations can be comparable to the GW many-body corrections to Kohn-Sham eigenenergies and, thus, need to be considered in electronic structure calculations. The temperature dependence of the renormalizations is also considered, and in all materials, the eigenenergy renormalization at the band gap and around the Fermi level increases with increasing temperature.

  7. Characteristics of laser assisted machining for silicon nitride ceramic according to machining parameters

    International Nuclear Information System (INIS)

    Kim, Jong Do; Lee, Su Jin; Suh, Jeong

    2011-01-01

    This paper describes the Laser Assisted Machining (LAM) that cuts and removes softened parts by locally heating the ceramic with laser. Silicon nitride ceramics can be machined with general machining tools as well, because YSiAlON, which was made up ceramics, is soften at about 1,000 .deg. C. In particular, the laser, which concentrates on highly dense energy, can locally heat materials and very effectively control the temperature of the heated part of specimen. Therefore, this paper intends to propose an efficient machining method of ceramic by deducing the machining governing factors of laser assisted machining and understanding its mechanism. While laser power is the machining factor that controls the temperature, the CBN cutting tool could cut the material more easily as the material gets deteriorated from the temperature increase by increasing the laser power, but excessive oxidation can negatively affect the quality of the material surface after machining. As the feed rate and cutting depth increase, the cutting force increases and tool lifespan decreases, but surface oxidation also decreases. In this experiment, the material can be cut to 3 mm of cutting depth. And based on the results of the experiment, the laser assisted machining mechanism is clarified

  8. Silicon nitride gradient film as the underlayer of ultra-thin tetrahedral amorphous carbon overcoat for magnetic recording slider

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guigen, E-mail: wanggghit@yahoo.com [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055 (China); Kuang Xuping; Zhang Huayu; Zhu Can [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055 (China); Han Jiecai [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055 (China); Center for Composite Materials, Harbin Institute of Technology, Harbin 150080 (China); Zuo Hongbo [Center for Composite Materials, Harbin Institute of Technology, Harbin 150080 (China); Ma Hongtao [SAE Technologies Development (Dongguan) Co., Ltd., Dongguan 523087 (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The ultra-thin carbon films with different silicon nitride (Si-N) film underlayers were prepared. Black-Right-Pointing-Pointer It highlighted the influences of Si-N underlayers. Black-Right-Pointing-Pointer The carbon films with Si-N underlayers obtained by nitriding especially at the substrate bias of -150 V, can exhibit better corrosion protection properties - Abstract: There are higher technical requirements for protection overcoat of magnetic recording slider used in high-density storage fields for the future. In this study, silicon nitride (Si-N) composition-gradient films were firstly prepared by nitriding of silicon thin films pre-sputtered on silicon wafers and magnetic recording sliders, using microwave electron cyclotron resonance plasma source. The ultra-thin tetrahedral amorphous carbon films were then deposited on the Si-N films by filtered cathodic vacuum arc method. Compared with amorphous carbon overcoats with conventional silicon underlayers, the overcoats with Si-N underlayers obtained by plasma nitriding especially at the substrate bias of -150 V, can provide better corrosion protection for high-density magnetic recording sliders.

  9. Silicon nitride gradient film as the underlayer of ultra-thin tetrahedral amorphous carbon overcoat for magnetic recording slider

    International Nuclear Information System (INIS)

    Wang Guigen; Kuang Xuping; Zhang Huayu; Zhu Can; Han Jiecai; Zuo Hongbo; Ma Hongtao

    2011-01-01

    Highlights: ► The ultra-thin carbon films with different silicon nitride (Si-N) film underlayers were prepared. ► It highlighted the influences of Si-N underlayers. ► The carbon films with Si-N underlayers obtained by nitriding especially at the substrate bias of −150 V, can exhibit better corrosion protection properties - Abstract: There are higher technical requirements for protection overcoat of magnetic recording slider used in high-density storage fields for the future. In this study, silicon nitride (Si-N) composition-gradient films were firstly prepared by nitriding of silicon thin films pre-sputtered on silicon wafers and magnetic recording sliders, using microwave electron cyclotron resonance plasma source. The ultra-thin tetrahedral amorphous carbon films were then deposited on the Si-N films by filtered cathodic vacuum arc method. Compared with amorphous carbon overcoats with conventional silicon underlayers, the overcoats with Si-N underlayers obtained by plasma nitriding especially at the substrate bias of −150 V, can provide better corrosion protection for high-density magnetic recording sliders.

  10. Effect of additive gases and injection methods on chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F2 remote plasmas

    International Nuclear Information System (INIS)

    Yun, Y. B.; Park, S. M.; Kim, D. J.; Lee, N.-E.; Kim, K. S.; Bae, G. H.

    2007-01-01

    The authors investigated the effects of various additive gases and different injection methods on the chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F 2 remote plasmas. N 2 and N 2 +O 2 gases in the F 2 /Ar/N 2 and F 2 /Ar/N 2 /O 2 remote plasmas effectively increased the etch rate of the layers. The addition of direct-injected NO gas increased the etch rates most significantly. NO radicals generated by the addition of N 2 and N 2 +O 2 or direct-injected NO molecules contributed to the effective removal of nitrogen and oxygen in the silicon nitride and oxide layers, by forming N 2 O and NO 2 by-products, respectively, and thereby enhancing SiF 4 formation. As a result of the effective removal of the oxygen, nitrogen, and silicon atoms in the layers, the chemical dry etch rates were enhanced significantly. The process regime for the etch rate enhancement of the layers was extended at elevated temperature

  11. Formation of porous surface layers in reaction bonded silicon nitride during processing

    Science.gov (United States)

    Shaw, N. J.; Glasgow, T. K.

    1979-01-01

    Microstructural examination of reaction bonded silicon nitride (RBSN) has shown that there is often a region adjacent to the as-nitrided surfaces that is even more porous than the interior of this already quite porous material. Because this layer of large porosity is considered detrimental to both the strength and oxidation resistance of RBSN, a study was undertaken to determine if its formation could be prevented during processing. All test bars studied were made from a single batch of Si powder which was milled for 4 hours in heptane in a vibratory mill using high density alumina cylinders as the grinding media. After air drying the powder, bars were compacted in a single acting die and hydropressed.

  12. Study Trapped Charge Distribution in P-Channel Silicon-Oxide-Nitride-Oxide-Silicon Memory Device Using Dynamic Programming Scheme

    Science.gov (United States)

    Li, Fu-Hai; Chiu, Yung-Yueh; Lee, Yen-Hui; Chang, Ru-Wei; Yang, Bo-Jun; Sun, Wein-Town; Lee, Eric; Kuo, Chao-Wei; Shirota, Riichiro

    2013-04-01

    In this study, we precisely investigate the charge distribution in SiN layer by dynamic programming of channel hot hole induced hot electron injection (CHHIHE) in p-channel silicon-oxide-nitride-oxide-silicon (SONOS) memory device. In the dynamic programming scheme, gate voltage is increased as a staircase with fixed step amplitude, which can prohibits the injection of holes in SiN layer. Three-dimensional device simulation is calibrated and is compared with the measured programming characteristics. It is found, for the first time, that the hot electron injection point quickly traverses from drain to source side synchronizing to the expansion of charged area in SiN layer. As a result, the injected charges quickly spread over on the almost whole channel area uniformly during a short programming period, which will afford large tolerance against lateral trapped charge diffusion by baking.

  13. Direct comparison of the electrical properties in metal/oxide/nitride/oxide/silicon and metal/aluminum oxide/nitride/oxide/silicon capacitors with equivalent oxide thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    An, Ho-Myoung; Seo, Yu Jeong; Kim, Hee Dong; Kim, Kyoung Chan; Kim, Jong-Guk [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Cho, Won-Ju; Koh, Jung-Hyuk [Department of Electronic Materials Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Sung, Yun Mo [Department of Materials and Science Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Tae Geun, E-mail: tgkim1@korea.ac.k [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2009-07-31

    We examine the electrical properties of metal/oxide/nitride/oxide/silicon (MONOS) capacitors with two different blocking oxides, SiO{sub 2} and Al{sub 2}O{sub 3}, under the influence of the same electric field. The thickness of the Al{sub 2}O{sub 3} layer is set to 150 A, which is electrically equivalent to a thickness of the SiO{sub 2} layer of 65 A, in the MONOS structure for this purpose. The capacitor with the Al{sub 2}O{sub 3} blocking layer shows a larger capacitance-voltage memory window of 8.6 V, lower program voltage of 7 V, faster program/erase speeds of 10 ms/1 {mu}s, lower leakage current of 100 pA and longer data retention than the one with the SiO{sub 2} blocking layer does. These improvements are attributed to the suppression of the carrier transport to the gate electrode afforded by the use of an Al{sub 2}O{sub 3} blocking layer physically thicker than the SiO{sub 2} one, as well as the effective charge-trapping by Al{sub 2}O{sub 3} at the deep energy levels in the nitride layer.

  14. A deep-level transient spectroscopy study of gamma-ray irradiation on the passivation properties of silicon nitride layer on silicon

    Science.gov (United States)

    Dong, Peng; Yu, Xuegong; Ma, Yao; Xie, Meng; Li, Yun; Huang, Chunlai; Li, Mo; Dai, Gang; Zhang, Jian

    2017-08-01

    Plasma-enhanced chemical vapor deposited silicon nitride (SiNx) films are extensively used as passivation material in the solar cell industry. Such SiNx passivation layers are the most sensitive part to gamma-ray irradiation in solar cells. In this work, deep-level transient spectroscopy has been applied to analyse the influence of gamma-ray irradiation on the passivation properties of SiNx layer on silicon. It is shown that the effective carrier lifetime decreases with the irradiation dose. At the same time, the interface state density is significantly increased after irradiation, and its energy distribution is broadened and shifts deeper with respect to the conduction band edge, which makes the interface states becoming more efficient recombination centers for carriers. Besides, C-V characteristics show a progressive negative shift with increasing dose, indicating the generation of effective positive charges in SiNx films. Such positive charges are beneficial for shielding holes from the n-type silicon substrates, i. e. the field-effect passivation. However, based on the reduced carrier lifetime after irradiation, it can be inferred that the irradiation induced interface defects play a dominant role over the trapped positive charges, and therefore lead to the degradation of passivation properties of SiNx on silicon.

  15. Back scattering involving embedded silicon nitride (SiN) nanoparticles for c-Si solar cells

    Science.gov (United States)

    Ghosh, Hemanta; Mitra, Suchismita; Siddiqui, M. S.; Saxena, A. K.; Chaudhuri, Partha; Saha, Hiranmay; Banerjee, Chandan

    2018-04-01

    A novel material, structure and method of synthesis for dielectric light trapping have been presented in this paper. First, the light scattering behaviour of silicon nitride nanoparticles have been theoretically studied in order to find the optimized size for dielectric back scattering by FDTD simulations from Lumerical Inc. The optical results have been used in electrical analysis and thereby, estimate the effect of nanoparticles on efficiency of the solar cells depending on substrate thickness. Experimentally, silicon nitride (SiN) nanoparticles have been formed using hydrogen plasma treatment on SiN layer deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD). The size and area coverage of the nanoparticles were controlled by varying the working pressure, power density and treatment duration. The nanoparticles were integrated with partial rear contact c-Si solar cells as dielectric back reflector structures for the light trapping in thin silicon solar cells. Experimental results revealed the increases of current density by 2.7% in presence of SiN nanoparticles.

  16. Remote PECVD silicon nitride films with improved electrical properties for GaAs P-HEMT passivation

    CERN Document Server

    Sohn, M K; Kim, K H; Yang, S G; Seo, K S

    1998-01-01

    In order to obtain thin silicon nitride films with excellent electrical and mechanical properties, we employed RPECVD (Remote Plasma Enhanced Chemical Vapor Deposition) process which produces less plasma-induced damage than the conventional PECVD. Through the optical and electrical measurements of the deposited films, we optimized the various RPECVD process parameters. The optimized silicon nitride films showed excellent characteristics such as small etch rate (approx 33 A/min by 7:1 BHF), high breakdown field (>9 MV/cm), and low compressive stress (approx 3.3x10 sup 9 dyne/cm sup 2). We successfully applied thin RPECVD silicon nitride films to the surface passivation of GaAs pseudomorphic high electron mobility transistors (P-HEMTs) with negligible degradations in DC and RF characteristics.

  17. Strength and fatigue of NT551 silicon nitride and NT551 diesel exhaust valves

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M.J.; Werezczak, A.A.; Kirkland, T.P.; Breder, K.

    2000-02-01

    The content of this report is excerpted from Mark Andrew's Ph.D. Thesis (Andrews, 1999), which was funded by a DOE/OTT High Temperature Materials Laboratory Graduate Fellowship. It involves the characterization of NT551 and valves fabricated with it. The motivations behind using silicon nitride (Si{sub 3}N{sub 4}) as an exhaust valve for a diesel engine are presented in this section. There are several economic factors that have encouraged the design and implementation of ceramic components for internal combustion (IC) engines. The reasons for selecting the diesel engine valve for this are also presented.

  18. Polishing of silicon based advanced ceramics

    Science.gov (United States)

    Klocke, Fritz; Dambon, Olaf; Zunke, Richard; Waechter, D.

    2009-05-01

    Silicon based advanced ceramics show advantages in comparison to other materials due to their extreme hardness, wear and creep resistance, low density and low coefficient of thermal expansion. As a matter of course, machining requires high efforts. In order to reach demanded low roughness for optical or tribological applications a defect free surface is indispensable. In this paper, polishing of silicon nitride and silicon carbide is investigated. The objective is to elaborate scientific understanding of the process interactions. Based on this knowledge, the optimization of removal rate, surface quality and form accuracy can be realized. For this purpose, fundamental investigations of polishing silicon based ceramics are undertaken and evaluated. Former scientific publications discuss removal mechanisms and wear behavior, but the scientific insight is mainly based on investigations in grinding and lapping. The removal mechanisms in polishing are not fully understood due to complexity of interactions. The role of, e.g., process parameters, slurry and abrasives, and their influence on the output parameters is still uncertain. Extensive technological investigations demonstrate the influence of the polishing system and the machining parameters on the stability and the reproducibility. It is shown that the interactions between the advanced ceramics and the polishing systems is of great relevance. Depending on the kind of slurry and polishing agent the material removal mechanisms differ. The observed effects can be explained by dominating mechanical or chemo-mechanical removal mechanisms. Therefore, hypotheses to state adequate explanations are presented and validated by advanced metrology devices, such as SEM, AFM and TEM.

  19. The influence of processing conditions on the microstructure and the mechanical properties of reaction sintered silicon nitride

    International Nuclear Information System (INIS)

    Heinrich, J.

    1979-09-01

    The microstructure of reaction sintered silicon nitride (RBSN) was changed in a wide range of varying green density, grain size of the silicon starting powder, nitriding conditions, and by introducing artificial pores. The influence of single microstructural parameters on mechanical properties like room temperature strength, creep behaviour, and resistance to thermal shock has been investigated. The essential factors influencing these properties were found to be total porosity, pore size distribution, and the fractions of α- and β-Si 3 N 4 . In view of high temperature engineering applications of RBSN possibilities to optimize the material's properties by controlled processing are discussed. (orig.) [de

  20. A SRF niobium cylindrical cavity with a large silicon nitride niobium-coated membrane as one end-wall

    Science.gov (United States)

    Martinez, Luis; Castelli, Alessandro; Pate, Jacob; Thompson, Johnathon; Delmas, William; Sharping, Jay; Chiao, Raymond; Chiao Team; Sharping Team

    The development of large silicon nitride membranes and niobium film deposition techniques motivate new architectures in opto-mechanics and microwave devices that can exploit the extremely high Q's obtainable with superconducting radio frequency (SRF) niobium cavities. We present a X-band SRF cylindrical cavity-membrane system in which one end-wall of the cavity is replaced by a niobium coated centimeter-sized silicon nitride membrane. We report moderately high Q factors above 10 million. Experimental results characterizing the system and potential future applications for such schemes in microwave devices and optomechanics are discussed.

  1. Sub-micron silicon nitride waveguide fabrication using conventional optical lithography.

    Science.gov (United States)

    Huang, Yuewang; Zhao, Qiancheng; Kamyab, Lobna; Rostami, Ali; Capolino, Filippo; Boyraz, Ozdal

    2015-03-09

    We demonstrate a novel technique to fabricate sub-micron silicon nitride waveguides using conventional contact lithography with MEMS-grade photomasks. Potassium hydroxide anisotropic etching of silicon facilitates line reduction and roughness smoothing and is key to the technique. The fabricated waveguides is measured to have a propagation loss of 0.8dB/cm and nonlinear coefficient of γ = 0.3/W/m. A low anomalous dispersion of <100ps/nm/km is also predicted. This type of waveguide is highly suitable for nonlinear optics. The channels naturally formed on top of the waveguide also make it promising for plasmonics and quantum efficiency enhancement in sensing applications.

  2. Deposition of silicon oxynitride films by low energy ion beam assisted nitridation at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Youroukov, S; Kitova, S; Danev, G [Central Laboratory of Photoprocesses, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 109, 113 Sofia (Bulgaria)], E-mail: skitova@clf.bas.bg

    2008-05-01

    The possibility is studied of growing thin silicon oxynitride films by e-gun evaporation of SiO and SiO{sub 2} together with concurrent bombardment with low energy N{sub 2}{sup +} ions from a cyclotron resonance (ECR) source at room temperature of substrates. The degree of nitridation and oxidation of the films is investigated by means of X-ray spectroscopy. The optical characteristics of the films, their environmental stability and adhesion to different substrates are examined. The results obtained show than the films deposited are transparent. It is found that in the case of SiO evaporation with concurrent N{sub 2}{sup +} ion bombardment, reactive implantation of nitrogen within the films takes place at room temperature of the substrate with the formation of a new silicon oxynitride compound even at low ion energy (150-200 eV)

  3. Deposition of silicon oxynitride films by low energy ion beam assisted nitridation at room temperature

    Science.gov (United States)

    Youroukov, S.; Kitova, S.; Danev, G.

    2008-05-01

    The possibility is studied of growing thin silicon oxynitride films by e-gun evaporation of SiO and SiO2 together with concurrent bombardment with low energy N2+ ions from a cyclotron resonance (ECR) source at room temperature of substrates. The degree of nitridation and oxidation of the films is investigated by means of X-ray spectroscopy. The optical characteristics of the films, their environmental stability and adhesion to different substrates are examined. The results obtained show than the films deposited are transparent. It is found that in the case of SiO evaporation with concurrent N2+ ion bombardment, reactive implantation of nitrogen within the films takes place at room temperature of the substrate with the formation of a new silicon oxynitride compound even at low ion energy (150-200 eV).

  4. Determination of impurities in silicon nitride by particle induced x-ray emission analysis

    International Nuclear Information System (INIS)

    Miyagawa, Yoshiko; Saito, Kazuo; Niwa, Hiroaki; Ishizuka, Toshio; Miyagawa, Soji

    1985-01-01

    A method is presented for quantitative particle induced X-ray emission (PIXE) analysis of impurities in the thick samples of silicon nitride. In the analysis of ceramic materials such as silicon nitride, chemical treatments are required to prepare thin enough samples. However, the chemical treatments are undesirable for the PIXE analysis, because another complications are brought about. Our method does not need any chemical treatments and thick samples can be subjected to the measurements. The determination of impurities were made by on-line use of a personal computer in which standard X-ray intensity data were stored. The method and procedures are as follows: After subtracting a buckground spectrum from an observed PIXE spectrum, the resultant peaks are assigned to individual elements. Then, in order to determine the contents of the impurities, the intensity of each peak is compared with a Gaussian curve which is generated from the standard X-ray intensity data. The latter data were determined theoretically. The results were in satisfactory agreement with those obtained by ICP emission spectrometry. (author)

  5. Effect of Silicon Nitride Balls and Rollers on Rolling Bearing Life

    Science.gov (United States)

    Zaretsky, Erwin V.; Vlcek, Brian L.; Hendricks, Robert C.

    2005-01-01

    Three decades have passed since the introduction of silicon nitride rollers and balls into conventional rolling-element bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel bearings. Life factors were determined and reported for hybrid bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and cylindrical roller hybrid bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid bearings are predicted to have a lower fatigue life than all-steel bearings by 58 percent for deep-groove bearings, 41 percent for angular-contact bearings, and 28 percent for cylindrical roller bearings.

  6. Effect of Projectile Materials on Foreign Object Damage of a Gas-Turbine Grade Silicon Nitride

    Science.gov (United States)

    Choi, Sung R.; Racz, Zsolt; Bhatt, Ramakrishna T.; Brewer, David N.; Gyekenyesi, John P.

    2005-01-01

    Foreign object damage (FOD) behavior of AS800 silicon nitride was determined using four different projectile materials at ambient temperature. The target test specimens rigidly supported were impacted at their centers by spherical projectiles with a diameter of 1.59 mm. Four different types of projectiles were used including hardened steel balls, annealed steel balls, silicon nitride balls, and brass balls. Post-impact strength of each target specimen impacted was determined as a function of impact velocity to better understand the severity of local impact damage. The critical impact velocity where target specimens fail upon impact was highest with brass balls, lowest with ceramic ball, and intermediate with annealed and hardened steel balls. Degree of strength degradation upon impact followed the same order as in the critical impact velocity with respect to projectile materials. For steel balls, hardened projectiles yielded more significant impact damage than annealed counterparts. The most important material parameter affecting FOD was identified as hardness of projectiles and was correlated in terms of critical impact velocity, impact deformation, and impact load.

  7. Phosphorus-doped Amorphous Silicon Nitride Films Applied to Crystalline Silicon Solar Cells

    NARCIS (Netherlands)

    Feinäugle, Matthias

    2008-01-01

    The Photovoltaics Group at the Universitat Politècnica de Catalunya is investigating silicon carbide (SiC) for the electronic passivation of the surface of crystalline silicon solar cells. The doping of SiC passivation layers with phosphorus resulted in a clear improvement of the minority carrier

  8. The synthesis of a high quality, low cost silicon nitride powder by the carbothermal reduction of silica

    International Nuclear Information System (INIS)

    Cochran, G.A.; Conner, C.L.; Eisman, G.A.; Weimer, A.W.; Carroll, D.F.; Dunmead, S.D.; Hwang, C.J.

    1994-01-01

    The development and emergence of silicon nitride in the marketplace depends on the availability of a high quality, low cost powder which meets or exceeds the requirements for the customer's part application. The Dow Chemical Company, funded by the United States Department of Energy Oak Ridge National Laboratory, is engaged in developing a process which will economically synthesize commercial quantities of such a high quality powder. The Dow Chemical Company's approach is based on the carbothermal reduction of silica and has been shown to produce a sub-micron, equi-axed powder with high alpha content (> 95%), low oxygen (< 2%), and minimal carbon and impurities. This paper will review The Dow Chemical Company program and present preliminary results of the synthesis and powder processing efforts. (orig.)

  9. Low temperature gaseous nitriding of Ni based superalloys

    DEFF Research Database (Denmark)

    Eliasen, K. M.; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2010-01-01

    In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr......In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr...

  10. Graphitic carbon nitride based nanocomposites: a review

    Science.gov (United States)

    Zhao, Zaiwang; Sun, Yanjuan; Dong, Fan

    2014-11-01

    Graphitic carbon nitride (g-C3N4), as an intriguing earth-abundant visible light photocatalyst, possesses a unique two-dimensional structure, excellent chemical stability and tunable electronic structure. Pure g-C3N4 suffers from rapid recombination of photo-generated electron-hole pairs resulting in low photocatalytic activity. Because of the unique electronic structure, the g-C3N4 could act as an eminent candidate for coupling with various functional materials to enhance the performance. According to the discrepancies in the photocatalytic mechanism and process, six primary systems of g-C3N4-based nanocomposites can be classified and summarized: namely, the g-C3N4 based metal-free heterojunction, the g-C3N4/single metal oxide (metal sulfide) heterojunction, g-C3N4/composite oxide, the g-C3N4/halide heterojunction, g-C3N4/noble metal heterostructures, and the g-C3N4 based complex system. Apart from the depiction of the fabrication methods, heterojunction structure and multifunctional application of the g-C3N4-based nanocomposites, we emphasize and elaborate on the underlying mechanisms in the photocatalytic activity enhancement of g-C3N4-based nanocomposites. The unique functions of the p-n junction (semiconductor/semiconductor heterostructures), the Schottky junction (metal/semiconductor heterostructures), the surface plasmon resonance (SPR) effect, photosensitization, superconductivity, etc. are utilized in the photocatalytic processes. Furthermore, the enhanced performance of g-C3N4-based nanocomposites has been widely employed in environmental and energetic applications such as photocatalytic degradation of pollutants, photocatalytic hydrogen generation, carbon dioxide reduction, disinfection, and supercapacitors. This critical review ends with a summary and some perspectives on the challenges and new directions in exploring g-C3N4-based advanced nanomaterials.

  11. Surface wet-ability modification of thin PECVD silicon nitride layers by 40 keV argon ion treatments

    Science.gov (United States)

    Caridi, F.; Picciotto, A.; Vanzetti, L.; Iacob, E.; Scolaro, C.

    2015-10-01

    Measurements of wet-ability of liquid drops have been performed on a 30 nm silicon nitride (Si3N4) film deposited by a PECVD reactor on a silicon wafer and implanted by 40 keV argon ions at different doses. Surface treatments by using Ar ion beams have been employed to modify the wet-ability. The chemical composition of the first Si3N4 monolayer was investigated by means of X-ray Photoelectron Spectroscopy (XPS). The surface morphology was tested by Atomic Force Microscopy (AFM). Results put in evidence the best implantation conditions for silicon nitride to increase or to reduce the wet-ability of the biological liquid. This permits to improve the biocompatibility and functionality of Si3N4. In particular experimental results show that argon ion bombardment increases the contact angle, enhances the oxygen content and increases the surface roughness.

  12. High performance SONOS flash memory with in-situ silicon nanocrystals embedded in silicon nitride charge trapping layer

    Science.gov (United States)

    Lim, Jae-Gab; Yang, Seung-Dong; Yun, Ho-Jin; Jung, Jun-Kyo; Park, Jung-Hyun; Lim, Chan; Cho, Gyu-seok; Park, Seong-gye; Huh, Chul; Lee, Hi-Deok; Lee, Ga-Won

    2018-02-01

    In this paper, SONOS-type flash memory device with highly improved charge-trapping efficiency is suggested by using silicon nanocrystals (Si-NCs) embedded in silicon nitride (SiNX) charge trapping layer. The Si-NCs were in-situ grown by PECVD without additional post annealing process. The fabricated device shows high program/erase speed and retention property which is suitable for multi-level cell (MLC) application. Excellent performance and reliability for MLC are demonstrated with large memory window of ∼8.5 V and superior retention characteristics of 7% charge loss for 10 years. High resolution transmission electron microscopy image confirms the Si-NC formation and the size is around 1-2 nm which can be verified again in X-ray photoelectron spectroscopy (XPS) where pure Si bonds increase. Besides, XPS analysis implies that more nitrogen atoms make stable bonds at the regular lattice point. Photoluminescence spectra results also illustrate that Si-NCs formation in SiNx is an effective method to form deep trap states.

  13. Silicon-based sleeve devices for chemical reactions

    Science.gov (United States)

    Northrup, M. Allen; Mariella, Jr., Raymond P.; Carrano, Anthony V.; Balch, Joseph W.

    1996-01-01

    A silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

  14. Analysis of the properties of silicon nitride based ceramic (Si{sub 3}N{sub 4}) cutting tool using different addictive; Analise das propriedades de ferramenta de corte ceramicas de nitreto de silicio (Si{sub 3}N{sub 4}) usando diferentes aditivos

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Joaquim Lopes; Souza, Jose Vitor Candido de; Raymundo, Emerson Augusto [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Silva, Oliverio Macedo Moreira [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil)

    2013-06-15

    The constant search for new materials is part of the scientific and technological development of the industries. Ceramic been presenting important developments in terms of scientific and technological development, highlighting the predominance of covalent ceramics, which has important applications where abrasion resistance and hardness are required. Between covalent materials, several research papers in search of property improvements and cost reduction. However the production of ceramics of silicon nitride (Si{sub 3}N{sub 4}) with a reduced cost is possible only if used methods and different additives. The aim of this work is the development of compositions based on silicon nitride (Si{sub 3}N{sub 4}) using different additives such as Y{sub 2}O{sub 3}, CeO{sub 2}, Al{sub 2}O{sub 3} , and CTR{sub 2}O{sub 3} in varying amounts. For the development of ceramics, the mixtures were homogenized, dried, compacted and sintered using the sintering process of 1850°C for 1 hour, with a heating rate of 25°C/min. The characterizations were performed as a function of relative density by Archimedes method, the mass loss measured before and after sintering, phase analysis by X-ray diffraction, microstructure by scanning electron microscopy (SEM), and hardness and fracture toughness indentation method. The results showed relative density 97-98, Vickers hardness 17-19 GPa, fracture toughness from 5.6 to 6.8 MPa.m{sup 1/2}. The different phases were obtained depending on the types of additives used. The obtained results are promising for tribological applications. (author)

  15. Steel bonded dense silicon nitride compositions and method for their fabrication

    Science.gov (United States)

    Landingham, Richard L.; Shell, Thomas E.

    1987-01-01

    A two-stage bonding technique for bonding high density silicon nitride and other ceramic materials to stainless steel and other hard metals, and multilayered ceramic-metal composites prepared by the technique are disclosed. The technique involves initially slurry coating a surface of the ceramic material at about 1500.degree. C. in a vacuum with a refractory material and the stainless steel is then pressure bonded to the metallic coated surface by brazing it with nickel-copper-silver or nickel-copper-manganese alloys at a temperature in the range of about 850.degree. to 950.degree. C. in a vacuum. The two-stage bonding technique minimizes the temperature-expansion mismatch between the dissimilar materials.

  16. Observation of ultraslow stress release in silicon nitride films on CaF2

    International Nuclear Information System (INIS)

    Guo, Tianyi; Deen, M. Jamal; Xu, Changqing; Fang, Qiyin; Selvaganapathy, P. Ravi; Zhang, Haiying

    2015-01-01

    Silicon nitride thin films are deposited by plasma-enhanced chemical vapor deposition on (100) and (111) CaF 2 crystalline substrates. Delaminated wavy buckles formed during the release of internal compressive stress in the films and the stress releasing processes are observed macroscopically and microscopically. The stress release patterns start from the substrate edges and propagate to the center along defined directions aligned with the crystallographic orientations of the substrate. The stress releasing velocity of SiN x film on (111) CaF 2 is larger than that of SiN x film with the same thickness on (100) CaF 2 . The velocities of SiN x film on both (100) and (111) CaF 2 increase with the film thickness. The stress releasing process is initiated when the films are exposed to atmosphere, but it is not a chemical change from x-ray photoelectron spectroscopy

  17. MgB2 thin films on silicon nitride substrates prepared by an in situ method

    International Nuclear Information System (INIS)

    Monticone, Eugenio; Gandini, Claudio; Portesi, Chiara; Rajteri, Mauro; Bodoardo, Silvia; Penazzi, Nerino; Dellarocca, Valeria; Gonnelli, Renato S

    2004-01-01

    Large-area MgB 2 thin films were deposited on silicon nitride and sapphire substrates by co-deposition of Mg and B. After a post-annealing in Ar atmosphere at temperatures between 773 and 1173 K depending on the substrate, the films showed a critical temperature higher than 35 K with a transition width less than 0.5 K. The x-ray diffraction pattern suggested a c-axis preferential orientation in films deposited on amorphous substrate. The smooth surface and the good structural properties of these MgB 2 films allowed their reproducible patterning by a standard photolithographic process down to dimensions of the order of 10 μm and without a considerable degradation of the superconducting properties

  18. Observation of ultraslow stress release in silicon nitride films on CaF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Tianyi [School of Biomedical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1, Canada and Institute of Microelectronics, Chinese Academy of Science, Beijing 100029 (China); Deen, M. Jamal, E-mail: jamal@mcmaster.ca [Department of Electrical and Computer Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1, Canada and School of Biomedical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1 (Canada); Xu, Changqing; Fang, Qiyin [Department of Engineering Physics, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4L7 (Canada); Selvaganapathy, P. Ravi [Department of Mechanical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4L7 (Canada); Zhang, Haiying [Institute of Microelectronics, Chinese Academy of Science, Beijing 100029 (China)

    2015-07-15

    Silicon nitride thin films are deposited by plasma-enhanced chemical vapor deposition on (100) and (111) CaF{sub 2} crystalline substrates. Delaminated wavy buckles formed during the release of internal compressive stress in the films and the stress releasing processes are observed macroscopically and microscopically. The stress release patterns start from the substrate edges and propagate to the center along defined directions aligned with the crystallographic orientations of the substrate. The stress releasing velocity of SiN{sub x} film on (111) CaF{sub 2} is larger than that of SiN{sub x} film with the same thickness on (100) CaF{sub 2}. The velocities of SiN{sub x} film on both (100) and (111) CaF{sub 2} increase with the film thickness. The stress releasing process is initiated when the films are exposed to atmosphere, but it is not a chemical change from x-ray photoelectron spectroscopy.

  19. Dependence of wet etch rate on deposition, annealing conditions and etchants for PECVD silicon nitride film

    International Nuclear Information System (INIS)

    Tang Longjuan; Zhu Yinfang; Yang Jinling; Li Yan; Zhou Wei; Xie Jing; Liu Yunfei; Yang Fuhua

    2009-01-01

    The influence of deposition, annealing conditions, and etchants on the wet etch rate of plasma enhanced chemical vapor deposition (PECVD) silicon nitride thin film is studied. The deposition source gas flow rate and annealing temperature were varied to decrease the etch rate of SiN x :H by HF solution. A low etch rate was achieved by increasing the SiH 4 gas flow rate or annealing temperature, or decreasing the NH 3 and N2 gas flow rate. Concentrated, buffered, and dilute hydrofluoric acid were utilized as etchants for SiO 2 and SiN x :H. A high etching selectivity of SiO 2 over SiN x :H was obtained using highly concentrated buffered HF.

  20. Characterization of the porosity of silicon nitride thin layers by Electrochemical Impedance Spectroscopy

    International Nuclear Information System (INIS)

    Barrès, T.; Tribollet, B.; Stephan, O.; Montigaud, H.; Boinet, M.; Cohin, Y.

    2017-01-01

    Silicon nitride thin films are widely used as diffusion barriers within stacks in the glass industry but turn out to be porous at the nanometric scale. EIS measurements were conducted on SiNx thin layers deposited on a gold layer. An electrochemical model was established to fit the EIS measurements making use of data from other complementary techniques. In particular, Transmission Electron Microscopy was performed on these thin layers to determine the diameter and the qualitative morphology of the pores. A quantitative determination of the through-porosity of the layer was deduced from the EIS model and was in good agreement with TEM measurements. Moreover, combining EIS with local observations enabled inhomogeneities in the layer to be probed by highlighting a specific region in the layer.

  1. Effect of loading rate on dynamic fracture of reaction bonded silicon nitride

    Science.gov (United States)

    Liaw, B. M.; Kobayashi, A. S.; Emery, A. F.

    1986-01-01

    Wedge-loaded, modified tapered double cantilever beam (WL-MTDCB) specimens under impact loading were used to determine the room temperature dynamic fracture response of reaction bonded silicon nitride (RBSN). The crack extension history, with the exception of the terminal phase, was similar to that obtained under static loading. Like its static counterpart, a distinct crack acceleration phase, which was not observed in dynamic fracture of steel and brittle polymers, was noted. Unlike its static counterpart, the crack continued to propagate at nearly its terminal velocity under a low dynamic stress intensity factor during the terminal phase of crack propagation. These and previously obtained results for glass and RBSN show that dynamic crack arrest under a positive dynamic stress intensity factor is unlikely in static and impact loaded structural ceramics.

  2. Pressure bonding molybdenum alloy (TZM) to reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Huffsmith, S.A.; Landingham, R.L.

    1978-01-01

    Topping cycles could boost the energy efficiencies of a variety of systems by using what is now waste heat. One such topping cycle uses a ceramic helical expander and would require that a reaction-bonded silicon nitride (RBSN) rotor be bonded to a shaft of TZM (Mo-0.5 wt % Ti-0.08 wt % Zr). Coupon studies show that TZM can be bonded to RBSN at 1300 0 C and 69 MPa if there is an interlayer of MoSi 2 . A layer of finely ground (10 μm) MoSi 2 facilitates bond formation and provides a thicker bond interface. The hardness and grain structure of the TZM and RBSN were not affected by the temperature and pressure required to bond the coupons

  3. Deuterated silicon nitride photonic devices for broadband optical frequency comb generation

    Science.gov (United States)

    Chiles, Jeff; Nader, Nima; Hickstein, Daniel D.; Yu, Su Peng; Briles, Travis Crain; Carlson, David; Jung, Hojoong; Shainline, Jeffrey M.; Diddams, Scott; Papp, Scott B.; Nam, Sae Woo; Mirin, Richard P.

    2018-04-01

    We report and characterize low-temperature, plasma-deposited deuterated silicon nitride thin films for nonlinear integrated photonics. With a peak processing temperature less than 300$^\\circ$C, it is back-end compatible with pre-processed CMOS substrates. We achieve microresonators with a quality factor of up to $1.6\\times 10^6 $ at 1552 nm, and $>1.2\\times 10^6$ throughout $\\lambda$ = 1510 -- 1600 nm, without annealing or stress management. We then demonstrate the immediate utility of this platform in nonlinear photonics by generating a 1 THz free spectral range, 900-nm-bandwidth modulation-instability microresonator Kerr comb and octave-spanning, supercontinuum-broadened spectra.

  4. Broadband enhancement of single photon emission and polarization dependent coupling in silicon nitride waveguides.

    Science.gov (United States)

    Bisschop, Suzanne; Guille, Antoine; Van Thourhout, Dries; Hens, Zeger; Brainis, Edouard

    2015-06-01

    Single-photon (SP) sources are important for a number of optical quantum information processing applications. We study the possibility to integrate triggered solid-state SP emitters directly on a photonic chip. A major challenge consists in efficiently extracting their emission into a single guided mode. Using 3D finite-difference time-domain simulations, we investigate the SP emission from dipole-like nanometer-sized inclusions embedded into different silicon nitride (SiNx) photonic nanowire waveguide designs. We elucidate the effect of the geometry on the emission lifetime and the polarization of the emitted SP. The results show that highly efficient and polarized SP sources can be realized using suspended SiNx slot-waveguides. Combining this with the well-established CMOS-compatible processing technology, fully integrated and complex optical circuits for quantum optics experiments can be developed.

  5. Direct bonding of ALD Al2O3 to silicon nitride thin films

    DEFF Research Database (Denmark)

    Laganà, Simone; Mikkelsen, E. K.; Marie, Rodolphe

    2017-01-01

    microscopy (TEM) by improving low temperature annealing bonding strength when using atomic layer deposition of aluminum oxide. We have investigated and characterized bonding of Al2O3-SixNy (low stress silicon rich nitride) and Al2O3-Si3N4 (stoichiometric nitride) thin films annealed from room temperature up......O3 can be bonded to. Preliminary tests demonstrating a well-defined nanochannel system with-100 nm high channels successfully bonded and tests against leaks using optical fluorescence technique and transmission electron microscopy (TEM) characterization of liquid samples are also reported. Moreover...

  6. Stressing effects on the charge trapping of silicon oxynitride prepared by thermal oxidation of LPCVD Si-rich silicon nitride

    International Nuclear Information System (INIS)

    Choi, H.Y.; Wong, H.; Filip, V.; Sen, B.; Kok, C.W.; Chan, M.; Poon, M.C.

    2006-01-01

    It was recently found that the silicon oxynitride prepared by oxidation of silicon-rich silicon nitride (SRN) has several important features. The high nitrogen and extremely low hydrogen content of this material allows it to have a high dielectric constant and a low trap density. The present work investigates in further detail the electrical reliability of this kind of gate dielectric films by studying the charge trapping and interface state generation induced by constant current stressing. Capacitance-voltage (C-V) measurements indicate that for oxidation temperatures of 850 and 950 deg. C, the interface trap generation is minimal because of the high nitrogen content at the interface. At a higher oxidation temperature of 1050 deg. C, a large flatband shift is found for constant current stressing. This observation can be explained by the significant reduction of the nitrogen content and the phase separation effect at this temperature as found by X-ray photoelectron spectroscopy study. In addition to the high nitrogen content, the Si atoms at the interface exist in the form of random bonding to oxygen and nitrogen atoms for samples oxidized at 850 and 950 deg. C. This structure reduces the interface bonding constraint and results in the low interface trap density. For heavily oxidized samples the trace amount of interface nitrogen atoms exist in the form of a highly constraint SiN 4 phase and the interface oxynitride layer is a random mixture of SiO 4 and SiN 4 phases, which consequently reduces the reliability against high energy electron stressing

  7. Analytical and experimental evaluation of joining silicon nitride to metal and silicon carbide to metal for advanced heat engine applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.; Selverian, J.H.; O`Neil, D.; Kim, H. [GTE Labs., Inc., Waltham, MA (US); Kim, K. [Brown Univ., Providence, RI (US). Div. of Engineering

    1993-05-01

    This report summarizes the results of Phase 2 of Analytical and Experimental Evaluation of Joining Silicon Nitride to Metal and Silicon Carbide to Metal for Advanced Heat Engine Applications. A general methodology was developed to optimize the joint geometry and material systems for 650{degrees}C applications. Failure criteria were derived to predict the fracture of the braze and ceramic. Extensive finite element analyses (FEA) were performed to examine various joint geometries and to evaluate the affect of different interlayers on the residual stress state. Also, material systems composed of coating materials, interlayers, and braze alloys were developed for the program based on the chemical stability and strength of the joints during processing, and service. The FEA results were compared with experiments using two methods: (1) an idealized strength relationship of the ceramic, and (2) a probabilistic analysis of the ceramic strength (NASA CARES). The results showed that the measured strength of the joint reached 30--80% of the strength predicted by FEA. Also, potential high-temperature braze alloys were developed and evaluated for the high-temperature application of ceramic-metal joints. 38 tabs, 29 figs, 20 refs.

  8. Amorphous silicon based particle detectors

    OpenAIRE

    Wyrsch, N.; Franco, A.; Riesen, Y.; Despeisse, M.; Dunand, S.; Powolny, F.; Jarron, P.; Ballif, C.

    2012-01-01

    Radiation hard monolithic particle sensors can be fabricated by a vertical integration of amorphous silicon particle sensors on top of CMOS readout chip. Two types of such particle sensors are presented here using either thick diodes or microchannel plates. The first type based on amorphous silicon diodes exhibits high spatial resolution due to the short lateral carrier collection. Combination of an amorphous silicon thick diode with microstrip detector geometries permits to achieve micromete...

  9. Effect of the stoichiometry of Si-rich silicon nitride thin films on their photoluminescence and structural properties

    Energy Technology Data Exchange (ETDEWEB)

    Torchynska, T.V., E-mail: ttorch@esfm.ipn.mx [ESFM—Instituto Politecnico Nacional, Mexico DF 07738 (Mexico); Casas Espinola, J.L. [ESFM—Instituto Politecnico Nacional, Mexico DF 07738 (Mexico); Vergara Hernandez, E. [UPIITA—Instituto Politecnico Nacional, Mexico DF 07320 (Mexico); Khomenkova, L., E-mail: khomen@ukr.net [V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028 Kyiv (Ukraine); Delachat, F.; Slaoui, A. [ICube, 23 rue du Loess, BP 20 CR, 67037 Strasbourg Cedex 2 (France)

    2015-04-30

    Si-rich Silicon nitride films were grown on silicon substrates by plasma enhanced chemical vapor deposition. The film stoichiometry was controlled via the variation of NH{sub 3}/SiH{sub 4} ratio from 0.45 up to 1.0. Thermal annealing at 1100 °C for 30 min in the nitrogen flow was applied to form the Si nanocrystals in the films that have been investigated by means of photoluminescence and Raman scattering methods, as well as transmission electron microscopy. Several emission bands have been detected with the peak positions at: 2.8–3.0 eV, 2.5–2.7 eV, 2.10–2.25 eV, and 1.75–1.98 eV. The temperature dependences of photoluminescence spectra were studied with the aim to confirm the types of optical transitions and the nature of light emitting defects in silicon nitride. The former three bands were assigned to the defects in silicon nitride, whereas the last one (1.75–1.98 eV) was attributed to the exciton recombination inside of Si nanocrystals. The photoluminescence mechanism is discussed. - Highlights: • Substoichiometric silicon nitride films were grown by PECVD technique. • The variation of the NH{sub 3}/SiH{sub 4} ratio controls excess Si content in the films. • Both Si nanocrystals and amorphous Si phase were observed in annealed films. • Temperature evolution of carrier recombination via Si nanocrystals and host defects.

  10. Electronic Biosensors Based on III-Nitride Semiconductors.

    Science.gov (United States)

    Kirste, Ronny; Rohrbaugh, Nathaniel; Bryan, Isaac; Bryan, Zachary; Collazo, Ramon; Ivanisevic, Albena

    2015-01-01

    We review recent advances of AlGaN/GaN high-electron-mobility transistor (HEMT)-based electronic biosensors. We discuss properties and fabrication of III-nitride-based biosensors. Because of their superior biocompatibility and aqueous stability, GaN-based devices are ready to be implemented as next-generation biosensors. We review surface properties, cleaning, and passivation as well as different pathways toward functionalization, and critically analyze III-nitride-based biosensors demonstrated in the literature, including those detecting DNA, bacteria, cancer antibodies, and toxins. We also discuss the high potential of these biosensors for monitoring living cardiac, fibroblast, and nerve cells. Finally, we report on current developments of covalent chemical functionalization of III-nitride devices. Our review concludes with a short outlook on future challenges and projected implementation directions of GaN-based HEMT biosensors.

  11. Numerical study of self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride substrate

    International Nuclear Information System (INIS)

    Ding Yanfang; Zhu Ziqiang; Zhu Ming; Lin Chenglu

    2006-01-01

    Compared with bulk-silicon technology, silicon-on-insulator (SOI) technology possesses many advantages but it is inevitable that the buried silicon dioxide layer also thermally insulates the metal-oxide-silicon field-effect transistors (MOSFETs) from the bulk due to the low thermal conductivity. One of the alternative insulator to replace the buried oxide layer is aluminum nitride (MN), which has a thermal conductivity that is about 200 times higher than that of SiO 2 (320 W·m -1 ·K -1 versus 1.4 W·m -1 ·K -l ). To investigate the self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride (SOAN) substrate, a two-dimensional numerical analysis is performed by using a device simulator called MEDICI run on a Solaris workstation to simulate the electrical characteristics and temperature distribution by comparing with those of bulk and standard SOI MOSFETs. Our study suggests that AIN is a suitable alternative to silicon dioxide as a buried dielectric in SOI and expands the applications of SOI to high temperature conditions. (authors)

  12. Synthesis and corrosion properties of silicon nitride films by ion beam assisted deposition

    Science.gov (United States)

    Baba, K.; Hatada, R.; Emmerich, R.; Enders, B.; Wolf, G. K.

    1995-12-01

    Silicon nitride films SiN x were deposited on 316L austenitic stainless steel substrates by silicon evaporation and simultaneous nitrogen ion irradiation with an acceleration voltage of 2 kV. In order to study the influence of the nitrogen content on changes in stoichiometry, structure, morphology, thermal oxidation behaviour and corrosion behaviour, the atom to ion transport ratio was systematically varied. The changes of binding states and the stoichiometry were evaluated with XPS and AES analysis. A maximum nitrogen content was reached with a {Si}/{N} transport ratio lower than 2. The films are chemically inert when exposed to laboratory atmosphere up to a temperature of more than 1000°C. XRD and SEM measurements show amorphous and featureless films for transport ratios {Si}/{N} from 1 up to 10. The variation of the corrosion behaviour of coated stainless steel substrates in sulphuric acid and hydrochloric acid shows a minimum at medium transport ratios. This goes parallel with changes in porosity and adhesion. Additional investigations showed that titanium implantation as an intermediate step improves the corrosion resistance considerably.

  13. Silicon rich nitride ring resonators for rare - earth doped telecommunications-band amplifiers pumped at the O-band.

    Science.gov (United States)

    Xing, P; Chen, G F R; Zhao, X; Ng, D K T; Tan, M C; Tan, D T H

    2017-08-22

    Ring resonators on silicon rich nitride for potential use as rare-earth doped amplifiers pumped at 1310 nm with amplification at telecommunications-band are designed and characterized. The ring resonators are fabricated on 300 nm and 400 nm silicon rich nitride films and characterized at both 1310 nm and 1550 nm. We demonstrate ring resonators exhibiting similar quality factors exceeding 10,000 simultaneously at 1310 nm and 1550 nm. A Dysprosium-Erbium material system exhibiting photoluminescence at 1510 nm when pumped at 1310 nm is experimentally demonstrated. When used together with Dy-Er co-doped particles, these resonators with similar quality factors at 1310 nm and 1550 nm may be used for O-band pumped amplifiers for the telecommunications-band.

  14. Matrix density effects on the mechanical properties of SiC fiber-reinforced silicon nitride matrix properties

    Science.gov (United States)

    Bhatt, Ramakrishna T.; Kiser, Lames D.

    1990-01-01

    The room temperature mechanical properties were measured for SiC fiber reinforced reaction-bonded silicon nitride composites (SiC/RBSN) of different densities. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers (Textron SCS-6) in a reaction-bonded Si3N4 matrix. The composite density was varied by changing the consolidation pressure during RBSN processing and by hot isostatically pressing the SiC/RBSN composites. Results indicate that as the consolidation pressure was increased from 27 to 138 MPa, the average pore size of the nitrided composites decreased from 0.04 to 0.02 microns and the composite density increased from 2.07 to 2.45 gm/cc. Nonetheless, these improvements resulted in only small increases in the first matrix cracking stress, primary elastic modulus, and ultimate tensile strength values of the composites. In contrast, HIP consolidation of SiC/RBSN resulted in a fully dense material whose first matrix cracking stress and elastic modulus were approx. 15 and 50 percent higher, respectively, and ultimate tensile strength values were approx. 40 percent lower than those for unHIPed SiC/RBSN composites. The modulus behavior for all specimens can be explained by simple rule-of-mixture theory. Also, the loss in ultimate strength for the HIPed composites appears to be related to a degradation in fiber strength at the HIP temperature. However, the density effect on matrix fracture strength was much less than would be expected based on typical monolithic Si3N4 behavior, suggesting that composite theory is indeed operating. Possible practical implications of these observations are discussed.

  15. WEAR PERFORMANCE OPTIMIZATION OF SILICON NITRIDE USING GENETIC AND SIMULATED ANNEALING ALGORITHM

    Directory of Open Access Journals (Sweden)

    SACHIN GHALME

    2017-12-01

    Full Text Available Replacing damaged joint with the suitable alternative material is a prime requirement in a patient who has arthritis. Generation of wear particles in the artificial joint during action or movement is a serious issue and leads to aseptic loosening of joint. Research in the field of bio-tribology is trying to evaluate materials with minimum wear volume loss so as to extend joint life. Silicon nitride (Si3N4 is non-oxide ceramic suggested as a new alternative for hip/knee joint replacement. Hexagonal Boron Nitride (hBN is recommended as a solid additive lubricant to improve the wear performance of Si3N4 . In this paper, an attempt has been made to evaluate the optimum combination of load and % volume of hBN in Si3N4 to minimize wear volume loss (WVL. The experiments were conducted according to Design of Experiments (DoE – Taguchi method and a mathematical model is developed. Further, this model is processed with Genetic Algorithm (GA and Simulated Annealing (SA to find out the optimum percentage of hBN in Si3N4 to minimize wear volume loss against Alumina (Al2O3 counterface. Taguchi method presents 15 N load and 8% volume of hBN to minimize WVL of Si3N4 . While GA and SA optimization offer 11.08 N load, 12.115% volume of hBN and 11.0789 N load, 12.128% volume of hBN respectively to minimize WVL in Si3N4. .

  16. Dissolution performance of plutonium nitride based fuel materials

    Energy Technology Data Exchange (ETDEWEB)

    Aneheim, E.; Hedberg, M. [Nuclear Chemistry, Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivaegen 4, Gothenburg, SE41296 (Sweden)

    2016-07-01

    Nitride fuels have been regarded as one viable fuel option for Generation IV reactors due to their positive features compared to oxides. To be able to close the fuel cycle and follow the Generation IV concept, nitrides must, however, demonstrate their ability to be reprocessed. This means that the dissolution performance of actinide based nitrides has to be thoroughly investigated and assessed. As the zirconium stabilized nitrides show even better potential as fuel material than does the pure actinide containing nitrides, investigations on the dissolution behavior of both PuN and (Pu,Zr)N has been undertaken. If possible it is desirable to perform the fuel dissolutions using nitric acid. This, as most reprocessing strategies using solvent-solvent extraction are based on a nitride containing aqueous matrix. (Pu,Zr)N/C microspheres were produced using internal gelation. The spheres dissolution performance was investigated using nitric acid with and without additions of HF and Ag(II). In addition PuN fuel pellets were produced from powder and their dissolution performance were also assessed in a nitric acid based setting. It appears that both PuN and (Pu,Zr)N/C fuel material can be completely dissolved in nitric acid of high concentration with the use of catalytic amounts of HF. The amount of HF added strongly affects dissolution kinetics of (Pu, Zr)N and the presence of HF affects the 2 solutes differently, possibly due to inhomogeneity o the initial material. Large additions of Ag(II) can also be used to facilitate the dissolution of (Pu,Zr)N in nitric acid. PuN can be dissolved by pure nitric acid of high concentration at room temperature while (Pu, Zr)N is unaffected under similar conditions. At elevated temperature (reflux), (Pu,Zr)N can, however, also be dissolved by concentrated pure nitric acid.

  17. Imprinted silicon-based nanophotonics

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Olsen, Brian Bilenberg; Frandsen, Lars Hagedorn

    2007-01-01

    We demonstrate and optically characterize silicon-on-insulator based nanophotonic devices fabricated by nanoimprint lithography. In our demonstration, we have realized ordinary and topology-optimized photonic crystal waveguide structures. The topology-optimized structures require lateral pattern ...

  18. Effects of silicon-nitride passivation on the electrical behavior of 0.1-μm pseudomorphic high-electron-mobility transistors

    International Nuclear Information System (INIS)

    Oh, Jung-Hun; Sul, Woo-Suk; Han, Hyo-Jong; Jang, Hae-Kang; Son, Myung-Sik; Rhee, Jin-Koo; Kim, Sam- Dong

    2004-01-01

    We examine the effects of surface state formation due to silicon-nitride passivation on the electrical characteristics of GaAs-based 0.1-μm pseudomorphic high-electron-mobility transistors (pHEMTs). In this study, DC and noise characteristic are investigated before and after the passivation of the pHEMTs. After the passivation, we observe significant degradation of noise performance in the frequency range of 55 - 62 GHz. We also observe clear increases in the drain-source saturation current at a gate voltage of 0 V and in the extrinsic transconductance at a drain voltage of 1 V from 325 and 264 to 365 mA/mm and 304 mS/mm, respectively, with no significant variation in pinchoff voltage. We propose that the observed variations in the DC and the noise characteristics are due to the positively charged surface state after deposition of the silicon nitride passivation film. Hydrodynamic device model simulations were performed based upon the proposed mechanisms for the change in electrical behavior, and the calculated results show good agreement with the experimental results.

  19. Silicon oxynitride based photonics

    NARCIS (Netherlands)

    Worhoff, Kerstin; Klein, E.J.; Hussein, M.G.; Driessen, A.; Marciniak, M.; Jaworski, M.; Zdanowicz, M.

    2008-01-01

    Silicon oxynitride is a very attractive material for integrated optics. Besides possessing excellent optical properties it can be deposited with refractive indices varying over a wide range by tuning the material composition. In this contribution we will summarize the key properties of this material

  20. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    International Nuclear Information System (INIS)

    To, Thien Dien; Nguyen, Anh Tuan; Phan, Khoa Nhat Thanh; Truong, An Thu Thi; Doan, Tin Chanh Duc; Dang, Chien Mau

    2015-01-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES. (paper)

  1. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Science.gov (United States)

    Wananuruksawong, R.; Jinawath, S.; Padipatvuthikul, P.; Wasanapiarnpong, T.

    2011-10-01

    Silicon nitride (Si3N4) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si3N4 ceramic as a dental core material. The white Si3N4 was prepared by pressureless sintering at relative low sintering temperature of 1650 °C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si3N4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si3N4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (tube furnace between 1000-1200°C. The veneered specimens fired at 1100°C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98×10-6 °C-1, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  2. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2015-07-01

    The stopping power and energy straggling of {sup 12}C{sup 3+} and {sup 16}O{sup 3+} ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C{sup 3+} ion energy losses comparing to O{sup 3+} ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%.

  3. Identification of light elements in silicon nitride by aberration-corrected scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Idrobo, Juan C., E-mail: idrobojc@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Walkosz, Weronika [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 (United States); Klie, Robert F.; Oeguet, Serdar [Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 (United States)

    2012-12-15

    In silicon nitride structural ceramics, the overall mechanical and thermal properties are controlled by the atomic and electronic structures at the interface between the ceramic grains and the amorphous intergranular films (IGFs) formed by various sintering additives. In the last ten years the atomic arrangements of heavy elements (rare-earths) at the Si{sub 3}N{sub 4}/IGF interfaces have been resolved. However, the atomic position of light elements, without which it is not possible to obtain a complete description of the interfaces, has been lacking. This review article details the authors' efforts to identify the atomic arrangement of light elements such as nitrogen and oxygen at the Si{sub 3}N{sub 4}/SiO{sub 2} interface and in bulk Si{sub 3}N{sub 4} using aberration-corrected scanning transmission electron microscopy. -- Highlights: Black-Right-Pointing-Pointer Revealing the atomic structure of the {alpha}-Si{sub 3}N{sub 4}/SiO{sub 2} interface. Black-Right-Pointing-Pointer Identification and lattice location of oxygen impurities in bulk {alpha}-Si{sub 3}N{sub 4}. Black-Right-Pointing-Pointer Short range ordering of nitrogen and oxygen at the {beta}-Si{sub 3}N{sub 4}/SiO{sub 2} interface.

  4. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    International Nuclear Information System (INIS)

    Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T; Padipatvuthikul, P

    2011-01-01

    Silicon nitride (Si 3 N 4 ) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si 3 N 4 ceramic as a dental core material. The white Si 3 N 4 was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si 3 N 4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si 3 N 4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder ( 2 O 3 - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si 3 N 4 specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10 -6 deg. C -1 , rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  5. EXPERIMENTAL INVESTIGATION ON TRIBOLOGICAL CHARACTERISTICS OF SILICON NITRIDE REINFORCED ALUMINIUM METAL MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    D. BHUVANESH

    2017-05-01

    Full Text Available Aluminium alloy (LM25 reinforced with silicon nitride was fabricated by liquid metallurgy route. The fabricated composite was investigated for dry sliding wear behaviour by conducting experiments using pin-on-disc tribometer. Set of experiments were planned using Taguchi’s technique and data analysis was carried out using L27 orthogonal array. Analysis of Variance (ANOVA technique was used to determine the significance of parameter with respect to wear rate. Signal-to-Noise ratio was employed to detect the most and least influential parameter as well as their level of influence. ‘Smaller the wear’ characteristic was chosen for the analysis of dry sliding wear. Results implied that, the load has the primary effect on the wear succeeded by the effect of sliding velocity and sliding distance. Scanning Electronic Microscopic studies were carried out on worn surfaces to understand the wear mechanism.Tribological results indicated that LM25 aluminium alloy could be better utilized as a material for piston, rotor and bearings for long life in low speed applications.

  6. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    International Nuclear Information System (INIS)

    Mikšová, R.; Hnatowicz, V.; Macková, A.; Malinský, P.; Slepička, P.

    2015-01-01

    The stopping power and energy straggling of 12 C 3+ and 16 O 3+ ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C 3+ ion energy losses comparing to O 3+ ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%

  7. Atomic Layer Deposition of Silicon Nitride from Bis(tert-butylamino)silane and N2 Plasma.

    Science.gov (United States)

    Knoops, Harm C M; Braeken, Eline M J; de Peuter, Koen; Potts, Stephen E; Haukka, Suvi; Pore, Viljami; Kessels, Wilhelmus M M

    2015-09-09

    Atomic layer deposition (ALD) of silicon nitride (SiNx) is deemed essential for a variety of applications in nanoelectronics, such as gate spacer layers in transistors. In this work an ALD process using bis(tert-butylamino)silane (BTBAS) and N2 plasma was developed and studied. The process exhibited a wide temperature window starting from room temperature up to 500 °C. The material properties and wet-etch rates were investigated as a function of plasma exposure time, plasma pressure, and substrate table temperature. Table temperatures of 300-500 °C yielded a high material quality and a composition close to Si3N4 was obtained at 500 °C (N/Si=1.4±0.1, mass density=2.9±0.1 g/cm3, refractive index=1.96±0.03). Low wet-etch rates of ∼1 nm/min were obtained for films deposited at table temperatures of 400 °C and higher, similar to that achieved in the literature using low-pressure chemical vapor deposition of SiNx at >700 °C. For novel applications requiring significantly lower temperatures, the temperature window from room temperature to 200 °C can be a solution, where relatively high material quality was obtained when operating at low plasma pressures or long plasma exposure times.

  8. Reprint of: Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film.

    Science.gov (United States)

    Nishiyama, Hidetoshi; Suga, Mitsuo; Ogura, Toshihiko; Maruyama, Yuusuke; Koizumi, Mitsuru; Mio, Kazuhiro; Kitamura, Shinichi; Sato, Chikara

    2010-11-01

    Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. High-Efficiency Nitride-Based Solid-State Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Paul T. Fini; Shuji Nakamura

    2005-07-30

    In this final technical progress report we summarize research accomplished during Department of Energy contract DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. Two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and the Lighting Research Center at Rensselaer Polytechnic Institute (led by Dr. N. Narendran), pursued the goals of this contract from thin film growth, characterization, and packaging/luminaire design standpoints. The UCSB team initially pursued the development of blue gallium nitride (GaN)-based vertical-cavity surface-emitting lasers, as well as ultraviolet GaN-based light emitting diodes (LEDs). In Year 2, the emphasis shifted to resonant-cavity light emitting diodes, also known as micro-cavity LEDs when extremely thin device cavities are fabricated. These devices have very directional emission and higher light extraction efficiency than conventional LEDs. Via the optimization of thin-film growth and refinement of device processing, we decreased the total cavity thickness to less than 1 {micro}m, such that micro-cavity effects were clearly observed and a light extraction efficiency of over 10% was reached. We also began the development of photonic crystals for increased light extraction, in particular for so-called ''guided modes'' which would otherwise propagate laterally in the device and be re-absorbed. Finally, we pursued the growth of smooth, high-quality nonpolar a-plane and m-plane GaN films, as well as blue light emitting diodes on these novel films. Initial nonpolar LEDs showed the expected behavior of negligible peak wavelength shift with increasing drive current. M-plane LEDs in particular show promise, as unpackaged devices had unsaturated optical output power of {approx} 3 mW at 200 mA drive current. The LRC's tasks were aimed at developing the subcomponents necessary for packaging UCSB's light

  10. Efficient continuous-wave nonlinear frequency conversion in high-Q gallium nitride photonic crystal cavities on silicon

    Directory of Open Access Journals (Sweden)

    Mohamed Sabry Mohamed

    2017-03-01

    Full Text Available We report on nonlinear frequency conversion from the telecom range via second harmonic generation (SHG and third harmonic generation (THG in suspended gallium nitride slab photonic crystal (PhC cavities on silicon, under continuous-wave resonant excitation. Optimized two-dimensional PhC cavities with augmented far-field coupling have been characterized with quality factors as high as 4.4 × 104, approaching the computed theoretical values. The strong enhancement in light confinement has enabled efficient SHG, achieving a normalized conversion efficiency of 2.4 × 10−3 W−1, as well as simultaneous THG. SHG emission power of up to 0.74 nW has been detected without saturation. The results herein validate the suitability of gallium nitride for integrated nonlinear optical processing.

  11. Galvanic corrosion of structural non-stoichiometric silicon nitride thin films and its implications on reliability of microelectromechanical devices

    Energy Technology Data Exchange (ETDEWEB)

    Broas, M., E-mail: mikael.broas@aalto.fi; Mattila, T. T.; Paulasto-Kröckel, M. [Department of Electrical Engineering and Automation, Aalto University, Espoo, P.O. Box 13500, FIN-00076 Aalto (Finland); Liu, X.; Ge, Y. [Department of Materials Science and Engineering, Aalto University, Espoo, P.O. Box 16200, FIN-00076 Aalto (Finland)

    2015-06-28

    This paper describes a reliability assessment and failure analysis of a poly-Si/non-stoichiometric silicon nitride thin film composite structure. A set of poly-Si/SiN{sub x} thin film structures were exposed to a mixed flowing gas (MFG) environment, which simulates outdoor environments, for 90 days, and an elevated temperature and humidity (85 °C/95% R.H.) test for 140 days. The mechanical integrity of the thin films was observed to degrade during exposure to the chemically reactive atmospheres. The degree of degradation was analyzed with nanoindentation tests. Statistical analysis of the forces required to initiate a fracture in the thin films indicated degradation due to the exposure to the MFG environment in the SiN{sub x} part of the films. Scanning electron microscopy revealed a porous-like reaction layer on top of SiN{sub x}. The morphology of the reaction layer resembled that of galvanically corroded poly-Si. Transmission electron microscopy further clarified the microstructure of the reaction layer which had a complex multi-phase structure extending to depths of ∼100 nm. Furthermore, the layer was oxidized two times deeper in a 90 days MFG-tested sample compared to an untested reference. The formation of the layer is proposed to be caused by galvanic corrosion of elemental silicon in non-stoichiometric silicon nitride during hydrofluoric acid etching. The degradation is proposed to be due uncontrolled oxidation of the films during the stress tests.

  12. First-principles study of the effects of halogen dopants on the properties of intergranular films in silicon nitride ceramics

    International Nuclear Information System (INIS)

    Painter, Gayle S.; Becher, Paul F.; Kleebe, H.-J.; Pezzotti, G.

    2002-01-01

    The nanoscale intergranular films that form in the sintering of ceramics often occur as adherent glassy phases separating the crystalline grains in the ceramic. Consequently, the properties of these films are often equal in importance to those of the constituent grains in determining the ceramic's properties. The measured characteristics of the silica-rich phase separating the crystalline grains in Si 3 N 4 and many other ceramics are so reproducible that SiO 2 has become a model system for studies of intergranular films (IGF's). Recently, the influence of fluorine and chlorine dopants in SiO 2 -rich IGF's in silicon nitride was precisely documented by experiment. Along with the expected similarities between the halogens, some dramatically contrasting effects were found. But the atomic-scale mechanisms distinguishing the effects F and Cl on IGF behavior have not been well understood. First-principles density functional calculations reported here provide a quantum-level description of how these dopant-host interactions affect the properties of IGF's, with specific modeling of F and Cl in the silica-rich IGF in silicon nitride. Calculations were carried out for the energetics, structural changes, and forces on the atoms making up a model cluster fragment of an SiO 2 intergranular film segment in silicon nitride with and without dopants. Results show that both anions participate in the breaking of bonds within the IGF, directly reducing the viscosity of the SiO 2 -rich film and promoting decohesion. Observed differences in the way fluorine and chlorine affect IGF behavior become understandable in terms of the relative stabilities of the halogens as they interact with Si atoms that have lost one if their oxygen bridges

  13. Performance improvement of silicon nitride ball bearings by ion implantation. CRADA final report

    International Nuclear Information System (INIS)

    Williams, J.M.; Miner, J.

    1998-01-01

    The present report summarizes technical results of CRADA No. ORNL 92-128 with the Pratt and Whitney Division of United Technologies Corporation. The stated purpose of the program was to assess the 3effect of ion implantation on the rolling contact performance of engineering silicon nitride bearings, to determine by post-test analyses of the bearings the reasons for improved or reduced performance and the mechanisms of failure, if applicable, and to relate the overall results to basic property changes including but not limited to swelling, hardness, modulus, micromechanical properties, and surface morphology. Forty-two control samples were tested to an intended runout period of 60 h. It was possible to supply only six balls for ion implantation, but an extended test period goal of 150 h was used. The balls were implanted with C-ions at 150 keV to a fluence of 1.1 x 10 17 /cm 2 . The collection of samples had pre-existing defects called C-cracks in the surfaces. As a result, seven of the control samples had severe spalls before reaching the goal of 60 h for an unacceptable failure rate of 0.003/sample-h. None of the ion-implanted samples experienced engineering failure in 150 h of testing. Analytical techniques have been used to characterize ion implantation results, to characterize wear tracks, and to characterize microstructure and impurity content. In possible relation to C-cracks. It is encouraging that ion implantation can mitigate the C-crack failure mode. However, the practical implications are compromised by the fact that bearings with C-cracks would, in no case, be acceptable in engineering practice, as this type of defect was not anticipated when the program was designed. The most important reason for the use of ceramic bearings is energy efficiency

  14. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Energy Technology Data Exchange (ETDEWEB)

    Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Padipatvuthikul, P, E-mail: raayaa_chula@hotmail.com [Faculty of Dentistry, Srinakharinwirot University, Bangkok (Thailand)

    2011-10-29

    Silicon nitride (Si{sub 3}N{sub 4}) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si{sub 3}N{sub 4} ceramic as a dental core material. The white Si{sub 3}N{sub 4} was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si{sub 3}N{sub 4} ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si{sub 3}N{sub 4} specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y{sub 2}O{sub 3} - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si{sub 3}N{sub 4} specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10{sup -6} deg. C{sup -1}, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  15. Thermal Response of Cooled Silicon Nitride Plate Due to Thermal Conductivity Effects Analyzed

    Science.gov (United States)

    Baaklini, George Y.; Abdul-Aziz, Ali; Bhatt, Ramakrishna

    2003-01-01

    Lightweight, strong, tough high-temperature materials are required to complement efficiency improvements for next-generation gas turbine engines that can operate with minimum cooling. Because of their low density, high-temperature strength, and high thermal conductivity, ceramics are being investigated as materials to replace the nickelbase superalloys that are currently used for engine hot-section components. Ceramic structures can withstand higher operating temperatures and a harsh combustion environment. In addition, their low densities relative to metals help reduce component mass (ref. 1). To complement the effectiveness of the ceramics and their applicability for turbine engine applications, a parametric study using the finite element method is being carried out. The NASA Glenn Research Center remains very active in conducting and supporting a variety of research activities related to ceramic matrix composites through both experimental and analytical efforts (ref. 1). The objectives of this work are to develop manufacturing technology, develop a thermal and environmental barrier coating (TBC/EBC), develop an analytical modeling capability to predict thermomechanical stresses, and perform a minimal burner rig test on silicon nitride (Si3N4) and SiC/SiC turbine nozzle vanes under simulated engine conditions. Moreover, we intend to generate a detailed database of the material s property characteristics and their effects on structural response. We expect to offer a wide range of data since the modeling will account for other variables, such as cooling channel geometry and spacing. Comprehensive analyses have begun on a plate specimen with Si3N4 cooling holes.

  16. III-nitride based light emitting diodes and applications

    CERN Document Server

    Han, Jung; Amano, Hiroshi; Morkoç, Hadis

    2017-01-01

    The revised edition of this important book presents updated and expanded coverage of light emitting diodes (LEDs) based on heteroepitaxial GaN on Si substrates, and includes new chapters on tunnel junction LEDs, green/yellow LEDs, and ultraviolet LEDs. Over the last two decades, significant progress has been made in the growth, doping and processing technologies of III-nitride based semiconductors, leading to considerable expectations for nitride semiconductors across a wide range of applications. LEDs are already used in traffic signals, signage lighting, and automotive applications, with the ultimate goal of the global replacement of traditional incandescent and fluorescent lamps, thus reducing energy consumption and cutting down on carbon-dioxide emission. However, some critical issues must be addressed to allow the further improvements required for the large-scale realization of solid-state lighting, and this book aims to provide the readers with details of some contemporary issues on which the performanc...

  17. Influence of hydrogen effusion from hydrogenated silicon nitride layers on the regeneration of boron-oxygen related defects in crystalline silicon

    International Nuclear Information System (INIS)

    Wilking, S.; Ebert, S.; Herguth, A.; Hahn, G.

    2013-01-01

    The degradation effect boron doped and oxygen-rich crystalline silicon materials suffer from under illumination can be neutralized in hydrogenated silicon by the application of a regeneration process consisting of a combination of slightly elevated temperature and carrier injection. In this paper, the influence of variations in short high temperature steps on the kinetics of the regeneration process is investigated. It is found that hotter and longer firing steps allowing an effective hydrogenation from a hydrogen-rich silicon nitride passivation layer result in an acceleration of the regeneration process. Additionally, a fast cool down from high temperature to around 550 °C seems to be crucial for a fast regeneration process. It is suggested that high cooling rates suppress hydrogen effusion from the silicon bulk in a temperature range where the hydrogenated passivation layer cannot release hydrogen in considerable amounts. Thus, the hydrogen content of the silicon bulk after the complete high temperature step can be increased resulting in a faster regeneration process. Hence, the data presented here back up the theory that the regeneration process might be a hydrogen passivation of boron-oxygen related defects

  18. Influence of post-annealing on the electrical properties of metal/oxide/silicon nitride/oxide/silicon capacitors for flash memories

    International Nuclear Information System (INIS)

    Kim, Hee Dong; An, Ho-Myoung; Kim, Kyoung Chan; Seo, Yu Jeong; Kim, Tae Geun

    2008-01-01

    We report the effect of post-annealing on the electrical properties of metal/oxide/silicon nitride/oxide/silicon (MONOS) capacitors. Four samples, namely as-deposited and annealed at 750, 850 and 950 °C for 30 s in nitrogen ambient by a rapid thermal process, were prepared and characterized for comparison. The best performance with the largest memory window of 4.4 V and the fastest program speed of 10 ms was observed for the sample annealed at 850 °C. In addition, the highest traps density of 6.84 × 10 18 cm −3 was observed with ideal trap distributions for the same sample by capacitance–voltage (C–V) measurement. These results indicate that the memory traps in the ONO structure can be engineered by post-annealing to improve the electrical properties of the MONOS device

  19. Determination of molecular stopping cross section of {sup 12}C, {sup 16}O, {sup 28}Si, {sup 35}Cl, {sup 58}Ni, {sup 79}Br, and {sup 127}I in silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Barradas, N.P., E-mail: nunoni@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Unversidade de Lisboa, Estrada Nacional 10 ao km 139.7, 2695-066 Bobadela LRS (Portugal); Bergmaier, A. [Institut für Angewandte Physik und Messtechnik, Fakultät für Luft und Raumfahrttechnik, Werner-Heisenberg-Weg 39, D-85577 Neubiberg (Germany); Mizohata, K. [Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 University of Helsinki (Finland); Msimanga, M. [iThemba LABS Gauteng, National Research Foundation, Private Bag 11, WITS 2050, Johannesburg (South Africa); Department of Physics, Tshwane University of Technology, Private Bag X680, Pretoria 0001 (South Africa); Räisänen, J. [Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 University of Helsinki (Finland); Sajavaara, T. [Department of Physics, University of Jyväskylä, Survontie 9, 40014 Jyväskylä (Finland); Simon, A. [International Atomic Energy Agency, Division of Physical and Chemical Sciences, Vienna International Centre, P.O. Box 100, A-1400 Vienna (Austria); Institute of Nuclear Research of the Hungarian Academy of Sciences, (ATOMKI), P.O. Box 51, H-4001 Debrecen (Hungary)

    2015-10-01

    Silicon nitride is a technologically important material in a range of applications due to a combination of important properties. Ion beam analysis techniques, and in particular, heavy ion elastic recoil detection analysis can be used to determine the stoichiometry of silicon nitride films, which often deviates from the ideal Si{sub 3}N{sub 4}, as well as the content of impurities such as hydrogen, even in the presence of other materials or in a matrix containing heavier elements. Accurate quantification of IBA results depends on the basic data used in the data analysis. Quantitative depth profiling relies on the knowledge of the stopping power cross sections of the materials studied for the ions involved, which in the case of HI-ERDA is both the primary beam, and the recoiled species. We measured the stopping cross section of {sup 12}C, {sup 16}O, {sup 28}Si, {sup 35}Cl, {sup 58}Ni, {sup 79}Br, and {sup 127}I in a well-characterised silicon nitride membrane. The measurements were made by independent groups utilising different experimental setups and methods. In some cases there is extensive overlap of the energy range in different experiments, allowing a comparison of the different results. The four independent data sets reported in this work are in excellent agreement with each other, in the cases where similar energy ranges were measured. On the other hand, the data are in most cases higher than calculations made with the interpolative schemes SRIM and MSTAR together with the Bragg rule. Better agreement is found with MSTAR in some of the cases studied. This work is a significant extension of the heavy ion stopping power data base for silicon nitride.

  20. Assessments of Mechanical and Life Limiting Properties of Two Candidate Silicon Nitrides for Stirling Convertor Heater Head Applications

    Science.gov (United States)

    Choi, Sung R.; Krause, David L.

    2006-01-01

    NASA Glenn Research Center is developing advanced technology for Stirling convertors with a target of significantly improving the specific power and efficiency of the convertor and overall generator for Mars rovers and deep space missions. One specific approach to the target has been recognized as the use of appropriate high-temperature materials. As a series of ceramic material approaches in Advanced Stirling Convertor Development Program in fiscal year 2005, two commercial, structural silicon nitrides AS800 (Honeywell, Torrence, California) and SN282 (Kyocera, Vancouver, Washington) were selected and their mechanical and life limiting properties were characterized at 1050 C in air. AS800 exhibited both strength and Weibull modulus greater than SN282. A life limiting phenomenon was apparent in AS800 with a low slow crack growth parameter n = 15; whereas, a much increased resistance to slow crack growth was found in SN282 with n greater than 100. Difference in elastic modulus and thermal conductivity was negligible up to 1200 C between the two silicon nitrides. The same was true for the coefficient of thermal expansion up to 1400 C.

  1. Embedded nonvolatile memory devices with various silicon nitride energy band gaps on glass used for flat panel display applications

    International Nuclear Information System (INIS)

    Son, Dang Ngoc; Van Duy, Nguyen; Jung, Sungwook; Yi, Junsin

    2010-01-01

    Nonvolatile memory (NVM) devices with a nitride–nitride–oxynitride stack structure on a rough poly-silicon (poly-Si) surface were fabricated using a low-temperature poly-Si (LTPS) thin film transistor technology on glass substrates for application of flat panel display (FPD). The plasma-assisted oxidation/nitridation method is used to form a uniform oxynitride with an ultrathin tunneling layer on a rough LTPS surface. The NVMs, using a Si-rich silicon nitride film as a charge-trapping layer, were proposed as one of the solutions for the improvement of device performance such as the program/erase speed, the memory window and the charge retention characteristics. To further improve the vertical scaling and charge retention characteristics of NVM devices, the high-κ high-density N-rich SiN x films are used as a blocking layer. The fabricated NVM devices have outstanding electrical properties, such as a low threshold voltage, a high ON/OFF current ratio, a low subthreshold swing, a low operating voltage of less than ±9 V and a large memory window of 3.7 V, which remained about 1.9 V over a period of 10 years. These characteristics are suitable for electrical switching and data storage with in FPD application

  2. Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

    KAUST Repository

    Yang, Xinbo; Aydin, Erkan; Xu, Hang; Kang, Jingxuan; Hedhili, Mohamed N.; Liu, Wenzhu; Wan, Yimao; Peng, Jun; Samundsett, Christian; Cuevas, Andres; De Wolf, Stefaan

    2018-01-01

    novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties

  3. The combined effects of Fe and H2 on the nitridation of silicon

    Science.gov (United States)

    Shaw, N. J.

    1982-01-01

    In view of the support offered by previous work for the suggestion that Fe may affect alpha-Si3N4 formation and microstructural development, a two-part study was conducted to differentiate the effects of H2 and Fe in, first, the nitridation of pure and of Fe-containing powder in N2 and N2-4% H2, and then the nitridation of (1 1 1) Si single crystal wafers with and without Fe powder on the surface. The degree of nitridation is most strongly affected by H2 at 1200 C, but by Fe at 1375 C, where Fe-containing samples in either atmosphere were almost completely nitrided. While neither H2 nor Fe alone changed the ratio of alpha-Si3N4 to beta-Si3N4, the combination of H2 and Fe increased it at both temperatures.

  4. Structure, phonons and related properties in zinc-IV-nitride (IV = silicon, germanium, tin), scandium nitride, and rare-earth nitrides

    Science.gov (United States)

    Paudel, Tula R.

    This thesis presents a study of the phonons and related properties in two sets of nitride compounds, whose properties are until now relatively poorly known. The Zn-IV-N2 group of compounds with the group IV elements Si, Ge and Sn, form a series analogous to the well known III-N nitride series with group III element Al, Ga, In. Structurally, they can be derived by doubling the period of III-V compounds in the plane in two directions and replacing the group-III elements with Zn and a group-IV element in a particular ordered pattern. Even though they are similar to the well-known III-V nitride compounds, the study of the properties of these materials is in its early stages. The phonons in these materials and their relation to the phonons in the corresponding group-III nitrides are of fundamental interest. They are also of practical interest because the phonon related spectra such as infrared absorption and Raman spectroscopy are sensitive to the structural quality of the material and can thus be used to quantify the degree of crystalline perfection of real samples. First-principles calculations of the phonons and related ground state properties of these compounds were carried out using Density Functional Perturbation Theory (DFPT) with the Local Density Approximation (LDA) for exchange and correlation and using a pseudopotential plane wave implementation which was developed by several authors over the last decades. The main focus of our study is on the phonons at the center of the Brillouin zone because the latter are most directly related to commonly used spectroscopies to probe the vibrations in a solid: infrared reflectivity and Raman spectroscopy. For a semiconducting or insulating compound, a splitting occurs between transverse and longitudinal phonons at the Gamma-point because of the long-range nature of electrostatic forces. The concepts required to handle this problem are reviewed. Our discussion emphasizes how the various quantities required are related to

  5. Silicon nitride films fabricated by a plasma-enhanced chemical vapor deposition method for coatings of the laser interferometer gravitational wave detector

    Science.gov (United States)

    Pan, Huang-Wei; Kuo, Ling-Chi; Huang, Shu-Yu; Wu, Meng-Yun; Juang, Yu-Hang; Lee, Chia-Wei; Chen, Hsin-Chieh; Wen, Ting Ting; Chao, Shiuh

    2018-01-01

    Silicon is a potential substrate material for the large-areal-size mirrors of the next-generation laser interferometer gravitational wave detector operated in cryogenics. Silicon nitride thin films uniformly deposited by a chemical vapor deposition method on large-size silicon wafers is a common practice in the silicon integrated circuit industry. We used plasma-enhanced chemical vapor deposition to deposit silicon nitride films on silicon and studied the physical properties of the films that are pertinent to application of mirror coatings for laser interferometer gravitational wave detectors. We measured and analyzed the structure, optical properties, stress, Young's modulus, and mechanical loss of the films, at both room and cryogenic temperatures. Optical extinction coefficients of the films were in the 10-5 range at 1550-nm wavelength. Room-temperature mechanical loss of the films varied in the range from low 10-4 to low 10-5 within the frequency range of interest. The existence of a cryogenic mechanical loss peak depended on the composition of the films. We measured the bond concentrations of N - H , Si - H , Si - N , and Si - Si bonds in the films and analyzed the correlations between bond concentrations and cryogenic mechanical losses. We proposed three possible two-level systems associated with the N - H , Si - H , and Si - N bonds in the film. We inferred that the dominant source of the cryogenic mechanical loss for the silicon nitride films is the two-level system of exchanging position between a H+ and electron lone pair associated with the N - H bond. Under our deposition conditions, superior properties in terms of high refractive index with a large adjustable range, low optical absorption, and low mechanical loss were achieved for films with lower nitrogen content and lower N - H bond concentration. Possible pairing of the silicon nitride films with other materials in the quarter-wave stack is discussed.

  6. Dual mechanical behaviour of hydrogen in stressed silicon nitride thin films

    International Nuclear Information System (INIS)

    Volpi, F.; Braccini, M.; Pasturel, A.; Devos, A.; Raymond, G.; Morin, P.

    2014-01-01

    In the present article, we report a study on the mechanical behaviour displayed by hydrogen atoms and pores in silicon nitride (SiN) films. A simple three-phase model is proposed to relate the physical properties (stiffness, film stress, mass density, etc.) of hydrogenated nanoporous SiN thin films to the volume fractions of hydrogen and pores. This model is then applied to experimental data extracted from films deposited by plasma enhanced chemical vapour deposition, where hydrogen content, stress, and mass densities range widely from 11% to 30%, −2.8 to 1.5 GPa, and 2.0 to 2.8 g/cm 3 , respectively. Starting from the conventional plotting of film's Young's modulus against film porosity, we first propose to correct the conventional calculation of porosity volume fraction with the hydrogen content, thus taking into account both hydrogen mass and concentration. The weight of this hydrogen-correction is found to evolve linearly with hydrogen concentration in tensile films (in accordance with a simple “mass correction” of the film density calculation), but a clear discontinuity is observed toward compressive stresses. Then, the effective volume occupied by hydrogen atoms is calculated taking account of the bond type (N-H or Si-H bonds), thus allowing a precise extraction of the hydrogen volume fraction. These calculations applied to tensile films show that both volume fractions of hydrogen and porosity are similar in magnitude and randomly distributed against Young's modulus. However, the expected linear dependence of the Young's modulus is clearly observed when both volume fractions are added. Finally, we show that the stiffer behaviour of compressive films cannot be only explained on the basis of this (hydrogen + porosity) volume fraction. Indeed this stiffness difference relies on a dual mechanical behaviour displayed by hydrogen atoms against the film stress state: while they participate to the stiffness in compressive films, hydrogen atoms mainly

  7. Improving the Microstructure and Electrical Properties of Aluminum Induced Polysilicon Thin Films Using Silicon Nitride Capping Layer

    Directory of Open Access Journals (Sweden)

    Min-Hang Weng

    2014-01-01

    Full Text Available We investigated the capping layer effect of SiNx (silicon nitride on the microstructure, electrical, and optical properties of poly-Si (polycrystalline silicon prepared by aluminum induced crystallization (AIC. The primary multilayer structure comprised Al (30 nm/SiNx (20 nm/a-Si (amorphous silicon layer (100 nm/ITO coated glass and was then annealed in a low annealing temperature of 350°C with different annealing times, 15, 30, 45, and 60 min. The crystallization properties were analyzed and verified by X-ray diffraction (XRD and Raman spectra. The grain growth was analyzed via optical microscope (OM and scanning electron microscopy (SEM. The improved electrical properties such as Hall mobility, resistivity, and dark conductivity were investigated by using Hall and current-voltage (I-V measurements. The results show that the amorphous silicon film has been effectively induced even at a low temperature of 350°C and a short annealing time of 15 min and indicate that the SiNx capping layer can improve the grain growth and reduce the metal content in the induced poly-Si film. It is found that the large grain size is over 20 μm and the carrier mobility values are over 80 cm2/V-s.

  8. Influence of the structural and compositional properties of PECVD silicon nitride layers on the passivation of AIGaN/GaN HEMTs

    NARCIS (Netherlands)

    Karouta, F.; Krämer, M.C.J.C.M.; Kwaspen, J.J.M.; Grzegorczyk, A.; Hageman, P.R.; Hoex, B.; Kessels, W.M.M.; Klootwijk, J.H.; Timmering, E.C.; Smit, M.K.; Wang, J.; Shiojima, K.

    2008-01-01

    We have investigated the influence of the structural and compositional properties of silicon nitride layers on the passivation of AlGaN/GaN HEMTs grown on sapphire substrates by assessing their continuous wave (CW) and pulsed current-voltage (I-V) characteristics. We have looked at the effect of

  9. Optical characterisation of III-V nitride-based multiphase and diluted magnetic semiconductors

    International Nuclear Information System (INIS)

    Wegscheider, M.

    2009-01-01

    The present work is devoted to the investigation of the optical properties of transition metal doped Gallium nitride. The Gallium nitride layers are epitaxially grown in a full metalorganic chemical vapour deposition process whereas the transition metals iron or manganese as well as the n and p-type dopants silicon and magnesium are incorporated simultaneously. Background and driving force of the realization of such material systems is basically the evocation of ferromagnetic spin alignment where free carriers ensure the correspondence between the localized spin state provided by the metal ions. The production of completely new devices for semiconductor industries based on the possibility to switch on or off the ferrimagnetic alignment by changing the free carrier concentration can be expected in the near future. In this context photoluminescence studies in the ultraviolet and mid infrared spectral range at temperatures between the liquid helium point and room temperature at atmospheric pressure were made. These measurements basically provide information on optical transitions between the conduction and valence band and deep defects as well as on crystal field forced transitions within the d-orbitals of the metal ion involved. In this context valuable knowledge could have been gained on doping concentrations, growth fashions and parameters, formation of secondary phases as well as on the doping efficiency and incorporation sites of the metal atoms. (author) [de

  10. A phototactic micromotor based on platinum nanoparticle decorated carbon nitride.

    Science.gov (United States)

    Ye, Zhenrong; Sun, Yunyu; Zhang, Hui; Song, Bo; Dong, Bin

    2017-11-30

    In this paper, we report a unique phototactic (both positive and negative) micromotor based on platinum nanoparticle decorated carbon nitride. The phototaxis relies on the self-diffusiophoretic mechanism and different surface modifications. The micromotor reported in the current study does not require the addition of any external fuels and shows versatile motion behaviour, i.e. start, stop, directional and programmable motion, which is controlled by light. In addition, since the actuation of the precipitated micromotors at the bottom of a solution using light results in the opacity changes from transparent to translucent, we anticipate that the current micromotor may have potential application in the field of smart windows.

  11. Effect of pyrolysis atmospheres on the morphology of polymer-derived silicon oxynitrocarbide ceramic films coated aluminum nitride surface and the thermal conductivity of silicone rubber composites

    Science.gov (United States)

    Chiu, Hsien T.; Sukachonmakul, Tanapon; Wang, Chen H.; Wattanakul, Karnthidaporn; Kuo, Ming T.; Wang, Yu H.

    2014-02-01

    Amorphous silicon oxycarbide (SiOC) and silicon oxynitrocarbide (SiONC) ceramic films coated aluminum nitride (AlN) were prepared by using preceramic-polysilazane (PSZ) with dip-coating method, followed by pyrolysis at 700 °C in different (air, Ar, N2 and NH3) atmospheres to converted PSZ into SiOCair and SiONC(Ar,N2andNH3) ceramic. The existence of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface was characterized by FTIR, XRD and XPS. The interfacial adhesion between silicone rubber and AlN was significantly improved after the introduction of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. It can be observed from AFM that the pyrolysis of PSZ at different atmosphere strongly affected to films morphology on AlN surface as SiOCair and SiONCNH3 ceramic films were more flat and smooth than SiONCN2 and SiONCAr ceramic films. Besides, the enhancement of the thermal conductivity of silicone rubber composites was found to be related to the decrease in the surface roughness of SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. This present work provided an alternative surface modification of thermally conductive fillers to improve the thermal conductivity of silicon rubber composites by coating with amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films.

  12. Surface modification of aluminum nitride by polysilazane and its polymer-derived amorphous silicon oxycarbide ceramic for the enhancement of thermal conductivity in silicone rubber composite

    Science.gov (United States)

    Chiu, Hsien Tang; Sukachonmakul, Tanapon; Kuo, Ming Tai; Wang, Yu Hsiang; Wattanakul, Karnthidaporn

    2014-02-01

    Polysilazane (PSZ) and its polymer-derived amorphous silicon oxycarbide (SiOC) ceramic were coated on aluminum nitride (AlN) by using a dip-coating method to allow moisture-crosslinking of PSZ on AlN, followed by heat treatment at 700 °C in air to convert PSZ into SiOC on AlN. The results from FTIR, XPS and SEM indicated that the surface of AlN was successfully coated by PSZ and SiOC film. It was found that the introduction of PSZ and SiOC film help improve in the interfacial adhesion between the modified AlN (PSZ/AlN and SiOC/AlN) and silicone rubber lead to the increase in the thermal conductivity of the composites since the thermal boundary resistance at the filler-matrix interface was decreased. However, the introduction of SiOC as an intermediate layer between AlN and silicone rubber could help increase the thermal energy transport at the filler-matrix interface rather than using PSZ. This result was due to the decrease in the surface roughness and thickness of SiOC film after heat treatment at 700 °C in air. Thus, in the present work, a SiOC ceramic coating could provide a new surface modification for the improvement of the interfacial adhesion between the thermally conductive filler and the matrix in which can enhance the thermal conductivity of the composites.

  13. Preparation and characterization of silicon nitride (Si−N)-coated carbon fibers and their effects on thermal properties in composites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeon-Hye [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of); Nano& Advanced Materials Engineering, Jeonju University, Jeonju 560-759 (Korea, Republic of); Han, Woong [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of); Lee, Hae-seong [Nano& Advanced Materials Engineering, Jeonju University, Jeonju 560-759 (Korea, Republic of); Min, Byung-Gak [Department of Polymer Science & Engineering, Korea National University of Transportation, Chungju 380-702 (Korea, Republic of); Kim, Byung-Joo, E-mail: ap2-kbj@hanmail.net [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of)

    2015-10-15

    Graphical abstract: We report preparation and characterization of silicon nitride (Si−N)-coated carbon fibers and their effects on thermal properties in composites. Thermally composites showed enhanced thermal conductivity increasing from up to 59% by the thermal network. - Highlights: • A new method of Si−N coating on carbon fibers was reported. • Silane layer were successfully converted to Si−N layer on carbon fiber surface. • Si−N formation was confirmed by FT-IR, XPS, and EDX. • Thermal conductivity of Si−N coated CF composites were enhanced to 0.59 W/mK. - Abstract: This study investigates the effect of silicon nitride (Si−N)-coated carbon fibers on the thermal conductivity of carbon-fiber-reinforced epoxy composite. The surface properties of the Si−N-coated carbon fibers (SiNCFs) were observe using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy, and the thermal stability was analyzed using thermogravimetric analysis. SiNCFs were fabricated through the wet thermal treatment of carbon fibers (Step 1: silane finishing of the carbon fibers; Step 2: high-temperature thermal treatment in a N{sub 2}/NH{sub 3} environment). As a result, the Si−N belt was exhibited by SEM. The average thickness of the belt were 450–500 nm. The composition of Si−N was the mixture of Si−N, Si−O, and C−Si−N as confirmed by XPS. Thermal residue of the SiNCFs in air was enhanced from 3% to 50%. Thermal conductivity of the composites increased from 0.35 to 0.59 W/mK after Si−N coating on carbon surfaces.

  14. Laterally vibrating resonator based elasto-optic modulation in aluminum nitride

    Directory of Open Access Journals (Sweden)

    Siddhartha Ghosh

    2016-06-01

    Full Text Available An integrated strain-based optical modulator driven by a piezoelectric laterally vibrating resonator is demonstrated. The composite structure consists of an acoustic Lamb wave resonator, in which a photonic racetrack resonator is internally embedded to enable overlap of the guided optical mode with the induced strain field. Both types of resonators are defined in an aluminum nitride (AlN thin film, which rests upon a layer of silicon dioxide in order to simultaneously define optical waveguides, and the structure is released from a silicon substrate. Lateral vibrations produced by the acoustic resonator are transferred through a partially etched layer of AlN, producing a change in the effective index of the guided wave through the interaction of the strain components with the AlN elasto-optic (p coefficients. Optical modulation through the elasto-optic effect is demonstrated at electromechanically actuated frequencies of 173 MHz and 843 MHz. This device geometry further enables the development of MEMS-based optical modulators in addition to studying elasto-optic interactions in suspended piezoelectric thin films.

  15. Silicon Alloying On Aluminium Based Alloy Surface

    International Nuclear Information System (INIS)

    Suryanto

    2002-01-01

    Silicon alloying on surface of aluminium based alloy was carried out using electron beam. This is performed in order to enhance tribological properties of the alloy. Silicon is considered most important alloying element in aluminium alloy, particularly for tribological components. Prior to silicon alloying. aluminium substrate were painted with binder and silicon powder and dried in a furnace. Silicon alloying were carried out in a vacuum chamber. The Silicon alloyed materials were assessed using some techniques. The results show that silicon alloying formed a composite metal-non metal system in which silicon particles are dispersed in the alloyed layer. Silicon content in the alloyed layer is about 40% while in other place is only 10.5 %. The hardness of layer changes significantly. The wear properties of the alloying alloys increase. Silicon surface alloying also reduced the coefficient of friction for sliding against a hardened steel counter face, which could otherwise be higher because of the strong adhesion of aluminium to steel. The hardness of the silicon surface alloyed material dropped when it underwent a heating cycle similar to the ion coating process. Hence, silicon alloying is not a suitable choice for use as an intermediate layer for duplex treatment

  16. Corrosion stability of cermets on the base of titanium nitride

    International Nuclear Information System (INIS)

    Kajdash, O.N.; Marinich, M.A.; Kuzenkova, M.A.; Manzheleev, I.V.

    1991-01-01

    Corrosion resistance of titanium nitride and its cermets in 5% of HCl, 7% of HNO 3 , 10% of H 2 SO 4 is studied. It is established that alloys TiN-Ni-Mo alloyed with chromium (from 10 to 15%) possess the highest corrosion resistance. Cermet TiN-Cr has the higher stability than titanium nitride due to formation of binary nitride (Ti, Cr)N

  17. Iron-based alloy and nitridation treatment for PEM fuel cell bipolar plates

    Science.gov (United States)

    Brady, Michael P [Oak Ridge, TN; Yang, Bing [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN

    2010-11-09

    A corrosion resistant electrically conductive component that can be used as a bipolar plate in a PEM fuel cell application is composed of an alloy substrate which has 10-30 wt. % Cr, 0.5 to 7 wt. % V, and base metal being Fe, and a continuous surface layer of chromium nitride and vanadium nitride essentially free of base metal. A oxide layer of chromium vanadium oxide can be disposed between the alloy substrate and the continuous surface nitride layer. A method to prepare the corrosion resistant electrically conductive component involves a two-step nitridization sequence by exposing the alloy to a oxygen containing gas at an elevated temperature, and subsequently exposing the alloy to an oxygen free nitrogen containing gas at an elevated temperature to yield a component where a continuous chromium nitride layer free of iron has formed at the surface.

  18. Development of microwave amplifier based on gallium nitride semiconductor structures

    International Nuclear Information System (INIS)

    Pavlov, D.Yi.; Prokopenko, O.V.; Tsvyirko, Yu.A.; Pavlov, Yi.L.

    2014-01-01

    Microwave properties of microwave amplifier based on gallium nitride (GN) semiconductor structures has been calculated numerically. We proposed the method of numerical calculation of device. This method is accurately sets the value of its characteristics depending on the elements that are used in design of amplifier. It is shown that the device based on GN HEMT-transistors could have amplification factor about 50 dB, while its sizes are 27x18x5.5 mm 3 . Also was provided the absolute stability an amplifier in the whole operating frequency range. It is quite important when using this type of amplifiers in different conditions of exploitation and various fields of use the radioelectronic equipment

  19. RF plasma nitriding of severely deformed iron-based alloys

    International Nuclear Information System (INIS)

    Ferkel, H.; Glatzer, M.; Estrin, Y.; Valiev, R.Z.; Blawert, C.; Mordike, B.L.

    2003-01-01

    The effect of severe plastic deformation by cold high pressure torsion (HPT) on radio frequency (RF) plasma nitriding of pure iron, as well as St2K50 and X5CrNi1810 steels was investigated. Nitriding was carried out for 3 h in a nitrogen atmosphere at a pressure of 10 -5 bar and temperatures of 350 and 400 deg. C. Nitrided specimens were analysed by scanning electron microscopy (SEM), X-ray diffraction and micro hardness measurements. It was found that HPT enhances the effect of nitriding leading almost to doubling of the thickness of the nitrided layer for pure iron and the high alloyed steel. The largest increase in hardness was observed when HPT was combined with RF plasma nitriding at 350 deg. C. In the case of pure iron, the X-ray diffraction spectra showed the formation of ε and γ' nitrides in the compound layer, with a preferential formation of γ' at the expense of the α-phase at the higher nitriding temperature. The corresponding surface hardness was up to 950 HV0.01. While the HPT-processed St2K50 exhibits both nitride phases after nitriding at 350 deg. C, only the γ'-phase was observed after nitriding at 400 deg. C. A surface hardness of up to 1050 HV0.01 was measured for this steel. The high alloyed steel X5CrNi1810 exhibited the highest increase in surface hardness when HPT was combined with nitriding at 350 deg. C. The surface hardness of this steel was greater than 1400 HV0.025. The XRD analyses indicate the formation of the expanded austenite (S-phase) in the surface layer as a result of RF plasma nitriding. Furthermore, after HPT X5CrNi1810 was transformed completely into deformation martensite which did not transform back to austenite under thermochemical treatment. However, in the case of nitriding of the HPT-processed high alloyed steel at 400 deg. C, the formation of the S-phase was less pronounced. In view of the observed XRD peak broadening, the formation of nitrides, such as e.g. CrN, cannot be ruled out

  20. High resolution medium energy ion scattering study of silicon oxidation and oxy nitridation

    International Nuclear Information System (INIS)

    Gusev, E.P.; Lu, H.C.; Garfunkel, E.; Gustafsson, T.

    1998-01-01

    Full text: Silicon oxide is likely to remain the material of choice for gate oxides in microelectronics for the foreseeable future. As device become ever smaller and faster, the thickness of these layers in commercial products is predicted to be less than 50 Angstroms in just a few years. An understanding of such devices will therefore likely to be based on microscopic concepts and should now be investigated by atomistic techniques. With medium energy ion scattering (MEIS) using an electrostatic energy analyzer, depth profiling of thin (<60 Angstroms) silicon oxide films on Si(100) with 3 - 5 Angstroms depth resolution in the near region has been done. The growth mechanism of thin oxide films on Si(100) has been studied, using sequential oxygen isotope exposures. It is found that the oxide films are stoichiometric to within approx. 10 Angstroms of the interface. It is also found that the oxidation reactions occur at the surface, in the transition region and at interface, with only the third region being included in the conventional (Deal-Grove) model for oxide formation. Nitrogen is sometimes added to gate oxides, as it has been found empirically that his improves some of the electrical properties. The role, location and even the amount of nitrogen that exists in such films are poorly understood, and represent interesting analytical challenges. MEIS data will be presented that address these questions, measured for a number of different processing conditions. We have recently demonstrated how to perform nitrogen nano-engineering in such ultrathin gate dielectrics, and these results will also be discussed

  1. Preparation and characterization of electrochemically deposited carbon nitride films on silicon substrate

    International Nuclear Information System (INIS)

    Yan Xingbin; Xu Tao; Chen Gang; Yang Shengrong; Liu Huiwen; Xue Qunji

    2004-01-01

    Carbon nitride films (CN x films) were deposited on Si(100) substrates by the electrolysis of methanol-urea solution at high voltage, atmospheric pressure, and low temperature. The microstructure and morphology of the resulting CN x films were analysed by means of Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometry (FTIR), x-ray diffraction (XRD), and atomic force microscopy. The tribological properties of the CN x films were examined on an UMT-2MT friction and wear test rig. The Raman spectrum showed two characteristic bands: a graphite G band and a disordered D band of carbon, which suggested the presence of an amorphous carbon matrix. XPS and FTIR measurements suggested the existence of both single and double carbon-nitride bonds in the film and the hydrogenation of the carbon nitride phase. The XRD spectrum showed various peaks of different d values, which could confirm the existence of the polycrystalline carbon nitride phase. The hydrogenated CN x films were compact and uniform, with a root mean square roughness of about 18 nm. The films showed excellent friction-reduction and wear-resistance, with the friction coefficient in the stable phase being about 0.08. In addition, the growth mechanism of the CN x films in liquid phase electro-deposition was discussed as well. It was assumed that the molecules of CH 3 OH and CO(NH 2 ) 2 were polarized under high electric field, and the CN x film was formed on the substrate through the reaction of the -CH 3 and -NH 2 groups on the cathode

  2. Development of III-nitride semiconductors by molecular beam epitaxy and cluster beam epitaxy and fabrication of LEDs based on indium gallium nitride MQWs

    Science.gov (United States)

    Chen, Tai-Chou Papo

    The family of III-Nitrides (the binaries InN, GaN, AIN, and their alloys) is one of the most important classes of semiconductor materials. Of the three, Indium Nitride (InN) and Aluminum Nitride (AIN) have been investigated much less than Gallium Nitride (GaN). However, both of these materials are important for optoelectronic infrared and ultraviolet devices. In particular, since InN was found recently to be a narrow gap semiconductor (Eg=0.7eV), its development should extend the applications of nitride semiconductors to the spectral region appropriate to fiber optics communication and photovoltaic applications. Similarly, the development of AIN should lead to deep UV light emitting diodes (LEDs). The first part of this work addresses the evaluation of structural, optical and transport properties of InN films grown by two different deposition methods. In one method, active nitrogen was produced in the form of nitrogen radicals by a radio frequency (RF) plasma-assisted source. In an alternative method, active nitrogen was produced in the form of clusters containing approximately 2000 nitrogen molecules. These clusters were produced by adiabatic expansion from high stagnation pressure through a narrow nozzle into vacuum. The clusters were singly or doubly ionized with positive charge by electron impact and accelerated up to approximately 20 to 25 KV prior to their disintegration on the substrate. Due to the high local temperature produced during the impact of clusters with the substrate, this method is suitable for the deposition of InN at very low temperatures. The films are auto-doped n-type with carrier concentrations varying from 3 x 1018 to 1020 cm-3 and the electron effective mass of these films was determined to be 0.09m0. The majority of the AIN films was grown by the cluster beam epitaxy method and was doped n- and p- type by incorporating silicon (Si) and magnesium (Mg) during the film deposition. All films were grown under Al-rich conditions at relatively

  3. Joining technique of silicon nitride and silicon carbide in a mixture and/or in contact with high-melting metals and alloys

    International Nuclear Information System (INIS)

    Mueller-Zell, A.

    1980-01-01

    The following work gives a survey on possible joining techniques of silicon nitride (Si 3 N 4 ) and silicon carbide (SiC) in a mixture and/or in contact with high-melting metals and alloys. The problem arose because special ceramic materials such as Si 3 N 4 and SiC are to be used in gas turbines. The special ceramics in use may unavoidably come into contact with metals or the one hand, or form intended composite systems with them on the other hand, like e.g. the joining of a Si 3 N 4 disc with a metallic drive axis or ceramic blades with a metal wheel. The mixed body of X% ceramic (Si 3 N 4 , SiC) and Y% metal powder were prepared depending on the material combination at 1200 0 C-1750 0 C by hot-pressing or at 1200 0 C-2050 0 C by hot-pressing or pressureless sintering. The following possible ways were chosen as interlaminar bonding ceramic/metal/ceramic: on the one hand pressure welding (composite hot pressing) and the solid-state bonding in direct contact and by means of artificially included transition mixed layers, as well as material intermediate layers between metal and ceramic and on the other hand, soldering with active solder with molten phase. (orig./RW) [de

  4. Novel Cyclosilazane-Type Silicon Precursor and Two-Step Plasma for Plasma-Enhanced Atomic Layer Deposition of Silicon Nitride.

    Science.gov (United States)

    Park, Jae-Min; Jang, Se Jin; Lee, Sang-Ick; Lee, Won-Jun

    2018-03-14

    We designed cyclosilazane-type silicon precursors and proposed a three-step plasma-enhanced atomic layer deposition (PEALD) process to prepare silicon nitride films with high quality and excellent step coverage. The cyclosilazane-type precursor, 1,3-di-isopropylamino-2,4-dimethylcyclosilazane (CSN-2), has a closed ring structure for good thermal stability and high reactivity. CSN-2 showed thermal stability up to 450 °C and a sufficient vapor pressure of 4 Torr at 60 °C. The energy for the chemisorption of CSN-2 on the undercoordinated silicon nitride surface as calculated by density functional theory method was -7.38 eV. The PEALD process window was between 200 and 500 °C, with a growth rate of 0.43 Å/cycle. The best film quality was obtained at 500 °C, with hydrogen impurity of ∼7 atom %, oxygen impurity less than 2 atom %, low wet etching rate, and excellent step coverage of ∼95%. At 300 °C and lower temperatures, the wet etching rate was high especially at the lower sidewall of the trench pattern. We introduced the three-step PEALD process to improve the film quality and the step coverage on the lower sidewall. The sequence of the three-step PEALD process consists of the CSN-2 feeding step, the NH 3 /N 2 plasma step, and the N 2 plasma step. The H radicals in NH 3 /N 2 plasma efficiently remove the ligands from the precursor, and the N 2 plasma after the NH 3 plasma removes the surface hydrogen atoms to activate the adsorption of the precursor. The films deposited at 300 °C using the novel precursor and the three-step PEALD process showed a significantly improved step coverage of ∼95% and an excellent wet etching resistance at the lower sidewall, which is only twice as high as that of the blanket film prepared by low-pressure chemical vapor deposition.

  5. Silicone-based Dielectric Elastomers

    DEFF Research Database (Denmark)

    Skov, Anne Ladegaard

    Efficient conversion of energy from one form to another (transduction) is an important topic in our daily day, and it is a necessity in moving away from the fossil based society. Dielectric elastomers hold great promise as soft transducers, since they are compliant and light-weight amongst many...... energy efficient solutions are highly sought. These properties allow for interesting products ranging very broadly, e.g. from eye implants over artificial skins over soft robotics to huge wave energy harvesting plants. All these products utilize the inherent softness and compliance of the dielectric...... elastomer transducers. The subject of this thesis is improvement of properties of silicone-based dielectric elastomers with special focus on design guides towards electrically, mechanically, and electromechanically reliable elastomers. Strategies for improving dielectric elastomer performance are widely...

  6. Discrete Charge Storage Nonvolatile Memory Based on Si Nanocrystals with Nitridation Treatment

    International Nuclear Information System (INIS)

    Xian-Gao, Zhang; Kun-Ji, Chen; Zhong-Hui, Fang; Xin-Ye, Qian; Guang-Yuan, Liu; Xiao-Fan, Jiang; Zhong-Yuan, Ma; Jun, Xu; Xin-Fan, Huang; Jian-Xin, Ji; Fei, He; Kuang-Bao, Song; Jun, Zhang; Hui, Wan; Rong-Hua, Wang

    2010-01-01

    A nonvolatile memory device with nitrided Si nanocrystals embedded in a Boating gate was fabricated. The uniform Si nanocrystals with high density (3 × 10 11 cm −2 ) were deposited on ultra-thin tunnel oxide layer (∼ 3 nm) and followed by a nitridation treatment in ammonia to form a thin silicon nitride layer on the surface of nanocrystals. A memory window of 2.4 V was obtained and it would be larger than 1.3 V after ten years from the extrapolated retention data. The results can be explained by the nitrogen passivation of the surface traps of Si nanocrystals, which slows the charge loss rate. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  7. III-nitride based light emitting diodes and applications

    CERN Document Server

    Han, Jung; Amano, Hiroshi; Morkoç, Hadis

    2013-01-01

    Light emitting diodes (LEDs) are already used in traffic signals, signage lighting, and automotive applications. However, its ultimate goal is to replace traditional illumination through LED lamps since LED lighting significantly reduces energy consumption and cuts down on carbon-dioxide emission. Despite dramatic advances in LED technologies (e.g., growth, doping and processing technologies), however, there remain critical issues for further improvements yet to be achieved for the realization of solid-state lighting. This book aims to provide the readers with some contemporary LED issues, which have not been comprehensively discussed in the published books and, on which the performance of LEDs is seriously dependent. For example, most importantly, there must be a breakthrough in the growth of high-quality nitride semiconductor epitaxial layers with a low density of dislocations, in particular, in the growth of Al-rich and and In-rich GaN-based semiconductors. The materials quality is directly dependent on th...

  8. Silicon nitride and intrinsic amorphous silicon double antireflection coatings for thin-film solar cells on foreign substrates

    International Nuclear Information System (INIS)

    Li, Da; Kunz, Thomas; Wolf, Nadine; Liebig, Jan Philipp; Wittmann, Stephan; Ahmad, Taimoor; Hessmann, Maik T.; Auer, Richard; Göken, Mathias; Brabec, Christoph J.

    2015-01-01

    Hydrogenated intrinsic amorphous silicon (a-Si:H) was investigated as a surface passivation method for crystalline silicon thin film solar cells on graphite substrates. The results of the experiments, including quantum efficiency and current density-voltage measurements, show improvements in cell performance. This improvement is due to surface passivation by an a-Si:H(i) layer, which increases the open circuit voltage and the fill factor. In comparison with our previous work, we have achieved an increase of 0.6% absolute cell efficiency for a 40 μm thick 4 cm 2 aperture area on the graphite substrate. The optical properties of the SiN x /a-Si:H(i) stack were studied using spectroscopic ellipsometer techniques. Scanning transmission electron microscopy inside a scanning electron microscope was applied to characterize the cross section of the SiN x /a-Si:H(i) stack using focus ion beam preparation. - Highlights: • We report a 10.8% efficiency for thin-film silicon solar cell on graphite. • Hydrogenated intrinsic amorphous silicon was applied for surface passivation. • SiN x /a-Si:H(i) stacks were characterized by spectroscopic ellipsometer techniques. • Cross-section micrograph was obtained by scanning transmission electron microscopy. • Quantum efficiency and J-V measurements show improvements in the cell performance

  9. Studies of the composition, tribology and wetting behavior of silicon nitride films formed by pulsed reactive closed-field unbalanced magnetron sputtering

    International Nuclear Information System (INIS)

    Yao, Zh.Q.; Yang, P.; Huang, N.; Wang, J.; Wen, F.; Leng, Y.X.

    2006-01-01

    Silicon nitride films were formed by pulsed reactive closed-field unbalanced magnetron sputtering of high purity Si targets in an Ar-N 2 mixture. The effects of N 2 fraction on the chemical composition, and tribological and wetting behaviors were investigated. The films deposited at a high N 2 fraction were consistently N-rich. The surface microstructure changed from continuous granular surrounded by tiny void regions to a homogeneous and dense microstructure, and densitied as the N 2 fraction is increased. The as-deposited films have a relatively low friction coefficient and better wear resistance than 316L stainless steel under dry sliding friction and experienced only abrasive wear. The decreased surface roughness and increased nitrogen incorporation in the film give rise to increased contact angle with double-stilled water from 24 deg. to 49.6 deg. To some extent, the silicon nitride films deposited are hydrophilic in nature

  10. Luminescence properties of Ce3+-activated alkaline earth silicon nitride M2Si5N8 (M = Ca, Sr, Ba) materials

    NARCIS (Netherlands)

    Li, Y.Q.; With, de G.; Hintzen, H.T.J.M.

    2006-01-01

    The luminescence properties of Ce3+, Li+ or Na+ co-doped alkaline-earth silicon nitride M2Si5N8 (M=Ca, Sr, Ba) are reported. The solubility of Ce3+ and optical properties of M2-2xCexLixSi5N8 (x0.1) materials have been investigated as function of the cerium concentration by X-ray powder diffraction

  11. Silicon nanowire-based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Stelzner, Th; Pietsch, M; Andrae, G; Falk, F; Ose, E; Christiansen, S [Institute of Photonic Technology, Albert-Einstein-Strasse 9, D-07745 Jena (Germany)], E-mail: thomas.stelzner@ipht-jena.de

    2008-07-23

    The fabrication of silicon nanowire-based solar cells on silicon wafers and on multicrystalline silicon thin films on glass is described. The nanowires show a strong broadband optical absorption, which makes them an interesting candidate to serve as an absorber in solar cells. The operation of a solar cell is demonstrated with n-doped nanowires grown on a p-doped silicon wafer. From a partially illuminated area of 0.6 cm{sup 2} open-circuit voltages in the range of 230-280 mV and a short-circuit current density of 2 mA cm{sup -2} were obtained.

  12. Silicon nanowire-based solar cells

    International Nuclear Information System (INIS)

    Stelzner, Th; Pietsch, M; Andrae, G; Falk, F; Ose, E; Christiansen, S

    2008-01-01

    The fabrication of silicon nanowire-based solar cells on silicon wafers and on multicrystalline silicon thin films on glass is described. The nanowires show a strong broadband optical absorption, which makes them an interesting candidate to serve as an absorber in solar cells. The operation of a solar cell is demonstrated with n-doped nanowires grown on a p-doped silicon wafer. From a partially illuminated area of 0.6 cm 2 open-circuit voltages in the range of 230-280 mV and a short-circuit current density of 2 mA cm -2 were obtained

  13. Damage Mechanisms and Controlled Crack Propagation in a Hot Pressed Silicon Nitride Ceramic. Ph.D. Thesis - Northwestern Univ., 1993

    Science.gov (United States)

    Calomino, Anthony Martin

    1994-01-01

    The subcritical growth of cracks from pre-existing flaws in ceramics can severely affect the structural reliability of a material. The ability to directly observe subcritical crack growth and rigorously analyze its influence on fracture behavior is important for an accurate assessment of material performance. A Mode I fracture specimen and loading method has been developed which permits the observation of stable, subcritical crack extension in monolithic and toughened ceramics. The test specimen and procedure has demonstrated its ability to generate and stably propagate sharp, through-thickness cracks in brittle high modulus materials. Crack growth for an aluminum oxide ceramic was observed to be continuously stable throughout testing. Conversely, the fracture behavior of a silicon nitride ceramic exhibited crack growth as a series of subcritical extensions which are interrupted by dynamic propagation. Dynamic initiation and arrest fracture resistance measurements for the silicon nitride averaged 67 and 48 J/sq m, respectively. The dynamic initiation event was observed to be sudden and explosive. Increments of subcritical crack growth contributed to a 40 percent increase in fracture resistance before dynamic initiation. Subcritical crack growth visibly marked the fracture surface with an increase in surface roughness. Increments of subcritical crack growth loosen ceramic material near the fracture surface and the fracture debris is easily removed by a replication technique. Fracture debris is viewed as evidence that both crack bridging and subsurface microcracking may be some of the mechanisms contributing to the increase in fracture resistance. A Statistical Fracture Mechanics model specifically developed to address subcritical crack growth and fracture reliability is used together with a damaged zone of material at the crack tip to model experimental results. A Monte Carlo simulation of the actual experiments was used to establish a set of modeling input

  14. Silicon nitride grids are compatible with correlative negative staining electron microscopy and tip-enhanced Raman spectroscopy for use in the detection of micro-organisms.

    Science.gov (United States)

    Lausch, V; Hermann, P; Laue, M; Bannert, N

    2014-06-01

    Successive application of negative staining transmission electron microscopy (TEM) and tip-enhanced Raman spectroscopy (TERS) is a new correlative approach that could be used to rapidly and specifically detect and identify single pathogens including bioterrorism-relevant viruses in complex samples. Our objective is to evaluate the TERS-compatibility of commonly used electron microscopy (EM) grids (sample supports), chemicals and negative staining techniques and, if required, to devise appropriate alternatives. While phosphortungstic acid (PTA) is suitable as a heavy metal stain, uranyl acetate, paraformaldehyde in HEPES buffer and alcian blue are unsuitable due to their relatively high Raman scattering. Moreover, the low thermal stability of the carbon-coated pioloform film on copper grids (pioloform grids) negates their utilization. The silicon in the cantilever of the silver-coated atomic force microscope tip used to record TERS spectra suggested that Si-based grids might be employed as alternatives. From all evaluated Si-based TEM grids, the silicon nitride (SiN) grid was found to be best suited, with almost no background Raman signals in the relevant spectral range, a low surface roughness and good particle adhesion properties that could be further improved by glow discharge. Charged SiN grids have excellent particle adhesion properties. The use of these grids in combination with PTA for contrast in the TEM is suitable for subsequent analysis by TERS. The study reports fundamental modifications and optimizations of the negative staining EM method that allows a combination with near-field Raman spectroscopy to acquire a spectroscopic signature from nanoscale biological structures. This should facilitate a more precise diagnosis of single viral particles and other micro-organisms previously localized and visualized in the TEM. © 2014 The Society for Applied Microbiology.

  15. Electronic structure of nitride-based quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Winkelnkemper, Momme

    2008-11-07

    In the present work the electronic and optical properties of In{sub x}Ga{sub 1-x}N/GaN and GaN/AlN QDs are studied by means of eight-band k.p theory. Experimental results are interpreted in detail using the theoretical results. The k.p model for the QD electronicstructure calculations accounts for strain, piezo- and pyroelectric effects, spin-orbit and crystal-field splitting, and is implemented for arbitrarily shaped QDs on a finite differences grid. Few-particle corrections are included using the self-consistent Hartree method. Band parameters for the wurtzite and zinc-blende phases of GaN, AlN, and InN are derived from first-principle G{sub 0}W{sub 0} band-structure calculations. Reliable values are also provided for parameters that have not been determined experimentally yet. The electronic properties of nitride QDs are dominated by the large built-in piezo- and pyroelectric fields, which lead to a pronounced red-shift of excitonic transition energies and extremely long radiative lifetimes in large GaN/AlN QDs. In In{sub x}Ga{sub 1-x}N/GaN QDs these fields induce a pronounced dependence of the radiative excitonic lifetimes on the exact QD shape and composition. It is demonstrated that the resulting variations of the radiative lifetimes in an inhomogeneous QD ensemble are the origin of the multi-exponential luminescence decay frequently observed in time-resolved ensemble measurements on In{sub x}Ga{sub 1-x}N/GaN QDs. A polarization mechanism in nitride QDs based on strain-induced valence-band mixing effects is discovered. Due to the valence-band structure of wurtzite group-III nitrides and the specific strain situation in c-plane QDs, the confined hole states are formed predominantly by the two highest valence bands. In particular, the hole ground state (h{sub 0} {identical_to} h{sub A}) is formed by the A band, and the first excited hole state (h{sub 1} {identical_to} h{sub B}) by the B band. It is shown that the interband transitions involving h{sub A} or h

  16. Silicon based ultrafast optical waveform sampling

    DEFF Research Database (Denmark)

    Ji, Hua; Galili, Michael; Pu, Minhao

    2010-01-01

    A 300 nmx450 nmx5 mm silicon nanowire is designed and fabricated for a four wave mixing based non-linear optical gate. Based on this silicon nanowire, an ultra-fast optical sampling system is successfully demonstrated using a free-running fiber laser with a carbon nanotube-based mode-locker as th......A 300 nmx450 nmx5 mm silicon nanowire is designed and fabricated for a four wave mixing based non-linear optical gate. Based on this silicon nanowire, an ultra-fast optical sampling system is successfully demonstrated using a free-running fiber laser with a carbon nanotube-based mode......-locker as the sampling source. A clear eye-diagram of a 320 Gbit/s data signal is obtained. The temporal resolution of the sampling system is estimated to 360 fs....

  17. Proton irradiation effects on gallium nitride-based devices

    Science.gov (United States)

    Karmarkar, Aditya P.

    Proton radiation effects on state-of-the-art gallium nitride-based devices were studied using Schottky diodes and high electron-mobility transistors. The device degradation was studied over a wide range of proton fluences. This study allowed for a correlation between proton irradiation effects between different types of devices and enhanced the understanding of the mechanisms responsible for radiation damage in GaN-based devices. Proton irradiation causes reduced carrier concentration and increased series resistance and ideality factor in Schottky diodes. 1.0-MeV protons cause greater degradation than 1.8-MeV protons because of their higher non-ionizing energy loss. The displacement damage in Schottky diodes recovers during annealing. High electron-mobility transistors exhibit extremely high radiation tolerance, continuing to perform up to a fluence of ˜1014 cm-2 of 1.8-MeV protons. Proton irradiation creates defect complexes in the thin-film structure. Decreased sheet carrier mobility due to increased carrier scattering and decreased sheet carrier density due to carrier removal by the defect centers are the primary damage mechanisms. Interface disorder at either the Schottky or the Ohmic contact plays a relatively unimportant part in overall device degradation in both Schottky diodes and high electron-mobility transistors.

  18. A Modified Nitride-Based Fuel for Long Core Life and Proliferation Resistance

    International Nuclear Information System (INIS)

    Ebbinghaus, B; Choi, J; Meier, T

    2003-01-01

    A modified nitride-based uranium fuel to support the small, secured, transportable, and autonomous reactor (SSTAR) concept is initiated at Lawrence Livermore National laboratory (LLNL). This project centers on the evaluation of modified uranium nitride fuels imbedded with other inert (e.g. ZrN), neutron-absorbing (e.g. HfN) , or breeding (e.g. ThN) nitrides to enhance the fuel properties to achieve long core life with a compact reactor design. A long-life fuel could minimize the need for on-site refueling and spent-fuel storage. As a result, it could significantly improve the proliferation resistance of the reactor/fuel systems. This paper discusses the potential benefits and detriments of modified nitride-based fuels using the criteria of compactness, long-life, proliferation resistance, fuel safety, and waste management. Benefits and detriments are then considered in recommending a select set of compositions for further study

  19. Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-06-15

    The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

  20. DNA Physical Mapping via the Controlled Translocation of Single Molecules through a 5-10nm Silicon Nitride Nanopore

    Science.gov (United States)

    Stein, Derek; Reisner, Walter; Jiang, Zhijun; Hagerty, Nick; Wood, Charles; Chan, Jason

    2009-03-01

    The ability to map the binding position of sequence-specific markers, including transcription-factors, protein-nucleic acids (PNAs) or deactivated restriction enzymes, along a single DNA molecule in a nanofluidic device would be of key importance for the life-sciences. Such markers could give an indication of the active genes at particular stage in a cell's transcriptional cycle, pinpoint the location of mutations or even provide a DNA barcode that could aid in genomics applications. We have developed a setup consisting of a 5-10 nm nanopore in a 20nm thick silicon nitride film coupled to an optical tweezer setup. The translocation of DNA across the nanopore can be detected via blockades in the electrical current through the pore. By anchoring one end of the translocating DNA to an optically trapped microsphere, we hope to stretch out the molecule in the nanopore and control the translocation speed, enabling us to slowly scan across the genome and detect changes in the baseline current due to the presence of bound markers.

  1. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    Science.gov (United States)

    Reyes, R.; Cremona, M.; Achete, C. A.

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq3) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq3/Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  2. Oxidation effects on the mechanical properties of SiC fiber-reinforced reaction-bonded silicon nitride matrix composites

    Science.gov (United States)

    Bhatt, Ramakrishna T.

    1989-01-01

    The room temperature mechanical properties of SiC fiber reinforced reaction bonded silicon nitride composites were measured after 100 hrs exposure at temperatures to 1400 C in nitrogen and oxygen environments. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers in a reaction bonded Si3N4 matrix. The results indicate that composites heat treated in a nitrogen environment at temperatures to 1400 C showed deformation and fracture behavior equivalent to that of the as-fabricated composites. Also, the composites heat treated in an oxidizing environment beyond 400 C yielded significantly lower tensile strength values. Specifically in the temperature range from 600 to 1000 C, composites retained approx. 40 percent of their as-fabricated strength, and those heat treated in the temperatures from 1200 to 1400 C retained 70 percent. Nonetheless, for all oxygen heat treatment conditions, composite specimens displayed strain capability beyond the matrix fracture stress; a typical behavior of a tough composite.

  3. Compositional analysis of silicon nitride films on Si and GaAs by backscattering spectrometry and nuclear resonance reaction analysis

    International Nuclear Information System (INIS)

    Kumar, Sanjiv; Raju, V.S.

    2004-01-01

    This paper describes the application of proton and α-backscattering spectrometry for the determination of atomic ratio of Si to N in 1100-5000 A silicon nitride films on Si and GaAs. The conventional α-Rutherford backscattering spectrometry is suitable for the analysis of films on Si; it is rather inadequate for films on GaAs due to higher background from the substrate. It is shown that these films can be analysed by 14 N(α,α) 14 N scattering with 3.5 MeV α-particles. Proton elastic scattering with enhanced cross sections for 28 Si(p,p) 28 Si and 14 N(p,p) 14 N scatterings, is also suitable for analysing films on GaAs. However, the analysis of films on Si by this technique is difficult due to interferences between the signals of Si from the film and the substrate. In addition, the hydrogen content in films is determined by 1 H( 19 F,αγ) 16 O nuclear reaction analysis using the resonance at 6.4 MeV. The combination of backscattering spectrometry with nuclear reaction analysis provides compositional analysis of ternary Si 1-(x+y) N x H y films

  4. Effect of Primary Recrystallized Microstructure and Nitriding on Secondary Recrystallization in Grain Oriented Silicon Steel by Low Temperature Slab Reheating

    Directory of Open Access Journals (Sweden)

    LIU Gong-tao

    2018-01-01

    Full Text Available Different primary recrystallized grain sizes were obtained by controlling decarburization process in grain oriented silicon steel produced by low temperature slab reheating technique. The effect of primary grain size on secondary recrystallization and magnetic properties was studied. The appropriate nitrogen content after nitriding was explored in case of very large primary grain size, and the effect of {411}〈148〉 primary recrystallized texture on the abnormal growth behavior was discussed. The results show that an increase in average primary grain size from 10μm to 15μm leads to an increase of secondary recrystallization temperature and a sharper Goss texture with higher magnetic permeability, in the condition of a very large average primary grain size of 28μm, the suitable amount of nitrogen increases to about 6×10-4. The {411}〈148〉 oriented grains in primary recrystallized microstructure can easily grow into larger sizes due to their size advantage, and thus hinder the abnormal growth of secondary grains, moreover, the hindering effect is more pronounced in the abnormal growth of Brass-oriented grains due to their misorientation with low migration rate other than Goss grains.

  5. Experimental evidence of the impact of rare-earth elements on particle growth and mechanical behaviour of silicon nitride

    International Nuclear Information System (INIS)

    Satet, Raphaelle L.; Hoffmann, Michael J.; Cannon, Rowland M.

    2006-01-01

    The impact of various rare-earth and related doping elements (R = Lu, Sc, Yb, Y, Sm, La) on the grain growth anisotropy and the mechanical properties of polycrystalline β-silicon nitride ceramics has been studied. Model experiments, in which Si 3 N 4 particles can grow freely in an R-Si-Mg-oxynitride glass matrix, show that, with increasing ionic radius of the additive, grain anisotropy increases due to non-linear growth kinetics. Toughness and strength are affected by the rare-earth element. Samples of equivalent grain sizes and morphologies yield an increasing toughness with increasing ion size of the R 3+ , reflecting an increasingly intergranular crack path. These samples are also strong and flaw tolerant, but the trends of strength and toughness do not exactly match. The choice of the rare-earth is essential to tailor microstructure, interfacial strength and mechanical properties. However, somewhat different trends for properties from IIIb and lanthanide additives indicate that more than the R 3+ size (i.e., purely ionic bond strength between R 3+ and its neighbours) is important. The electronic structure of the R-element is responsible for the type of dopant adsorption and the properties of the interface

  6. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, R [Facultad de Ingenieria Quimica y Textil, Universidad Nacional de Ingenieria, Av. Tupac Amaru SN, Lima (Peru); Cremona, M [Departamento de Fisica, PontifIcia Universidade Catolica de Rio de Janeiro, PUC-Rio, Cx. Postal 38071, Rio de Janeiro, RJ, CEP 22453-970 (Brazil); Achete, C A, E-mail: rreyes@uni.edu.pe [Departamento de Engenheria Metalurgica e de Materiais, Universidade Federal do Rio de Janeiro, Cx. Postal 68505, Rio de Janeiro, RJ, CEP 21945-970 (Brazil)

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq{sub 3}) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq{sub 3}/Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  7. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    International Nuclear Information System (INIS)

    Reyes, R; Cremona, M; Achete, C A

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq 3 ) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq 3 /Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  8. Demonstration of AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors with silicon-oxy-nitride as the gate insulator

    International Nuclear Information System (INIS)

    Balachander, K.; Arulkumaran, S.; Egawa, T.; Sano, Y.; Baskar, K.

    2005-01-01

    AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOSHEMTs) were fabricated with plasma enhanced chemical vapor deposited silicon oxy-nitride (SiON) as an insulating layer. The compositions of SiON thin films were confirmed using X-ray photoelectron spectroscopy. The fabricated MOSHEMTs exhibited a very high saturation current density of 1.1 A/mm coupled with high positive operational gate voltage up to +7 V. The MOSHEMTs also exhibited four orders of low gate leakage current and high forward-on voltage when compared with the conventional HEMTs. The drain current collapse using gate pulse measurements showed only a negligible difference in the saturation current density revealing the drastic improvement in passivation of the surface states due to the high quality of dielectric thin films deposited. Thus, based on the improved direct-current operation, SiON can be considered to be a potential gate oxide comparable with other dielectric insulators

  9. Packaged mode multiplexer based on silicon photonics

    NARCIS (Netherlands)

    Chen, H.; Koonen, A.M.J.; Snyder, B.; Raz, O.; Boom, van den H.P.A.; Chen, X.

    2012-01-01

    A silicon photonics based mode multiplexer is proposed. Four chirped grating couplers structure can support all 6 channels in a two-mode fiber and realize LP01 and LP11 mode selective exciting. The packaged device is tested.

  10. Estimation of sensing characteristics for refractory nitrides based gain assisted core-shell plasmonic nanoparticles

    Science.gov (United States)

    Shishodia, Manmohan Singh; Pathania, Pankaj

    2018-04-01

    Refractory transition metal nitrides such as zirconium nitride (ZrN), hafnium nitride (HfN) and titanium nitride (TiN) have emerged as viable alternatives to coinage metals based plasmonic materials, e.g., gold (Au) and silver (Ag). The present work assesses the suitability of gain assisted ZrN-, HfN- and TiN-based conventional core-shell nanoparticles (CCSNPs) and multilayered core-shell nanoparticles (MCSNPs) for refractive index sensing. We report that the optical gain incorporation in the dielectric layer leads to multifold enhancement of the scattering efficiency (Qsca), substantial reduction of the spectral full width at half maximum, and a higher figure of merit (FOM). In comparison with CCSNPs, the MCSNP system exhibits superior sensing characteristics such as higher FOM, ˜ 45% reduction in the critical optical gain, response shift towards the biological window, and higher degree of tunability. Inherent biocompatibility, growth compatibility, chemical stability and flexible spectral tuning of refractory nitrides augmented by superior sensing properties in the present work may pave the way for refractory nitrides based low cost sensing.

  11. Silicon based multilayer photoelectrodes for photoelectrolysis of water to produce hydrogen from the sun

    Science.gov (United States)

    Faruque, Faisal

    The main objective of this work is to study different materials for the direct photosynthesis of hydrogen from water. A variety of photocatalysts such as titanium dioxide, titanium oxy-nitride, silicon carbide, and gallium nitride are being investigated by others for the clean production of hydrogen for fuel cells and hydrogen economy. Our approach was to deposit suitable metallic regions on photocatalyst nanoparticles to direct the efficient synthesis of hydrogen to a particular site for convenient collection. We studied different electrode metals such as gold, platinum, titanium, palladium, and tungsten. We also studied different solar cell materials such as silicon (p- and n-types), silicon carbide and titanium dioxide semiconductors in order to efficiently generate electrons under illumination. We introduced a novel silicon-based multilayer photosynthesis device to take advantage of suitable properties of silicon and tungsten to efficiently produce hydrogen. The device consisted of a silicon (0.5mm) substrate, a deposited atomic layer of Al2O 3 (1nm), a doped polysilicon (0.1microm), and finally a tungsten nanoporous (5-10nm) layer acting as an interface electrode with water. The Al2O 3 layer was introduced to reduce leakage current and to prevent the spreading of the diffused p-n junction layer between the silicon and doped polysilicon layers. The surface of the photoelectrode was coated with nanotextured tungsten nanopores (TNP), which increased the surface area of the electrodes to the electrolyte, assisting in electron-hole mobility, and acting as a photocatalyst. The reported device exhibited a fill factor (%FF) of 27.22% and solar-to-hydrogen conversion efficiency of 0.03174%. This thesis describes the structures of the device, and offers a characterization and comparison between different photoelectrodes.

  12. Surface Preparation and Deposited Gate Oxides for Gallium Nitride Based Metal Oxide Semiconductor Devices

    Directory of Open Access Journals (Sweden)

    Paul C. McIntyre

    2012-07-01

    Full Text Available The literature on polar Gallium Nitride (GaN surfaces, surface treatments and gate dielectrics relevant to metal oxide semiconductor devices is reviewed. The significance of the GaN growth technique and growth parameters on the properties of GaN epilayers, the ability to modify GaN surface properties using in situ and ex situ processes and progress on the understanding and performance of GaN metal oxide semiconductor (MOS devices are presented and discussed. Although a reasonably consistent picture is emerging from focused studies on issues covered in each of these topics, future research can achieve a better understanding of the critical oxide-semiconductor interface by probing the connections between these topics. The challenges in analyzing defect concentrations and energies in GaN MOS gate stacks are discussed. Promising gate dielectric deposition techniques such as atomic layer deposition, which is already accepted by the semiconductor industry for silicon CMOS device fabrication, coupled with more advanced physical and electrical characterization methods will likely accelerate the pace of learning required to develop future GaN-based MOS technology.

  13. Spontaneously-acoustic hypersound long-range stimulation of silicon nitride synthesis in silicon at argon ion irradiation

    CERN Document Server

    Demidov, E S; Markov, K A; Sdobnyakov, V V

    2001-01-01

    The work is dedicated to the nature of the average energy ions implantation process effect on the crystal defective system at the distances, exceeding by three-four orders the averagely projected ions run value. It is established that irradiation by the argon ions stimulated the Si sub 3 N sub 4 phase formation in the preliminarily nitrogen-saturated layers at the distances of approximately 600 mu m from the ions deceleration zone. It is supposed that there appear sufficiently effective pulse sources of the hypersonic shock waves in the area of the Ar sup + deceleration zone. These waves are the result of the jump-like origination and grid evolution of the loop-shaped dislocations and argon blisters as well as of the blisters explosion, The evaluations show that the peak pressure in wave due to the synchronized explosion of blisters in the nitrogen-saturated area on the reverse side of the silicon plate 600 mu m thick may exceed 10 sup 8 Pa and cause experimentally observed changes

  14. Co-implantation of carbon and nitrogen into silicon dioxide for synthesis of carbon nitride materials

    CERN Document Server

    Huang, M B; Nuesca, G; Moore, R

    2002-01-01

    Materials synthesis of carbon nitride has been attempted with co-implantation of carbon and nitrogen into thermally grown SiO sub 2. Following implantation of C and N ions to doses of 10 sup 1 sup 7 cm sup - sup 2 , thermal annealing of the implanted SiO sub 2 sample was conducted at 1000 degree sign C in an N sub 2 ambient. As evidenced in Fourier transform infrared measurements and X-ray photoelectron spectroscopy, different bonding configurations between C and N, including C-N single bonds, C=N double bonds and C=N triple bonds, were found to develop in the SiO sub 2 film after annealing. Chemical composition profiles obtained with secondary ion mass spectroscopy were correlated with the depth information of the chemical shifts of N 1s core-level electrons, allowing us to examine the formation of C-N bonding for different atomic concentration ratios between N and C. X-ray diffraction and transmission electron microscopy showed no sign of the formation of crystalline C sub 3 N sub 4 precipitates in the SiO ...

  15. Single layer and multilayer vacuum-arc coatings based on the nitride TiAlSiYN: composition, structure, properties

    International Nuclear Information System (INIS)

    Beresnev, V.M.; Litovchenko, S.V.; Nemchenko, U.S.; Srebnyuk, P.A.; Mazilin, B.A.; Sobol, O.V.; Mejlekhov, A.A.; Barmin, A.E.; Serenko, TA.; Pogrebnyak, A.D.; Ivanov, O.N.; Kritsyna, E.V.; Stolbovoj, V.A.; Novikov, V.Yu.; Malikov, L.V.

    2017-01-01

    Using high-technological vacuum-arc evaporation in the atmosphere of nitrogen with ion bombardment, single- and multilayer coatings based on TiAlSiYN with high mechanical characteristics were obtained: hardness of the coatings reached 49.5 GPa, resistance to wear, with the value of the critical point L_C_5 reaching 184.92 N. The peculiarities of radiation-induced effect at applying bias potential U_b were found: formation of nitride coatings based on fcc metallic lattice with the preferred orientation of crystallites with the texture axis [111], as well as simultaneous growth of hardness. Hardness of both single- and multilayer coatings increases by 40...50% at the increase of U_b from 50 to 200 V. Formation of silicon-containing layers of TiAlSiYN during the deposition contributes to reaching increased hardness, which, in the case of single-layer coating obtained at U_b = -200 V is 49.5 GPa, which corresponds to superhard state. The mechanisms of structure formation, defining the resulting mechanical characteristics of single- and multi-layer coatings based on TiAlSiYN nitride have been discussed.

  16. Layer-by-layer composition and structure of silicon subjected to combined gallium and nitrogen ion implantation for the ion synthesis of gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, D. S.; Mikhaylov, A. N.; Belov, A. I.; Vasiliev, V. K.; Guseinov, D. V.; Okulich, E. V. [Nizhny Novgorod State University (Russian Federation); Shemukhin, A. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Surodin, S. I.; Nikolitchev, D. E.; Nezhdanov, A. V.; Pirogov, A. V.; Pavlov, D. A.; Tetelbaum, D. I., E-mail: tetelbaum@phys.unn.ru [Nizhny Novgorod State University (Russian Federation)

    2016-02-15

    The composition and structure of silicon surface layers subjected to combined gallium and nitrogen ion implantation with subsequent annealing have been studied by the X-ray photoelectron spectroscopy, Rutherford backscattering, electron spin resonance, Raman spectroscopy, and transmission electron microscopy techniques. A slight redistribution of the implanted atoms before annealing and their substantial migration towards the surface during annealing depending on the sequence of implantations are observed. It is found that about 2% of atoms of the implanted layer are replaced with gallium bonded to nitrogen; however, it is impossible to detect the gallium-nitride phase. At the same time, gallium-enriched inclusions containing ∼25 at % of gallium are detected as candidates for the further synthesis of gallium-nitride inclusions.

  17. High temperature and low pressure chemical vapor deposition of silicon nitride on AlGaN: Band offsets and passivation studies

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Pramod; Washiyama, Shun; Kaess, Felix; Hernandez-Balderrama, Luis H.; Haidet, Brian B.; Alden, Dorian; Franke, Alexander; Sarkar, Biplab; Kohn, Erhard; Collazo, Ramon; Sitar, Zlatko [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); Hayden Breckenridge, M. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); REU, Physics Department at Wofford College, Spartanburg, South Carolina 29303 (United States)

    2016-04-14

    In this work, we employed X-ray photoelectron spectroscopy to determine the band offsets and interface Fermi level at the heterojunction formed by stoichiometric silicon nitride deposited on Al{sub x}Ga{sub 1-x}N (of varying Al composition “x”) via low pressure chemical vapor deposition. Silicon nitride is found to form a type II staggered band alignment with AlGaN for all Al compositions (0 ≤ x ≤ 1) and present an electron barrier into AlGaN even at higher Al compositions, where E{sub g}(AlGaN) > E{sub g}(Si{sub 3}N{sub 4}). Further, no band bending is observed in AlGaN for x ≤ 0.6 and a reduced band bending (by ∼1 eV in comparison to that at free surface) is observed for x > 0.6. The Fermi level in silicon nitride is found to be at 3 eV with respect to its valence band, which is likely due to silicon (≡Si{sup 0/−1}) dangling bonds. The presence of band bending for x > 0.6 is seen as a likely consequence of Fermi level alignment at Si{sub 3}N{sub 4}/AlGaN hetero-interface and not due to interface states. Photoelectron spectroscopy results are corroborated by current-voltage-temperature and capacitance-voltage measurements. A shift in the interface Fermi level (before band bending at equilibrium) from the conduction band in Si{sub 3}N{sub 4}/n-GaN to the valence band in Si{sub 3}N{sub 4}/p-GaN is observed, which strongly indicates a reduction in mid-gap interface states. Hence, stoichiometric silicon nitride is found to be a feasible passivation and dielectric insulation material for AlGaN at any composition.

  18. Growth and characterisation of group-III nitride-based nanowires for devices

    Energy Technology Data Exchange (ETDEWEB)

    Meijers, R J

    2007-08-30

    One of the main goals of this thesis was to get more insight into the mechanisms driving the growth of nitride nanowires by plasma-assisted molecular beam epitaxy (PA-MBE). The influence of the group-III and group-V flux as well as the substrate temperature T{sub sub} has been studied leading to the conclusion that the III-V ratio determines the growth mode. Ga desorption limits the temperature range to grow GaN nanowires and dissociation of InN is the limiting factor for InN nanowire growth. A reduction of the surface diffusivity on polar surfaces under N-rich conditions explains the anisotropic growth. Growth kinetics of the nanowires show that there are two important contributions to the growth. The first is growth by direct impingement and its contribution is independent of the nanowire diameter. The second contribution comes from atoms, which absorb on the substrate or wire sidewalls and diffuse along the sidewalls to the top of the wire, which acts as an effective sink for the adatoms due to a reduced surface mobility on the polar top of the wires. This diffusion channel, which is enhanced at higher T{sub sub}, becomes more significant for smaller wire diameters, because its contribution scales like 1/d. Experiments with an interruption of the growth and sharp interfaces in TEM images of heterostructures show that the suggestion in literature of a droplet-mediated PA-MBE nitride growth has to be discarded. Despite a thin amorphous silicon nitride wetting layer on the substrate surface, both GaN and InN nanowires grow in the wurtzite structure and epitaxially in a one-to-one relation to the Si(111) substrate surface. There is no evidence for cubic phases. TEM images and optical studies display a high crystalline and optical quality of GaN and InN nanowires. The substrate induces some strain in the bottom part of the nanowires, especially in InN due to the lower T{sub sub} than for GaN, which is released without the formation of dislocations. Only some stacking

  19. Gallium nitride based thin films for photon and particle radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hofstetter, Markus

    2012-07-23

    Ionization chambers have been used since the beginning of the 20th century for measuring ionizing radiation and still represent the ''gold standard'' in dosimetry. However, since the sensitivity of the devices is proportional to the detection volume, ionization chambers are not common in numerous medical applications, such as imaging. In these fields, spatially resolved dose information is, beside film-systems, usually measured with scintillators and photo-multipliers, which is a relatively complex and expensive technique. For thus much effort has been focused on the development of novel detection systems in the last decades and especially in the last few years. Examples include germanium or silicon photoconductive detectors, MOSFETs, and PIN-diodes. Although for these systems, miniaturization for spatially resolved detection is possible, they suffer from a range of disadvantages. Characteristics such as poor measurement stability, material degradation, and/or a limited measurement range prevent routine application of these techniques in medical diagnostic devices. This work presents the development and evaluation of gallium nitride (GaN) thin films and heterostructures to validate their application in x-ray detection in the medical regime. Furthermore, the impact of particle radiation on device response was investigated. Although previous publications revealed relatively low energy absorption of GaN, it is possible to achieve very high signal amplification factors inside the material due to an appropriate sensor configuration, which, in turn, compensates the low energy absorption. Thus, gallium nitride can be used as a photo-conductor with ohmic contacts. The conductive volume of the sensor changes in the presence of external radiation, which results in an amplified measurement signal after applying a bias voltage to the device. Experiments revealed a sensitivity of the device between air kerma rates of 1 {mu}Gy/s and 20 mGy/s. In this range

  20. Effect of Silicon Nitride Incorporation on Microstructure and Hardness of Ni-Co Metal Matrix Nanocomposite

    Directory of Open Access Journals (Sweden)

    Ridwan

    2015-01-01

    Full Text Available Ni-Co-Si3N4 nanocomposite coatings were prepared by electrodeposition technique. The deposition was performed at 50 mA cm-2 on copper substrate. The working temperature of electrodepostion was constant at 500C in an acidic environment of pH 4. The effects of silicon in the nickel-cobalt metal matrix composite were investigated. Energy dispersive X-ray spectroscopy was used to determine the composition. The Co content in the coatings is in the range 27-49 at.%. The phase present in the Ni-Co-Si3N4 were examined with an X-ray diffraction analysis. All the reflection patterns indicate that the coatings are having face-centered cubic (fcc structure. The microhardness of the Ni-Co-Si3N4 nanocomposite coating increases with increasing silicon content. The microhardness of the Ni-Co-Si3N4 nanocomposite coating increased from 549 HV for Nickel-cobalt alloy coating to 641 HV for Ni-Co-Si3N4 nanocomposite coating with 5.47 at.% Si.

  1. In situ characterization of thin film growth: Boron nitride on silicon

    International Nuclear Information System (INIS)

    Fukarek, W.

    2001-01-01

    Real-time ellipsometry (RTE) in combination with particle flux measurement is applied to ion beam assisted deposition of boron nitride (BN) films. RTE is used as a tool for process diagnostic to improve the deposition stability. A novel technique for the determination of absolute density depth profiles from dynamic growth rate data and film forming particle flux is employed. From real-time cantilever curvature measurement and simultaneously recorded film thickness data instantaneous stress depth profiles are derived with a depth resolution in the nm range. The synergistic effects on the information obtained from RTE, particle flux, and cantilever bending data are demonstrated. The density of turbostratic BN (tBN) is found to increase slightly with film thickness while the compressive stress decreases, indicating an increasing quality and/or size of crystallites in the course of film growth. Refractive index and density depth profiles in cubic BN (cBN) films correspond perfectly to structural information obtained from dark field transmission electron microscope graphs. The established tBN/cBN two-layer model is found to be a crude approximation that has to be replaced by a three-layer model including nucleation, grain growth, and coalescence of cBN. The instantaneous compressive stress in a homogeneous tBN film is found to decrease, while the density increases during growth. The instantaneous compressive stress depth profiles in cBN films are more complex and not easy to understand but reliable information on the structural evolution during growth can be extracted

  2. Improving optical properties of silicon nitride films to be applied in the middle infrared optics by a combined high-power impulse/unbalanced magnetron sputtering deposition technique.

    Science.gov (United States)

    Liao, Bo-Huei; Hsiao, Chien-Nan

    2014-02-01

    Silicon nitride films are prepared by a combined high-power impulse/unbalanced magnetron sputtering (HIPIMS/UBMS) deposition technique. Different unbalance coefficients and pulse on/off ratios are applied to improve the optical properties of the silicon nitride films. The refractive indices of the Si3N4 films vary from 2.17 to 2.02 in the wavelength ranges of 400-700 nm, and all the extinction coefficients are smaller than 1×10(-4). The Fourier transform infrared spectroscopy and x-ray diffractometry measurements reveal the amorphous structure of the Si3N4 films with extremely low hydrogen content and very low absorption between the near IR and middle IR ranges. Compared to other deposition techniques, Si3N4 films deposited by the combined HIPIMS/UBMS deposition technique possess the highest refractive index, the lowest extinction coefficient, and excellent structural properties. Finally a four-layer coating is deposited on both sides of a silicon substrate. The average transmittance from 3200 to 4800 nm is 99.0%, and the highest transmittance is 99.97% around 4200 nm.

  3. Efficient and Stable CsPbBr3 Quantum-Dot Powders Passivated and Encapsulated with a Mixed Silicon Nitride and Silicon Oxide Inorganic Polymer Matrix.

    Science.gov (United States)

    Yoon, Hee Chang; Lee, Soyoung; Song, Jae Kyu; Yang, Heesun; Do, Young Rag

    2018-04-11

    Despite the excellent optical features of fully inorganic cesium lead halide (CsPbX 3 ) perovskite quantum dots (PeQDs), their unstable nature has limited their use in various optoelectronic devices. To mitigate the instability issues of PeQDs, we demonstrate the roles of dual-silicon nitride and silicon oxide ligands of the polysilazane (PSZ) inorganic polymer to passivate the surface defects and form a barrier layer coated onto green CsPbBr 3 QDs to maintain the high photoluminescence quantum yield (PLQY) and improve the environmental stability. The mixed SiN x /SiN x O y /SiO y passivated and encapsulated CsPbBr 3 /PSZ core/shell composite can be prepared by a simple hydrolysis reaction involving the addition of adding PSZ as a precursor and a slight amount of water into a colloidal CsPbBr 3 QD solution. The degree of the moisture-induced hydrolysis reaction of PSZ can affect the compositional ratio of SiN x , SiN x O y , and SiO y liganded to the surfaces of the CsPbBr 3 QDs to optimize the PLQY and the stability of CsPbBr 3 /PSZ core/shell composite, which shows a high PLQY (∼81.7%) with improved thermal, photo, air, and humidity stability as well under coarse conditions where the performance of CsPbBr 3 QDs typically deteriorate. To evaluate the suitability of the application of the CsPbBr 3 /PSZ powder to down-converted white-light-emitting diodes (DC-WLEDs) as the backlight of a liquid crystal display (LCD), we fabricated an on-package type of tricolor-WLED by mixing the as-synthesized green CsPbBr 3 /PSZ composite powder with red K 2 SiF 6 :Mn 4+ phosphor powder and a poly(methyl methacrylate)-encapsulating binder and coating this mixed paste onto a cup-type blue LED. The fabricated WLED show high luminous efficacy of 138.6 lm/W (EQE = 51.4%) and a wide color gamut of 128% and 111% without and with color filters, respectively, at a correlated color temperature of 6762 K.

  4. A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon–Gallium-Nitride Slot Waveguide Structures

    Directory of Open Access Journals (Sweden)

    Dror Malka

    2016-06-01

    Full Text Available In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI coupler in a silicon (Si–gallium nitride (GaN slot waveguide structure is presented—to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM. Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530–1565 nm into four output ports with low insertion losses (0.07 dB.

  5. A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon–Gallium-Nitride Slot Waveguide Structures

    Science.gov (United States)

    Malka, Dror; Danan, Yossef; Ramon, Yehonatan; Zalevsky, Zeev

    2016-01-01

    In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI) coupler in a silicon (Si)–gallium nitride (GaN) slot waveguide structure is presented—to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM). Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530–1565 nm) into four output ports with low insertion losses (0.07 dB). PMID:28773638

  6. Surface topography of silicon nitride affects antimicrobial and osseointegrative properties of tibial implants in a murine model.

    Science.gov (United States)

    Ishikawa, Masahiro; de Mesy Bentley, Karen L; McEntire, Bryan J; Bal, B Sonny; Schwarz, Edward M; Xie, Chao

    2017-12-01

    While silicon nitride (Si 3 N 4 ) is an antimicrobial and osseointegrative orthopaedic biomaterial, the contribution of surface topography to these properties is unknown. Using a methicillin-resistant strain of Staphylococcus aureus (MRSA), this study evaluated Si 3 N 4 implants in vitro utilizing scanning electron microscopy (SEM) with colony forming unit (CFU) assays, and later in an established in vivo murine tibia model of implant-associated osteomyelitis. In vitro, the "as-fired" Si 3 N 4 implants displayed significant reductions in adherent bacteria versus machined Si 3 N 4 (2.6 × 10 4 vs. 8.7 × 10 4 CFU, respectively; p SEM imaging demonstrated that MRSA cannot directly adhere to native as-fired Si 3 N 4 . Subsequently, a cross-sectional study was completed in which sterile or MRSA contaminated as-fired and machined Si 3 N 4 implants were inserted into the tibiae of 8-week old female Balb/c mice, and harvested on day 1, 3, 5, 7, 10, or 14 post-operatively for SEM. The findings demonstrated that the antimicrobial activity of the as-fired implants resulted from macrophage clearance of the bacteria during biofilm formation on day 1, followed by osseointegration through the apparent recruitment of mesenchymal stem cells on days 3-5, which differentiated into osteoblasts on days 7-14. In contrast, the antimicrobial behavior of the machined Si 3 N 4 was due to repulsion of the bacteria, a phenomenon that also limited osteogenesis, as host cells were also unable to adhere to the machined surface. Taken together, these results suggest that the in vivo biological behavior of Si 3 N 4 orthopaedic implants is driven by critical features of their surface nanotopography. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3413-3421, 2017. © 2017 Wiley Periodicals, Inc.

  7. Development of a Silicon Based Electron Beam Transmission Window for Use in a KrF Excimer Laser System

    International Nuclear Information System (INIS)

    Gentile, C.A.; Fan, H.M.; Hartfield, J.W.; Hawryluk, R.J.; Hegeler, F.; Heitzenroeder, P.J.; Jun, C.H.; Ku, L.P.; LaMarche, P.H.; Myers, M.C.; Parker, J.J.; Parsells, R.F.; Payen, M.; Raftopoulos, S.; Sethian, J.D.

    2002-01-01

    The Princeton Plasma Physics Laboratory (PPPL), in collaboration with the Naval Research Laboratory (NRL), is currently investigating various novel materials (single crystal silicon, , and ) for use as electron-beam transmission windows in a KrF excimer laser system. The primary function of the window is to isolate the active medium (excimer gas) from the excitation mechanism (field-emission diodes). Chosen window geometry must accommodate electron energy transfer greater than 80% (750 keV), while maintaining structural integrity during mechanical load (1.3 to 2.0 atm base pressure differential, approximate 0.5 atm cyclic pressure amplitude, 5 Hz repetition rate) and thermal load across the entire hibachi area (approximate 0.9 W · cm superscript ''-2''). In addition, the window must be chemically resistant to attack by fluorine free-radicals (hydrofluoric acid, secondary). In accordance with these structural, functional, and operational parameters, a 22.4 mm square silicon prototype window, coated with 500 nm thin-film silicon nitride (Si 3 N 4 ), has been fabricated. The window consists of 81 square panes with a thickness of 0.019 mm ± 0.001 mm. Stiffened (orthogonal) sections are 0.065 mm in width and 0.500 mm thick (approximate). Appended drawing (Figure 1) depicts the window configuration. Assessment of silicon (and silicon nitride) material properties and CAD modeling and analysis of the window design suggest that silicon may be a viable solution to inherent parameters and constraints

  8. Photonic Crystal Sensors Based on Porous Silicon

    Directory of Open Access Journals (Sweden)

    Claudia Pacholski

    2013-04-01

    Full Text Available Porous silicon has been established as an excellent sensing platform for the optical detection of hazardous chemicals and biomolecular interactions such as DNA hybridization, antigen/antibody binding, and enzymatic reactions. Its porous nature provides a high surface area within a small volume, which can be easily controlled by changing the pore sizes. As the porosity and consequently the refractive index of an etched porous silicon layer depends on the electrochemial etching conditions photonic crystals composed of multilayered porous silicon films with well-resolved and narrow optical reflectivity features can easily be obtained. The prominent optical response of the photonic crystal decreases the detection limit and therefore increases the sensitivity of porous silicon sensors in comparison to sensors utilizing Fabry-Pérot based optical transduction. Development of porous silicon photonic crystal sensors which allow for the detection of analytes by the naked eye using a simple color change or the fabrication of stacked porous silicon photonic crystals showing two distinct optical features which can be utilized for the discrimination of analytes emphasize its high application potential.

  9. Photonic Crystal Sensors Based on Porous Silicon

    Science.gov (United States)

    Pacholski, Claudia

    2013-01-01

    Porous silicon has been established as an excellent sensing platform for the optical detection of hazardous chemicals and biomolecular interactions such as DNA hybridization, antigen/antibody binding, and enzymatic reactions. Its porous nature provides a high surface area within a small volume, which can be easily controlled by changing the pore sizes. As the porosity and consequently the refractive index of an etched porous silicon layer depends on the electrochemial etching conditions photonic crystals composed of multilayered porous silicon films with well-resolved and narrow optical reflectivity features can easily be obtained. The prominent optical response of the photonic crystal decreases the detection limit and therefore increases the sensitivity of porous silicon sensors in comparison to sensors utilizing Fabry-Pérot based optical transduction. Development of porous silicon photonic crystal sensors which allow for the detection of analytes by the naked eye using a simple color change or the fabrication of stacked porous silicon photonic crystals showing two distinct optical features which can be utilized for the discrimination of analytes emphasize its high application potential. PMID:23571671

  10. Hot-pressed silicon nitride with various lanthanide oxides as sintering additives

    Science.gov (United States)

    Ueno, K.; Toibana, Y.

    1984-01-01

    The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in hot-pressing at 1800 C under 300-400kg/ centimeters squared for 60 min. The crystallization of yttrium and lanthanide-silicon oxynitrides which was observed inn the sintered body containing yttrium-lanthanide mixed oxides as additives led to the formation of a highly refractory Si3N4 ceramic having a bending strength of 82 and 84 kg/millimeters squared at room temperature and 1300 C respectively. In a Y2O3+La2O3 system, a higher molar ratio of La2O3 to Y2O3 gave a higher hardness and strength at high temperatures. It was found that 90 min was an optimum sintering time for the highest strength.

  11. Amorphous silicon based radiation detectors

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Cho, G.; Drewery, J.; Jing, T.; Kaplan, S.N.; Qureshi, S.; Wildermuth, D.; Fujieda, I.; Street, R.A.

    1991-07-01

    We describe the characteristics of thin(1 μm) and thick (>30μm) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-rays and γ rays. For x-ray, γ ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For direct detection of charged particles with high resistance to radiation damage, we use the thick p-i-n diode arrays. 13 refs., 7 figs

  12. Conduction Mechanism and Improved Endurance in HfO2-Based RRAM with Nitridation Treatment

    Science.gov (United States)

    Yuan, Fang-Yuan; Deng, Ning; Shih, Chih-Cheng; Tseng, Yi-Ting; Chang, Ting-Chang; Chang, Kuan-Chang; Wang, Ming-Hui; Chen, Wen-Chung; Zheng, Hao-Xuan; Wu, Huaqiang; Qian, He; Sze, Simon M.

    2017-10-01

    A nitridation treatment technology with a urea/ammonia complex nitrogen source improved resistive switching property in HfO2-based resistive random access memory (RRAM). The nitridation treatment produced a high performance and reliable device which results in superior endurance (more than 109 cycles) and a self-compliance effect. Thus, the current conduction mechanism changed due to defect passivation by nitrogen atoms in the HfO2 thin film. At a high resistance state (HRS), it transferred to Schottky emission from Poole-Frenkel in HfO2-based RRAM. At low resistance state (LRS), the current conduction mechanism was space charge limited current (SCLC) after the nitridation treatment, which suggests that the nitrogen atoms form Hf-N-Ox vacancy clusters (Vo +) which limit electron movement through the switching layer.

  13. Nitridated fibrous silica (KCC-1) as a sustainable solid base nanocatalyst

    KAUST Repository

    Bouhrara, Mohamed; Ranga, Chanakya; Fihri, Aziz; Shaikh, Rafik; Sarawade, Pradip; Emwas, Abdul-Hamid M.; Hedhili, Mohamed N.; Polshettiwar, Vivek

    2013-01-01

    We observed that support morphology has dramatic effects on the performance of nitridated silica as a base. By simply replacing conventional silica supports (such as SBA-15 and MCM-41) with fibrous nanosilica (KCC-1), we observed multifold enhancement in the catalytic activity of the nitridated solid base for Knoevenagel condensations and transesterification reactions. This enhancement of the activity can be explained by amine accessibility, which is excellent in KCC-1 due to its open and flexible fibrous structure, that facilitates penetration and interaction with basic amine sites. © 2013 American Chemical Society.

  14. Nitridated fibrous silica (KCC-1) as a sustainable solid base nanocatalyst

    KAUST Repository

    Bouhrara, Mohamed

    2013-09-03

    We observed that support morphology has dramatic effects on the performance of nitridated silica as a base. By simply replacing conventional silica supports (such as SBA-15 and MCM-41) with fibrous nanosilica (KCC-1), we observed multifold enhancement in the catalytic activity of the nitridated solid base for Knoevenagel condensations and transesterification reactions. This enhancement of the activity can be explained by amine accessibility, which is excellent in KCC-1 due to its open and flexible fibrous structure, that facilitates penetration and interaction with basic amine sites. © 2013 American Chemical Society.

  15. Coplanar transitions based on aluminum nitride interposer substrate for terabit transceivers

    DEFF Research Database (Denmark)

    Dong, Yunfeng; Johansen, Tom Keinicke; Zhurbenko, Vitaliy

    2017-01-01

    This paper presents two types of coplanar transitions based on aluminum nitride (AlN) substrate for interposer designs of terabit transceivers. The designs of coupled coplanar waveguide (CCPW), coupled line, coplanar waveguide (CPW), and coplanar stripline (CPS) based on AlN substrate are explained...

  16. Silicon nitride and silicon etching by CH{sub 3}F/O{sub 2} and CH{sub 3}F/CO{sub 2} plasma beams

    Energy Technology Data Exchange (ETDEWEB)

    Kaler, Sanbir S.; Lou, Qiaowei; Donnelly, Vincent M., E-mail: vmdonnelly@uh.edu; Economou, Demetre J., E-mail: economou@uh.edu [Department of Chemical and Biomolecular Engineering, Plasma Processing Laboratory, University of Houston, Houston, Texas 77204 (United States)

    2016-07-15

    Silicon nitride (SiN, where Si:N ≠ 1:1) films low pressure-chemical vapor deposited on Si substrates, Si films on Ge on Si substrates, and p-Si samples were exposed to plasma beams emanating from CH{sub 3}F/O{sub 2} or CH{sub 3}F/CO{sub 2} inductively coupled plasmas. Conditions within the plasma beam source were maintained at power of 300 W (1.9 W/cm{sup 3}), pressure of 10 mTorr, and total gas flow rate of 10 sccm. X-ray photoelectron spectroscopy was used to determine the thicknesses of Si/Ge in addition to hydrofluorocarbon polymer films formed at low %O{sub 2} or %CO{sub 2} addition on p-Si and SiN. Polymer film thickness decreased sharply as a function of increasing %O{sub 2} or %CO{sub 2} addition and dropped to monolayer thickness above the transition point (∼48% O{sub 2} or ∼75% CO{sub 2}) at which the polymer etchants (O and F) number densities in the plasma increased abruptly. The C(1s) spectra for the polymer films deposited on p-Si substrates appeared similar to those on SiN. Spectroscopic ellipsometry was used to measure the thickness of SiN films etched using the CH{sub 3}F/O{sub 2} and CH{sub 3}F/CO{sub 2} plasma beams. SiN etching rates peaked near 50% O{sub 2} addition and 73% CO{sub 2} addition. Faster etching rates were measured in CH{sub 3}F/CO{sub 2} than CH{sub 3}F/O{sub 2} plasmas above 70% O{sub 2} or CO{sub 2} addition. The etching of Si stopped after a loss of ∼3 nm, regardless of beam exposure time and %O{sub 2} or %CO{sub 2} addition, apparently due to plasma assisted oxidation of Si. An additional GeO{sub x}F{sub y} peak was observed at 32.5 eV in the Ge(3d) region, suggesting deep penetration of F into Si, under the conditions investigated.

  17. Internal nitridation of nickel-base alloys; Innere Nitrierung von Nickelbasis-Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Krupp, U.; Christ, H.J. [Siegen Univ. (Gesamthochschule) (Germany). Inst. fuer Werkstofftechnik

    1998-12-31

    The chromuim concentration is the crucial variable in nitridation processes in nickel-base alloys. Extensive nitridation experiments with various specimen alloys of the system Ni-Cr-Al-Ti have shown that the Cr itself starts to form nitrides as from elevated initial concentrations of about 10 to 20 weight%, (depending on temperature), but that lower concentrations have an earlier effect in that they induce a considerable increase in the N-solubility of the nickel-base alloys. This causes an accelerated nitridation attack on the alloying elements Ti and Al. Apart from experimental detection and analysis, the phenomenon of internal nitridation could be described as well by means of a mathematical model calculating the diffusion with the finite-differences method and determining the precipitation thermodynamics by way of integrated equilibrium calculations. (orig./CB) [Deutsch] Im Verlauf der Hochtemperaturkorrosion von Nickelbasis-Superlegierungen kann durch beanspruchungsbedingte Schaedigungen der Oxiddeckschicht ein Verlust der Schutzwirkung erfolgen und als Konsequenz Stickstoff aus der Atmosphaere in den Werkstoff eindringen. Der eindiffundierende Stickstoff bildet vor allem mit den Legierungselementen Al, Cr und Ti Nitridausscheidungen, die zu einer relativ rasch fortschreitenden Schaedigung fuehren koennen. Eine bedeutende Rolle bei diesen Nitrierungsprozessen in Nickelbasislegierungen spielt die Cr-Konzentration in der Legierung. So ergaben umfangreiche Nitrierungsexperimente an verschiedenen Modellegierungen des Systems Ni-Cr-Al-Ti, dass Cr zwar selbst erst ab Ausgangskonzentrationen von ca. 10-20 Gew.% (abhaengig von der Temperatur) Nitride bildet, allerdings bereits bei geringen Konzentrationen die N-Loeslichkeit von Nickelbasis-Legierungen entscheidend erhoeht. Dies hat zur Folge, dass es zu einem beschleunigten Nitrierungsangriff auf die Legierungselemente Ti und Al kommt. Neben den experimentellen Untersuchungen konnte das Phaenomen der inneren

  18. Investigation of Emerging Materials for Optoelectronic Devices Based on III-Nitrides

    KAUST Repository

    Mumthaz Muhammed, Mufasila

    2018-01-01

    performance due to dislocation defects, remains an obstacle to their further improvement. In this dissertation, I present a significant enhancement of III-nitride devices based on emerging materials. A promising substrate, (-201)-oriented β-Ga2O3 with unique

  19. Photo-Electrical Characterization of Silicon Micropillar Arrays with Radial p/n Junctions Containing Passivation and Anti-Reflection Coatings

    NARCIS (Netherlands)

    Vijselaar, Wouter; Elbersen, R.; Tiggelaar, Roald M.; Gardeniers, Han; Huskens, Jurriaan

    2017-01-01

    In order to assess the contributions of anti-reflective and passivation effects in microstructured silicon-based solar light harvesting devices, thin layers of aluminum oxide (Al2O3), silicon dioxide (SiO2), silicon-rich silicon nitride (SiNx), and indium tin oxide (ITO), with a thickness ranging

  20. Mocvd Growth of Group-III Nitrides on Silicon Carbide: From Thin Films to Atomically Thin Layers

    Science.gov (United States)

    Al Balushi, Zakaria Y.

    Group-III nitride semiconductors (AlN, GaN, InN and their alloys) are considered one of the most important class of materials for electronic and optoelectronic devices. This is not limited to the blue light-emitting diode (LED) used for efficient solid-state lighting, but other applications as well, such as solar cells, radar and a variety of high frequency power electronics, which are all prime examples of the technological importance of nitride based wide bandgap semiconductors in our daily lives. The goal of this dissertation work was to explore and establish new growth schemes to improve the structural and optical properties of thick to atomically thin films of group-III nitrides grown by metalorganic chemical vapor deposition (MOCVD) on SiC substrates for future novel devices. The first research focus of this dissertation was on the growth of indium gallium nitride (InGaN). This wide bandgap semiconductor has attracted much research attention as an active layer in LEDs and recently as an absorber material for solar cells. InGaN has superior material properties for solar cells due to its wavelength absorption tunability that nearly covers the entire solar spectrum. This can be achieved by controlling the indium content in thick grown material. Thick InGaN films are also of interest as strain reducing based layers for deep-green and red light emitters. The growth of thick films of InGaN is, however, hindered by several combined problems. This includes poor incorporation of indium in alloys, high density of structural and morphological defects, as well as challenges associated with the segregation of indium in thick films. Overcoming some of these material challenges is essential in order integrate thick InGaN films into future optoelectronics. Therefore, this dissertation research investigated the growth mechanism of InGaN layers grown in the N-polar direction by MOCVD as a route to improve the structural and optical properties of thick InGaN films. The growth

  1. The Influence of Hot-Rolled Temperature on Plasma Nitriding Behavior of Iron-Based Alloys

    Science.gov (United States)

    El-Hossary, F. M.; Khalil, S. M.; Lotfy, Kh.; Kassem, M. A.

    2009-07-01

    Experiments were performed with an aim of studying the effect of hot-rolled temperature (600 and 900°C) on radio frequency (rf) plasma nitriding of Fe93Ni4Zr3 alloy. Nitriding was carried out for 10 min in a nitrogen atmosphere at a base pressure of 10-2 mbarr. Different continuous plasma processing powers of 300-550 W in steps 50 W or less were applied. Nitrided hot-rolled specimens were characterized by optical microscopy (OM), X-ray diffraction (XRD) and microhardness measurements. The results reveal that the surface of hot-rolled rf plasma nitrided specimens at 600°C is characterized with a fine microstructure as a result of the high nitrogen solubility and diffusivity. Moreover, the hot-rolled treated samples at 600°C exhibit higher microhardness value than the associated values of hot-rolled treated samples at 900°C. The enhancement of microhardness is due to precipitation and predominance of new phases ( γ and ɛ phases). Mainly, this conclusion has been attributed to the high defect densities and small grain sizes of the samples hot-rolled at 600°C. Generally, the refinement of grain size plays a dramatic role in improvement of mechanical properties of tested samples.

  2. Amorphous silicon-based microchannel plates

    International Nuclear Information System (INIS)

    Franco, Andrea; Riesen, Yannick; Wyrsch, Nicolas; Dunand, Sylvain; Powolny, François; Jarron, Pierre; Ballif, Christophe

    2012-01-01

    Microchannel plates (MCP) based on hydrogenated amorphous silicon (a-Si:H) were recently introduced to overcome some of the limitations of crystalline silicon and glass MCP. The typical thickness of a-Si:H based MCPs (AMCP) ranges between 80 and 100 μm and the micromachining of the channels is realized by deep reactive ion etching (DRIE). Advantages and issues regarding the fabrication process are presented and discussed. Electron amplification is demonstrated and analyzed using Electron Beam Induced Current (EBIC) technique. The gain increases as a function of the bias voltage, limited to −340 V on account of high leakage currents across the structure. EBIC maps on 10° tilted samples confirm that the device active area extend to the entire channel opening. AMCP characterization with the electron beam shows gain saturation and signal quenching which depends on the effectiveness of the charge replenishment in the channel walls.

  3. High-Efficiency Nitride-Based Solid-State Lighting. Final Technical Progress Report

    International Nuclear Information System (INIS)

    Paul T. Fini; Shuji Nakamura

    2005-01-01

    In this final technical progress report we summarize research accomplished during Department of Energy contract DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. Two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and the Lighting Research Center at Rensselaer Polytechnic Institute (led by Dr. N. Narendran), pursued the goals of this contract from thin film growth, characterization, and packaging/luminaire design standpoints. The UCSB team initially pursued the development of blue gallium nitride (GaN)-based vertical-cavity surface-emitting lasers, as well as ultraviolet GaN-based light emitting diodes (LEDs). In Year 2, the emphasis shifted to resonant-cavity light emitting diodes, also known as micro-cavity LEDs when extremely thin device cavities are fabricated. These devices have very directional emission and higher light extraction efficiency than conventional LEDs. Via the optimization of thin-film growth and refinement of device processing, we decreased the total cavity thickness to less than 1 (micro)m, such that micro-cavity effects were clearly observed and a light extraction efficiency of over 10% was reached. We also began the development of photonic crystals for increased light extraction, in particular for so-called ''guided modes'' which would otherwise propagate laterally in the device and be re-absorbed. Finally, we pursued the growth of smooth, high-quality nonpolar a-plane and m-plane GaN films, as well as blue light emitting diodes on these novel films. Initial nonpolar LEDs showed the expected behavior of negligible peak wavelength shift with increasing drive current. M-plane LEDs in particular show promise, as unpackaged devices had unsaturated optical output power of ∼ 3 mW at 200 mA drive current. The LRC's tasks were aimed at developing the subcomponents necessary for packaging UCSB's light emitting diodes, and packaging them to produce a white light

  4. Optimization of Controllable Factors in the Aluminum Silicon Eutectic Paste and Rear Silicon Nitride Mono-Passivation Layer of PERC Solar Cells

    Science.gov (United States)

    Park, Sungeun; Park, Hyomin; Kim, Dongseop; Yang, JungYup; Lee, Dongho; Kim, Young-Su; Kim, Hyun-Jong; Suh, Dongchul; Min, Byoung Koun; Kim, Kyung Nam; Park, Se Jin; Kim, Donghwan; Lee, Hae-Seok; Nam, Junggyu; Kang, Yoonmook

    2018-05-01

    Passivated emitter and rear contact (PERC) is a promising technology owing to high efficiency can be achieved with p-type wafer and their easily applicable to existing lines. In case of using p-type mono wafer, 0.5-1% efficiency increase is expected with PERC technologies compared to existing Al BSF solar cells, while for multi-wafer solar cells it is 0.5-0.8%. We addressed the optimization of PERC solar cells using the Al paste. The paste was prepared from the aluminum-silicon alloy with eutectic composition to avoid the formation of voids that degrade the open-circuit voltage. The glass frit of the paste was changed to improve adhesion. Scanning electron microscopy revealed voids and local back surface field between the aluminum electrode and silicon base. We confirmed the conditions on the SiNx passivation layer for achieving higher efficiency and better adhesion for long-term stability. The cell characteristics were compared across cells containing different pastes. PERC solar cells with the Al/Si eutectic paste exhibited the efficiency of 19.6%.

  5. Chemical vapor deposition of refractory ternary nitrides for advanced diffusion barriers

    Energy Technology Data Exchange (ETDEWEB)

    Custer, Jonathan S.; Fleming, James G.; Roherty-Osmun, Elizabeth; Smith, Paul Martin

    1998-09-22

    Refractory ternary nitride films for diffusion barriers in microelectronics have been grown using chemical vapor deposition. Thin films of titanium-silicon-nitride, tungsten-boron-nitride, and tungsten-silicon-nitride of various compositions have been deposited on 150 mm Si wafers. The microstructure of the films are either fully amorphous for the tungsten based films, or nauocrystalline TiN in an amorphous matrix for titanium-silicon-nitride. All films exhibit step coverages suitable for use in future microelectronics generations. Selected films have been tested as diffusion barriers between copper and silicon, and generally perform extremely weH. These fiIms are promising candidates for advanced diffusion barriers for microelectronics applications. The manufacturing of silicon wafers into integrated circuits uses many different process and materials. The manufacturing process is usually divided into two parts: the front end of line (FEOL) and the back end of line (BEOL). In the FEOL the individual transistors that are the heart of an integrated circuit are made on the silicon wafer. The responsibility of the BEOL is to wire all the transistors together to make a complete circuit. The transistors are fabricated in the silicon itself. The wiring is made out of metal, currently aluminum and tungsten, insulated by silicon dioxide, see Figure 1. Unfortunately, silicon will diffuse into aluminum, causing aluminum spiking of junctions, killing transistors. Similarly, during chemical vapor deposition (CVD) of tungsten from ~fj, the reactivity of the fluorine can cause "worn-holes" in the silicon, also destroying transistors. The solution to these problems is a so-called diffusion barrier, which will allow current to pass from the transistors to the wiring, but will prevent reactions between silicon and the metal.

  6. The influence of powder composition and sintering temperature on transformation kinetics, structure and mechanical properties of hot-pressed silicon nitride

    International Nuclear Information System (INIS)

    Knoch, H.; Ziegler, G.

    1977-01-01

    The strength at room temperature of hot-pressed silicon nitride is strongly dependent on the structure which in turn depends on powder composition and process parameters. Connections between production conditions (MgO content, pressing temperature, pressing time), structure (α/β content and morphology), and the properties at room temperature are discussed. The growth of oblong β grains - as a direct result of phase transition from α- to β-Si 3 N 4 - results in microstructural meshing and thus in a higher strength. Optimum mechanical properties are achieved after full phase transformation and with a microstructure as fine as possible. The direct connection between strength and transformed β fraction indicates a possible way for a relatively fast determination of optimum properties for a given initial powder. (orig.) [de

  7. Relative SHG measurements of metal thin films: Gold, silver, aluminum, cobalt, chromium, germanium, nickel, antimony, titanium, titanium nitride, tungsten, zinc, silicon and indium tin oxide

    Directory of Open Access Journals (Sweden)

    Franklin Che

    Full Text Available We have experimentally measured the surface second-harmonic generation (SHG of sputtered gold, silver, aluminum, zinc, tungsten, copper, titanium, cobalt, nickel, chromium, germanium, antimony, titanium nitride, silicon and indium tin oxide thin films. The second-harmonic response was measured in reflection using a 150 fs p-polarized laser pulse at 1561 nm. We present a clear comparison of the SHG intensity of these films relative to each other. Our measured relative intensities compare favorably with the relative intensities of metals with published data. We also report for the first time to our knowledge the surface SHG intensity of tungsten and antimony relative to that of well known metallic thin films such as gold and silver. Keywords: Surface second-harmonic generation, Nonlinear optics, Metal thin films

  8. Theoretical study of charge trapping levels in silicon nitride using the LDA-1/2 self-energy correction scheme for excited states

    International Nuclear Information System (INIS)

    Patrocinio, Weslley S.; Ribeiro, Mauro; Fonseca, Leonardo R.C.

    2012-01-01

    Silicon nitride, with a permittivity mid-way between SiO 2 and common high-k materials such as HfO 2 , is widely used in microelectronics as an insulating layer on top of oxides where it serves as an impurity barrier with the positive side effect of increasing the dielectric constant of the insulator when it is SiO 2 . It is also employed as charge storage in nonvolatile memory devices thanks to its high concentration of charge traps. However, in the case of memories, it is still unclear which defects are responsible for charge trapping and what is the impact of defect concentration on the structural and electronic properties of SiN x . Indeed, for the amorphous phase the band gap was measured in the range 5.1–5.5 eV, with long tails in the density of states penetrating the gap region. It is still not clear which defects are responsible for the tails. On the other hand, the K-center defects have been associated with charge trapping, though its origin is assigned to one Si back bond. To investigate the contribution of defect states to the band edge tails and band gap states, we adopted the β phase of stoichiometric silicon nitride (β-Si 3 N 4 ) as our model material and calculated its electronic properties employing ab initio DFT/LDA simulations with self-energy correction to improve the location of defect states in the SiN x band gap through the correction of the band gap underestimation typical of DFT/LDA. We considered some important defects in SiN x , as the Si anti-site and the N vacancy with H saturation, in two defect concentrations. The location of our calculated defect levels in the band gap correlates well with the available experimental data, offering a structural explanation to the measured band edge tails and charge trapping characteristics.

  9. Temperature detectors on irradiated silicon base

    International Nuclear Information System (INIS)

    Karimov, M.; Dzhalelov, M.A.; Kurbanov, A.O.

    2005-01-01

    It is well known, that the most suitable for thermal resistors production is compensated silicon with impurities forming deep lying in forbidden zone, having big negative resistance temperature coefficients (RTC). In the capacity of initial materials for thermal resistors with negative RTC the n-type monocrystalline silicon with specific resistance ∼30 Ω·cm at 300 K is applied. Before the irradiation the phosphorus diffusion is realizing at temperature ∼1000 deg. C for 10 min. Irradiation is putting into practise by WWR-SM reactor fast neutrons within the range (7-10)·10 13 cm -2 . The produced resistors have nominal resistance range (8-20)·10 3 Ω·cm, coefficient of the thermal sensitivity B=4000-6000 deg. C., RTC α 300K =4-6.6 %/grad. It is shown, that offered method allows to obtain same type resistors characteristics on the base of neutron-irradiated material

  10. Industrial Silicon Wafer Solar Cells

    OpenAIRE

    Neuhaus, Dirk-Holger; Münzer, Adolf

    2007-01-01

    In 2006, around 86% of all wafer-based silicon solar cells were produced using screen printing to form the silver front and aluminium rear contacts and chemical vapour deposition to grow silicon nitride as the antireflection coating onto the front surface. This paper reviews this dominant solar cell technology looking into state-of-the-art equipment and corresponding processes for each process step. The main efficiency losses of this type of solar cell are analyzed to demonstrate the future e...

  11. Multifunctional Electroactive Nanocomposites Based on Piezoelectric Boron Nitride Nanotubes

    Science.gov (United States)

    Kang, Jin Ho; Sauti, Godfrey; Park, Cheol; Yamakov, Vesselin I.; Wise, Kristopher E.; Lowther, Sharon E.; Fay, Catharine C.; Thibeault, Sheila A.; Bryant, Robert G.

    2015-01-01

    Space exploration missions require sensors and devices capable of stable operation in harsh environments such as those that include high thermal fluctuation, atomic oxygen, and high-energy ionizing radiation. However, conventional or state-of-the-art electroactive materials like lead zirconate titanate, poly(vinylidene fluoride), and carbon nanotube (CNT)-doped polyimides have limitations on use in those extreme applications. Theoretical studies have shown that boron nitride nanotubes (BNNTs) have strength-to-weight ratios comparable to those of CNTs, excellent high-temperature stability (to 800 C in air), large electroactive characteristics, and excellent neutron radiation shielding capability. In this study, we demonstrated the experimental electroactive characteristics of BNNTs in novel multifunctional electroactive nanocomposites. Upon application of an external electric field, the 2 wt % BNNT/polyimide composite was found to exhibit electroactive strain composed of a superposition of linear piezoelectric and nonlinear electrostrictive components. When the BNNTs were aligned by stretching the 2 wt % BNNT/polyimide composite, electroactive characteristics increased by about 460% compared to the nonstretched sample. An all-nanotube actuator consisting of a BNNT buckypaper layer between two single-walled carbon nanotube buck-paper electrode layers was found to have much larger electroactive properties. The additional neutron radiation shielding properties and ultraviolet/visible/near-infrared optical properties of the BNNT composites make them excellent candidates for use in the extreme environments of space missions. utilizing the unique characteristics of BNNTs.

  12. Bipolar resistive switching in metal-insulator-semiconductor nanostructures based on silicon nitride and silicon oxide

    Science.gov (United States)

    Koryazhkina, M. N.; Tikhov, S. V.; Mikhaylov, A. N.; Belov, A. I.; Korolev, D. S.; Antonov, I. N.; Karzanov, V. V.; Gorshkov, O. N.; Tetelbaum, D. I.; Karakolis, P.; Dimitrakis, P.

    2018-03-01

    Bipolar resistive switching in metal-insulator-semiconductor (MIS) capacitor-like structures with an inert Au top electrode and a Si3N4 insulator nanolayer (6 nm thick) has been observed. The effect of a highly doped n +-Si substrate and a SiO2 interlayer (2 nm) is revealed in the changes in the semiconductor space charge region and small-signal parameters of parallel and serial equivalent circuit models measured in the high- and low-resistive capacitor states, as well as under laser illumination. The increase in conductivity of the semiconductor capacitor plate significantly reduces the charging and discharging times of capacitor-like structures.

  13. Silicon based light-emitting materials and devices

    International Nuclear Information System (INIS)

    Chen Weide

    1999-01-01

    Silicon based light-emitting materials and devices are the key to optoelectronic integration. Recently, there has been significant progress in materials engineering methods. The author reviews the latest developments in this area including erbium doped silicon, porous silicon, nanocrystalline silicon and Si/SiO 2 superlattice structures. The incorporation of these different materials into devices is described and future device prospects are assessed

  14. Surface wave photonic device based on porous silicon multilayers

    International Nuclear Information System (INIS)

    Guillermain, E.; Lysenko, V.; Benyattou, T.

    2006-01-01

    Porous silicon is widely studied in the field of photonics due to its interesting optical properties. In this work, we present theoretical and first experimental studies of a new kind of porous silicon photonic device based on optical surface wave. A theoretical analysis of the device is presented using plane-wave approximation. The porous silicon multilayered structures are realized using electrochemical etching of p + -type silicon. Morphological and optical characterizations of the realized structures are reported

  15. Ordered silicon nanostructures for silicon-based photonics devices

    Czech Academy of Sciences Publication Activity Database

    Fojtík, A.; Valenta, J.; Pelant, Ivan; Kálal, M.; Fiala, P.

    2007-01-01

    Roč. 5, Suppl. (2007), S250-S253 ISSN 1671-7694 R&D Projects: GA AV ČR IAA1010316 Grant - others:GA MŠk(CZ) ME 933 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystals * silicon * self-assembled monolayers Subject RIV: BM - Solid Matter Physics ; Magnetism

  16. Low Working-Temperature Acetone Vapor Sensor Based on Zinc Nitride and Oxide Hybrid Composites.

    Science.gov (United States)

    Qu, Fengdong; Yuan, Yao; Guarecuco, Rohiverth; Yang, Minghui

    2016-06-01

    Transition-metal nitride and oxide composites are a significant class of emerging materials that have attracted great interest for their potential in combining the advantages of nitrides and oxides. Here, a novel class of gas sensing materials based on hybrid Zn3 N2 and ZnO composites is presented. The Zn3 N2 /ZnO (ZnNO) composites-based sensor exhibits selectivity and high sensitivity toward acetone vapor, and the sensitivity is dependent on the nitrogen content of the composites. The ZnNO-11.7 described herein possesses a low working temperature of 200 °C. The detection limit (0.07 ppm) is below the diabetes diagnosis threshold (1.8 ppm). In addition, the sensor shows high reproducibility and long-term stability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Anomalous Threshold Voltage Variability of Nitride Based Charge Storage Nonvolatile Memory Devices

    Directory of Open Access Journals (Sweden)

    Meng Chuan Lee

    2013-01-01

    Full Text Available Conventional technology scaling is implemented to meet the insatiable demand of high memory density and low cost per bit of charge storage nonvolatile memory (NVM devices. In this study, effect of technology scaling to anomalous threshold voltage ( variability is investigated thoroughly on postcycled and baked nitride based charge storage NVM devices. After long annealing bake of high temperature, cell’s variability of each subsequent bake increases within stable distribution and found exacerbate by technology scaling. Apparent activation energy of this anomalous variability was derived through Arrhenius plots. Apparent activation energy (Eaa of this anomalous variability is 0.67 eV at sub-40 nm devices which is a reduction of approximately 2 times from 110 nm devices. Technology scaling clearly aggravates this anomalous variability, and this poses reliability challenges to applications that demand strict control, for example, reference cells that govern fundamental program, erase, and verify operations of NVM devices. Based on critical evidence, this anomalous variability is attributed to lateral displacement of trapped charges in nitride storage layer. Reliability implications of this study are elucidated. Moreover, potential mitigation methods are proposed to complement technology scaling to prolong the front-runner role of nitride based charge storage NVM in semiconductor flash memory market.

  18. Properties of minor actinide nitrides

    International Nuclear Information System (INIS)

    Takano, Masahide; Itoh, Akinori; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo

    2004-01-01

    The present status of the research on properties of minor actinide nitrides for the development of an advanced nuclear fuel cycle based on nitride fuel and pyrochemical reprocessing is described. Some thermal stabilities of Am-based nitrides such as AmN and (Am, Zr)N were mainly investigated. Stabilization effect of ZrN was cleary confirmed for the vaporization and hydrolytic behaviors. New experimental equipments for measuring thermal properties of minor actinide nitrides were also introduced. (author)

  19. Silicon-Based Nanoscale Composite Energetic Materials

    Science.gov (United States)

    2013-02-01

    1193-1211. 9. Krishnamohan, G., E.M. Kurian, and H.R. Rao, Thermal Analysis and Inverse Burning Rate Studies on Silicon-Potassium Nitrate System...reported in a journal paper and appears in the Appendix. Multiscale Nanoporous Silicon Combustion Introduction for nanoporous silicon effort While

  20. Gallium nitride based transistors for high-efficiency microwave switch-mode amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Maroldt, Stephan

    2012-07-01

    Highly-efficient switch-mode power amplifiers form key elements in future fully-digital base stations for mobile communication. This novel digital base station concept reduces system energy consumption, complexity, size and costs, while the flexibility in terms of multi-band operation and signal modulation improves. In this work, innovative core circuits for digital high-efficiency class-D and class-S power amplifiers based on gallium nitride (GaN) technology were developed for the application in digital base stations. A combination of optimized GaN devices and improvements in circuit design allow a highly-efficient switch-mode operation at mobile communication frequencies between 0.45 GHz and 2 GHz. Transistor device modeling for switch-mode operation, the simulation environment, and a broadband measurement system were established for the design and evaluation of digital switchmode power amplifiers. The design of broadband core circuits for switch-mode amplifier concepts was analyzed for dual-stage amplifier circuits, using an initial GaN technology with a gate length of 0.25 {mu}m. A speed-enhanced driver stage improved the circuit switching speed sufficiently above 1 GHz. Speed and efficiency of the amplifier core circuits were studied related to transistor parameters like cut-off frequency or gate capacitance. A reduced gate length was found to improve the switching speed, while a lower on-resistance allows the reduction of the inherent static losses of the GaN-based switches. Apart from this, the restriction of a 50 Ohm environment was found to be a major output power and switching speed limitation, due to a poor switching drive capability of the input capacitance of the GaN circuit. Finally, the optimized transistor and circuit design with an output gate width of 1.2 mm were effectively implemented in the given environment for an operation up to 2 GHz with a high drain efficiency of >65% and a digital output power of 5 W. A maximum output power of 9.7 W and a

  1. Enhancing the wettability of high aspect-ratio through-silicon vias lined with LPCVD silicon nitride or PE-ALD titanium nitride for void-free bottom-up copper electroplating

    NARCIS (Netherlands)

    Saadaoui, M.; Zeijl, H. van; Wien, W.H.A.; Pham, H.T.M.; Kwakernaak, C.; Knoops, H.C.M.; Erwin Kessels, W.M.M.; Sanden, R.M.C.M. van de; Voogt, F.C.; Roozeboom, F.; Sarro, P.M.

    2011-01-01

    One of the critical steps toward producing void-free and uniform bottom-up copper electroplating in high aspect-ratio (AR) through-silicon vias (TSVs) is the ability of the copper electrolyte to spontaneously flow through the entire depth of the via. This can be accomplished by reducing the

  2. Enhancing the Wettability of High Aspect-Ratio Through-Silicon Vias Lined with LPCVD Silicon Nitride or PE-ALD Titanium Nitride for Void-Free Bottom-Up Copper Electroplating

    NARCIS (Netherlands)

    Saadaoui, M.; van Zeijl, H.; Wien, W. H. A.; Pham, H. T. M.; Kwakernaak, C.; Knoops, H. C. M.; Kessels, W. M. M.; R. van de Sanden,; Voogt, F. C.; Roozeboom, F.; Sarro, P. M.

    2011-01-01

    One of the critical steps toward producing void-free and uniform bottom-up copper electroplating in high aspect-ratio (AR) through-silicon vias (TSVs) is the ability of the copper electrolyte to spontaneously flow through the entire depth of the via. This can be accomplished by reducing the

  3. Silicon technology-based micro-systems for atomic force microscopy/photon scanning tunnelling microscopy.

    Science.gov (United States)

    Gall-Borrut, P; Belier, B; Falgayrettes, P; Castagne, M; Bergaud, C; Temple-Boyer, P

    2001-04-01

    We developed silicon nitride cantilevers integrating a probe tip and a wave guide that is prolonged on the silicon holder with one or two guides. A micro-system is bonded to a photodetector. The resulting hybrid system enables us to obtain simultaneously topographic and optical near-field images. Examples of images obtained on a longitudinal cross-section of an optical fibre are shown.

  4. Study the effect of nitrogen flow rate on tribological properties of tantalum nitride based coatings

    Science.gov (United States)

    Chauhan, Dharmesh B.; Chauhan, Kamlesh V.; Sonera, Akshay L.; Makwana, Nishant S.; Dave, Divyeshkumar P.; Rawal, Sushant K.

    2018-05-01

    Tantalum Nitride (TaN) based coatings are well-known for their high temperature stability and chemical inertness. We have studied the effect of nitrogen flow rate variation on the structural and tribological properties of TaN based coating deposited by RF magnetron sputtering process. The nitrogen flow rate was varied from 5 to 30 sccm. X-ray diffractometer (XRD) and Atomic Force Microscopy (AFM) were used to determine structure and surface topography of coating. Pin on disc tribometer was used to determine tribological properties of coating. TaN coated brass and mild steel substrates shows higher wear resistance compared to uncoated substrates of brass and mild steel.

  5. Optical polarization based logic functions (XOR or XNOR) with nonlinear Gallium nitride nanoslab.

    Science.gov (United States)

    Bovino, F A; Larciprete, M C; Giardina, M; Belardini, A; Centini, M; Sibilia, C; Bertolotti, M; Passaseo, A; Tasco, V

    2009-10-26

    We present a scheme of XOR/XNOR logic gate, based on non phase-matched noncollinear second harmonic generation from a medium of suitable crystalline symmetry, Gallium nitride. The polarization of the noncollinear generated beam is a function of the polarization of both pump beams, thus we experimentally investigated all possible polarization combinations, evidencing that only some of them are allowed and that the nonlinear interaction of optical signals behaves as a polarization based XOR. The experimental results show the peculiarity of the nonlinear optical response associated with noncollinear excitation, and are explained using the expression for the effective second order optical nonlinearity in noncollinear scheme.

  6. Near infrared photodetector based on polymer and indium nitride nanorod organic/inorganic hybrids

    International Nuclear Information System (INIS)

    Lai, Wei-Jung; Li, Shao-Sian; Lin, Chih-Cheng; Kuo, Chun-Chiang; Chen, Chun-Wei; Chen, Kuei-Hsien; Chen, Li-Chyong

    2010-01-01

    We propose a nanostructured near infrared photodetector based on indium nitride (InN) nanorod/poly(3-hexylthiophene) hybrids. The current-voltage characteristic of the hybrid device demonstrates the typical p-n heterojunction diode behavior, consisting of p-type polymer and n-type InN nanorods. The device shows a photoresponse range of 900-1260 nm under various reverse biases. An external quantum efficiency of 3.4% at 900 nm operated at -10 V reverse bias was obtained, which is comparable with devices based on lead sulfide and lead selenide hybrid systems.

  7. Plasma-spray synthesis and characterization of ti-based nitride and oxide nanogranules

    Energy Technology Data Exchange (ETDEWEB)

    Antipas, Georgios S.E., E-mail: gantipas@metal.ntua.gr [School of Mining Engineering and Metallurgy, National Technical University of Athens, Athens (Greece)

    2014-09-15

    The synthesis of nanosized Ti-based nanogranules via plasma spraying is reported. The synthesis route involved use of both nitrogen and oxygen gases with varying results. In the case of nitrogen, a mixture of titanium nitrides were produced, yielding both the Ti2N and the sub-stoichiometric TiN0.61 compounds. In the case of oxygen, both the stoichiometric rutile and TiO ceramic phases were indexed. Based on EDS analysis, even fractional oxygen concentrations caused tungsten impurities which originated from the cathode electrode. The method yielded particle mass median sizes of the order of 15nm and the smallest particles detected were 5nm. (author)

  8. The SNAP trial: a double blind multi-center randomized controlled trial of a silicon nitride versus a PEEK cage in transforaminal lumbar interbody fusion in patients with symptomatic degenerative lumbar disc disorders: study protocol

    Science.gov (United States)

    2014-01-01

    Background Polyetheretherketone (PEEK) cages have been widely used in the treatment of lumbar degenerative disc disorders, and show good clinical results. Still, complications such as subsidence and migration of the cage are frequently seen. A lack of osteointegration and fibrous tissues surrounding PEEK cages are held responsible. Ceramic implants made of silicon nitride show better biocompatible and osteoconductive qualities, and therefore are expected to lower complication rates and allow for better fusion. Purpose of this study is to show that fusion with the silicon nitride cage produces non-inferior results in outcome of the Roland Morris Disability Questionnaire at all follow-up time points as compared to the same procedure with PEEK cages. Methods/Design This study is designed as a double blind multi-center randomized controlled trial with repeated measures analysis. 100 patients (18–75 years) presenting with symptomatic lumbar degenerative disorders unresponsive to at least 6 months of conservative treatment are included. Patients will be randomly assigned to a PEEK cage or a silicon nitride cage, and will undergo a transforaminal lumbar interbody fusion with pedicle screw fixation. Primary outcome measure is the functional improvement measured by the Roland Morris Disability Questionnaire. Secondary outcome parameters are the VAS leg, VAS back, SF-36, Likert scale, neurological outcome and radiographic assessment of fusion. After 1 year the fusion rate will be measured by radiograms and CT. Follow-up will be continued for 2 years. Patients and clinical observers who will perform the follow-up visits will be blinded for type of cage used during follow-up. Analyses of radiograms and CT will be performed independently by two experienced radiologists. Discussion In this study a PEEK cage will be compared with a silicon nitride cage in the treatment of symptomatic degenerative lumbar disc disorders. To our knowledge, this is the first randomized controlled

  9. Silicon Based Direct Methanol Fuel Cells

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent

    The purpose of this project has been to investigate and fabricate small scale Micro Direct Methanol Fuel Cells (μDMFC). They are investigated as a possible alternative for Zinc-air batteries in small size consumer devices such as hearing aids. In such devices the conventional rechargeable batteries...... such as lithium-ion batteries have insufficiently low energy density. Methanol is a promising fuel for such devices due to the high energy density and ease of refueling compared to charging batteries, making μDMFC a suitable replacement energy source. In this Ph.D. dissertation, silicon micro fabrication...... techniques where utilized to build μDMFCs with the purpose of engineering the structures, both on the micro and nano scales in order to realize a high level of control over the membrane and catalyst components. The work presents four different monolithic fuel cell designs. The primary design is based...

  10. III-nitride disk-in-nanowire 1.2 μm monolithic diode laser on (001)silicon

    KAUST Repository

    Hazari, Arnab

    2015-11-12

    III-nitride nanowirediodeheterostructures with multiple In0.85Ga0.15N disks and graded InGaN mode confining regions were grown by molecular beam epitaxy on (001)Si substrates. The aerial density of the 60 nm nanowires is ∼3 × 1010 cm−2. A radiative recombination lifetime of 1.84 ns in the disks is measured by time-resolved luminescence measurements. Edge-emitting nanowire lasers have been fabricated and characterized. Measured values of Jth, T0, and dg/dn in these devices are 1.24 kA/cm2, 242 K, and 5.6 × 10−17 cm2, respectively. The peak emission is observed at ∼1.2 μm.

  11. Silicon-based metallic micro grid for electron field emission

    International Nuclear Information System (INIS)

    Kim, Jaehong; Jeon, Seok-Gy; Kim, Jung-Il; Kim, Geun-Ju; Heo, Duchang; Shin, Dong Hoon; Sun, Yuning; Lee, Cheol Jin

    2012-01-01

    A micro-scale metal grid based on a silicon frame for application to electron field emission devices is introduced and experimentally demonstrated. A silicon lattice containing aperture holes with an area of 80 × 80 µm 2 and a thickness of 10 µm is precisely manufactured by dry etching the silicon on one side of a double-polished silicon wafer and by wet etching the opposite side. Because a silicon lattice is more rigid than a pure metal lattice, a thin layer of Au/Ti deposited on the silicon lattice for voltage application can be more resistant to the geometric stress caused by the applied electric field. The micro-fabrication process, the images of the fabricated grid with 88% geometric transparency and the surface profile measurement after thermal feasibility testing up to 700 °C are presented. (paper)

  12. A cubic boron nitride film-based fluorescent sensor for detecting Hg2+

    Science.gov (United States)

    Liu, W. M.; Zhao, W. W.; Zhang, H. Y.; Wang, P. F.; Chong, Y. M.; Ye, Q.; Zou, Y. S.; Zhang, W. J.; Zapien, J. A.; Bello, I.; Lee, S. T.

    2009-05-01

    Cubic boron nitride (cBN) film-based sensors for detecting Hg2+ ions were developed by surface functionalization with dansyl chloride. To immobilize dansyl chloride, 3-aminopropyltriethoxy silane was modified on hydroxylated cBN surfaces to form an amino-group-terminated self-assembled monolayer. The covalent attachment of the amino groups was confirmed by x-ray photoelectron spectroscopy. The selectivity and sensitivity of the sensors to detect diverse metal cations in ethanol solutions were studied by using fluorescence spectroscopy, revealing a great selectivity to Hg2+ ions. Significantly, the dansyl-chloride-functionalized cBN film sensors were recyclable after the sensing test.

  13. Technical assistance for development of thermally conductive nitride filler for epoxy molding compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Ho Jin; Song, Kee Chan; Jung, In Ha

    2005-07-15

    Technical assistance was carried out to develop nitride filler for thermally conductive epoxy molding compounds. Carbothermal reduction method was used to fabricate silicon nitride powder from mixtures of silica and graphite powders. Microstructure and crystal structure were observed by using scanning electron microscopy and x-ray diffraction technique. Thermal properties of epoxy molding compounds containing silicon nitride were measured by using laser flash method. Fabrication process of silicon nitride nanowire was developed and was applied to a patent.

  14. Investigation of deposition characteristics and properties of high-rate deposited silicon nitride films prepared by atmospheric pressure plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kakiuchi, H.; Nakahama, Y.; Ohmi, H.; Yasutake, K.; Yoshii, K.; Mori, Y.

    2005-01-01

    Silicon nitride (SiN x ) films have been prepared at extremely high deposition rates by the atmospheric pressure plasma chemical vapor deposition (AP-PCVD) technique on Si(001) wafers from gas mixtures containing He, H 2 , SiH 4 and N 2 or NH 3 . A 150 MHz very high frequency (VHF) power supply was used to generate high-density radicals in the atmospheric pressure plasma. Deposition rate, composition and morphology of the SiN x films prepared with various deposition parameters were studied by scanning electron microscopy and Auger electron spectroscopy. Fourier transformation infrared (FTIR) absorption spectroscopy was also used to characterize the structure and the chemical bonding configurations of the films. Furthermore, etching rate with buffered hydrofluoric acid (BHF) solution, refractive index and capacitance-voltage (C-V) characteristics were measured to evaluate the dielectric properties of the films. It was found that effective passivation of dangling bonds and elimination of excessive hydrogen atoms at the film-growing surface seemed to be the most important factor to form SiN x film with a dense Si-N network. The C-V curve of the optimized film showed good interface properties, although further improvement was necessary for use in the industrial metal-insulator-semiconductor (MIS) applications

  15. Investigation of Emerging Materials for Optoelectronic Devices Based on III-Nitrides

    KAUST Repository

    Muhammed, Mufasila Mumthaz

    2018-03-11

    III-nitride direct bandgap semiconductors have attracted significant research interest due to their outstanding potential for modern optoelectronic and electronic applications. However, the high cost of III-nitride devices, along with low performance due to dislocation defects, remains an obstacle to their further improvement. In this dissertation, I present a significant enhancement of III-nitride devices based on emerging materials. A promising substrate, (-201)-oriented β-Ga2O3 with unique properties that combine high transparency and conductivity, is used for the first time in the development of high-quality vertical III-nitride devices, which can be cost-effective for large-scale production. In addition, hybridizing GaN with emerging materials, mainly perovskite, is shown to extend the functionality of III-nitride applications. As a part of this investigation, high-performance and high-responsivity fast perovskite/GaN-based UV-visible broadband photodetectors were developed. State-of-the-art GaN epilayers grown on (-201)-oriented β-Ga2O3 using AlN and GaN buffer layers are discussed, and their high optical quality without using growth enhancement techniques is demonstrated. In particular, a low lattice mismatch (⁓4.7%) between GaN and the substrate results in a low density of dislocations ~4.8Å~107 cm−2. To demonstrates the effect of (-201)-oriented β-Ga2O3 substrate on the quality of III-nitride alloys, high-quality ternary alloy InxGa1−xN film is studied, followed by the growth of high quality InxGa1−xN/GaN single and multiple quantum wells (QWs). The optical characterization and carrier dynamics by photoluminescence (PL) and time-resolved PL measurements were subsequently performed. Lastly, to investigate the performance of a vertical emitting device based on InGaN/GaN multiple QWs grown on (-201)-oriented β-Ga2O3 substrate, high-efficiency vertical-injection emitting device is developed and extensively investigated. The conductive nature of

  16. Origin of high oxide to nitride polishing selectivity of ceria-based slurry in the presence of picolinic acid

    International Nuclear Information System (INIS)

    Wang Liang-Yong; Liu Bo; Song Zhi-Tang; Liu Wei-Li; Feng Song-Lin; David Huang; Babu, S.V

    2011-01-01

    We report on the investigation of the origin of high oxide to nitride polishing selectivity of ceria-based slurry in the presence of picolinic acid. The oxide to nitride removal selectivity of the ceria slurry with picolinic acid is as high as 76.6 in the chemical mechanical polishing. By using zeta potential analyzer, particle size analyzer, horizon profilometer, thermogravimetric analysis and Fourier transform infrared spectroscopy, the pre- and the post-polished wafer surfaces as well as the pre- and the post-used ceria-based slurries are compared. Possible mechanism of high oxide to nitride selectivity with using ceria-based slurry with picolinic acid is discussed. (interdisciplinary physics and related areas of science and technology)

  17. Origin of high oxide to nitride polishing selectivity of ceria-based slurry in the presence of picolinic acid

    Institute of Scientific and Technical Information of China (English)

    Wang Liang-Yong; Liu Bo; Song Zhi-Tang; Liu Wei-Li; Feng Song-Lin; David Huang; S.V Babu

    2011-01-01

    We report on the investigation of the origin of high oxide to nitride polishing selectivity of ceria-based slurry in the presence of picolinic acid. The oxide to nitride removal selectivity of the ceria slurry with picolinic acid is as high as 76.6 in the chemical mechanical polishing. By using zeta potential analyzer, particle size analyzer, horizon profilometer, thermogravimetric analysis and Fourier transform infrared spectroscopy, the pre-and the post-polished wafer surfaces as well as the pre-and the post-used ceria-based slurries are compared. Possible mechanism of high oxide to nitride selectivity with using ceria-based slurry with picolinic acid is discussed.

  18. A silicon-based electrical source for surface plasmon polaritons

    NARCIS (Netherlands)

    Walters, Robert J.; van Loon, Rob V.A.; Brunets, I.; Schmitz, Jurriaan; Polman, Albert

    2009-01-01

    This work demonstrates the fabrication of a silicon-based electrical source for surface plasmon polaritons (SPPs) at low temperatures using silicon nanocrystal doped alumina within a metal-insulator-metal (MIM) waveguide geometry. The fabrication method uses established microtechnology processes

  19. pH sensor based on boron nitride nanotubes.

    Science.gov (United States)

    Huang, Q; Bando, Y; Zhao, L; Zhi, C Y; Golberg, D

    2009-10-14

    A submicrometer-sized pH sensor based on biotin-fluorescein-functionalized multiwalled BN nanotubes with anchored Ag nanoparticles is designed. Intrinsic pH-dependent photoluminescence and Raman signals in attached fluorescein molecules enhanced by Ag nanoparticles allow this novel nanohybrid to perform as a practical pH sensor. It is able to work in a submicrometer-sized space. For example, the sensor may determine the environmental pH of sub-units in living cells where a traditional optical fiber sensor fails because of spatial limitations.

  20. pH sensor based on boron nitride nanotubes

    International Nuclear Information System (INIS)

    Huang, Q; Bando, Y; Zhao, L; Zhi, C Y; Golberg, D

    2009-01-01

    A submicrometer-sized pH sensor based on biotin-fluorescein-functionalized multiwalled BN nanotubes with anchored Ag nanoparticles is designed. Intrinsic pH-dependent photoluminescence and Raman signals in attached fluorescein molecules enhanced by Ag nanoparticles allow this novel nanohybrid to perform as a practical pH sensor. It is able to work in a submicrometer-sized space. For example, the sensor may determine the environmental pH of sub-units in living cells where a traditional optical fiber sensor fails because of spatial limitations.

  1. Nanocomposites based on hierarchical porous carbon fiber@vanadium nitride nanoparticles as supercapacitor electrodes.

    Science.gov (United States)

    Ran, Fen; Wu, Yage; Jiang, Minghuan; Tan, Yongtao; Liu, Ying; Kong, Lingbin; Kang, Long; Chen, Shaowei

    2018-03-28

    In this study, a hybrid electrode material for supercapacitors based on hierarchical porous carbon fiber@vanadium nitride nanoparticles is fabricated using the method of phase-separation mediated by the PAA-b-PAN-b-PAA tri-block copolymer. In the phase-separation procedure, the ionic block copolymer self-assembled on the surface of carbon nanofibers, and is used to adsorb NH 4 VO 3 . Thermal treatment at controlled temperatures under an NH 3  : N 2 atmosphere led to the formation of vanadium nitride nanoparticles that are distributed uniformly on the nanofiber surface. By changing the PAN to PAA-b-PAN-b-PAA ratio in the casting solution, a maximum specific capacitance of 240.5 F g -1 is achieved at the current density of 0.5 A g -1 with good rate capability at a capacitance retention of 72.1% at 5.0 A g -1 in an aqueous electrolyte of 6 mol L -1 KOH within the potential range of -1.10 to 0 V (rN/A = 1.5/1.0). Moreover, an asymmetric supercapacitor is assembled by using the hierarchical porous carbon fiber@vanadium nitride as the negative electrode and Ni(OH) 2 as the positive electrode. Remarkably, at the power density of 400 W kg -1 , the supercapacitor device delivers a better energy density of 39.3 W h kg -1 . It also shows excellent electrochemical stability, and thus might be used as a promising energy-storage device.

  2. III-nitride disk-in-nanowire 1.2 μm monolithic diode laser on (001)silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hazari, Arnab; Aiello, Anthony; Bhattacharya, Pallab [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Ng, Tien-Khee; Ooi, Boon S. [Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)

    2015-11-09

    III-nitride nanowire diode heterostructures with multiple In{sub 0.85}Ga{sub 0.15}N disks and graded InGaN mode confining regions were grown by molecular beam epitaxy on (001)Si substrates. The aerial density of the 60 nm nanowires is ∼3 × 10{sup 10} cm{sup −2}. A radiative recombination lifetime of 1.84 ns in the disks is measured by time-resolved luminescence measurements. Edge-emitting nanowire lasers have been fabricated and characterized. Measured values of J{sub th}, T{sub 0}, and dg/dn in these devices are 1.24 kA/cm{sup 2}, 242 K, and 5.6 × 10{sup −17} cm{sup 2}, respectively. The peak emission is observed at ∼1.2 μm.

  3. Lithium ion batteries based on nanoporous silicon

    Science.gov (United States)

    Tolbert, Sarah H.; Nemanick, Eric J.; Kang, Chris Byung-Hwa

    2015-09-22

    A lithium ion battery that incorporates an anode formed from a Group IV semiconductor material such as porous silicon is disclosed. The battery includes a cathode, and an anode comprising porous silicon. In some embodiments, the anode is present in the form of a nanowire, a film, or a powder, the porous silicon having a pore diameters within the range between 2 nm and 100 nm and an average wall thickness of within the range between 1 nm and 100 nm. The lithium ion battery further includes, in some embodiments, a non-aqueous lithium containing electrolyte. Lithium ion batteries incorporating a porous silicon anode demonstrate have high, stable lithium alloying capacity over many cycles.

  4. Design and Performance of Property Gradient Ternary Nitride Coating Based on Process Control.

    Science.gov (United States)

    Yan, Pei; Chen, Kaijie; Wang, Yubin; Zhou, Han; Peng, Zeyu; Jiao, Li; Wang, Xibin

    2018-05-09

    Surface coating is an effective approach to improve cutting tool performance, and multiple or gradient coating structures have become a common development strategy. However, composition mutations at the interfaces decrease the performance of multi-layered coatings. The key mitigation technique has been to reduce the interface effect at the boundaries. This study proposes a structure design method for property-component gradient coatings based on process control. The method produces coatings with high internal cohesion and high external hardness, which could reduce the composition and performance mutations at the interface. A ZrTiN property gradient ternary nitride coating was deposited on cemented carbide by multi-arc ion plating with separated Ti and Zr targets. The mechanical properties, friction behaviors, and cutting performances were systematically investigated, compared with a single-layer coating. The results indicated that the gradient coating had better friction and wear performance with lower wear rate and higher resistance to peeling off during sliding friction. The gradient coating had better wear and damage resistance in cutting processes, with lower machined surface roughness Ra. Gradient-structured coatings could effectively inhibit micro crack initiation and growth under alternating force and temperature load. This method could be extended to similar ternary nitride coatings.

  5. Oxidation and corrosion of silicon-based ceramics and composites

    International Nuclear Information System (INIS)

    Jacobson, N.S.; Fox, D.S.; Smialek, J.L.

    1997-01-01

    Silica scales exhibit slow growth rates and a low activation energy. Thus silica-protected materials are attractive high temperature structural materials for their potentially excellent oxidation resistance and well-documented high temperature strength. This review focuses on silicon carbide, silicon nitride, and composites of these materials. It is divided into four parts: (i) Fundamental oxidation mechanisms, (ii) Special properties of silica scales, (iii) Protective coatings, and (iv) Internal oxidation behavior of composites. While the fundamental oxidation mechanism of SiC is understood, there are still many questions regarding the oxidation mechanism of Si 3 N 4 . Silica scales exhibit many unique properties as compared to chromia and alumina. These include slower growth rates, SiO(g) formation, sensitivity to water vapor and impurities, and dissolution by basic molten salts. Protective coatings can limit the deleterious effects. The fourth area-internal oxidation of fibers and fiber coatings in composites-has limited the application of these novel materials. Strategies for understanding and limiting this internal oxidation are discussed. (orig.)

  6. Stretchable and foldable silicon-based electronics

    KAUST Repository

    Cavazos Sepulveda, Adrian Cesar

    2017-03-30

    Flexible and stretchable semiconducting substrates provide the foundation for novel electronic applications. Usually, ultra-thin, flexible but often fragile substrates are used in such applications. Here, we describe flexible, stretchable, and foldable 500-μm-thick bulk mono-crystalline silicon (100) “islands” that are interconnected via extremely compliant 30-μm-thick connectors made of silicon. The thick mono-crystalline segments create a stand-alone silicon array that is capable of bending to a radius of 130 μm. The bending radius of the array does not depend on the overall substrate thickness because the ultra-flexible silicon connectors are patterned. We use fracture propagation to release the islands. Because they allow for three-dimensional monolithic stacking of integrated circuits or other electronics without any through-silicon vias, our mono-crystalline islands can be used as a “more-than-Moore” strategy and to develop wearable electronics that are sufficiently robust to be compatible with flip-chip bonding.

  7. Stretchable and foldable silicon-based electronics

    KAUST Repository

    Cavazos Sepulveda, Adrian Cesar; Diaz Cordero, M. S.; Carreno, Armando Arpys Arevalo; Nassar, Joanna M.; Hussain, Muhammad Mustafa

    2017-01-01

    Flexible and stretchable semiconducting substrates provide the foundation for novel electronic applications. Usually, ultra-thin, flexible but often fragile substrates are used in such applications. Here, we describe flexible, stretchable, and foldable 500-μm-thick bulk mono-crystalline silicon (100) “islands” that are interconnected via extremely compliant 30-μm-thick connectors made of silicon. The thick mono-crystalline segments create a stand-alone silicon array that is capable of bending to a radius of 130 μm. The bending radius of the array does not depend on the overall substrate thickness because the ultra-flexible silicon connectors are patterned. We use fracture propagation to release the islands. Because they allow for three-dimensional monolithic stacking of integrated circuits or other electronics without any through-silicon vias, our mono-crystalline islands can be used as a “more-than-Moore” strategy and to develop wearable electronics that are sufficiently robust to be compatible with flip-chip bonding.

  8. Technology for bonding silicon nitride ceramics. Heat treatment technology to improve diffusion bonding strength; Chikka keiso ceramics no setsugo gijutsu. Kakusan setsugo kyodo kaizen no tame no metsushori gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, M.; Shigematsu, K. [National Industrial Research Institute of Nagoya,Nagoya (Japan)

    1999-01-25

    Silicon nitride ceramics is a structural ceramics with excellent high temperature strength and tenacity, being expected of expansion of application as a high temperature material. However, its processibility is poor, and special sintering technique is required to manufacture members of complex shapes. Therefore, development has been made on a technology to manufacture bonded materials with high mechanical strength, by which diffusion bonding in high temperature nitrogen gas and heat treatment are combined, and crystalline structure in the vicinity of bonding interface is controlled. (translated by NEDO)

  9. Study of silicon-silicon nitride interface properties on planar (1 0 0), planar (1 1 1) and textured surfaces using deep-level transient spectroscopy

    International Nuclear Information System (INIS)

    Gong, Chun; Simoen, Eddy; Posthuma, Niels E; Van Kerschaver, Emmanuel; Poortmans, Jef; Mertens, Robert

    2010-01-01

    Deep-level transient spectroscopy (DLTS) has been applied to metal-insulator-semiconductor (MIS) capacitors fabricated on planar (1 0 0), planar (1 1 1) orientations and textured n-type silicon wafers. Low frequency direct plasma-enhanced chemical vapour deposition Si-SiN x interface properties with and without plasma NH 3 pre-treatment, with and without rapid thermal annealing (RTA) have been investigated. It is shown that three different kinds of defect states are identified at the Si-SiN x interface. For the planar (1 0 0) surface, samples with plasma NH 3 pre-treatment plus RTA show the lowest DLTS signals, which suggests the lowest overall interface states density. For planar (1 1 1) Si surfaces, plasma NH 3 pre-treatment and RTA yield a small improvement. With the textured surface, the RTA step improves the surface passivation quality further but no obvious impact is found with plasma NH 3 pre-treatment. Energy-dependent electron capture cross sections were also measured by small-pulse DLTS. The capture cross sections depend strongly on the energy level and decrease towards the conduction band edge.

  10. Graphitic carbon nitride nanosheet electrode-based high-performance ionic actuator

    Science.gov (United States)

    Wu, Guan; Hu, Ying; Liu, Yang; Zhao, Jingjing; Chen, Xueli; Whoehling, Vincent; Plesse, Cédric; Nguyen, Giao T. M.; Vidal, Frédéric; Chen, Wei

    2015-01-01

    Ionic actuators have attracted attention due to their remarkably large strain under low-voltage stimulation. Because actuation performance is mainly dominated by the electrochemical and electromechanical processes of the electrode layer, the electrode material and structure are crucial. Here, we report a graphitic carbon nitride nanosheet electrode-based ionic actuator that displays high electrochemical activity and electromechanical conversion abilities, including large specific capacitance (259.4 F g−1) with ionic liquid as the electrolyte, fast actuation response (0.5±0.03% in 300 ms), large electromechanical strain (0.93±0.03%) and high actuation stability (100,000 cycles) under 3 V. The key to the high performance lies in the hierarchical pore structure with dominant size actuation performance. PMID:26028354

  11. A simple model for conduction band states of nitride-based double heteroestructures

    Energy Technology Data Exchange (ETDEWEB)

    Gaggero-Sager, L M; Mora-Ramos, M E, E-mail: lgaggero@uaem.m [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico)

    2009-05-01

    In this work we propose an analytical expression for the approximate modeling of the potential energy function describing conduction band bending in III-V nitride quantum wells. It is an alternative approach to the self-consistent Poisson-Schoedinger calculation. The model considers the influence of the many electron system and the built-in electric field inside the well. Hartree and exchange contributions are included along the lines of a local-density Thomas-Fermi-based theory. The effects due to the modulated doping in the barriers is also considered. We report the calculation of the energy spectrum as a function of several input parameters: alloy composition in the barriers, barrier doping concentration, and quantum well width. Our results could be of usefulness in the study of optoelectronic properties in this kind of systems.

  12. Challenges in calculating the bandgap of triazine-based carbon nitride structures

    KAUST Repository

    Steinmann, Stephan N.

    2017-02-08

    Graphitic carbon nitrides form a popular family of materials, particularly as photoharvesters in photocatalytic water splitting cells. Recently, relatively ordered g-C3N4 and g-C6N9H3 were characterized by X-ray diffraction and their ability to photogenerate excitons was subsequently estimated using density functional theory. In this study, the ability of triazine-based g-C3N4 and g-C6N9H3 to photogenerate excitons was studied using self-consistent GW computations followed by solving the Bethe–Salpeter Equation (BSE). In particular, monolayers, bilayers and 3D-periodic systems were characterized. The predicted optical band gaps are in the order of 1 eV higher than the experimentally measured ones, which is explained by a combination of shortcomings in the adopted model, small defects in the experimentally obtained structures and the particular nature of the experimental determination of the band gap.

  13. Influence of the alloy composition on the oxidation and internal-nitridation behaviour of nickel-base superalloys

    International Nuclear Information System (INIS)

    Krupp, U.; Christ, H.-J.

    1999-01-01

    Internal nitridation of nickel-base superalloys takes place as a consequence of the failure of protecting oxide scales (Al 2 O 3 and Cr 2 O 3 , respectively) and leads to a deterioration of the material properties due to near-surface embrittlement caused by the nitrides precipitated (TiN and AlN, respectively) and due to near-surface dissolution of the γ' phase. By using thermogravimetric methods in a temperature range between 800 C and 1100 C supplemented by microstructural examinations, the failure potential due to internal nitridation could be documented. A quantification was carried out by extending the experimental program to thermogravimetric studies in a nearly oxygen-free nitrogen atmosphere which was also applied to various model alloys of the system Ni-Cr-Al-Ti. It could be shown that the nitrogen diffusivity and solubility in nickel-base alloys is influenced particularly by the chromium concentration. An increasing chromium content leads to an enhanced internal-nitridation attack. (orig.)

  14. Application of hydrogen-plasma technology for property modification of silicon and producing the silicon-based structures

    International Nuclear Information System (INIS)

    Fedotov, A.K.; Mazanik, A.V.; Ul'yashin, A.G.; Dzhob, R; Farner, V.R.

    2000-01-01

    Effects of atomic hydrogen on the properties of Czochralski-grown single crystal silicon as well as polycrystalline shaped silicon have been investigated. It was established that the buried defect layers created by high-energy hydrogen or helium ion implantation act as a good getter centers for hydrogen atoms introduced in silicon in the process of hydrogen plasma hydrogenation. Atomic hydrogen was shown to be active as a catalyzer significantly enhancing the rate of thermal donors formation in p-type single crystal silicon. This effect can be used for n-p- and p-n-p-silicon based device structures producing [ru

  15. Double side multicrystalline silicon passivation by one step stain etching-based porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Seifeddine Belhadj; Ben Rabha, Mohamed; Bessais, Brahim [Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia)

    2012-10-15

    In this paper, we investigate the effect of stain etching-based porous silicon on the double side multicrystalline silicon. Special attention is given to the use of the stain etched PS as an antireflection coating as well as for surface passivating capabilities. Stain etching of double side multicrystalline silicon leads to the formation of PS nanostructures, that dramatically decrease the surface reflectivity from 30% to about 7% and increase the effective lifetime from 1 {mu}s to 10 {mu}s at a minority carrier density ({Delta}n) of 10{sup 15} cm{sup -3}. These results let us correlate the rise of the lifetime values to the photoluminescence intensity to the hydrogen and oxide passivation as shown by FTIR analysis. This low-cost PS formation process can be applied in the photovoltaic cell technology as a standard procedure (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. An FPGA-based silicon neuronal network with selectable excitability silicon neurons

    Directory of Open Access Journals (Sweden)

    Jing eLi

    2012-12-01

    Full Text Available This paper presents a digital silicon neuronal network which simulates the nerve system in creatures and has the ability to execute intelligent tasks, such as associative memory. Two essential elements, the mathematical-structure-based digital spiking silicon neuron (DSSN and the transmitter release based silicon synapse, allow the network to show rich dynamic behaviors and are computationally efficient for hardware implementation. We adopt mixed pipeline and parallel structure and shift operations to design a sufficient large and complex network without excessive hardware resource cost. The network with $256$ full-connected neurons is built on a Digilent Atlys board equipped with a Xilinx Spartan-6 LX45 FPGA. Besides, a memory control block and USB control block are designed to accomplish the task of data communication between the network and the host PC. This paper also describes the mechanism of associative memory performed in the silicon neuronal network. The network is capable of retrieving stored patterns if the inputs contain enough information of them. The retrieving probability increases with the similarity between the input and the stored pattern increasing. Synchronization of neurons is observed when the successful stored pattern retrieval occurs.

  17. Enhanced dispersion of boron nitride nanosheets in aqueous media by using bile acid-based surfactants

    Science.gov (United States)

    Chae, Ari; Park, Soo-Jin; Min, Byunggak; In, Insik

    2018-01-01

    Facile noncovalent surface functionalization of hydroxylated boron nitride nanosheet (BNNS-OH) was attempted through the sonication-assisted exfoliation of h-BN in aqueous media in the presence of bile acid-based surfactants such as sodium cholic acid (SC) or sodium deoxycholic acid (SDC), resulting in SC- or SDC-BNNS-OH dispersion with high up to 2 mg ml-1 and enhanced dispersion stability due to the increased negative zeta potential. While prepared SC-BNNS-OH revealed multi-layered BNNS structures, the large lateral sizes of hundreds nanometers and clear h-BN lattice structures are very promising for the preparation and application of water-processable BNNS-based nanomaterials. It is regarded that noncovalent functionalization of BNNS-OH based on σ-π interaction between with σ-rich bile acid-based amphiphiles and π-rich BNNS is very effective to formulate multi-functional BNNS-based nanomaterials or hybrids that can be utilized in various applications where both the pristine properties of BNNS and the extra functions are simultaneously required.

  18. Effect of porous silicon on the performances of silicon solar cells during the porous silicon-based gettering procedure

    Energy Technology Data Exchange (ETDEWEB)

    Nouri, H.; Bessais, B. [Laboratoire de Nanomateriaux et des Systemes pour l' Energie, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia); Bouaicha, M. [Laboratoire de Photovoltaique, des Semi-conducteurs et des Nanostructures, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia)

    2009-10-15

    In this work we analyse the effect of porous silicon on the performances of multicrystalline silicon (mc-Si) solar cells during the porous silicon-based gettering procedure. This procedure consists of forming PS layers on both front and back sides of the mc-Si wafers followed by an annealing in an infrared furnace under a controlled atmosphere at different temperatures. Three sets of samples (A, B and C) have been prepared; for samples A and B, the PS films were removed before and after annealing, respectively. In order to optimize the annealing temperature, we measure the defect density at a selected grain boundary (GB) using the dark current-voltage (I-V) characteristics across the GB itself. The annealing temperature was optimized to 1000 C. The effect of these treatments on the performances of mc-Si solar cells was studied by means of the current-voltage characteristic (at AM 1.5) and the internal quantum efficiency (IQE). The results obtained for cell A and cell B were compared to those obtained on a reference cell (C). (author)

  19. Characterization of electrical and optical properties of silicon based materials

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Guobin

    2009-12-04

    In this work, the electrical and luminescence properties of a series of silicon based materials used for photovoltaics, microelectronics and nanoelectronics have been investigated by means of electron beam induced current (EBIC), cathodoluminescence (CL), photoluminescence (PL) and electroluminescence (EL) methods. Photovoltaic materials produced by block casting have been investigated by EBIC on wafers sliced from different parts of the ingot. Various solar cell processings have been compared in parallel wafers by means of EBIC collection efficiency measurements and contrast-temperature C(T) behaviors of the extended defects, i. e. dislocations and grain boundaries (GBs). It was found that the solar cell processing with phosphorus diffusion gettering (PDG) followed with a SiN firing greatly reduces the recombination activity of extended defects at room temperature, and improves the bulk property simultaneously. A remaining activity of the dislocations indicates the limitation of the PDG at extended defects. Abnormal behavior of the dislocation activity after certain solar cell processes was also observed in the region with high dislocation density, the dislocations are activated after certain solar cell processings. In order to evaluate the properties of a thin polycrystalline silicon layer prepared by Al-induced layer exchange (Alile) technique, epitaxially layer grown on silicon substrate with different orientations was used as a model system to investigate the impact by the process temperature and the substrates. EBIC energy dependent collection efficiency measurements reveal an improvement of the epilayer quality with increasing substrate temperature during the growth from 450 C to 650 C, and a decrease of epilayer quality at 700 C. PL measurements on the epitaxially grown Si layer on silicon substrates revealed no characteristic dislocation-related luminescence (DRL) lines at room temperature and 77 K, while in the samples prepared by Alile process, intense

  20. Design of silicon-based fractal antennas

    KAUST Repository

    Ghaffar, Farhan A.

    2012-11-20

    This article presents Sierpinski carpet fractal antennas implemented in conventional low resistivity (Ï =10 Ω cm) as well as high resistivity (Ï =1500 Ω cm) silicon mediums. The fractal antenna is 36% smaller as compared with a typical patch antenna at 24 GHz and provides 13% bandwidth on high resistivity silicon, suitable for high data rate applications. For the first time, an on-chip fractal antenna array is demonstrated in this work which provides double the gain of a single fractal element as well as enhanced bandwidth. A custom test fixture is utilized to measure the radiation pattern and gain of these probe-fed antennas. In addition to gain and impedance characterization, measurements have also been made to study intrachip communication through these antennas. The comparison between the low resistivity and high resistivity antennas indicate that the former is not a suitable medium for array implementation and is only suitable for short range communication whereas the latter is appropriate for short and medium range wireless communication. The design is well-suited for compact, high data rate System-on-Chip (SoC) applications as well as for intrachip communication such as wireless global clock distribution in synchronous systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:180-186, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27245 Copyright © 2012 Wiley Periodicals, Inc.

  1. Design of silicon-based fractal antennas

    KAUST Repository

    Ghaffar, Farhan A.; Shamim, Atif

    2012-01-01

    This article presents Sierpinski carpet fractal antennas implemented in conventional low resistivity (Ï =10 Ω cm) as well as high resistivity (Ï =1500 Ω cm) silicon mediums. The fractal antenna is 36% smaller as compared with a typical patch antenna at 24 GHz and provides 13% bandwidth on high resistivity silicon, suitable for high data rate applications. For the first time, an on-chip fractal antenna array is demonstrated in this work which provides double the gain of a single fractal element as well as enhanced bandwidth. A custom test fixture is utilized to measure the radiation pattern and gain of these probe-fed antennas. In addition to gain and impedance characterization, measurements have also been made to study intrachip communication through these antennas. The comparison between the low resistivity and high resistivity antennas indicate that the former is not a suitable medium for array implementation and is only suitable for short range communication whereas the latter is appropriate for short and medium range wireless communication. The design is well-suited for compact, high data rate System-on-Chip (SoC) applications as well as for intrachip communication such as wireless global clock distribution in synchronous systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:180-186, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27245 Copyright © 2012 Wiley Periodicals, Inc.

  2. Silicon-on-Insulator Nanowire Based Optical Waveguide Biosensors

    International Nuclear Information System (INIS)

    Li, Mingyu; Liu, Yong; Chen, Yangqing; He, Jian-Jun

    2016-01-01

    Optical waveguide biosensors based on silicon-on-insulator (SOI) nanowire have been developed for label free molecular detection. This paper reviews our work on the design, fabrication and measurement of SOI nanowire based high-sensitivity biosensors employing Vernier effect. Biosensing experiments using cascaded double-ring sensor and Mach-Zehnder- ring sensor integrated with microfluidic channels are demonstrated (paper)

  3. Silicon-Based Detectors at the HL-LHC

    CERN Document Server

    Hartmann, Frank

    2018-01-01

    This document discusses the silicon-based detectors planned for the High Luminosity LHC. The special aspects to cope with the new environment and its challenges, e.g. very high radiation levels and very high instantaneous luminosity thus high pile-up, high occupancy and high data rates, are addressed. The different design choices of the detectors are put into perspective. Exciting topics like trackers, high granularity silicon-based calorimetry with novel 8~inch processing, fast timing and new triggers are described.

  4. Soft silicone based interpenetrating networks as materials for actuators

    DEFF Research Database (Denmark)

    Yu, Liyun; Gonzalez, Lidia; Hvilsted, Søren

    2014-01-01

    A new approach based on silicone interpenetrating networks with orthogonal chemistries has been investigated with focus on developing soft and flexible elastomers with high energy densities and small viscous losses. The interpenetrating networks are made as simple two pot mixtures...... as for the commercial available silylation based elastomers such as Elastosil RT625. The resulting interpenetrating networks are formulated to be softer than RT625 to increase the actuation caused when applying a voltage due to their softness combined with the significantly higher permittivity than the pure silicone...

  5. A nitride-based epitaxial surface layer formed by ammonia treatment of silicene-terminated ZrB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wiggers, F. B., E-mail: F.B.Wiggers@utwente.nl; Van Bui, H.; Schmitz, J.; Kovalgin, A. Y.; Jong, M. P. de [MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands); Friedlein, R.; Yamada-Takamura, Y. [School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292 (Japan)

    2016-04-07

    We present a method for the formation of an epitaxial  surface layer involving B, N, and Si atoms on a ZrB{sub 2}(0001) thin film on Si(111). It has the potential to be an insulating growth template for 2D semiconductors. The chemical reaction of NH{sub 3} molecules with the silicene-terminated ZrB{sub 2}  surface was characterized by synchrotron-based, high-resolution core-level photoelectron spectroscopy and low-energy electron diffraction. In particular, the dissociative chemisorption of NH{sub 3} at 400 °C leads to surface  nitridation, and subsequent annealing up to 830 °C results in a solid phase reaction with the ZrB{sub 2} subsurface layers. In this way, a new nitride-based epitaxial  surface layer is formed with hexagonal symmetry and a single in-plane crystal orientation.

  6. Plasma deposition of amorphous silicon-based materials

    CERN Document Server

    Bruno, Giovanni; Madan, Arun

    1995-01-01

    Semiconductors made from amorphous silicon have recently become important for their commercial applications in optical and electronic devices including FAX machines, solar cells, and liquid crystal displays. Plasma Deposition of Amorphous Silicon-Based Materials is a timely, comprehensive reference book written by leading authorities in the field. This volume links the fundamental growth kinetics involving complex plasma chemistry with the resulting semiconductor film properties and the subsequent effect on the performance of the electronic devices produced. Key Features * Focuses on the plasma chemistry of amorphous silicon-based materials * Links fundamental growth kinetics with the resulting semiconductor film properties and performance of electronic devices produced * Features an international group of contributors * Provides the first comprehensive coverage of the subject, from deposition technology to materials characterization to applications and implementation in state-of-the-art devices.

  7. Nanostructured and nanolayer coatings based on nitrides of the metals structure study and structure and composition standard samples set development

    Directory of Open Access Journals (Sweden)

    E. B. Chabina

    2014-01-01

    Full Text Available Researches by methods of analytical microscopy and the x-ray analysis have allowed to develop a set of standard samples of composition and structure of the strengthening nanostructured and nanolayer coatings for control of the strengthening nanostructured and nanolayer coatings based on nitrides of the metals used to protect critical parts of the compressor of the gas turbine engine from dust erosion, corrosion and oxidation.

  8. Eliminating dependence of hole depth on aspect ratio by forming ammonium bromide during plasma etching of deep holes in silicon nitride and silicon dioxide

    Science.gov (United States)

    Iwase, Taku; Yokogawa, Kenetsu; Mori, Masahito

    2018-06-01

    The reaction mechanism during etching to fabricate deep holes in SiN/SiO2 stacks by using a HBr/N2/fluorocarbon-based gas plasma was investigated. To etch SiN and SiO2 films simultaneously, HBr/fluorocarbon gas mixture ratio was controlled to achieve etching selectivity closest to one. Deep holes were formed in the SiN/SiO2 stacks by one-step etching at several temperatures. The surface composition of the cross section of the holes was analyzed by time-of-flight secondary-ion mass spectrometry. It was found that bromine ions (considered to be derived from NH4Br) were detected throughout the holes in the case of low-temperature etching. It was also found that the dependence of hole depth on aspect ratio decreases as temperature decreases, and it becomes significantly weaker at a substrate temperature of 20 °C. It is therefore concluded that the formation of NH4Br supplies the SiN/SiO2 etchant to the bottom of the holes. Such a finding will make it possible to alleviate the decrease in etching rate due to a high aspect ratio.

  9. Porous silicon based anode material formed using metal reduction

    Science.gov (United States)

    Anguchamy, Yogesh Kumar; Masarapu, Charan; Deng, Haixia; Han, Yongbong; Venkatachalam, Subramanian; Kumar, Sujeet; Lopez, Herman A.

    2015-09-22

    A porous silicon based material comprising porous crystalline elemental silicon formed by reducing silicon dioxide with a reducing metal in a heating process followed by acid etching is used to construct negative electrode used in lithium ion batteries. Gradual temperature heating ramp(s) with optional temperature steps can be used to perform the heating process. The porous silicon formed has a high surface area from about 10 m.sup.2/g to about 200 m.sup.2/g and is substantially free of carbon. The negative electrode formed can have a discharge specific capacity of at least 1800 mAh/g at rate of C/3 discharged from 1.5V to 0.005V against lithium with in some embodiments loading levels ranging from about 1.4 mg/cm.sup.2 to about 3.5 mg/cm.sup.2. In some embodiments, the porous silicon can be coated with a carbon coating or blended with carbon nanofibers or other conductive carbon material.

  10. Fabrication and Characterization of Nanopillars for Silicon-Based Thermoelectrics

    Science.gov (United States)

    Stranz, A.; Sökmen, Ü.; Wehmann, H.-H.; Waag, A.; Peiner, E.

    2010-09-01

    Si-based nanopillars of various sizes were fabricated by lateral structuring using anisotropic etching and thermal oxidation. We obtained pillars of diameter <500 nm, about 25 μm in height, with an aspect ratio of more than 50. The distance between pillars was varied from 500 nm to 10 μm. Besides the fabrication and structural characterization of silicon nanopillars, implementation of adequate metrology for measuring single pillars is described. Commercial tungsten probes, self-made gold probes, and piezoresistive silicon cantilever probes were used for measurements of nanopillars in a scanning electron microscope (SEM) equipped with nanomanipulators.

  11. The influence of process parameters and additives on the densification, creep properties and strength of hot pressed silicon nitride

    International Nuclear Information System (INIS)

    Becker, R.

    1979-03-01

    One method of production of Si 3 N 4 parts is the hot pressing of powder compacts. According to the current technological know how, a liquid phase building additive (e.g. MgO) is essential for the complete densification of Si 3 N 4 . In this work it has been shown, how dense Si 3 N 4 may be produced without the conventional additives. The SiO 2 -coating of Si 3 N 4 particles here results in the liquid phase formation. On the basis of the above concept, the effect of MgO, Mg 3 N 2 , Al 2 O 3 and A1N-additions to a pure Si 3 N 4 powder have been studied in detail and the resulting material properties: densification, creep and high temperature strengths have been determined. Based on the results, it may be concluded, that HPSN is a dispersion of crystalline Si 3 N 4 in an amorphous matrix (glass content between 4-10 vol%). Depending on the amount and composition of the boundary phase (silicate glass) widely variing material properties may be obtained. (orig./GSCH) [de

  12. Fast neutron dosimeter with wide base silicon diode

    International Nuclear Information System (INIS)

    Ma Lu

    1986-01-01

    This paper briefly introduces a wide base silicon diode fast neutron dosimeter with wide measuring range and good energy response to fast neutron. It is suitable to be used to detect fast neutrons in the mixed field of γ-ray, thermal neutrons and fast neutrons

  13. Novel Concepts for Silicon Based Photovoltaics and Photoelectrochemistry

    NARCIS (Netherlands)

    Han, L.

    2015-01-01

    Long term concerns about climate change and fossil fuel depletion will require a transition towards energy systems powered by solar radiation or other renewable sources. Novel concepts based on silicon materials and devices are investigated for applications in the next generation photovoltaic (PV)

  14. Fabrication of silicon based glass fibres for optical communication

    Indian Academy of Sciences (India)

    Silicon based glass fibres are fabricated by conventional fibre drawing process. First, preform fabrication is carried out by means of conventional MCVD technique by using various dopants such as SiCl4, GeCl4, POCl3, and FeCl3. The chemicals are used in such a way that step index single mode fibre can be drawn.

  15. Hydrogen Sensors Using Nitride-Based Semiconductor Diodes: The Role of Metal/Semiconductor Interfaces

    Directory of Open Access Journals (Sweden)

    Yoshihiro Irokawa

    2011-01-01

    Full Text Available In this paper, I review my recent results in investigating hydrogen sensors using nitride-based semiconductor diodes, focusing on the interaction mechanism of hydrogen with the devices. Firstly, effects of interfacial modification in the devices on hydrogen detection sensitivity are discussed. Surface defects of GaN under Schottky electrodes do not play a critical role in hydrogen sensing characteristics. However, dielectric layers inserted in metal/semiconductor interfaces are found to cause dramatic changes in hydrogen sensing performance, implying that chemical selectivity to hydrogen could be realized. The capacitance-voltage (C-V characteristics reveal that the work function change in the Schottky metal is not responsible mechanism for hydrogen sensitivity. The interface between the metal and the semiconductor plays a critical role in the interaction of hydrogen with semiconductor devises. Secondly, low-frequency C-V characterization is employed to investigate the interaction mechanism of hydrogen with diodes. As a result, it is suggested that the formation of a metal/semiconductor interfacial polarization could be attributed to hydrogen-related dipoles. In addition, using low-frequency C-V characterization leads to clear detection of 100 ppm hydrogen even at room temperature where it is hard to detect hydrogen by using conventional current-voltage (I-V characterization, suggesting that low-frequency C-V method would be effective in detecting very low hydrogen concentrations.

  16. Piezoelectric actuated micro-resonators based on the growth of diamond on aluminum nitride thin films

    International Nuclear Information System (INIS)

    Hees, J; Heidrich, N; Pletschen, W; Sah, R E; Wolfer, M; Lebedev, V; Nebel, C E; Ambacher, O; Williams, O A

    2013-01-01

    Unimorph heterostructures based on piezoelectric aluminum nitride (AlN) and diamond thin films are highly desirable for applications in micro- and nanoelectromechanical systems. In this paper, we present a new approach to combine thin conductive boron-doped as well as insulating nanocrystalline diamond (NCD) with sputtered AlN films without the need for any buffer layers between AlN and NCD or polishing steps. The zeta potentials of differently treated nanodiamond (ND) particles in aqueous colloids are adjusted to the zeta potential of AlN in water. Thereby, the nucleation density for the initial growth of diamond on AlN can be varied from very low (10 8 cm −2 ), in the case of hydrogen-treated ND seeding particles, to very high values of 10 11 cm −2 for oxidized ND particles. Our approach yielding high nucleation densities allows the growth of very thin NCD films on AlN with thicknesses as low as 40 nm for applications such as microelectromechanical beam resonators. Fabricated piezo-actuated micro-resonators exhibit enhanced mechanical properties due to the incorporation of boron-doped NCD films. Highly boron-doped NCD thin films which replace the metal top electrode offer Young’s moduli of more than 1000 GPa. (paper)

  17. Ultrahigh Tunneling-Magnetoresistance Ratios in Nitride-Based Perpendicular Magnetic Tunnel Junctions from First Principles

    Science.gov (United States)

    Yang, Baishun; Tao, Lingling; Jiang, Leina; Chen, Weizhao; Tang, Ping; Yan, Yu; Han, Xiufeng

    2018-05-01

    We report a first-principles study of electronic structures, magnetic properties, and the tunneling-magnetoresistance (TMR) effect of a series of ferromagnetic nitride M4N (M =Fe , Co, Ni)-based magnetic tunnel junctions (MTJs). It is found that bulk Fe4 N reveals a half-metal nature in terms of the Δ1 state. A perpendicular magnetic anisotropy is observed in the periodic system Fe4 N /MgO . In particular, the ultrahigh TMR ratio of over 24 000% is predicted in the Fe4 N /MgO /Fe4N MTJ due to the interface resonance tunneling and relatively high transmission for states of other symmetry. Besides, the large TMR can be maintained with the change of atomic details at the interface, such as the order-disorder interface, the change of thickness of the MgO barrier, and different in-plane lattice constants of the MTJ. The physical origin of the TMR effect can be well understood by analyzing the band structure and transmission channel of bulk Fe4 N as well as the transmission in momentum space of Fe4 N /MgO /Fe4N . Our results suggest that the Fe4 N /MgO /Fe4N MTJ is a benefit for spintronic applications.

  18. Atomistic description of large nanostructures based on III-nitride semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Molina-Sanchez, Alejandro; Garcia-Cristobal, Alberto; Cantarero, Andres [Instituto de Ciencia de Materiales de la Universidad de Valencia (Spain); Terentjevs, Aleksandrs; Cicero, Giancarlo [Physics and Materials Science and Chemical Engineering Departments, Politecnico di Torino (Italy)

    2010-07-01

    Semiconductor nanocolumns exhibiting a growth without dislocations and high crystalline quality are of great interest in nanotechnology applications. Specifically, InN-based nanocolumns are good candidates to develop multi-junction solar cells due to their small gap, 0.67 eV, and the possibility of alloying with other nitrides (as GaN and AlN) to cover the entire solar spectrum. A proper description of optical properties of the nanostructures described above can start with an atomistic treatment of the electronic structure in order to keep the essential geometry and symmetry of the objects. Unfortunately, the best description realized with ab initio electronic structure software is strongly limited by the nanocolumn diameter to a few nanometers. By using a combination of ab initio and empirical tight-binding methods, we can connect the quality of the first principles calculations (performed with the Espresso code), with the versatility of an empirical approach. Once we have an ab initio quality parameter set for the empirical tight-binding code, we can study larger nanostructures with this approach, reducing the computation time in orders of magnitude.

  19. First-principle approach based bandgap engineering for cubic boron nitride doped with group IIA elements

    Science.gov (United States)

    Li, Yubo; Wang, Pengtao; Hua, Fei; Zhan, Shijie; Wang, Xiaozhi; Luo, Jikui; Yang, Hangsheng

    2018-03-01

    Electronic properties of cubic boron nitride (c-BN) doped with group IIA elements were systematically investigated using the first principle calculation based on density functional theory. The electronic bandgap of c-BN was found to be narrowed when the impurity atom substituted either the B (IIA→B) or the N (IIA→N) atom. For IIA→B, a shallow accept level degenerated into valence band (VB); while for IIA→N, a shallow donor level degenerated conduction band (CB). In the cases of IIBe→N and IIMg→N, deep donor levels were also induced. Moreover, a zigzag bandgap narrowing pattern was found, which is in consistent with the variation pattern of dopants' radius of electron occupied outer s-orbital. From the view of formation energy, the substitution of B atom under N-rich conditions and the substitution of N atom under B-rich conditions were energetically favored. Our simulation results suggested that Mg and Ca are good candidates for p-type dopants, and Ca is the best candidate for n-type dopant.

  20. Nitride-based Schottky diodes and HFETs fabricated by photo-enhanced chemical wet etching

    International Nuclear Information System (INIS)

    Su, Y.K.; Chang, S.J.; Kuan, T.M.; Ko, C.H.; Webb, J.B.; Lan, W.H.; Cherng, Y.T.; Chen, S.C.

    2004-01-01

    Photo-enhanced chemical (PEC) wet etching technology was used to etch GaN and AlGaN epitaxial layers. It was found that the maximum etch rates were 510, 1960, 300, and 0 nm/mm for GaN, Al 0.175 Ga 0.825 N, Al 0.23 Ga 0.77 N, and Al 0.4 Ga 0.6 N, respectively. It was also found that we could achieve a high Al 0.175 Ga 0.825 N to GaN etch rate ratio of 12.6. Nitride-based Schottky diodes and heterostructure field effect transistors (HFETs) were also fabricated by PEC wet etching. It was found that we could achieve a saturated I D larger than 850 mA/mm and a maximum g m about 163 mS/mm from PEC wet etched HFET with a 0.5 μm gate length. Compared with dry etched devices, the leakage currents observed from the PEC wet etched devices were also found to be smaller

  1. Photoionization spectroscopy of deep defects responsible for current collapse in nitride-based field effect transistors

    International Nuclear Information System (INIS)

    Klein, P B; Binari, S C

    2003-01-01

    This review is concerned with the characterization and identification of the deep centres that cause current collapse in nitride-based field effect transistors. Photoionization spectroscopy is an optical technique that has been developed to probe the characteristics of these defects. Measured spectral dependences provide information on trap depth, lattice coupling and on the location of the defects in the device structure. The spectrum of an individual trap may also be regarded as a 'fingerprint' of the defect, allowing the trap to be followed in response to the variation of external parameters. The basis for these measurements is derived through a modelling procedure that accounts quantitatively for the light-induced drain current increase in the collapsed device. Applying the model to fit the measured variation of drain current increase with light illumination provides an estimate of the concentrations and photoionization cross-sections of the deep defects. The results of photoionization studies of GaN metal-semiconductor field effect transistors and AlGaN/GaN high electron mobility transistors (HEMTs) grown by metal-organic chemical vapour deposition (MOCVD) are presented and the conclusions regarding the nature of the deep traps responsible are discussed. Finally, recent photoionization studies of current collapse induced by short-term (several hours) bias stress in AlGaN/GaN HEMTs are described and analysed for devices grown by both MOCVD and molecular beam epitaxy. (topical review)

  2. Chemical stability of the fiber coating/matrix interface in silicon-based ceramic matrix composites

    International Nuclear Information System (INIS)

    Lee, K.N.; Jacobson, N.S.

    1995-01-01

    Carbon and boron nitride are used as fiber coatings in silicon-based composites. In order to assess the long-term stability of these materials, reactions of carbon/Si 3 N 4 and BN/SiC were studied at high temperatures with Knudsen effusion, coupon tests, and by microstructural examination. in the carbon/Si 3 N 4 system, carbon reacted with Si 3 N 4 to form gaseous N 2 and SiC. The formation of SiC limited further reaction by physically separating the carbon and Si 3 N 4 . Consequently, the development of high p(N 2 ) at the interface, predicted from thermochemical calculations, did not occur, thus limiting the potential deleterious effects of the reaction on the composite. Strong indications of a reaction between BN and SiC were shown by TEM and SIMS analysis of the BN/SiC interface. In long-term exposures, this reaction can lead to a depletion of a BN coating and/or an unfavorable change of the interfacial properties, limiting the beneficial effects of the coating

  3. Chemical Stability of the Fiber Coating/Matrix Interface in Silicon-Based Ceramic Matrix Composites

    Science.gov (United States)

    Lee, Kang N.; Jacobson, Nathan S.

    1995-01-01

    Carbon and boron nitride are used as fiber coatings in silicon-based composites. In order to assess the long-term stability of these materials, reactions of carbon/Si3N4 and BN/SiC were studied at high temperatures with Knudsen effusion, coupon tests, and microstructural examination. In the carbon/Si3N4 system, carbon reacted with Si3N4 to form gaseous N2 and SiC. The formation of SiC limited further reaction by physically separating the carbon and Si3N4. Consequently, the development of high p(N2) at the interface, predicted from thermochemical calculations, did not occur, thus limiting the potential deleterious effects of the reaction on the composite. Strong indications of a reaction between BN and SiC were shown by TEM and SIMS analysis of the BN/SiC interface. In long-term exposures, this reaction can lead to a depletion of a BN coating and/or an unfavorable change of the interfacial properties, limiting the beneficial effects of the coating.

  4. Transformation-Toughened Silicon Nitride

    Science.gov (United States)

    1988-08-01

    of pores, could be eliminated by iso - statically pressing the green flexure test bars after the burnout operation and before the sintering...Company Fourth and Canal Streets PO Box 27003 Richmond, VA 23261 Stephen C. Danforth Rutgers University Post Office Box 909 Bowser Road

  5. Solidification phenomena in nickel base brazes containing boron and silicon

    International Nuclear Information System (INIS)

    Tung, S.K.; Lim, L.C.; Lai, M.O.

    1996-01-01

    Nickel base brazes containing boron and/or silicon as melting point depressants are used extensively in the repair and joining of aero-engine hot-section components. These melting point depressants form hard and brittle intermetallic compounds with nickel which are detrimental to the mechanical properties of brazed joints. The present investigation studied the microstructural evolution in nickel base brazes containing boron and/or silicon as melting point depressant(s) in simple systems using nickel as the base metal. The basic metallurgical reactions and formation of intermetallic compounds uncovered in these systems will be useful as a guide in predicting the evolution of microstructures in similar brazes in more complex systems involving base metals of nickel base superalloys. The four filler metal systems investigated in this study are: Ni-Cr-Si; Ni-Cr-B; Ni-Si-B and Ni-Cr-Fe-Si-B

  6. Electroplated contacts and porous silicon for silicon based solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Kholostov, Konstantin, E-mail: kholostov@diet.uniroma1.it [Department of information engineering, electronics and telecommunications, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome (Italy); Serenelli, Luca; Izzi, Massimo; Tucci, Mario [Enea Casaccia Research Centre Rome, via Anguillarese 301, 00123 Rome (Italy); Balucani, Marco [Department of information engineering, electronics and telecommunications, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome (Italy); Rise Technology S.r.l., Lungomare Paolo Toscanelli 170, 00121 Rome (Italy)

    2015-04-15

    Highlights: • Uniformity of the Ni–Si interface is crucial for performance of Cu–Ni contacts on Si. • Uniformly filled PS is the key to obtain the best performance of Cu–Ni contacts on Si. • Optimization of anodization and electroplating allows complete filling of PS layer. • Highly adhesive and low contact resistance Cu–Ni contacts are obtained on Si. - Abstract: In this paper, a two-layer metallization for silicon based solar cells is presented. The metallization consists of thin nickel barrier and thick copper conductive layers, both obtained by electrodeposition technique suitable for phosphorus-doped 70–90 Ω/sq solar cell emitter formed on p-type silicon substrate. To ensure the adhesion between metal contact and emitter a very thin layer of mesoporous silicon is introduced on the emitter surface before metal deposition. This approach allows metal anchoring inside pores and improves silicon–nickel interface uniformity. Optimization of metal contact parameters is achieved varying the anodization and electrodeposition conditions. Characterization of contacts between metal and emitter is carried out by scanning electron microscopy, specific contact resistance and current–voltage measurements. Mechanical strength of nickel–copper contacts is evaluated by the peel test. Adhesion strength of more than 4.5 N/mm and contact resistance of 350 μΩ cm{sup 2} on 80 Ω/sq emitter are achieved.

  7. Porous silicon-based passivation and gettering in polycrystalline silicon solar cells

    International Nuclear Information System (INIS)

    Dimassi, W.; Bouaiecha, M.; Saadoun, M.; Bessaies, B.; Ezzaouia, H.; Bennaceur, R.

    2002-01-01

    In this work, we report on the effect of introducing a superficial porous silicon (PS) layer on the electrical characteristics of polycrystalline silicon solar cells. The PS layer was formed using a vapour etching (VE)-based method. In addition to its known anti-reflecting action, the forming hydrogen-rich PS layer acts as a passivating agent for the surface of the cell. As a result we found an improvement of the I-V characteristics in dark conditions and AM1 illumination. We show that when the formation of a superficial PS layer is followed by a heat treatment, gettering of impurities from the polycrystalline silicon material is possible. After the removal of the PS layer and the formation of the photovoltaic (PV) structure, we observed an increase of the light-beam-induced-current (LBIC) for treatment temperatures not exceeding 900 deg. C. An improvement of the bulk minority carrier diffusion length and the grain boundary (GB) recombination velocity were observed as the temperature rises, although a global decrease of the LBIC current was observed for temperatures greater than 900 deg. C

  8. Substrate and Passivation Techniques for Flexible Amorphous Silicon-Based X-ray Detectors.

    Science.gov (United States)

    Marrs, Michael A; Raupp, Gregory B

    2016-07-26

    Flexible active matrix display technology has been adapted to create new flexible photo-sensing electronic devices, including flexible X-ray detectors. Monolithic integration of amorphous silicon (a-Si) PIN photodiodes on a flexible substrate poses significant challenges associated with the intrinsic film stress of amorphous silicon. This paper examines how altering device structuring and diode passivation layers can greatly improve the electrical performance and the mechanical reliability of the device, thereby eliminating one of the major weaknesses of a-Si PIN diodes in comparison to alternative photodetector technology, such as organic bulk heterojunction photodiodes and amorphous selenium. A dark current of 0.5 pA/mm² and photodiode quantum efficiency of 74% are possible with a pixelated diode structure with a silicon nitride/SU-8 bilayer passivation structure on a 20 µm-thick polyimide substrate.

  9. Oxide-nitride-oxide dielectric stacks with Si nanoparticles obtained by low-energy ion beam synthesis

    International Nuclear Information System (INIS)

    Ioannou-Sougleridis, V; Dimitrakis, P; Vamvakas, V Em; Normand, P; Bonafos, C; Schamm, S; Mouti, A; Assayag, G Ben; Paillard, V

    2007-01-01

    Formation of a thin band of silicon nanoparticles within silicon nitride films by low-energy (1 keV) silicon ion implantation and subsequent thermal annealing is demonstrated. Electrical characterization of metal-insulator-semiconductor capacitors reveals that oxide/Si-nanoparticles-nitride/oxide dielectric stacks exhibit enhanced charge transfer characteristics between the substrate and the silicon nitride layer compared to dielectric stacks using unimplanted silicon nitride. Attractive results are obtained in terms of write/erase memory characteristics and data retention, indicating the large potential of the low-energy ion-beam-synthesis technique in SONOS memory technology

  10. Advanced processing of gallium nitride and gallium nitride-based devices: Ultra-high temperature annealing and implantation incorporation

    Science.gov (United States)

    Yu, Haijiang

    into AlGaN/GaN high electron mobility transistor processing has been first demonstrated. An ultra-high temperature (1500°C) rapid thermal annealing technique was developed for the activation of Si dopants implanted in the source and drain. In comparison to control devices processed by conventional fabrication, the implanted device with nonalloyed ohmic contact showed comparable device performance with a contact resistance of 0.4 Omm Imax 730 mA/mm ft/f max; 26/62 GHz and power 3.4 W/mm on sapphire. These early results demonstrate the feasibility of implantation incorporation into GaN based device processing as well as the potential to increase yield, reproducibility and reliability in AlGaN/GaN HEMTs.

  11. Ballistic Spin Field Effect Transistor Based on Silicon Nanowires

    Science.gov (United States)

    Osintsev, Dmitri; Sverdlov, Viktor; Stanojevic, Zlatan; Selberherr, Siegfried

    2011-03-01

    We investigate the properties of ballistic spin field-effect transistors build on silicon nanowires. An accurate description of the conduction band based on the k . p} model is necessary in thin and narrow silicon nanostructures. The subband effective mass and subband splitting dependence on the nanowire dimensions is analyzed and used in the transport calculations. The spin transistor is formed by sandwiching the nanowire between two ferromagnetic metallic contacts. Delta-function barriers at the interfaces between the contacts and the silicon channel are introduced. The major contribution to the electric field-dependent spin-orbit interaction in confined silicon systems is due to the interface-induced inversion asymmetry which is of the Dresselhaus type. We study the current and conductance through the system for the contacts being in parallel and anti-parallel configurations. Differences between the [100] and [110] orientated structures are investigated in details. This work is supported by the European Research Council through the grant #247056 MOSILSPIN.

  12. Free vibration analysis of single-walled boron nitride nanotubes based on a computational mechanics framework

    Science.gov (United States)

    Yan, J. W.; Tong, L. H.; Xiang, Ping

    2017-12-01

    Free vibration behaviors of single-walled boron nitride nanotubes are investigated using a computational mechanics approach. Tersoff-Brenner potential is used to reflect atomic interaction between boron and nitrogen atoms. The higher-order Cauchy-Born rule is employed to establish the constitutive relationship for single-walled boron nitride nanotubes on the basis of higher-order gradient continuum theory. It bridges the gaps between the nanoscale lattice structures with a continuum body. A mesh-free modeling framework is constructed, using the moving Kriging interpolation which automatically satisfies the higher-order continuity, to implement numerical simulation in order to match the higher-order constitutive model. In comparison with conventional atomistic simulation methods, the established atomistic-continuum multi-scale approach possesses advantages in tackling atomic structures with high-accuracy and high-efficiency. Free vibration characteristics of single-walled boron nitride nanotubes with different boundary conditions, tube chiralities, lengths and radii are examined in case studies. In this research, it is pointed out that a critical radius exists for the evaluation of fundamental vibration frequencies of boron nitride nanotubes; opposite trends can be observed prior to and beyond the critical radius. Simulation results are presented and discussed.

  13. Development of graphite carbon nitride based fluorescent immune sensor for detection of alpha fetoprotein

    Science.gov (United States)

    Li, Yike; Dong, Lingyu; Wang, Xiangfeng; Liu, Yuan; Liu, Hailing; Xie, Mengxia

    2018-05-01

    A novel fluorescent immunosensor for determination of alpha fetoprotein (AFP) in serum samples has been developed based on the nano graphite carbon nitride (g-C3N4) as fluorophore and immunomagnetic beads (MBs) as separation material. The bulk g-C3N4 was obtained by thermal polymerization of melamine, and then carboxylated and exfoliated to acquire the carboxylated nano g-C3N4 (c-n-g-C3N4), which has been characterized and the results showed that it had excellent fluorescent properties. The antibodies of AFP (Ab1, Ab2) were conjugated to the MBs and the c-n-g-C3N4, respectively. In assay of AFP detection, the magnetic part of the immunosensor, MBs-Ab1, would form the sandwich type complex with the signal part of the sensor, c-n-g-C3N4-Ab2. The developed immunosensor could simplify the process of separation due to the MBs. The results illustrated that proposed approach held a good linearity between the fluorescence intensity of the sensor and the AFP concentration ranging from 5-600 ng/mL with the limit of detection as low as 0.43 ng/mL, and its spiking recoveries ranged from 98.2% to 105.9% with RSD from 2.1% to 3.5%. The fabricated fluorescent immunosensor possesses the merits of good sensitivity, excellent selectivity, high biocompatibility and low cost, and the results provide a novel clue to develop immunosensor for determination of the biomarkers in complex matrices.

  14. Resonance energy transfer based electrochemiluminescence and fluorescence sensing of riboflavin using graphitic carbon nitride quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huan [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070 (China); The Phytochemistry Key Laboratory of Tibetan Plateau of Qinghai Province, College of Pharmacy, Qinghai Nationalities University, Xining, Qinghai 810007 (China); Ma, Qin; Wang, Yanfeng; Wang, Caihe; Qin, Dongdong; Shan, Duoliang; Chen, Jing [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070 (China); Lu, Xiaoquan, E-mail: luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070 (China)

    2017-06-22

    Graphitic carbon nitride quantum dots (g-CNQDs) are rarely used in the field of electrochemiluminescence. In this paper, g-CNQDs have a strong and stable electrochemiluminescence (ECL) signal generated in the presence of co-reactant K{sub 2}S{sub 2}O{sub 8}. The ECL signal of g-CNQDs was quenched by the mechanism of resonance energy transfer (RET) between donor g-CNQDs and receptor riboflavin (RF) that is proved by UV-vis absorption spectroscopy, electrochemiluminescence and fluorescence emission spectroscopy analysis technology. Therefore, we achieved detection of the riboflavin content in the drug tablets of vitamin B{sub 2} using ECL and FL. The determination results of ECL showed that the riboflavin content of the drug vitamin B{sub 2} (VB{sub 2}) tablets was consistent with the fluorescence (FL) analysis, with wider linear range of 0.02–11 μM and lower minimum detection limit of 0.63 nM (S/N = 3) than FL. Hence, the riboflavin content in human serum was further detected using ECL. The relative standard deviation is less than 6.5%, with an acceptable recovery of 95.33%–104.22%, which means that this sensor has potential applications in the actual sample analysis. As a new ECL luminary, g-CNQDs have opened a new field for the development and application of ECL sensor. - Highlights: • G-CNQDs proposed as a new luminophore for ECL. • ECL signal was strong and stable in the presence of co-reactant K{sub 2}S{sub 2}O{sub 8}. • Based on the resonance energy transfer between g-CNQDs and riboflavin. • ECL has wider linear range and lower detection limit than FL.

  15. Resonance energy transfer based electrochemiluminescence and fluorescence sensing of riboflavin using graphitic carbon nitride quantum dots

    International Nuclear Information System (INIS)

    Wang, Huan; Ma, Qin; Wang, Yanfeng; Wang, Caihe; Qin, Dongdong; Shan, Duoliang; Chen, Jing; Lu, Xiaoquan

    2017-01-01

    Graphitic carbon nitride quantum dots (g-CNQDs) are rarely used in the field of electrochemiluminescence. In this paper, g-CNQDs have a strong and stable electrochemiluminescence (ECL) signal generated in the presence of co-reactant K 2 S 2 O 8 . The ECL signal of g-CNQDs was quenched by the mechanism of resonance energy transfer (RET) between donor g-CNQDs and receptor riboflavin (RF) that is proved by UV-vis absorption spectroscopy, electrochemiluminescence and fluorescence emission spectroscopy analysis technology. Therefore, we achieved detection of the riboflavin content in the drug tablets of vitamin B 2 using ECL and FL. The determination results of ECL showed that the riboflavin content of the drug vitamin B 2 (VB 2 ) tablets was consistent with the fluorescence (FL) analysis, with wider linear range of 0.02–11 μM and lower minimum detection limit of 0.63 nM (S/N = 3) than FL. Hence, the riboflavin content in human serum was further detected using ECL. The relative standard deviation is less than 6.5%, with an acceptable recovery of 95.33%–104.22%, which means that this sensor has potential applications in the actual sample analysis. As a new ECL luminary, g-CNQDs have opened a new field for the development and application of ECL sensor. - Highlights: • G-CNQDs proposed as a new luminophore for ECL. • ECL signal was strong and stable in the presence of co-reactant K 2 S 2 O 8 . • Based on the resonance energy transfer between g-CNQDs and riboflavin. • ECL has wider linear range and lower detection limit than FL.

  16. Group-III nitride based high electron mobility transistor (HEMT) with barrier/spacer layer

    Science.gov (United States)

    Chavarkar, Prashant; Smorchkova, Ioulia P.; Keller, Stacia; Mishra, Umesh; Walukiewicz, Wladyslaw; Wu, Yifeng

    2005-02-01

    A Group III nitride based high electron mobility transistors (HEMT) is disclosed that provides improved high frequency performance. One embodiment of the HEMT comprises a GaN buffer layer, with an Al.sub.y Ga.sub.1-y N (y=1 or y 1) layer on the GaN buffer layer. An Al.sub.x Ga.sub.1-x N (0.ltoreq.x.ltoreq.0.5) barrier layer on to the Al.sub.y Ga.sub.1-y N layer, opposite the GaN buffer layer, Al.sub.y Ga.sub.1-y N layer having a higher Al concentration than that of the Al.sub.x Ga.sub.1-x N barrier layer. A preferred Al.sub.y Ga.sub.1-y N layer has y=1 or y.about.1 and a preferred Al.sub.x Ga.sub.1-x N barrier layer has 0.ltoreq.x.ltoreq.0.5. A 2DEG forms at the interface between the GaN buffer layer and the Al.sub.y Ga.sub.1-y N layer. Respective source, drain and gate contacts are formed on the Al.sub.x Ga.sub.1-x N barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the Al.sub.y Ga.sub.1-y N layer and a nucleation layer between the Al.sub.x Ga.sub.1-x N buffer layer and the substrate.

  17. Adhesion between coating layers based on epoxy and silicone

    DEFF Research Database (Denmark)

    Svendsen, Jacob R.; Kontogeorgis, Georgios; Kiil, Søren

    2007-01-01

    The adhesion between a silicon tie-coat and epoxy primers, used in marine coating systems, has been studied in this work. Six epoxy coatings (with varying chain lengths of the epoxy resins), some of which have shown problems with adhesion to the tie-coat during service life, have been considered....... The experimental investigation includes measurements of the surface tension of the tie-coat and the critical surface tensions of the epoxies, topographic investigation of the surfaces of cured epoxy coatings via atomic force microscopy (AFM), and pull-off tests for investigating the strength of adhesion...... to the silicon/epoxy systems. Calculations for determining the roughness factor of the six epoxy coatings (based on the AFM topographies) and the theoretical work of adhesion have been carried out. The coating surfaces are also characterized based on the van Oss-Good theory. Previous studies on the modulus...

  18. Key Success Factors and Future Perspective of Silicon-Based Solar Cells

    Directory of Open Access Journals (Sweden)

    S. Binetti

    2013-01-01

    Full Text Available Today, after more than 70 years of continued progress on silicon technology, about 85% of cumulative installed photovolatic (PV modules are based on crystalline silicon (c-Si. PV devices based on silicon are the most common solar cells currently being produced, and it is mainly due to silicon technology that the PV has grown by 40% per year over the last decade. An additional step in the silicon solar cell development is ongoing, and it is related to a further efficiency improvement through defect control, device optimization, surface modification, and nanotechnology approaches. This paper attempts to briefly review the most important advances and current technologies used to produce crystalline silicon solar devices and in the meantime the most challenging and promising strategies acting to increase the efficiency to cost/ratio of silicon solar cells. Eventually, the impact and the potentiality of using a nanotechnology approach in a silicon-based solar cell are also described.

  19. THz generation from a nanocrystalline silicon-based photoconductive device

    International Nuclear Information System (INIS)

    Daghestani, N S; Persheyev, S; Cataluna, M A; Rose, M J; Ross, G

    2011-01-01

    Terahertz generation has been achieved from a photoconductive switch based on hydrogenated nanocrystalline silicon (nc-Si:H), gated by a femtosecond laser. The nc-Si:H samples were produced by a hot wire chemical vapour deposition process, a process with low production costs owing to its higher growth rate and manufacturing simplicity. Although promising ultrafast carrier dynamics of nc-Si have been previously demonstrated, this is the first report on THz generation from a nc-Si:H material

  20. An Educational Kit Based On a Modular Silicon Photomultiplier System

    International Nuclear Information System (INIS)

    Caccia, Massimo; Chmill, Valery; Ebolese, Amedeo; Martemyanov, Alexander; Risigo, Fabio; Santoro, Romualdo; Locatelli, Marco; Pieracci, Maura; Tintori, Carlo

    2013-06-01

    Silicon Photo-Multipliers (SiPM) are state of the art light detectors with unprecedented single photon sensitivity and photon number resolving capability, representing a breakthrough in several fundamental and applied Science domains. An educational experiment based on a SiPM set-up is proposed in this article, guiding the student towards a comprehensive knowledge of this sensor technology while experiencing the quantum nature of light and exploring the statistical properties of the light pulses emitted by a LED. (authors)

  1. Simulations for irradiation of silicon-based structures

    International Nuclear Information System (INIS)

    Sagatova, A.; Pavlovic, M.; Sedlackova, K.; Necas, V.; Hybler, P.; Zatko, B.

    2013-01-01

    The software ModePEB for modelling of electron beam processing in multilayer flat objects was shown to be a very useful tool for optimization of the irradiation of silicon based structures. Except its significant help in setting-up the accelerator parameters corresponding to a desired dose, its proven reliability and consistency with the measured data makes the ModePEB an inevitable instrument for design and optimization of electron irradiation experiments. (authors)

  2. Silicon-based optical integrated circuits for terabit communication networks

    International Nuclear Information System (INIS)

    Svidzinsky, K K

    2003-01-01

    A brief review is presented of the development of silicon-based optical integrated circuits used as components in modern all-optical communication networks with the terabit-per-second transmission capacity. The designs and technologies for manufacturing these circuits are described and the problems related to their development and application in WDM communication systems are considered. (special issue devoted to the memory of academician a m prokhorov)

  3. Low-temperature strain gauges based on silicon whiskers

    Directory of Open Access Journals (Sweden)

    Druzhinin A. A.

    2008-08-01

    Full Text Available To create low-temperature strain gauges based on p-type silicon whiskers tensoresistive characteristics of these crystals in 4,2—300 K temperature range were studied. On the basis of p-type Si whiskers with different resistivity the strain gauges for different materials operating at cryogenic temperatures with extremely high gauge factor at 4,2 K were developed, as well as strain gauges operating at liquid helium temperatures in high magnetic fields.

  4. Last Advances in Silicon-Based Optical Biosensors.

    Science.gov (United States)

    Fernández Gavela, Adrián; Grajales García, Daniel; Ramirez, Jhonattan C; Lechuga, Laura M

    2016-02-24

    We review the most important achievements published in the last five years in the field of silicon-based optical biosensors. We focus specially on label-free optical biosensors and their implementation into lab-on-a-chip platforms, with an emphasis on developments demonstrating the capability of the devices for real bioanalytical applications. We report on novel transducers and materials, improvements of existing transducers, new and improved biofunctionalization procedures as well as the prospects for near future commercialization of these technologies.

  5. Light Absorption Enhancement of Silicon-Based Photovoltaic Devices with Multiple Bandgap Structures of Porous Silicon

    Directory of Open Access Journals (Sweden)

    Kuen-Hsien Wu

    2015-09-01

    Full Text Available Porous-silicon (PS multi-layered structures with three stacked PS layers of different porosity were prepared on silicon (Si substrates by successively tuning the electrochemical-etching parameters in an anodization process. The three PS layers have different optical bandgap energy and construct a triple-layered PS (TLPS structure with multiple bandgap energy. Photovoltaic devices were fabricated by depositing aluminum electrodes of Schottky contacts on the surfaces of the developed TLPS structures. The TLPS-based devices exhibit broadband photoresponses within the spectrum of the solar irradiation and get high photocurrent for the incident light of a tungsten lamp. The improved spectral responses of devices are owing to the multi-bandgap structures of TLPS, which are designed with a layered configuration analog to a tandem cell for absorbing a wider energy range of the incidental sun light. The large photocurrent is mainly ascribed to an enhanced light-absorption ability as a result of applying nanoporous-Si thin films as the surface layers to absorb the short-wavelength light and to improve the Schottky contacts of devices. Experimental results reveal that the multi-bandgap PS structures produced from electrochemical-etching of Si wafers are potentially promising for development of highly efficient Si-based solar cells.

  6. Enhanced non-radiative energy transfer in hybrid III-nitride structures

    International Nuclear Information System (INIS)

    Smith, R. M.; Athanasiou, M.; Bai, J.; Liu, B.; Wang, T.

    2015-01-01

    The effect of surface states has been investigated in hybrid organic/inorganic white light emitting structures that employ high efficiency, nearfield non-radiative energy transfer (NRET) coupling. The structures utilize blue emitting InGaN/GaN multiple quantum well (MQW) nanorod arrays to minimize the separation with a yellow emitting F8BT coating. Surface states due to the exposed III-nitride surfaces of the nanostructures are found to reduce the NRET coupling rate. The surface states are passivated by deposition of a silicon nitride layer on the III-nitride nanorod surface leading to reduced surface recombination. A low thickness surface passivation is shown to increase the NRET coupling rate by 4 times compared to an un-passivated hybrid structure. A model is proposed to explain the increased NRET rate for the passivated hybrid structures based on the reduction in surface electron depletion of the passivated InGaN/GaN MQW nanorods surfaces

  7. Superplastic forging nitride ceramics

    Science.gov (United States)

    Panda, P.C.; Seydel, E.R.; Raj, R.

    1988-03-22

    A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

  8. Wafer scale formation of monocrystalline silicon-based Mie resonators via silicon-on-insulator dewetting.

    Science.gov (United States)

    Abbarchi, Marco; Naffouti, Meher; Vial, Benjamin; Benkouider, Abdelmalek; Lermusiaux, Laurent; Favre, Luc; Ronda, Antoine; Bidault, Sébastien; Berbezier, Isabelle; Bonod, Nicolas

    2014-11-25

    Subwavelength-sized dielectric Mie resonators have recently emerged as a promising photonic platform, as they combine the advantages of dielectric microstructures and metallic nanoparticles supporting surface plasmon polaritons. Here, we report the capabilities of a dewetting-based process, independent of the sample size, to fabricate Si-based resonators over large scales starting from commercial silicon-on-insulator (SOI) substrates. Spontaneous dewetting is shown to allow the production of monocrystalline Mie-resonators that feature two resonant modes in the visible spectrum, as observed in confocal scattering spectroscopy. Homogeneous scattering responses and improved spatial ordering of the Si-based resonators are observed when dewetting is assisted by electron beam lithography. Finally, exploiting different thermal agglomeration regimes, we highlight the versatility of this technique, which, when assisted by focused ion beam nanopatterning, produces monocrystalline nanocrystals with ad hoc size, position, and organization in complex multimers.

  9. Erosion resistance of composite materials on titanium, zirconium and aluminium nitride base under the electron beam effect

    International Nuclear Information System (INIS)

    Verkhoturov, A.D.; Kuzenkova, M.A.; Slutskin, M.G.; Kravchuk, L.A.

    1977-01-01

    Erosion resistance of composites based on nitrides of titanium, zirconium and aluminium to spark and electron beam processing has been studied. The erosion resistance in spark processing is shown to depend on specific electric resistance of the alloys. TiN-AlN and ZrN-AlN alloys containing more than 70% AlN (with specific electric resistance more than 10 6 -10 7 ohm/cm) caot be processed by spark method. It is shown that erosion of the composites by an electron beam depends primarily on the rate of evaporation of the components

  10. Silicon-Chip-Based Optical Frequency Combs

    Science.gov (United States)

    2015-10-26

    fiber-based polarization controllers and a polarization beam splitter , and the output power is monitored with a sensitive photodiode. We use a...a single CW laser beam coupled to a microresonators can produce stabilized, octave-spanning combs through highly cascaded four-wave mixing (FWM...resonator designs , the resonator and the coupling waveguide are monolithically integrated. Thus, the entire on-chip configuration of CMOS-compatible

  11. Solar selective performance of metal nitride/oxynitride based magnetron sputtered thin film coatings: a comprehensive review

    Science.gov (United States)

    Ibrahim, Khalil; Taha, Hatem; Mahbubur Rahman, M.; Kabir, Humayun; Jiang, Zhong-Tao

    2018-03-01

    Since solar-thermal collectors are considered to be the most direct way of converting solar energy into usable forms, in the last few years growing attention has been paid to the development of transition metal nitride and metal oxynitride based thin film selective surfaces for solar-thermal collectors, in order to harvest more solar energy. A solar-thermal energy system, generally, shows very high solar absorption of incident solar radiation from the solar-thermal collectors in the visible range (0.3 to 2.5 μm) and extremely low thermal losses through emission (or high reflection) in the infrared region (≥2.5 μm). The efficiency of a solar-thermal energy conversion system can be improved by the use of solar selective surfaces consisting of novel metallic nanoparticles embedded in metal nitride/oxynitride systems. In order to enhance the effectiveness of solar-thermal devices, solar selective surfaces with high thermal stability are a prerequisite. Over the years, substantial efforts have been made in the field of solar selective surfaces to attain higher solar absorptance and lower thermal emittance in high temperature (above 400 °C) applications. In this article, we review the present state-of-the-art transition metal nitride and/or oxynitride based vacuum sputtered nanostructured thin film coatings, with respect to their optical and solar selective surface applications. We have also summarized the solar selectivity data from recently published investigations, including discussion on some potential applications for these materials.

  12. Novel Non-Carbonate Based Electrolytes for Silicon Anodes

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ye [Wildcat Discovery Technologies, San Diego, CA (United States); Yang, Johnny [Wildcat Discovery Technologies, San Diego, CA (United States); Cheng, Gang [Wildcat Discovery Technologies, San Diego, CA (United States); Carroll, Kyler [Wildcat Discovery Technologies, San Diego, CA (United States); Clemons, Owen [Wildcat Discovery Technologies, San Diego, CA (United States); Strand, Diedre [Wildcat Discovery Technologies, San Diego, CA (United States)

    2016-09-09

    Substantial improvement in the energy density of rechargeable lithium batteries is required to meet the future needs for electric and plug-in electric vehicles (EV and PHEV). Present day lithium ion battery technology is based on shuttling lithium between graphitic carbon and inorganic oxides. Non-graphitic anodes, such as silicon can provide significant improvements in energy density but are currently limited in cycle life due to reactivity with the electrolyte. Wildcat/3M proposes the development of non-carbonate electrolyte formulations tailored for silicon alloy anodes. Combining these electrolytes with 3M’s anode and an NMC cathode will enable up to a 20% increase in the volumetric cell energy density, while still meeting the PHEV/EV cell level cycle/calendar life goals.

  13. Silicone-Based Triboelectric Nanogenerator for Water Wave Energy Harvesting.

    Science.gov (United States)

    Xiao, Tian Xiao; Jiang, Tao; Zhu, Jian Xiong; Liang, Xi; Xu, Liang; Shao, Jia Jia; Zhang, Chun Lei; Wang, Jie; Wang, Zhong Lin

    2018-01-31

    Triboelectric nanogenerator (TENG) has been proven to be efficient for harvesting water wave energy, which is one of the most promising renewable energy sources. In this work, a TENG with a silicone rubber/carbon black composite electrode was designed for converting the water wave energy into electricity. The silicone-based electrode with a soft texture provides a better contact with the dielectric film. Furthermore, a spring structure is introduced to transform low-frequency water wave motions into high-frequency vibrations. They together improve the output performance and efficiency of TENG. The output performances of TENGs are further enhanced by optimizing the triboelectric material pair and tribo-surface area. A spring-assisted TENG device with the segmented silicone rubber-based electrode structure was sealed into a waterproof box, which delivers a maximum power density of 2.40 W m -3 , as triggered by the water waves. The present work provides a new strategy for fabricating high-performance TENG devices by coupling flexible electrodes and spring structure for harvesting water wave energy.

  14. Angle-resolved diffraction grating biosensor based on porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Changwu; Li, Peng [School of Physical Science and Technology, Xinjiang University, Urumqi 830046 (China); Jia, Zhenhong, E-mail: jzhh@xju.edu.cn; Liu, Yajun; Mo, Jiaqing; Lv, Xiaoyi [College of Information Science and Engineering, Xinjiang University, Urumqi 830046 (China)

    2016-03-07

    In this study, an optical biosensor based on a porous silicon composite structure was fabricated using a simple method. This structure consists of a thin, porous silicon surface diffraction grating and a one-dimensional porous silicon photonic crystal. An angle-resolved diffraction efficiency spectrum was obtained by measuring the diffraction efficiency at a range of incident angles. The angle-resolved diffraction efficiency of the 2nd and 3rd orders was studied experimentally and theoretically. The device was sensitive to the change of refractive index in the presence of a biomolecule indicated by the shift of the diffraction efficiency spectrum. The sensitivity of this sensor was investigated through use of an 8 base pair antifreeze protein DNA hybridization. The shifts of the angle-resolved diffraction efficiency spectrum showed a relationship with the change of the refractive index, and the detection limit of the biosensor reached 41.7 nM. This optical device is highly sensitive, inexpensive, and simple to fabricate. Using shifts in diffraction efficiency spectrum to detect biological molecules has not yet been explored, so this study establishes a foundation for future work.

  15. Electroluminescence efficiencies of erbium in silicon-based hosts

    Energy Technology Data Exchange (ETDEWEB)

    Cueff, Sébastien, E-mail: sebastien-cueff@brown.edu, E-mail: christophe.labbe@ensicaen.fr [Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, Caen 14050 (France); School of Engineering, Brown University, Providence, Rhode Island 02912 (United States); Manel Ramírez, Joan; Berencén, Yonder; Garrido, Blas [MIND-IN2UB, Department Electrònica, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028 (Spain); Kurvits, Jonathan A.; Zia, Rashid [School of Engineering, Brown University, Providence, Rhode Island 02912 (United States); Department of Physics, Brown University, Providence, Rhode Island 02912 (United States); Rizk, Richard; Labbé, Christophe, E-mail: sebastien-cueff@brown.edu, E-mail: christophe.labbe@ensicaen.fr [Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, Caen 14050 (France)

    2013-11-04

    We report on room-temperature 1.5 μm electroluminescence from trivalent erbium (Er{sup 3+}) ions embedded in three different CMOS-compatible silicon-based hosts: SiO{sub 2}, Si{sub 3}N{sub 4}, and SiN{sub x}. We show that although the insertion of either nitrogen or excess silicon helps enhance electrical conduction and reduce the onset voltage for electroluminescence, it drastically decreases the external quantum efficiency of Er{sup 3+} ions from 2% in SiO{sub 2} to 0.001% and 0.0004% in SiN{sub x} and Si{sub 3}N{sub 4}, respectively. Furthermore, we present strong evidence that hot carrier injection is significantly more efficient than defect-assisted conduction for the electrical excitation of Er{sup 3+} ions. These results suggest strategies to optimize the engineering of on-chip electrically excited silicon-based nanophotonic light sources.

  16. Novel fabrication of silicon carbide based ceramics for nuclear applications

    Science.gov (United States)

    Singh, Abhishek Kumar

    Advances in nuclear reactor technology and the use of gas-cooled fast reactors require the development of new materials that can operate at the higher temperatures expected in these systems. These materials include refractory alloys based on Nb, Zr, Ta, Mo, W, and Re; ceramics and composites such as SiC--SiCf; carbon--carbon composites; and advanced coatings. Besides the ability to handle higher expected temperatures, effective heat transfer between reactor components is necessary for improved efficiency. Improving thermal conductivity of the fuel can lower the center-line temperature and, thereby, enhance power production capabilities and reduce the risk of premature fuel pellet failure. Crystalline silicon carbide has superior characteristics as a structural material from the viewpoint of its thermal and mechanical properties, thermal shock resistance, chemical stability, and low radioactivation. Therefore, there have been many efforts to develop SiC based composites in various forms for use in advanced energy systems. In recent years, with the development of high yield preceramic precursors, the polymer infiltration and pyrolysis (PIP) method has aroused interest for the fabrication of ceramic based materials, for various applications ranging from disc brakes to nuclear reactor fuels. The pyrolysis of preceramic polymers allow new types of ceramic materials to be processed at relatively low temperatures. The raw materials are element-organic polymers whose composition and architecture can be tailored and varied. The primary focus of this study is to use a pyrolysis based process to fabricate a host of novel silicon carbide-metal carbide or oxide composites, and to synthesize new materials based on mixed-metal silicocarbides that cannot be processed using conventional techniques. Allylhydridopolycarbosilane (AHPCS), which is an organometal polymer, was used as the precursor for silicon carbide. Inert gas pyrolysis of AHPCS produces near-stoichiometric amorphous

  17. Silicon-Rich Silicon Carbide Hole-Selective Rear Contacts for Crystalline-Silicon-Based Solar Cells.

    Science.gov (United States)

    Nogay, Gizem; Stuckelberger, Josua; Wyss, Philippe; Jeangros, Quentin; Allebé, Christophe; Niquille, Xavier; Debrot, Fabien; Despeisse, Matthieu; Haug, Franz-Josef; Löper, Philipp; Ballif, Christophe

    2016-12-28

    The use of passivating contacts compatible with typical homojunction thermal processes is one of the most promising approaches to realizing high-efficiency silicon solar cells. In this work, we investigate an alternative rear-passivating contact targeting facile implementation to industrial p-type solar cells. The contact structure consists of a chemically grown thin silicon oxide layer, which is capped with a boron-doped silicon-rich silicon carbide [SiC x (p)] layer and then annealed at 800-900 °C. Transmission electron microscopy reveals that the thin chemical oxide layer disappears upon thermal annealing up to 900 °C, leading to degraded surface passivation. We interpret this in terms of a chemical reaction between carbon atoms in the SiC x (p) layer and the adjacent chemical oxide layer. To prevent this reaction, an intrinsic silicon interlayer was introduced between the chemical oxide and the SiC x (p) layer. We show that this intrinsic silicon interlayer is beneficial for surface passivation. Optimized passivation is obtained with a 10-nm-thick intrinsic silicon interlayer, yielding an emitter saturation current density of 17 fA cm -2 on p-type wafers, which translates into an implied open-circuit voltage of 708 mV. The potential of the developed contact at the rear side is further investigated by realizing a proof-of-concept hybrid solar cell, featuring a heterojunction front-side contact made of intrinsic amorphous silicon and phosphorus-doped amorphous silicon. Even though the presented cells are limited by front-side reflection and front-side parasitic absorption, the obtained cell with a V oc of 694.7 mV, a FF of 79.1%, and an efficiency of 20.44% demonstrates the potential of the p + /p-wafer full-side-passivated rear-side scheme shown here.

  18. Silicon based quantum dot hybrid qubits

    Science.gov (United States)

    Kim, Dohun

    2015-03-01

    The charge and spin degrees of freedom of an electron constitute natural bases for constructing quantum two level systems, or qubits, in semiconductor quantum dots. The quantum dot charge qubit offers a simple architecture and high-speed operation, but generally suffers from fast dephasing due to strong coupling of the environment to the electron's charge. On the other hand, quantum dot spin qubits have demonstrated long coherence times, but their manipulation is often slower than desired for important future applications. This talk will present experimental progress of a `hybrid' qubit, formed by three electrons in a Si/SiGe double quantum dot, which combines desirable characteristics (speed and coherence) in the past found separately in qubits based on either charge or spin degrees of freedom. Using resonant microwaves, we first discuss qubit operations near the `sweet spot' for charge qubit operation. Along with fast (>GHz) manipulation rates for any rotation axis on the Bloch sphere, we implement two independent tomographic characterization schemes in the charge qubit regime: traditional quantum process tomography (QPT) and gate set tomography (GST). We also present resonant qubit operations of the hybrid qubit performed on the same device, DC pulsed gate operations of which were recently demonstrated. We demonstrate three-axis control and the implementation of dynamic decoupling pulse sequences. Performing QPT on the hybrid qubit, we show that AC gating yields π rotation process fidelities higher than 93% for X-axis and 96% for Z-axis rotations, which demonstrates efficient quantum control of semiconductor qubits using resonant microwaves. We discuss a path forward for achieving fidelities better than the threshold for quantum error correction using surface codes. This work was supported in part by ARO (W911NF-12-0607), NSF (PHY-1104660), DOE (DE-FG02-03ER46028), and by the Laboratory Directed Research and Development program at Sandia National Laboratories

  19. Direct DC 10 V comparison between two programmable Josephson voltage standards made of niobium nitride (NbN)-based and niobium (Nb)-based Josephson junctions

    Science.gov (United States)

    Solve, S.; Chayramy, R.; Maruyama, M.; Urano, C.; Kaneko, N.-H.; Rüfenacht, A.

    2018-04-01

    BIPM’s new transportable programmable Josephson voltage standard (PJVS) has been used for an on-site comparison at the National Metrology Institute of Japan (NMIJ) and the National Institute of Advanced Industrial Science and Technology (AIST) (NMIJ/AIST, hereafter called just NMIJ unless otherwise noted). This is the first time that an array of niobium-based Josephson junctions with amorphous niobium silicon Nb x Si1-x barriers, developed by the National Institute of Standards and Technology4 (NIST), has been directly compared to an array of niobium nitride (NbN)-based junctions (developed by the NMIJ in collaboration with the Nanoelectronics Research Institute (NeRI), AIST). Nominally identical voltages produced by both systems agreed within 5 parts in 1012 (0.05 nV at 10 V) with a combined relative uncertainty of 7.9  ×  10-11 (0.79 nV). The low side of the NMIJ apparatus is, by design, referred to the ground potential. An analysis of the systematic errors due to the leakage current to ground was conducted for this ground configuration. The influence of a multi-stage low-pass filter installed at the output measurement leads of the NMIJ primary standard was also investigated. The number of capacitances in parallel in the filter and their insulation resistance have a direct impact on the amplitude of the systematic voltage error introduced by the leakage current, even if the current does not necessarily return to ground. The filtering of the output of the PJVS voltage leads has the positive consequence of protecting the array from external sources of noise. Current noise, when coupled to the array, reduces the width or current range of the quantized voltage steps. The voltage error induced by the leakage current in the filter is an order of magnitude larger than the voltage error in the absence of all filtering, even though the current range of steps is significantly decreased without filtering.

  20. Nitride-based quantum structures and devices on modified GaN substrates

    International Nuclear Information System (INIS)

    Perlin, Piotr; Leszczynski, Mike; Grzegory, Izabella; Franssen, Gijs; Targowski, Grzegorz; Krysko, Marcin; Nowak, Grzegorz; Litwin-Staszewska, Elzbieta; Piotrzkowski, Ryszard; Lucznik, Bolek; Suski, Tadek; Szeszko, Justyna; Czernecki, R.; Grzanka, Szymon; Jakiela, Rafal; Albrecht, Martin

    2009-01-01

    We have studied the properties of InGaN layers and quantum wells grown on gallium nitride substrates with intentional surface misorientation with respect to its crystalline c-axis. Misorientation varied in the range from 0 up to 2 degree. The indium content was changed by using the different growth temperature (between 750 C and 820 C) during metalorganic vapor phase epitaxy. With increasing misorientation angle the average indium content decreased significantly. This effect was accompanied by the strong increase of the emission line bandwidth suggesting more pronounced indium segregation. The results of cathodoluminescence measurements show that these effects correspond to different number of atomic steps/terraces existing on the surface of gallium nitride substrate. Very interesting result is also demonstrated concerning p-type GaN layers. With increasing misorientation, the free hole density drastically increases above 10 18 cm -3 . This improvement in p-type doping is not related to the increased Mg concentration but to the reduction in the compensating donor density. Using this advantage we demonstrate nitride light emitters with improved electrical properties. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Development of aluminum gallium nitride based optoelectronic devices operating in deep UV and terahertz spectrum ranges

    Science.gov (United States)

    Zhang, Wei

    In this research project I have investigated AlGaN alloys and their quantum structures for applications in deep UV and terahertz optoelectronic devices. For the deep UV emitter applications the materials and devices were grown by rf plasma-assisted molecular beam epitaxy on 4H-SiC, 6H-SiC and c-plane sapphire substrates. In the growth of AlGaN/AlN multiple quantum wells on SiC substrates, the AlGaN wells were grown under excess Ga, far beyond than what is required for the growth of stoichiometric AlGaN films, which resulted in liquid phase epitaxy growth mode. Due to the statistical variations of the excess Ga on the growth front we found that this growth mode leads to films with lateral variations in the composition and thus, band structure potential fluctuations. Transmission electron microscopy shows that the wells in such structures are not homogeneous but have the appearance of quantum dots. We find by temperature dependent photoluminescence measurements that the multiple quantum wells with band structure potential fluctuations emit at 240 nm and have room temperature internal quantum efficiency as high as 68%. Furthermore, they were found to have a maximum net modal optical gain of 118 cm-1 at a transparency threshold corresponding to 1.4 x 1017 cm-3 excited carriers. We attribute this low transparency threshold to population inversion of only the regions of the potential fluctuations rather than of the entire matrix. Some prototype deep UV emitting LED structures were also grown by the same method on sapphire substrates. Optoelectronic devices for terahertz light emission and detection, based on intersubband transitions in III-nitride semiconductor quantum wells, were grown on single crystal c-plane GaN substrates. Growth conditions such the ratio of group III to active nitrogen fluxes, which determines the appropriate Ga-coverage for atomically smooth growth without requiring growth interruptions were employed. Emitters designed in the quantum cascade

  2. Dendritic Tip-on Polytriazine-Based Carbon Nitride Photocatalyst with High Hydrogen Evolution Activity

    KAUST Repository

    Bhunia, Manas Kumar

    2015-11-23

    Developing stable, ubiquitous and efficient water-splitting photocatalyst material that has extensive absorption in the visible-light range is desired for a sustainable solar energy-conversion device. We herein report a triazine-based carbon nitride (CN) material with different C/N ratios achieved by varying the monomer composition ratio between melamine (Mel) and 2,4,6-triaminopyrimidine (TAP). The CN material with a different C/N ratio was obtained through a two-step synthesis protocol: starting with the solution state dispersion of the monomers via hydrogen-bonding supramolecular aggregate, followed by a salt-melt high temperature polycondensation. This protocol ensures the production of a highly crystalline polytriazine imide (PTI) structure con-sisting of a copolymerized Mel-TAP network. The observed bandgap narrowing with an increasing TAP/Mel ratio is well simulated by density functional theory (DFT) calculations, revealing a positive shift in the valence band upon substitution of N with CH in the aromatic rings. Increasing the TAP amount could not maintain the crystalline PTI structure, consistent with DFT calculation showing the repulsion associated with additional C-H introduced in the aromatic rings. Due to the high exciton binding energy calculated by DFT for the obtained CN, the cocatalyst must be close to any portion of the material to assist the separation of excit-ed charge carriers for an improved photocatalytic performance. The photocatalytic activity was improved by providing a dendritic tip-on-like shape grown on a porous fibrous silica KCC-1 spheres, and highly dispersed Pt nanoparticles (<5 nm) were photodepos-ited to introduce heterojunction. As a result, the Pt/CN/KCC-1 photocatalyst exhibited an apparent quantum efficiency (AQE) as high as 22.1 ± 3% at 400 nm and the silica was also beneficial for improving photocatalytic stability. The results obtained by time-resolved transient absorption spectroscopy measurements were consistent with

  3. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    International Nuclear Information System (INIS)

    Kaminski, Yelena; Shauly, Eitan; Paz, Yaron

    2015-01-01

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect

  4. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Yelena [Department of Chemical Engineering, Technion, Haifa (Israel); TowerJazz Ltd. Migdal Haemek (Israel); Shauly, Eitan [TowerJazz Ltd. Migdal Haemek (Israel); Paz, Yaron, E-mail: paz@tx.technion.ac.il [Department of Chemical Engineering, Technion, Haifa (Israel)

    2015-12-07

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect.

  5. Silicon-germanium and platinum silicide nanostructures for silicon based photonics

    Science.gov (United States)

    Storozhevykh, M. S.; Dubkov, V. P.; Arapkina, L. V.; Chizh, K. V.; Mironov, S. A.; Chapnin, V. A.; Yuryev, V. A.

    2017-05-01

    This paper reports a study of two types of silicon based nanostructures prospective for applications in photonics. The first ones are Ge/Si(001) structures forming at room temperature and reconstructing after annealing at 600°C. Germanium, being deposited from a molecular beam at room temperature on the Si(001) surface, forms a thin granular film composed of Ge particles with sizes of a few nanometers. A characteristic feature of these films is that they demonstrate signs of the 2 x 1 structure in their RHEED patterns. After short-term annealing at 600°C under the closed system conditions, the granular films reconstruct to heterostructures consisting of a Ge wetting layer and oval clusters of Ge. A mixed type c(4x2) + p(2x2) reconstruction typical to the low-temperature MBE (Tgr Ge. The other type of the studied nanostructures is based on Pt silicides. This class of materials is one of the friendliest to silicon technology. But as silicide film thickness reaches a few nanometers, low resistivity becomes of primary importance. Pt3Si has the lowest sheet resistance among the Pt silicides. However, the development of a process of thin Pt3Si films formation is a challenging task. This paper describes formation of a thin Pt3Si/Pt2Si structures at room temperature on poly-Si films. Special attention is paid upon formation of poly-Si and amorphous Si films on Si3N4 substrates at low temperatures.

  6. Design and construction the identification of nitriding plasma process parameters using personal computer based on serial communication

    International Nuclear Information System (INIS)

    Frida Iswinning Diah; Slamet Santosa

    2012-01-01

    Design and construction the identification of process parameters using personal computer based on serial communication PLC M-series has been done. The function of this device is to identify the process parameters of a system (plan), to which then be analyzed and conducted a follow-up given to the plan by the user. The main component of this device is the M-Series T100MD1616 PLC and personal computer (PC). In this device the data plan parameters obtained from the corresponding sensor outputs in the form of voltage or current. While the analog parameter data is adjusted to the ADC analog input of the PLC using a signal conditioning system. Then, as the parameter is processed by the PLC then sent to a PC via RS232 to be displayed in the form of graphs or tables and stored in the database. Software to program the database is created using Visual Basic Programming V-6. The device operation test is performed for the measurement of temperature parameter and vacuum level on the plasma nitriding machine. The results indicate that the device has functioning as an identification device parameters process of plasma nitriding machine. (author)

  7. Passivating electron contact based on highly crystalline nanostructured silicon oxide layers for silicon solar cells

    Czech Academy of Sciences Publication Activity Database

    Stuckelberger, J.; Nogay, G.; Wyss, P.; Jeangros, Q.; Allebe, Ch.; Debrot, F.; Niquille, X.; Ledinský, Martin; Fejfar, Antonín; Despeisse, M.; Haug, F.J.; Löper, P.; Ballif, C.

    2016-01-01

    Roč. 158, Dec (2016), s. 2-10 ISSN 0927-0248 R&D Projects: GA MŠk LM2015087 Institutional support: RVO:68378271 Keywords : surface passivation * passivating contact * nanostructure * silicon oxide * nanocrystalline * microcrystalline * poly-silicon * crystallization * Raman * transmission line measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.784, year: 2016

  8. Nonlinear Silicon Photonic Signal Processing Devices for Future Optical Networks

    Directory of Open Access Journals (Sweden)

    Cosimo Lacava

    2017-01-01

    Full Text Available In this paper, we present a review on silicon-based nonlinear devices for all optical nonlinear processing of complex telecommunication signals. We discuss some recent developments achieved by our research group, through extensive collaborations with academic partners across Europe, on optical signal processing using silicon-germanium and amorphous silicon based waveguides as well as novel materials such as silicon rich silicon nitride and tantalum pentoxide. We review the performance of four wave mixing wavelength conversion applied on complex signals such as Differential Phase Shift Keying (DPSK, Quadrature Phase Shift Keying (QPSK, 16-Quadrature Amplitude Modulation (QAM and 64-QAM that dramatically enhance the telecom signal spectral efficiency, paving the way to next generation terabit all-optical networks.

  9. Last Advances in Silicon-Based Optical Biosensors

    Directory of Open Access Journals (Sweden)

    Adrián Fernández Gavela

    2016-02-01

    Full Text Available We review the most important achievements published in the last five years in the field of silicon-based optical biosensors. We focus specially on label-free optical biosensors and their implementation into lab-on-a-chip platforms, with an emphasis on developments demonstrating the capability of the devices for real bioanalytical applications. We report on novel transducers and materials, improvements of existing transducers, new and improved biofunctionalization procedures as well as the prospects for near future commercialization of these technologies.

  10. High performance hybrid silicon micropillar solar cell based on light trapping characteristics of Cu nanoparticles

    Directory of Open Access Journals (Sweden)

    Yulong Zhang

    2018-05-01

    Full Text Available High performance silicon combined structure (micropillar with Cu nanoparticles solar cell has been synthesized from N-type silicon substrates based on the micropillar array. The combined structure solar cell exhibited higher short circuit current rather than the silicon miropillar solar cell, which the parameters of micropillar array are the same. Due to the Cu nanoparticles were decorated on the surface of silicon micropillar array, the photovoltaic properties of cells have been improved. In addition, the optimal efficiency of 11.5% was measured for the combined structure solar cell, which is better than the silicon micropillar cell.

  11. High performance hybrid silicon micropillar solar cell based on light trapping characteristics of Cu nanoparticles

    Science.gov (United States)

    Zhang, Yulong; Fan, Zhiqiang; Zhang, Weijia; Ma, Qiang; Jiang, Zhaoyi; Ma, Denghao

    2018-05-01

    High performance silicon combined structure (micropillar with Cu nanoparticles) solar cell has been synthesized from N-type silicon substrates based on the micropillar array. The combined structure solar cell exhibited higher short circuit current rather than the silicon miropillar solar cell, which the parameters of micropillar array are the same. Due to the Cu nanoparticles were decorated on the surface of silicon micropillar array, the photovoltaic properties of cells have been improved. In addition, the optimal efficiency of 11.5% was measured for the combined structure solar cell, which is better than the silicon micropillar cell.

  12. Emerging heterogeneous integrated photonic platforms on silicon

    Directory of Open Access Journals (Sweden)

    Fathpour Sasan

    2015-05-01

    Full Text Available Silicon photonics has been established as a mature and promising technology for optoelectronic integrated circuits, mostly based on the silicon-on-insulator (SOI waveguide platform. However, not all optical functionalities can be satisfactorily achieved merely based on silicon, in general, and on the SOI platform, in particular. Long-known shortcomings of silicon-based integrated photonics are optical absorption (in the telecommunication wavelengths and feasibility of electrically-injected lasers (at least at room temperature. More recently, high two-photon and free-carrier absorptions required at high optical intensities for third-order optical nonlinear effects, inherent lack of second-order optical nonlinearity, low extinction ratio of modulators based on the free-carrier plasma effect, and the loss of the buried oxide layer of the SOI waveguides at mid-infrared wavelengths have been recognized as other shortcomings. Accordingly, several novel waveguide platforms have been developing to address these shortcomings of the SOI platform. Most of these emerging platforms are based on heterogeneous integration of other material systems on silicon substrates, and in some cases silicon is integrated on other substrates. Germanium and its binary alloys with silicon, III–V compound semiconductors, silicon nitride, tantalum pentoxide and other high-index dielectric or glass materials, as well as lithium niobate are some of the materials heterogeneously integrated on silicon substrates. The materials are typically integrated by a variety of epitaxial growth, bonding, ion implantation and slicing, etch back, spin-on-glass or other techniques. These wide range of efforts are reviewed here holistically to stress that there is no pure silicon or even group IV photonics per se. Rather, the future of the field of integrated photonics appears to be one of heterogenization, where a variety of different materials and waveguide platforms will be used for

  13. Hybrid Integrated Silicon Microfluidic Platform for Fluorescence Based Biodetection

    Directory of Open Access Journals (Sweden)

    André Darveau

    2007-09-01

    Full Text Available The desideratum to develop a fully integrated Lab-on-a-chip device capable ofrapid specimen detection for high throughput in-situ biomedical diagnoses and Point-of-Care testing applications has called for the integration of some of the novel technologiessuch as the microfluidics, microphotonics, immunoproteomics and Micro ElectroMechanical Systems (MEMS. In the present work, a silicon based microfluidic device hasbeen developed for carrying out fluorescence based immunoassay. By hybrid attachment ofthe microfluidic device with a Spectrometer-on-chip, the feasibility of synthesizing anintegrated Lab-on-a-chip type device for fluorescence based biosensing has beendemonstrated. Biodetection using the microfluidic device has been carried out usingantigen sheep IgG and Alexafluor-647 tagged antibody particles and the experimentalresults prove that silicon is a compatible material for the present application given thevarious advantages it offers such as cost-effectiveness, ease of bulk microfabrication,superior surface affinity to biomolecules, ease of disposability of the device etc., and is thussuitable for fabricating Lab-on-a-chip type devices.

  14. Design and construction of automatic operating system of double chamber plasma nitriding device PLC based

    International Nuclear Information System (INIS)

    Saminto; Slamet Santosa; Eko Priyono

    2012-01-01

    The automatic operating system of double chamber plasma nitriding device has been done. The system is used for operating double chamber plasma nitriding automatically as according to the standard operating procedure by pressing push button on the human machine interface (HMI). The system consists of hardware and software. The hardware was constructed using main components T100MD1616+ PLC module and supported by temperature signal conditioner module, Wheatstone bridge module, isolated amplifier module and EMS 30A H Bridge motor driver module. A software program that is planted on T100MD1616+ PLC using ladder diagrams and Tbasic program. Test system functions performed by inserting a set values of temperature and pressure by pressing the button on the human machine interface (HMI). The test results show that the temperature control with a set of values 100 °C obtained stable coverage of 98 °C to 102 °C, (Δ ± 2 °C) with a 2% tolerance and the output voltage of the DAC is 2.436 volts to 2.913 volts. The pressure control with a set of values 2.169 x 10 -1 mbar obtained stable coverage of 1.995 x 10 -1 mbar to 2.205 x 10 -1 mbar, (Δ ± 0.105 x 10 -1 mbar) with a 5% tol. (author)

  15. The Influence of Plasma-Based Nitriding and Oxidizing Treatments on the Mechanical and Corrosion Properties of CoCrMo Biomedical Alloy

    Science.gov (United States)

    Noli, Fotini; Pichon, Luc; Öztürk, Orhan

    2018-04-01

    Plasma-based nitriding and/or oxidizing treatments were applied to CoCrMo alloy to improve its surface mechanical properties and corrosion resistance for biomedical applications. Three treatments were performed. A set of CoCrMo samples has been subjected to nitriding at moderate temperatures ( 400 °C). A second set of CoCrMo samples was oxidized at 395 °C in pure O2. The last set of CoCrMo samples was nitrided and subsequently oxidized under the experimental conditions of previous sets (double treatment). The microstructure and morphology of the layers formed on the CoCrMo alloy were investigated by X-ray diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy. In addition, nitrogen and oxygen profiles were determined by Glow Discharge Optical Emission Spectroscopy, Rutherford Backscattering Spectroscopy, Energy-Dispersive X-ray, and Nuclear Reaction Analysis. Significant improvement of the Vickers hardness of the CoCrMo samples after plasma nitriding was observed due to the supersaturated nitrogen solution and the formation of an expanded FCC γ N phase and CrN precipitates. In the case of the oxidized samples, Vickers hardness improvement was minimal. The corrosion behavior of the samples was investigated in simulated body fluid (0.9 pct NaCl solution at 37 °C) using electrochemical techniques (potentiodynamic polarization and cyclic voltammetry). The concentration of metal ions released from the CoCrMo surfaces was determined by Instrumental Neutron Activation Analysis. The experimental results clearly indicate that the CoCrMo surface subjected to the double surface treatment consisting in plasma nitriding and plasma oxidizing exhibited lower deterioration and better resistance to corrosion compared to the nitrided, oxidized, and untreated samples. This enhancement is believed to be due to the formation of a thicker and more stable layer.

  16. Plasma nitriding of steels

    CERN Document Server

    Aghajani, Hossein

    2017-01-01

    This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods. .

  17. A small animal PET prototype based on Silicon Photomultipliers

    International Nuclear Information System (INIS)

    Marcatili, S; Belcari, N.; Bisogni, M.G.; Del Guerra, A.; Collazuol, G.; Pedreschi, E.; Spinella, F.; Sportelli, G.; Marzocca, C.

    2011-01-01

    Next generation PET scanners should full fill very high requirements in terms of spatial, energy and timing resolution. Modern scanner performances are inherently limited by the use of standard photomultiplier tubes. The use of Silicon Photomultiplier (Si P M) matrices is proposed for the construction of a small animal PET system consisting of two detector heads based on Lyso continuos crystals. The use of large area multi-pixel Silicon Photomultiplier (Si P M) detectors requires the development of a multichannel Digital Acquisition system (DAQ) as well as of a dedicated front-end in order not to degrade the intrinsic detector capabilities. At the University of Pisa and INFN Pisa we developed a DAQ board for the read-out of 2 64-pixel Si P M matrices in time coincidence for Positron Emission Tomography (PET) applications. The proof of principles is based on 64-pixel detectors, but the whole system has been conceived to be easily scalable to a higher number of channels. Here we describe the Group-V INFN DASi P M 2 (Development and Application of Si P M) project and related results.

  18. Silicon Micropore-Based Parallel Plate Membrane Oxygenator.

    Science.gov (United States)

    Dharia, Ajay; Abada, Emily; Feinberg, Benjamin; Yeager, Torin; Moses, Willieford; Park, Jaehyun; Blaha, Charles; Wright, Nathan; Padilla, Benjamin; Roy, Shuvo

    2018-02-01

    Extracorporeal membrane oxygenation (ECMO) is a life support system that circulates the blood through an oxygenating system to temporarily (days to months) support heart or lung function during cardiopulmonary failure until organ recovery or replacement. Currently, the need for high levels of systemic anticoagulation and the risk for bleeding are main drawbacks of ECMO that can be addressed with a redesigned ECMO system. Our lab has developed an approach using microelectromechanical systems (MEMS) fabrication techniques to create novel gas exchange membranes consisting of a rigid silicon micropore membrane (SμM) support structure bonded to a thin film of gas-permeable polydimethylsiloxane (PDMS). This study details the fabrication process to create silicon membranes with highly uniform micropores that have a high level of pattern fidelity. The oxygen transport across these membranes was tested in a simple water-based bench-top set-up as well in a porcine in vivo model. It was determined that the mass transfer coefficient for the system using SµM-PDMS membranes was 3.03 ± 0.42 mL O 2 min -1 m -2 cm Hg -1 with pure water and 1.71 ± 1.03 mL O 2 min -1 m -2 cm Hg -1 with blood. An analytic model to predict gas transport was developed using data from the bench-top experiments and validated with in vivo testing. This was a proof of concept study showing adequate oxygen transport across a parallel plate SµM-PDMS membrane when used as a membrane oxygenator. This work establishes the tools and the equipoise to develop future generations of silicon micropore membrane oxygenators. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  19. Novel detectors for silicon based microdosimetry, their concepts and applications

    Science.gov (United States)

    Rosenfeld, Anatoly B.

    2016-02-01

    This paper presents an overview of the development of semiconductor microdosimetry and the most current (state-of-the-art) Silicon on Insulator (SOI) detectors for microdosimetry based mainly on research and development carried out at the Centre for Medical Radiation Physics (CMRP) at the University of Wollongong with collaborators over the last 18 years. In this paper every generation of CMRP SOI microdosimeters, including their fabrication, design, and electrical and charge collection characterisation are presented. A study of SOI microdosimeters in various radiation fields has demonstrated that under appropriate geometrical scaling, the response of SOI detectors with the well-known geometry of microscopically sensitive volumes will record the energy deposition spectra representative of tissue cells of an equivalent shape. This development of SOI detectors for microdosimetry with increased complexity has improved the definition of microscopic sensitive volume (SV), which is modelling the deposition of ionising energy in a biological cell, that are led from planar to 3D SOI detectors with an array of segmented microscopic 3D SVs. The monolithic ΔE-E silicon telescope, which is an alternative to the SOI silicon microdosimeter, is presented, and as an example, applications of SOI detectors and ΔE-E monolithic telescope for microdosimetery in proton therapy field and equivalent neutron dose measurements out of field are also presented. An SOI microdosimeter "bridge" with 3D SVs can derive the relative biological effectiveness (RBE) in 12C ion radiation therapy that matches the tissue equivalent proportional counter (TEPC) quite well, but with outstanding spatial resolution. The use of SOI technology in experimental microdosimetry offers simplicity (no gas system or HV supply), high spatial resolution, low cost, high count rates, and the possibility of integrating the system onto a single device with other types of detectors.

  20. Study the gas sensing properties of boron nitride nanosheets

    International Nuclear Information System (INIS)

    Sajjad, Muhammad; Feng, Peter

    2014-01-01

    Graphical abstract: - Highlights: • We synthesized boron nitride nanosheets (BNNSs) on silicon substrate. • We analyzed gas sensing properties of BNNSs-based gas-sensor device. • CH 4 gas is used to measure gas-sensing properties of the device. • Quick response and recovery time of the device is recorded. • BNNSs showed excellent sensitivity to the working gas. - Abstract: In the present communication, we report on the synthesis of boron nitride nanosheets (BNNSs) and study of their gas sensing properties. BNNSs are synthesized by irradiating pyrolytic hexagonal boron nitride (h-BN) target using CO 2 laser pulses. High resolution transmission electron microscopic measurements (HRTEM) revealed 2-dientional honeycomb crystal lattice structure of BNNSs. HRTEM, electron diffraction, XRD and Raman scattering measurements clearly identified h-BN. Gas sensing properties of synthesized BNNSs were analyzed with prototype gas sensor using methane as working gas. A systematic response curve of the sensor is recorded in each cycle of gas “in” and “out”; suggesting excellent sensitivity and high performance of BNNSs-based gas-sensor