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Sample records for wet etch processing

  1. Summary of Chalcogenide Glass Processing: Wet-Etching and Photolithography

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Sundaram, S. K.; Johnson, Bradley R.; Saraf, Laxmikant V.

    2006-12-01

    This report describes a study designed to explore the different properties of two different chalcogenide materials, As2S3 and As24S38Se38, when subjected to photolithographic wet-etching techniques. Chalcogenide glasses are made by combining chalcogen elements S, Se, and Te with Group IV and/or V elements. The etchant was selected from the literature and was composed of sodium hydroxide, isopropyl alcohol, and deionized water and the types of chalcogenide glass for study were As2S3 and As24S38Se38. The main goals here were to obtain a single variable etch rate curve of etch depth per time versus NaOH overall solution concentration in M and to see the difference in etch rate between a given etchant when used on the different chalcogenide stoichiometries. Upon completion of these two goals, future studies will begin to explore creating complex, integrated photonic devices via these methods.

  2. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    In a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  3. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  4. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

    Energy Technology Data Exchange (ETDEWEB)

    Swain, Basudev, E-mail: swain@iae.re.kr [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Mishra, Chinmayee [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Hong, Hyun Seon [Sungshin University, Dept. of Interdisciplinary ECO Science, Seoul, 142-732 (Korea, Republic of); Cho, Sung-Soo [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of)

    2016-05-15

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m{sup 3} of copper and 1.35 kg/m{sup 3} of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching

  5. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

    International Nuclear Information System (INIS)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo

    2016-01-01

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m 3 of copper and 1.35 kg/m 3 of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching wastewater

  6. Level Set Approach to Anisotropic Wet Etching of Silicon

    Directory of Open Access Journals (Sweden)

    Branislav Radjenović

    2010-05-01

    Full Text Available In this paper a methodology for the three dimensional (3D modeling and simulation of the profile evolution during anisotropic wet etching of silicon based on the level set method is presented. Etching rate anisotropy in silicon is modeled taking into account full silicon symmetry properties, by means of the interpolation technique using experimentally obtained values for the etching rates along thirteen principal and high index directions in KOH solutions. The resulting level set equations are solved using an open source implementation of the sparse field method (ITK library, developed in medical image processing community, extended for the case of non-convex Hamiltonians. Simulation results for some interesting initial 3D shapes, as well as some more practical examples illustrating anisotropic etching simulation in the presence of masks (simple square aperture mask, convex corner undercutting and convex corner compensation, formation of suspended structures are shown also. The obtained results show that level set method can be used as an effective tool for wet etching process modeling, and that is a viable alternative to the Cellular Automata method which now prevails in the simulations of the wet etching process.

  7. Dynamic Wet Etching of Silicon through Isopropanol Alcohol Evaporation

    Directory of Open Access Journals (Sweden)

    Tiago S. Monteiro

    2015-10-01

    Full Text Available In this paper, Isopropanol (IPA availability during the anisotropic etching of silicon in Potassium Hydroxide (KOH solutions was investigated. Squares of 8 to 40 µm were patterned to (100 oriented silicon wafers through DWL (Direct Writing Laser photolithography. The wet etching process was performed inside an open HDPE (High Density Polyethylene flask with ultrasonic agitation. IPA volume and evaporation was studied in a dynamic etching process, and subsequent influence on the silicon etching was inspected. For the tested conditions, evaporation rates for water vapor and IPA were determined as approximately 0.0417 mL/min and 0.175 mL/min, respectively. Results demonstrate that IPA availability, and not concentration, plays an important role in the definition of the final structure. Transversal SEM (Scanning Electron Microscopy analysis demonstrates a correlation between microloading effects (as a consequence of structure spacing and the angle formed towards the (100 plane.

  8. Silicon etch process

    International Nuclear Information System (INIS)

    Day, D.J.; White, J.C.

    1984-01-01

    A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

  9. Damage-free back channel wet-etch process in amorphous indium-zinc-oxide thin-film transistors using a carbon-nanofilm barrier layer.

    Science.gov (United States)

    Luo, Dongxiang; Zhao, Mingjie; Xu, Miao; Li, Min; Chen, Zikai; Wang, Lang; Zou, Jianhua; Tao, Hong; Wang, Lei; Peng, Junbiao

    2014-07-23

    Amorphous indium-zinc-oxide thin film transistors (IZO-TFTs) with damage-free back channel wet-etch (BCE) process were investigated. A carbon (C) nanofilm was inserted into the interface between IZO layer and source/drain (S/D) electrodes as a barrier layer. Transmittance electron microscope images revealed that the 3 nm-thick C nanofilm exhibited a good corrosion resistance to a commonly used H3PO4-based etchant and could be easily eliminated. The TFT device with a 3 nm-thick C barrier layer showed a saturated field effect mobility of 14.4 cm(2) V(-1) s(-1), a subthreshold swing of 0.21 V/decade, an on-to-off current ratio of 8.3 × 10(10), and a threshold voltage of 2.0 V. The favorable electrical performance of this kind of IZO-TFTs was due to the protection of the inserted C to IZO layer in the back-channel-etch process. Moreover, the low contact resistance of the devices was proved to be due to the graphitization of the C nanofilms after annealing. In addition, the hysteresis and thermal stress testing confirmed that the usage of C barrier nanofilms is an effective method to fabricate the damage-free BCE-type devices with high reliability.

  10. Physical chemistry of wet chemical anisotropic etching of silicon

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1995-01-01

    In this paper we explain a view to understand the anisotropy of the etching of silicon in certain wet chemical agents (such as KOH). The starting point is the assumption that the [Left angle bracket]111[Right Angle Bracket] face of silicon is a flat face, the etch rate of which is then governed by a

  11. The mechanism of selective corrugation removal by KOH anisotropic wet etching

    International Nuclear Information System (INIS)

    Shikida, M; Inagaki, N; Sasaki, H; Amakawa, H; Fukuzawa, K; Sato, K

    2010-01-01

    The mechanism of selective corrugation removal by anisotropic wet etching—which reduces a periodic corrugation, called 'scalloping', formed on the sidewalls of microstructures by the Bosch process in deep reactive-ion etching (D-RIE)—was investigated. In particular, the corrugation-removal mechanism was analyzed by using the etching rate distribution pattern, and two equations for predicting the corrugation-removal time by the etching were derived. A Si{1 0 0} wafer was first etched by D-RIE at a depth of 29.4 µm (60 cycles) to form the corrugation on the sidewall surface. The height and pitch of the corrugation were 196 and 494 nm, respectively. Selective removal of the corrugation by using 50% KOH (40 °C) was experimentally tried. The corrugation formed on Si{1 0 0} sidewall surfaces was gradually reduced in size as the etching progressed, and it was completely removed after 5 min of etching. Similarly, the corrugation formed on a Si{1 1 0} sidewall surface was also selectively removed by KOH etching (etching time: 3 min). The roughness value of the sidewall surface was reduced from 17.6 nm to a few nanometers by the etching. These results confirm that the corrugation-removal mechanism using anisotropic wet etching can be explained in terms of the distribution pattern of etching rate

  12. Design and application of a metal wet-etching post-process for the improvement of CMOS-MEMS capacitive sensors

    International Nuclear Information System (INIS)

    Tsai, Ming-Han; Sun, Chih-Ming; Liu, Yu-Chia; Fang, Weileun; Wang, Chuanwei

    2009-01-01

    This study presents a process design methodology to improve the performance of a CMOS-MEMS gap-closing capacitive sensor. In addition to the standard CMOS process, the metal wet-etching approach is employed as the post-CMOS process to realize the present design. The dielectric layers of the CMOS process are exploited to form the main micro mechanical structures of the sensor. The metal layers of the CMOS process are used as the sensing electrodes and sacrificial layers. The advantages of the sensor design are as follows: (1) the parasitic capacitance is significantly reduced by the dielectric structure, (2) in-plane and out-of-plane sensing gaps can be reduced to increase the sensitivity, and (3) plate-type instead of comb-type out-of-plane sensing electrodes are available to increase the sensing electrode area. To demonstrate the feasibility of the present design, a three-axis capacitive CMOS-MEMS accelerometers chip is implemented and characterized. Measurements show that the sensitivities of accelerometers reach 11.5 mV G −1 (in the X-, Y-axes) and 7.8 mV G −1 (in the Z-axis), respectively, which are nearly one order larger than existing designs. Moreover, the detection of 10 mG excitation using the three-axis accelerometer is demonstrated for both in-plane and out-of-plane directions

  13. Study of surfactant-added TMAH for applications in DRIE and wet etching-based micromachining

    Science.gov (United States)

    Tang, B.; Shikida, M.; Sato, K.; Pal, P.; Amakawa, H.; Hida, H.; Fukuzawa, K.

    2010-06-01

    In this paper, etching anisotropy is evaluated for a number of different crystallographic orientations of silicon in a 0.1 vol% Triton-X-100 added 25 wt% tetramethylammonium hydroxide (TMAH) solution using a silicon hemisphere. The research is primarily aimed at developing advanced applications of wet etching in microelectromechanical systems (MEMS). The etching process is carried out at different temperatures in the range of 61-81 °C. The etching results of silicon hemisphere and different shapes of three-dimensional structures in {1 0 0}- and {1 1 0}-Si surfaces are analyzed. Significantly important anisotropy, different from a traditional etchant (e.g. pure KOH and TMAH), is investigated to extend the applications of the wet etching process in silicon bulk micromachining. The similar etching behavior of exact and vicinal {1 1 0} and {1 1 1} planes in TMAH + Triton is utilized selectively to remove the scalloping from deep reactive-ion etching (DRIE) etched profiles. The direct application of the present research is demonstrated by fabricating a cylindrical lens with highly smooth etched surface finish. The smoothness of a micro-lens at different locations is measured qualitatively by a scanning electron microscope and quantitatively by an atomic force microscope. The present paper provides a simple and effective fabrication method of the silicon micro-lens for optical MEMS applications.

  14. 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.

  15. Wet-etch sequence optimisation incorporating time dependent chemical maintenance

    NARCIS (Netherlands)

    Kruif, B.J. de

    2015-01-01

    Wafer fabrication is the major cost contributor in semiconductor manufacturing. One of the steps in the fabrication is the removal of exposed layers in an automatic wet-etch station with chemicals. In time, these chemicals get polluted and their effectiveness decreases. Therefore, the chemicals in

  16. Model of wet chemical etching of swift heavy ions tracks

    Science.gov (United States)

    Gorbunov, S. A.; Malakhov, A. I.; Rymzhanov, R. A.; Volkov, A. E.

    2017-10-01

    A model of wet chemical etching of tracks of swift heavy ions (SHI) decelerated in solids in the electronic stopping regime is presented. This model takes into account both possible etching modes: etching controlled by diffusion of etchant molecules to the etching front, and etching controlled by the rate of a reaction of an etchant with a material. Olivine ((Mg0.88Fe0.12)2SiO4) crystals were chosen as a system for modeling. Two mechanisms of chemical activation of olivine around the SHI trajectory are considered. The first mechanism is activation stimulated by structural transformations in a nanometric track core, while the second one results from neutralization of metallic atoms by generated electrons spreading over micrometric distances. Monte-Carlo simulations (TREKIS code) form the basis for the description of excitations of the electronic subsystem and the lattice of olivine in an SHI track at times up to 100 fs after the projectile passage. Molecular dynamics supplies the initial conditions for modeling of lattice relaxation for longer times. These simulations enable us to estimate the effects of the chemical activation of olivine governed by both mechanisms. The developed model was applied to describe chemical activation and the etching kinetics of tracks of Au 2.1 GeV ions in olivine. The estimated lengthwise etching rate (38 µm · h-1) is in reasonable agreement with that detected in the experiments (24 µm · h-1).

  17. Precision Recess of AlGaN/GaN with Controllable Etching Rate Using ICP-RIE Oxidation and Wet Etching

    NARCIS (Netherlands)

    Sokolovskij, R.; Sun, J.; Santagata, F.; Iervolino, E.; Li, S.; Zhang, G.Y.; Sarro, P.M.; Zhang, G.Q.

    2016-01-01

    A method for highly controllable etching of AlGaN/GaN for the fabrication of high sensitivity HEMT based sensors is developed. The process consists of cyclic oxidation of nitride with O2 plasma using ICP-RIE etcher followed by wet etching of the oxidized layer. Previously reported

  18. Etching of fused silica fiber by metallic laser-induced backside wet etching technique

    Energy Technology Data Exchange (ETDEWEB)

    Vass, Cs., E-mail: vasscsaba@physx.u-szeged.hu [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Kiss, B.; Kopniczky, J.; Hopp, B. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary)

    2013-08-01

    The tip of multimode fused silica fiber (core diameter: 550 μm) was etched by metallic laser-induced backside wet etching (M-LIBWE) method. Frequency doubled, Q-switched Nd:YAG laser (λ = 532 nm; τ{sub FWHM} = 8 ns) was used as laser source. The laser beam was coupled into the fiber by a fused silica lens with a focal length of 1500 mm. The other tip of the fiber was dipped into liquid gallium metallic absorber. The etching threshold fluence was measured to be 475 mJ/cm{sup 2}, while the highest fluence, which resulted etching without breaking the fiber, was 1060 mJ/cm{sup 2}. The progress of etching was followed by optical microscopy, and the etch rate was measured to be between 20 and 37 nm/pulse depending on the applied laser energy. The surface morphologies of the etched tips were studied by scanning electron microscopy. A possible application of the structured fibers was also tested.

  19. Etching of fused silica fiber by metallic laser-induced backside wet etching technique

    International Nuclear Information System (INIS)

    Vass, Cs.; Kiss, B.; Kopniczky, J.; Hopp, B.

    2013-01-01

    The tip of multimode fused silica fiber (core diameter: 550 μm) was etched by metallic laser-induced backside wet etching (M-LIBWE) method. Frequency doubled, Q-switched Nd:YAG laser (λ = 532 nm; τ FWHM = 8 ns) was used as laser source. The laser beam was coupled into the fiber by a fused silica lens with a focal length of 1500 mm. The other tip of the fiber was dipped into liquid gallium metallic absorber. The etching threshold fluence was measured to be 475 mJ/cm 2 , while the highest fluence, which resulted etching without breaking the fiber, was 1060 mJ/cm 2 . The progress of etching was followed by optical microscopy, and the etch rate was measured to be between 20 and 37 nm/pulse depending on the applied laser energy. The surface morphologies of the etched tips were studied by scanning electron microscopy. A possible application of the structured fibers was also tested.

  20. Characterization of deep wet etching of fused silica glass for single cell and optical sensor deposition

    International Nuclear Information System (INIS)

    Zhu, Haixin; Holl, Mark; Ray, Tathagata; Bhushan, Shivani; Meldrum, Deirdre R

    2009-01-01

    The development of a high-throughput single-cell metabolic rate monitoring system relies on the use of transparent substrate material for a single cell-trapping platform. The high optical transparency, high chemical resistance, improved surface quality and compatibility with the silicon micromachining process of fused silica make it very attractive and desirable for this application. In this paper, we report the results from the development and characterization of a hydrofluoric acid (HF) based deep wet-etch process on fused silica. The pin holes and notching defects of various single-coated masking layers during the etching are characterized and the most suitable masking materials are identified for different etch depths. The dependence of the average etch rate and surface roughness on the etch depth, impurity concentration and HF composition are also examined. The resulting undercut from the deep HF etch using various masking materials is also investigated. The developed and characterized process techniques have been successfully implemented in the fabrication of micro-well arrays for single cell trapping and sensor deposition. Up to 60 µm deep micro-wells have been etched in a fused silica substrate with over 90% process yield and repeatability. To our knowledge, such etch depth has never been achieved in a fused silica substrate by using a non-diluted HF etchant and a single-coated masking layer at room temperature

  1. A study on electric properties for pulse laser annealing of ITO film after wet etching

    International Nuclear Information System (INIS)

    Lee, C.J.; Lin, H.K.; Li, C.H.; Chen, L.X.; Lee, C.C.; Wu, C.W.; Huang, J.C.

    2012-01-01

    The electric properties of ITO thin film after UV or IR laser annealing and wet etching was analyzed via grazing incidence in-plane X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra and residual stress measurement. The laser annealing process readily induced microcracks or quasi-microcracks on the ITO thin film due to the residual tension stress of crystalline phase transformation between irradiated and non-irradiated areas, and these defects then became the preferred sites for a higher etching rate, resulting in discontinuities in the ITO thin film after the wet etching process. The discontinuities in the residual ITO thin film obstruct carrier transmission and further result in electric failure. - Highlights: ► The laser annealing process induces microcracks in InSnO 2 thin films. ► The defects result in higher local etching rate during wet etching. ► These process defects originate from residual tension stress. ► Decreasing the thermal shock is suggested in order to reduce these process defects.

  2. Aluminum oxide mask fabrication by focused ion beam implantation combined with wet etching

    International Nuclear Information System (INIS)

    Liu Zhengjun; Iltanen, Kari; Chekurov, Nikolai; Tittonen, Ilkka; Grigoras, Kestutis

    2013-01-01

    A novel aluminum oxide (Al 2 O 3 ) hard mask fabrication process with nanoscale resolution is introduced. The Al 2 O 3 mask can be used for various purposes, but in this work it was utilized for silicon patterning using cryogenic deep reactive ion etching (DRIE). The patterning of Al 2 O 3 is a two-step process utilizing focused ion beam (FIB) irradiation combined with wet chemical etching. Gallium (Ga + ) FIB maskless patterning confers wet etch selectivity between the irradiated region and the non-irradiated one on the Al 2 O 3 layer, and mask patterns can easily be revealed by wet etching. This method is a modification of Ga + FIB mask patterning for the silicon etch stop, which eliminates the detrimental lattice damage and doping of the silicon substrate in critical devices. The shallow surface gallium FIB irradiated Al 2 O 3 mask protects the underlying silicon from Ga + ions. The performance of the masking capacity was tested by drawing pairs consisting of a line and an empty space with varying width. The best result was seven such pairs for 1 μm. The smallest half pitch was 59 nm. This method is capable of arbitrary pattern generation. The fabrication of a freestanding single-ended tuning fork resonator utilizing the introduced masking method is demonstrated. (paper)

  3. Wet etching mechanism and crystallization of indium-tin oxide layer for application in light-emitting diodes

    Science.gov (United States)

    Su, Shui-Hsiang; Kong, Hsieng-Jen; Tseng, Chun-Lung; Chen, Guan-Yu

    2018-01-01

    In the article, we describe the etching mechanism of indium-tin oxide (ITO) film, which was wet-etched using a solution of hydrochloric acid (HCl) and ferric chloride (FeCl3). The etching mechanism is analyzed at various etching durations of ITO films by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and selective area diffraction (SAD) analysis. In comparison with the crystalline phase of SnO2, the In2O3 phase can be more easily transformed to In3+ and can form an inverted conical structure during the etching process. By adjusting the etching duration, the residual ITO is completely removed to show a designed pattern. This is attributed to the negative Gibbs energy of In2O3 transformed to In3+. The result also corresponds to the finding of energy-dispersive X-ray spectroscopy (EDS) analysis that the Sn/In ratio increases with increasing etching duration.

  4. Low-loss slot waveguides with silicon (111 surfaces realized using anisotropic wet etching

    Directory of Open Access Journals (Sweden)

    Kapil Debnath

    2016-11-01

    Full Text Available We demonstrate low-loss slot waveguides on silicon-on-insulator (SOI platform. Waveguides oriented along the (11-2 direction on the Si (110 plane were first fabricated by a standard e-beam lithography and dry etching process. A TMAH based anisotropic wet etching technique was then used to remove any residual side wall roughness. Using this fabrication technique propagation loss as low as 3.7dB/cm was realized in silicon slot waveguide for wavelengths near 1550nm. We also realized low propagation loss of 1dB/cm for silicon strip waveguides.

  5. Simulation of the evolution of fused silica's surface defect during wet chemical etching

    Science.gov (United States)

    Liu, Taixiang; Yang, Ke; Li, Heyang; Yan, Lianghong; Yuan, Xiaodong; Yan, Hongwei

    2017-08-01

    Large high-power-laser facility is the basis for achieving inertial confinement fusion, one of whose missions is to make fusion energy usable in the near future. In the facility, fused silica optics plays an irreplaceable role to conduct extremely high-intensity laser to fusion capsule. But the surface defect of fused silica is a major obstacle limiting the output power of the large laser facility and likely resulting in the failure of ignition. To mitigate, or event to remove the surface defect, wet chemical etching has been developed as a practical way. However, how the surface defect evolves during wet chemical etching is still not clearly known so far. To address this problem, in this work, the three-dimensional model of surface defect is built and finite difference time domain (FDTD) method is developed to simulate the evolution of surface defect during etching. From the simulation, it is found that the surface defect will get smooth and result in the improvement of surface quality of fused silica after etching. Comparatively, surface defects (e.g. micro-crack, scratch, series of pinholes, etc.) of a typical fused silica at different etching time are experimentally measured. It can be seen that the simulation result agrees well with the result of experiment, indicating the FDTD method is valid for investigating the evolution of surface defect during etching. With the finding of FDTD simulation, one can optimize the treatment process of fused silica in practical etching or even to make the initial characterization of surface defect traceable.

  6. The fabrication of silicon nanostructures by focused-ion-beam implantation and TMAH wet etching

    International Nuclear Information System (INIS)

    Sievilae, Paeivi; Chekurov, Nikolai; Tittonen, Ilkka

    2010-01-01

    Local gallium implantation of silicon by a focused ion beam (FIB) has been used to create a mask for anisotropic tetramethylammonium hydroxide (TMAH) wet etching. The dependence of the etch stop properties of gallium-doped silicon on the implanted dose has been investigated and a dose of 4 x 10 13 ions cm -2 has been determined to be the threshold value for achieving observable etching resistance. Only a thin, approx. 50 nm, surface layer is found to be durable enough to serve as a mask with a high selectivity of at least 2000:1 between implanted and non-implanted areas. The combined FIB-TMAH process has been used to generate various types of 3D nanostructures including nanochannels separated by thin vertical sidewalls with aspect ratios up to 1:30, ultra-narrow (approx. 25 nm) freestanding bridges and cantilevers, and gratings with a resolution of 20 lines μm -1 .

  7. Wet etching and chemical polishing of InAs/GaSb superlattice photodiodes

    International Nuclear Information System (INIS)

    Chaghi, R; Cervera, C; Aït-Kaci, H; Grech, P; Rodriguez, J B; Christol, P

    2009-01-01

    In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H 3 PO 4 ), citric acid (C 6 H 8 O 7 ) and H 2 O 2 , followed by chemical polishing with the sodium hypochlorite (NaClO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current–voltage measurements. The zero-bias resistance area product R 0 A above 4 × 10 5 Ω cm 2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air

  8. The influence of the laser spot size and the pulse number on laser-induced backside wet etching

    International Nuclear Information System (INIS)

    Boehme, R.; Zimmer, K.

    2005-01-01

    The laser-induced backside wet etching (LIBWE) of transparent solids at the interface to absorbing liquid is a new promising method for laser microstructuring. The influence of the laser spot size and the applied pulse number to the etch rate were investigated in detail for fused silica and two different liquids. Additional to the significant rise of the etch rate with increasing spot size considerable incubation effects have been observed at low laser fluences and pulse numbers. Based on the bubble formation during LIBWE processing, a relation between the bubble collapse time and the etch rate was ascertained. This relation fits the etch rate dependence on the spot size well. It is assumed that the deposition of decomposition products from the bubble accounts for the spot size influence the etch rate

  9. Fabrication of high quality GaN nanopillar arrays by dry and wet chemical etching

    OpenAIRE

    Paramanik, Dipak; Motayed, Abhishek; King, Matthew; Ha, Jong-Yoon; Kryluk, Sergi; Davydov, Albert V.; Talin, Alec

    2013-01-01

    We study strain relaxation and surface damage of GaN nanopillar arrays fabricated using inductively coupled plasma (ICP) etching and post etch wet chemical treatment. We controlled the shape and surface damage of such nanopillar structures through selection of etching parameters. We compared different substrate temperatures and different chlorine-based etch chemistries to fabricate high quality GaN nanopillars. Room temperature photoluminescence and Raman scattering measurements were carried ...

  10. Unveiling the wet chemical etching characteristics of polydimethylsiloxane film for soft micromachining applications

    International Nuclear Information System (INIS)

    Kakati, A; Maji, D; Das, S

    2017-01-01

    Micromachining of a polydimethylsiloxane (PDMS) microstructure by wet chemical etching is explored for microelectromechanical systems (MEMS) and microfluidic applications. A 100 µ m thick PDMS film was patterned with different microstructure designs by wet chemical etching using a N-methyl-2-pyrrolidone (C 16 H 36 FN) and tetra-n-butylammonium fluoride (C 5 H 9 NO) mixture solution with 3:1 volume ratio after lithography for studying etching characteristics. The patterning parameters, such as etch rate, surface roughness, pH of etchant solution with time, were thoroughly investigated. A detailed study of surface morphology with etching time revealed nonlinear behaviour of the PDMS surface roughness and etch rate. A maximum rate of 1.45 µ m min −1 for 10 min etching with surface roughness of 360 nm was achieved. A new approach of wet chemical etching with pH controlled doped etchant was introduced for lower surface roughness of etched microstructures, and a constant etch rate during etching. Variation of the etching rate and surface roughness by pH controlled etching was performed by doping 5–15 gm l −1 of silicic acid (SiO 2xH2 O) into the traditional etchant solution. PDMS etching by silicic acid doped etchant solution showed a reduction in surface roughness from 400 nm to 220 nm for the same 15 µ m etching. This study is beneficial for micromachining of various MEMS and microfluidic structures such as micropillars, microchannels, and other PDMS microstructures. (paper)

  11. Fabrication of 3D solenoid microcoils in silica glass by femtosecond laser wet etch and microsolidics

    Science.gov (United States)

    Meng, Xiangwei; Yang, Qing; Chen, Feng; Shan, Chao; Liu, Keyin; Li, Yanyang; Bian, Hao; Du, Guangqing; Hou, Xun

    2015-02-01

    This paper reports a flexible fabrication method for 3D solenoid microcoils in silica glass. The method consists of femtosecond laser wet etching (FLWE) and microsolidics process. The 3D microchannel with high aspect ratio is fabricated by an improved FLWE method. In the microsolidics process, an alloy was chosen as the conductive metal. The microwires are achieved by injecting liquid alloy into the microchannel, and allowing the alloy to cool and solidify. The alloy microwires with high melting point can overcome the limitation of working temperature and improve the electrical property. The geometry, the height and diameter of microcoils were flexibly fabricated by the pre-designed laser writing path, the laser power and etching time. The 3D microcoils can provide uniform magnetic field and be widely integrated in many magnetic microsystems.

  12. Simple fabrication of closed-packed IR microlens arrays on silicon by femtosecond laser wet etching

    Science.gov (United States)

    Meng, Xiangwei; Chen, Feng; Yang, Qing; Bian, Hao; Du, Guangqing; Hou, Xun

    2015-10-01

    We demonstrate a simple route to fabricate closed-packed infrared (IR) silicon microlens arrays (MLAs) based on femtosecond laser irradiation assisted by wet etching method. The fabricated MLAs show high fill factor, smooth surface and good uniformity. They can be used as optical devices for IR applications. The exposure and etching parameters are optimized to obtain reproducible microlens with hexagonal and rectangular arrangements. The surface roughness of the concave MLAs is only 56 nm. This presented method is a maskless process and can flexibly change the size, shape and the fill factor of the MLAs by controlling the experimental parameters. The concave MLAs on silicon can work in IR region and can be used for IR sensors and imaging applications.

  13. Process for etching zirconium metallic objects

    International Nuclear Information System (INIS)

    Panson, A.J.

    1988-01-01

    In a process for etching of zirconium metallic articles formed from zirconium or a zirconium alloy, wherein the zirconium metallic article is contacted with an aqueous hydrofluoric acid-nitric acid etching bath having an initial ratio of hydrofluoric acid to nitric acid and an initial concentration of hydrofluoric and nitric acids, the improvement, is described comprising: after etching of zirconium metallic articles in the bath for a period of time such that the etching rate has diminished from an initial rate to a lesser rate, adding hydrofluoric acid and nitric acid to the exhausted bath to adjust the concentration and ratio of hydrofluoric acid to nitric acid therein to a value substantially that of the initial concentration and ratio and thereby regenerate the etching solution without removal of dissolved zirconium therefrom; and etching further zirconium metallic articles in the regenerated etching bath

  14. 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

  15. Wet etching rates of InGaZnO for the fabrication of transparent thin-film transistors on plastic substrates

    International Nuclear Information System (INIS)

    Lee, Chi-Yuan; Chang, Chienliu; Shih, Wen-Pin; Dai, Ching-Liang

    2010-01-01

    The wet etch process for amorphous indium gallium zinc oxide (a-IGZO or a-InGaZnO) by using various etchants is reported. The etch rates of a-IGZO, compared to another indium-based oxides including indium gallium oxide (IGO), indium zinc oxide (IZO), and indium tin oxide (ITO), are measured by using acetic acid, citric acid, hydrochloric acid, perchloric acid, and aqua ammonia as etchants, respectively. In our experimental results, the etch rate of the transparent oxide semiconductor (TOS) films by using acid solutions ranked accordingly from high to low are IZO, IGZO, IGO and ITO. Comparatively, the etch rate of the TOS films by using alkaline ammonia solution ranked from high to low are IGZO, IZO, IGO and ITO, in that order. Using the proposed wet etching process with high etch selectivity, bottom-gate-type thin-film transistors (TFTs) based on a-IGZO channels and Y 2 O 3 gate-insulators were fabricated by radio-frequency sputtering on plastic substrates. The wet etch processed TFT with 30 μm gate length and 120 μm gate width exhibits a saturation mobility of 46.25 cm 2 V -1 s -1 , a threshold voltage of 1.3 V, a drain current on-off ratio > 10 6 , and subthreshold gate voltage swing of 0.29 V decade -1 . The performance of the TFTs ensures the applicability of the wet etching process for IGZO to electronic devices on organic polymer substrates.

  16. Nanowall formation by maskless wet-etching on a femtosecond laser irradiated silicon surface

    Science.gov (United States)

    Lee, Siwoo; Jo, Kukhyun; Keum, Hee-sung; Chae, Sangmin; Kim, Yonghyeon; Choi, Jiyeon; Lee, Hyun Hwi; Kim, Hyo Jung

    2018-04-01

    We found that micro-cells surrounded by nanowalls can be formed by a maskless wet-etching process on Si (100) surfaces possessing Laser Induced Periodic Surface Structure (LIPSS) by femtosecond laser irradiation. The LIPSS process could produce periodic one-dimensional micron scale ripples on a Si surface, which could be developed into micro-cells by a subsequent etching process. The solution etching conditions strongly affected both the micro-cell and nanowall shapes such as the height and the thickness of nanowalls. The tetramethylammonium hydroxide solution created thin nanowalls and the resulting micro-cells with a well-flattened bottom while the KOH solution formed thick walls and incomplete micro-cells. The bottoms of micro-cells surrounded by the nanowalls were considerably flat with a 3.10 nm surface roughness. A pentacene layer was deposited on the micro-cells of a Si surface to evaluate the film properties by grazing incidence wide angle x-ray scattering measurements. The pentacene film on the micro-cell Si surface showed a strong film phase, which was comparable to the film phase grown on the atomically flat Si surface.

  17. Quadrilateral Micro-Hole Array Machining on Invar Thin Film: Wet Etching and Electrochemical Fusion Machining

    Directory of Open Access Journals (Sweden)

    Woong-Kirl Choi

    2018-01-01

    Full Text Available Ultra-precision products which contain a micro-hole array have recently shown remarkable demand growth in many fields, especially in the semiconductor and display industries. Photoresist etching and electrochemical machining are widely known as precision methods for machining micro-holes with no residual stress and lower surface roughness on the fabricated products. The Invar shadow masks used for organic light-emitting diodes (OLEDs contain numerous micro-holes and are currently machined by a photoresist etching method. However, this method has several problems, such as uncontrollable hole machining accuracy, non-etched areas, and overcutting. To solve these problems, a machining method that combines photoresist etching and electrochemical machining can be applied. In this study, negative photoresist with a quadrilateral hole array pattern was dry coated onto 30-µm-thick Invar thin film, and then exposure and development were carried out. After that, photoresist single-side wet etching and a fusion method of wet etching-electrochemical machining were used to machine micro-holes on the Invar. The hole machining geometry, surface quality, and overcutting characteristics of the methods were studied. Wet etching and electrochemical fusion machining can improve the accuracy and surface quality. The overcutting phenomenon can also be controlled by the fusion machining. Experimental results show that the proposed method is promising for the fabrication of Invar film shadow masks.

  18. SEMICONDUCTOR TECHNOLOGY: TaN wet etch for application in dual-metal-gate integration technology

    Science.gov (United States)

    Yongliang, Li; Qiuxia, Xu

    2009-12-01

    Wet-etch etchants and the TaN film method for dual-metal-gate integration are investigated. Both HF/HN O3/H2O and NH4OH/H2O2 solutions can etch TaN effectively, but poor selectivity to the gate dielectric for the HF/HNO3/H2O solution due to HF being included in HF/HNO3/H2O, and the fact that TaN is difficult to etch in the NH4OH/H2O2 solution at the first stage due to the thin TaOxNy layer on the TaN surface, mean that they are difficult to individually apply to dual-metal-gate integration. A two-step wet etching strategy using the HF/HNO3/H2O solution first and the NH4OH/H2O2 solution later can fully remove thin TaN film with a photo-resist mask and has high selectivity to the HfSiON dielectric film underneath. High-k dielectric film surfaces are smooth after wet etching of the TaN metal gate and MOSCAPs show well-behaved C-V and Jg-Vg characteristics, which all prove that the wet etching of TaN has little impact on electrical performance and can be applied to dual-metal-gate integration technology for removing the first TaN metal gate in the PMOS region.

  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. Nanoscale silver-assisted wet etching of crystalline silicon for anti-reflection surface textures.

    Science.gov (United States)

    Li, Rui; Wang, Shuling; Chuwongin, Santhad; Zhou, Weidong

    2013-01-01

    We report here an electro-less metal-assisted chemical etching (MacEtch) process as light management surface-texturing technique for single crystalline Si photovoltaics. Random Silver nanostructures were formed on top of the Si surface based on the thin film evaporation and annealing process. Significant reflection reduction was obtained from the fabricated Si sample, with approximately 2% reflection over a wide spectra range (300 to 1050 nm). The work demonstrates the potential of MacEtch process for anti-reflection surface texture fabrication of large area, high efficiency, and low cost thin film solar cell.

  1. Nanosecond laser-induced back side wet etching of fused silica with a copper-based absorber liquid

    Science.gov (United States)

    Lorenz, Pierre; Zehnder, Sarah; Ehrhardt, Martin; Frost, Frank; Zimmer, Klaus; Schwaller, Patrick

    2014-03-01

    Cost-efficient machining of dielectric surfaces with high-precision and low-roughness for industrial applications is still challenging if using laser-patterning processes. Laser induced back side wet etching (LIBWE) using UV laser pulses with liquid heavy metals or aromatic hydrocarbons as absorber allows the fabrication of well-defined, nm precise, free-form surfaces with low surface roughness, e.g., needed for optical applications. The copper-sulphatebased absorber CuSO4/K-Na-Tartrate/NaOH/formaldehyde in water is used for laser-induced deposition of copper. If this absorber can also be used as precursor for laser-induced ablation, promising industrial applications combining surface structuring and deposition within the same setup could be possible. The etching results applying a KrF excimer (248 nm, 25 ns) and a Nd:YAG (1064 nm, 20 ns) laser are compared. The topography of the etched surfaces were analyzed by scanning electron microscopy (SEM), white light interferometry (WLI) as well as laser scanning microscopy (LSM). The chemical composition of the irradiated surface was studied by energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT-IR). For the discussion of the etching mechanism the laser-induced heating was simulated with finite element method (FEM). The results indicate that the UV and IR radiation allows micro structuring of fused silica with the copper-based absorber where the etching process can be explained by the laser-induced formation of a copper-based absorber layer.

  2. Carrier-lifetime-controlled selective etching process for semiconductors using photochemical etching

    International Nuclear Information System (INIS)

    Ashby, C.I.H.; Myers, D.R.

    1992-01-01

    This patent describes a process for selectively photochemically etching a semiconductor material. It comprises introducing at least one impurity into at least one selected region of a semiconductor material to be etched to increase a local impurity concentration in the at least one selected region relative to an impurity concentration in regions of the semiconductor material adjacent thereto, for reducing minority carrier lifetimes within the at least one selected region relative to the adjacent regions for thereby providing a photochemical etch-inhibiting mask at the at least one selected region; and etching the semiconductor material by subjecting the surface of the semiconductor material to a carrier-driven photochemical etching reaction for selectively etching the regions of the semiconductor material adjacent the at least one selected region having the increase impurity concentration; wherein the step of introducing at least one impurity is performed so as not to produce damage to the at least one selected region before any etching is performed

  3. Wet etch methods for InAs nanowire patterning and self-aligned electrical contacts

    Science.gov (United States)

    Fülöp, G.; d'Hollosy, S.; Hofstetter, L.; Baumgartner, A.; Nygård, J.; Schönenberger, C.; Csonka, S.

    2016-05-01

    Advanced synthesis of semiconductor nanowires (NWs) enables their application in diverse fields, notably in chemical and electrical sensing, photovoltaics, or quantum electronic devices. In particular, indium arsenide (InAs) NWs are an ideal platform for quantum devices, e.g. they may host topological Majorana states. While the synthesis has been continously perfected, only a few techniques have been developed to tailor individual NWs after growth. Here we present three wet chemical etch methods for the post-growth morphological engineering of InAs NWs on the sub-100 nm scale. The first two methods allow the formation of self-aligned electrical contacts to etched NWs, while the third method results in conical shaped NW profiles ideal for creating smooth electrical potential gradients and shallow barriers. Low temperature experiments show that NWs with etched segments have stable transport characteristics and can serve as building blocks of quantum electronic devices. As an example we report the formation of a single electrically stable quantum dot between two etched NW segments.

  4. SEMICONDUCTOR TECHNOLOGY: Wet etching characteristics of a HfSiON high-k dielectric in HF-based solutions

    Science.gov (United States)

    Yongliang, Li; Qiuxia, Xu

    2010-03-01

    The wet etching properties of a HfSiON high-k dielectric in HF-based solutions are investigated. HF-based solutions are the most promising wet chemistries for the removal of HfSiON, and etch selectivity of HF-based solutions can be improved by the addition of an acid and/or an alcohol to the HF solution. Due to densification during annealing, the etch rate of HfSiON annealed at 900 °C for 30 s is significantly reduced compared with as-deposited HfSiON in HF-based solutions. After the HfSiON film has been completely removed by HF-based solutions, it is not possible to etch the interfacial layer and the etched surface does not have a hydrophobic nature, since N diffuses to the interface layer or Si substrate formation of Si-N bonds that dissolves very slowly in HF-based solutions. Existing Si-N bonds at the interface between the new high-k dielectric deposit and the Si substrate may degrade the carrier mobility due to Coulomb scattering. In addition, we show that N2 plasma treatment before wet etching is not very effective in increasing the wet etch rate for a thin HfSiON film in our case.

  5. Wet etching characteristics of a HfSiON high-k dielectric in HF-based solutions

    International Nuclear Information System (INIS)

    Li Yongliang; Xu Qiuxia

    2010-01-01

    The wet etching properties of a HfSiON high-k dielectric in HF-based solutions are investigated. HF-based solutions are the most promising wet chemistries for the removal of HfSiON, and etch selectivity of HF-based solutions can be improved by the addition of an acid and/or an alcohol to the HF solution. Due to densification during annealing, the etch rate of HfSiON annealed at 900 0 C for 30 s is significantly reduced compared with as-deposited HfSiON in HF-based solutions. After the HfSiON film has been completely removed by HF-based solutions, it is not possible to etch the interfacial layer and the etched surface does not have a hydrophobic nature, since N diffuses to the interface layer or Si substrate formation of Si-N bonds that dissolves very slowly in HF-based solutions. Existing Si-N bonds at the interface between the new high-k dielectric deposit and the Si substrate may degrade the carrier mobility due to Coulomb scattering. In addition, we show that N 2 plasma treatment before wet etching is not very effective in increasing the wet etch rate for a thin HfSiON film in our case. (semiconductor technology)

  6. Composite shear bond strength to dry and wet enamel with three self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Shafiee F

    2006-01-01

    Full Text Available Background and Aim: The bonding mechanisms of self etching primers, based upon the simultaneous etching and priming of dentin, simplifies the bonding technique, but the efficiency of these systems is still controversial. This study compared the shear bond strength of three self etch adhesive systems in dry and wet conditions. Materials and Method: In this experimental study, 77 intact bovine lower incisors with flat 600 grit sanded enamel surface were fixed in acrylic molds and divided into 7 groups, of 11 teeth. The enamel surfaces were treated according to a special procedure as follows: Group 1: Prompt L-Pop (PLP in dry condition, Group 2: Prompt L-Pop in wet condition, Group 3: Clearfield SE Bond (CSEB in dry condition, Group 4: Clearfield SE Bond in wet condition, Group 5: iBond (iB in dry condition, Group 6: iBond in wet condition, Group 7: Margin Bond (Control in dry condition. Surfaces were air dried for ten seconds, or blot dried in wet condition. Composite resin was bonded on the enamel and built up by applying a cylindric teflon split mold (4 mm height 2mm diameter. After 24 hours storage in dionized water at room temperature, all specimens were thermocycled and shear bond test was employed by a universal testing machine (Instron with a cross-head speed of 1mm/min. The shear bond strength was recorded in MPa and data were analyzed with ANOVA and Scheffe statistical tests. P<0.05 was considered as statistically significant. The mode of failure was examined under a stereomicroscope. Results: 1- Shear bond strength of CSEB in dry condition (21.5 ± 4.8 MPa was significantly higher than PLP and iB groups (p<0.0001. 2- Shear bond strength of iB and PLP groups in dry condition (9.60 ± 2.2, 9.49 ± 3 MPa were significantly lower than CSEB and control (2.99 ± 5.1 MPa (P<0.0001. 3- There was no significant difference between PLP and iB groups in dry condition (P=1. 4- Shear bond strength of CSEB in wet condition (21.8 ± 3 MPa was

  7. Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

    Directory of Open Access Journals (Sweden)

    Chien-Wei Liu

    2012-01-01

    Full Text Available Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells.

  8. Micropore x-ray optics using anisotropic wet etching of (110) silicon wafers.

    Science.gov (United States)

    Ezoe, Yuichiro; Koshiishi, Masaki; Mita, Makoto; Mitsuda, Kazuhisa; Hoshino, Akio; Ishisaki, Yoshitaka; Yang, Zhen; Takano, Takayuki; Maeda, Ryutaro

    2006-12-10

    To develop x-ray mirrors for micropore optics, smooth silicon (111) sidewalls obtained after anisotropic wet etching of a silicon (110) wafer were studied. A sample device with 19 microm wide (111) sidewalls was fabricated using a 220 microm thick silicon (110) wafer and potassium hydroxide solution. For what we believe to be the first time, x-ray reflection on the (111) sidewalls was detected in the angular response measurement. Compared to ray-tracing simulations, the surface roughness of the sidewalls was estimated to be 3-5 nm, which is consistent with the atomic force microscope and the surface profiler measurements.

  9. Light-trapping optimization in wet-etched silicon photonic crystal solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Eyderman, Sergey, E-mail: sergey.eyderman@utoronto.ca [Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7 (Canada); John, Sajeev [Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7 (Canada); Department of Physics, King Abdul-Aziz University, Jeddah (Saudi Arabia); Hafez, M.; Al-Ameer, S. S.; Al-Harby, T. S.; Al-Hadeethi, Y. [Department of Physics, King Abdul-Aziz University, Jeddah (Saudi Arabia); Bouwes, D. M. [iX-factory GmbH, Konrad Adenauer–Allee 11, 44263 Dortmund (Germany)

    2015-07-14

    We demonstrate, by numerical solution of Maxwell's equations, near-perfect solar light-trapping and absorption over the 300–1100 nm wavelength band in silicon photonic crystal (PhC) architectures, amenable to fabrication by wet-etching and requiring less than 10 μm (equivalent bulk thickness) of crystalline silicon. These PhC's consist of square lattices of inverted pyramids with sides comprised of various (111) silicon facets and pyramid center-to-center spacing in the range of 1.3–2.5 μm. For a wet-etched slab with overall height H = 10 μm and lattice constant a = 2.5 μm, we find a maximum achievable photo-current density (MAPD) of 42.5 mA/cm{sup 2}, falling not far from 43.5 mA/cm{sup 2}, corresponding to 100% solar absorption in the range of 300–1100 nm. We also demonstrate a MAPD of 37.8 mA/cm{sup 2} for a thinner silicon PhC slab of overall height H = 5 μm and lattice constant a = 1.9 μm. When H is further reduced to 3 μm, the optimal lattice constant for inverted pyramids reduces to a = 1.3 μm and provides the MAPD of 35.5 mA/cm{sup 2}. These wet-etched structures require more than double the volume of silicon, in comparison to the overall mathematically optimum PhC structure (consisting of slanted conical pores), to achieve the same degree of solar absorption. It is suggested these 3–10 μm thick structures are valuable alternatives to currently utilized 300 μm-thick textured solar cells and are suitable for large-scale fabrication by wet-etching.

  10. Micropore x-ray optics using anisotropic wet etching of (110) silicon wafers

    International Nuclear Information System (INIS)

    Ezoe, Yuichiro; Koshiishi, Masaki; Mita, Makoto; Mitsuda, Kazuhisa; Hoshino, Akio; Ishisaki, Yoshitaka; Yang Zhen; Takano, Takayuki; Maeda, Ryutaro

    2006-01-01

    To develop x-ray mirrors for micropore optics, smooth silicon (111)sidewalls obtained after anisotropic wet etching of a silicon (110) wafer were studied. A sample device with 19 μm wide (111) sidewalls was fabricated using a 220 μm thick silicon (110) wafer and potassium hydroxide solution. For what we believe to be the first time,x-ray reflection on the (111) sidewalls was detected in the angular response measurement. Compared to ray-tracing simulations, the surface roughness of the sidewalls was estimated to be 3-5 nm, which is consistent with the atomic force microscope and the surface profiler measurements

  11. Prevention of sidewall redeposition of etched byproducts in the dry Au etch process

    International Nuclear Information System (INIS)

    Aydemir, A; Akin, T

    2012-01-01

    In this paper we present a new technique of etching thin Au film in a dual frequency inductively coupled plasma (ICP) system on Si substrate to prevent the redeposition of etched Au particles over the sidewall of the masking material known as veils. First, the effect of the lithography step was investigated. Then the effects of etch chemistry and the process parameters on the redeposition of etched Au particles on the sidewall of the masking material were investigated. The redeposition effect was examined by depositing a thin Ti film over the masking material acting as a hard mask. The results showed that depositing a thin Ti film over the masking material prevents the formation of veils after etching Au in plasma environments for submicron size structures. Based on the results of this study, we propose a new technique that completely eliminates formation of veils after etching Au in plasma environments for submicron size structures. (paper)

  12. Surface changes of biopolymers PHB and PLLA induced by Ar+ plasma treatment and wet etching

    Science.gov (United States)

    Slepičková Kasálková, N.; Slepička, P.; Sajdl, P.; Švorčík, V.

    2014-08-01

    Polymers, especially group of biopolymers find potential application in a wide range of disciplines due to their biodegradability. In biomedical applications these materials can be used as a scaffold or matrix. In this work, the influence of the Ar+ plasma treatment and subsequent wet etching (acetone/water) on the surface properties of polymers were studied. Two biopolymers - polyhydroxybutyrate with 8% polyhydroxyvalerate (PHB) and poly-L-lactic acid (PLLA) were used in these experiments. Modified surface layers were analyzed by different methods. Surface wettability was characterized by determination of water contact angle. Changes in elemental composition of modified surfaces were performed by X-ray Photoelectron Spectroscopy (XPS). Surface morphology and roughness was examined using Atomic Force Microscopy (AFM). Gravimetry method was used to study the mass loss. It was found that the modification from both with plasma and wet etching leads to dramatic changes of surface properties (surface chemistry, morphology and roughness). Rate of changes of these features strongly depends on the modification parameters.

  13. Comparative study of resist stabilization techniques for metal etch processing

    Science.gov (United States)

    Becker, Gerry; Ross, Matthew F.; Wong, Selmer S.; Minter, Jason P.; Marlowe, Trey; Livesay, William R.

    1999-06-01

    This study investigates resist stabilization techniques as they are applied to a metal etch application. The techniques that are compared are conventional deep-UV/thermal stabilization, or UV bake, and electron beam stabilization. The electron beam tool use din this study, an ElectronCure system from AlliedSignal Inc., ELectron Vision Group, utilizes a flood electron source and a non-thermal process. These stabilization techniques are compared with respect to a metal etch process. In this study, two types of resist are considered for stabilization and etch: a g/i-line resist, Shipley SPR-3012, and an advanced i-line, Shipley SPR 955- Cm. For each of these resist the effects of stabilization on resist features are evaluated by post-stabilization SEM analysis. Etch selectivity in all cases is evaluated by using a timed metal etch, and measuring resists remaining relative to total metal thickness etched. Etch selectivity is presented as a function of stabilization condition. Analyses of the effects of the type of stabilization on this method of selectivity measurement are also presented. SEM analysis was also performed on the features after a compete etch process, and is detailed as a function of stabilization condition. Post-etch cleaning is also an important factor impacted by pre-etch resist stabilization. Results of post- etch cleaning are presented for both stabilization methods. SEM inspection is also detailed for the metal features after resist removal processing.

  14. Analysis of InP-based single photon avalanche diodes based on a single recess-etching process

    Science.gov (United States)

    Lee, Kiwon

    2018-04-01

    Effects of the different etching techniques have been investigated by analyzing electrical and optical characteristics of two-types of single-diffused single photon avalanche diodes (SPADs). The fabricated two-types of SPADs have no diffusion depth variation by using a single diffusion process at the same time. The dry-etched SPADs show higher temperature dependence of a breakdown voltage, larger dark-count-rate (DCR), and lower photon-detection-efficiency (PDE) than those of the wet-etched SPADs due to plasma-induced damage of dry-etching process. The results show that the dry etching damages can more significantly affect the performance of the SPADs based on a single recess-etching process.

  15. Nickel silicide thin films as masking and structural layers for silicon bulk micro-machining by potassium hydroxide wet etching

    International Nuclear Information System (INIS)

    Bhaskaran, M; Sriram, S; Sim, L W

    2008-01-01

    This paper studies the feasibility of using titanium and nickel silicide thin films as mask materials for silicon bulk micro-machining. Thin films of nickel silicide were found to be more resistant to wet etching in potassium hydroxide. The use of nickel silicide as a structural material, by fabricating micro-beams of varying dimensions, is demonstrated. The micro-structures were realized using these thin films with wet etching using potassium hydroxide solution on (1 0 0) and (1 1 0) silicon substrates. These results show that nickel silicide is a suitable alternative to silicon nitride for silicon bulk micro-machining

  16. Growing Embossed Nanostructures of Polymer Brushes on Wet-Etched Silicon Templated via Block Copolymers

    Science.gov (United States)

    Lu, Xiaobin; Yan, Qin; Ma, Yinzhou; Guo, Xin; Xiao, Shou-Jun

    2016-02-01

    Block copolymer nanolithography has attracted enormous interest in chip technologies, such as integrated silicon chips and biochips, due to its large-scale and mass production of uniform patterns. We further modified this technology to grow embossed nanodots, nanorods, and nanofingerprints of polymer brushes on silicon from their corresponding wet-etched nanostructures covered with pendent SiHx (X = 1-3) species. Atomic force microscopy (AFM) was used to image the topomorphologies, and multiple transmission-reflection infrared spectroscopy (MTR-IR) was used to monitor the surface molecular films in each step for the sequential stepwise reactions. In addition, two layers of polymethacrylic acid (PMAA) brush nanodots were observed, which were attributed to the circumferential convergence growth and the diffusion-limited growth of the polymer brushes. The pH response of PMAA nanodots in the same region was investigated by AFM from pH 3.0 to 9.0.

  17. Fabrication of 3D electro-thermal micro actuators in silica glass by femtosecond laser wet etch and microsolidics

    Science.gov (United States)

    Li, Qichao; Shan, Chao; Yang, Qing; Chen, Feng; Bian, Hao; Hou, Xun

    2017-02-01

    This paper demonstrates a novel electro-thermal micro actuator's design, fabrication and device tests which combine microfluidic technology and microsolidics process. A three-dimensional solenoid microchannel with high aspect ratio is fabricated inside the silica glass by an improved femtosecond laser wet etch (FLWE) technology, and the diameter of the spiral coil is only 200 μm. Molten alloy (Bi/In/Sn/Pb) with high melting point is injected into the three-dimensional solenoid microchannel inside the silica glass , then it solidifys and forms an electro-thermal micro actuator. The device is capable of achieving precise temperature control and quick response, and can also be easily integrated into MEMS, sensors and `lab on a chip' (LOC) platform inside the fused silica substrate.

  18. The Investigation of Intermediate Stage of Template Etching with Metal Droplets by Wetting Angle Analysis on (001 GaAs Surface

    Directory of Open Access Journals (Sweden)

    Lyamkina AA

    2011-01-01

    Full Text Available Abstract In this work, we study metal droplets on a semiconductor surface that are the initial stage for both droplet epitaxy and local droplet etching. The distributions of droplet geometrical parameters such as height, radius and volume help to understand the droplet formation that strongly influences subsequent nanohole etching. To investigate the etching and intermixing processes, we offer a new method of wetting angle analysis. The aspect ratio that is defined as the ratio of the height to radius was used as an estimation of wetting angle which depends on the droplet material. The investigation of the wetting angle and the estimation of indium content revealed significant materials intermixing during the deposition time. AFM measurements reveal the presence of two droplet groups that is in agreement with nanohole investigations. To explain this observation, we consider arsenic evaporation and consequent change in the initial substrate. On the basis of our analysis, we suggest the model of droplet evolution and the formation of two droplet groups.

  19. Interface and transport properties of metallization contacts to flat and wet-etching roughed N-polar n-type GaN.

    Science.gov (United States)

    Wang, Liancheng; Liu, Zhiqiang; Guo, Enqing; Yang, Hua; Yi, Xiaoyan; Wang, Guohong

    2013-06-26

    The electrical characteristics of metallization contacts to flat (F-sample, without wet-etching roughed) and wet-etching roughed (R-sample) N-polar (Nitrogen-polar) n-GaN have been investigated. R-sample shows higher contact resistance (Rc) to Al/Ti/Au (~2.5 × 10(-5) Ω·cm(2)) and higher Schottky barriers height (SBH, ~0.386 eV) to Ni/Au, compared with that of F-sample (~1.3 × 10(-6) Ω·cm(2), ~0.154 eV). Reasons accounting for this discrepancy has been detail investigated and discussed: for R-sample, wet-etching process caused surface state and spontaneous polarization variation will degraded its electrical characteristics. Metal on R-sample shows smoother morphology, however, the effect of metal deposition state on electrical characteristics is negligible. Metallization contact area for both samples has also been further considered. Electrical characteristics of metallization contact to both samples show degradation upon annealing. The VLED chip (1 mm × 1 mm), which was fabricated on the basis of a hybrid scheme, coupling the advantage of F- and R-sample, shows the lowest forward voltage (2.75 V@350 mA) and the highest light output power.

  20. In-situ photoluminescence imaging for passivation-layer etching process control for photovoltaics

    Science.gov (United States)

    Lee, J. Z.; Michaelson, L.; Munoz, K.; Tyson, T.; Gallegos, A.; Sullivan, J. T.; Buonassisi, T.

    2014-07-01

    Light-induced plating (LIP) of solar-cell metal contacts is a scalable alternative to silver paste. However, LIP requires an additional patterning step to create openings in the silicon nitride (SiNx) antireflection coating (ARC) layer prior to metallization. One approach to pattern the SiNx is masking and wet chemical etching. In-situ real-time photoluminescence imaging (PLI) is demonstrated as a process-monitoring method to determine when SiNx has been fully removed during etching. We demonstrate that the change in PLI signal intensity during etching is caused by a combination of (1) decreasing light absorption from the reduction in SiNx ARC layer thickness and (2) decreasing surface lifetime as the SiNx/Si interface transitions to an etch-solution/Si. Using in-situ PLI to guide the etching process, we demonstrate a full-area plated single-crystalline silicon device. In-situ PLI has the potential to be integrated into a commercial processing line to improve process control and reliability.

  1. Visible and infrared emission from Si/Ge nanowires synthesized by metal-assisted wet etching.

    Science.gov (United States)

    Irrera, Alessia; Artoni, Pietro; Fioravanti, Valeria; Franzò, Giorgia; Fazio, Barbara; Musumeci, Paolo; Boninelli, Simona; Impellizzeri, Giuliana; Terrasi, Antonio; Priolo, Francesco; Iacona, Fabio

    2014-02-12

    Multi-quantum well Si/Ge nanowires (NWs) were realized by combining molecular beam epitaxy deposition and metal-assisted wet etching, which is a low-cost technique for the synthesis of extremely dense (about 1011 cm-2) arrays of NWs with a high and controllable aspect ratio. In particular, we prepared ultrathin Si/Ge NWs having a mean diameter of about 8 nm and lengths spanning from 1.0 to 2.7 μm. NW diameter is compatible with the occurrence of quantum confinement effects and, accordingly, we observed light emission assignable to the presence of Si and Ge nanostructures. We performed a detailed study of the photoluminescence properties of the NWs, with particular attention to the excitation and de-excitation properties as a function of the temperature and of the excitation photon flux, evaluating the excitation cross section and investigating the presence of non-radiative phenomena. PACS: 61.46.Km; 78.55.-m; 78.67.Lt.

  2. Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures.

    Science.gov (United States)

    Melkonyan, D; Fleischmann, C; Veloso, A; Franquet, A; Bogdanowicz, J; Morris, R J H; Vandervorst, W

    2018-03-01

    We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO 2 we demonstrate how the selective removal of SiO 2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Effects of UV light intensity on electrochemical wet etching of SiC for the fabrication of suspended graphene

    Science.gov (United States)

    O, Ryong-Sok; Takamura, Makoto; Furukawa, Kazuaki; Nagase, Masao; Hibino, Hiroki

    2015-03-01

    We report on the effects of UV light intensity on the photo assisted electrochemical wet etching of SiC(0001) underneath an epitaxially grown graphene for the fabrication of suspended structures. The maximum etching rate of SiC(0001) was 2.5 µm/h under UV light irradiation in 1 wt % KOH at a constant current of 0.5 mA/cm2. The successful formation of suspended structures depended on the etching rate of SiC. In the Raman spectra of the suspended structures, we did not observe a significant increase in the intensity of the D peak, which originates from defects in graphene sheets. This is most likely explained by the high quality of the single-crystalline graphene epitaxially grown on SiC.

  4. Influence of sputtering conditions on the optical and electrical properties of laser-annealed and wet-etched room temperature sputtered ZnO:Al thin films

    Energy Technology Data Exchange (ETDEWEB)

    Boukhicha, Rym, E-mail: rym.boukhicha@polytechnique.edu [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France); Charpentier, Coralie [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France); Total S and M — New Energies Division, R and D Division, Department of Solar Energies EN/BO/RD/SOL, Tour Michelet, 24 cours Michelet, La Défense 10, 92069 Paris La Défense Cedex (France); Prod' Homme, Patricia [Total S and M — New Energies Division, R and D Division, Department of Solar Energies EN/BO/RD/SOL, Tour Michelet, 24 cours Michelet, La Défense 10, 92069 Paris La Défense Cedex (France); Roca i Cabarrocas, Pere [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France); Lerat, Jean-François; Emeraud, Thierry [Photovoltaic Business Unit, Excico Group NV, Kempische Steenweg 305/2, B-3500 Hasselt (Belgium); Johnson, Erik [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France)

    2014-03-31

    We explore the influence of the sputtering deposition conditions on the outcome of an excimer laser anneal and chemical etching process with the goal of producing highly textured substrates for thin film silicon solar cells. Aluminum-doped zinc oxide (ZnO:Al) thin films were prepared on glass substrates by radio frequency magnetron sputtering from a ceramic target at room temperature. The effects of the process pressure (0.11–1.2 Pa) and oxygen flow (0–2 sccm) on the optical and electrical properties of ZnO:Al thin films have been studied both before and after an excimer laser annealing treatment followed by a dilute HCl chemical etch. The as-deposited films varied from completely opaque to yellowish. Thin film laser annealing dramatically improves the optical properties of the most opaque thin films. After laser annealing at the optimum fluence, the average transmittance in the visible wavelength range was around 80% for most films, and reasonable electrical performance was obtained for the films deposited at lower pressures and without oxygen flux (7 Ω/□ for films of 1 μm). After etching, all films displayed a dramatic improvement in haze, but only the low pressure, low oxygen films retained acceptable electrical properties (< 11 Ω/□). - Highlights: • Al:ZnO thin films were deposited at room temperature. • The ZnO:Al films were excimer laser annealed and then wet-etched. • The optical and electrical properties were studied in details.

  5. Imaging and etching, soft x-ray microscopy on whole wet cells

    International Nuclear Information System (INIS)

    Gilbert, J.R.; Pine, J.

    1993-01-01

    The authors have produced images of whole wet tissue culture cells with the Stony Brook/BNL scanning transmission x-ray microscope (STXM). For fixed cells the authors have taken images at theoretical resolutions of ∼50-75nm, and in practice have measured FWHM of features down to near 100nm, without any exotic image processing. For unfixed (i.e., initially live) cells the authors have imaged with 100nm pixels and measured features down to 250nm. In order to do this the authors have developed, tested and used a wet cell for maintaining fixed or live cells on the STXM stage during imaging. The design of the wet cell and the culture substrates that go with it make the STXM compatible with almost all standard systems for surface adherent tissue culture. The authors will show some new images of whole wet fixed and unfixed cells, with visible sub-micron features. The authors will also report data that helps to characterize the tissue damage due to x-ray absorption during STXM imaging

  6. Dry etch challenges for CD shrinkage in memory process

    Science.gov (United States)

    Matsushita, Takaya; Matsumoto, Takanori; Mukai, Hidefumi; Kyoh, Suigen; Hashimoto, Kohji

    2015-03-01

    Line pattern collapse attracts attention as a new problem of the L&S formation in sub-20nm H.P feature. Line pattern collapse that occurs in a slight non-uniformity of adjacent CD (Critical dimension) space using double patterning process has been studied with focus on micro-loading effect in Si etching. Bias RF pulsing plasma etching process using low duty cycle helped increase of selectivity Si to SiO2. In addition to the effect of Bias RF pulsing process, the thin mask obtained from improvement of selectivity has greatly suppressed micro-loading in Si etching. However it was found that micro-loading effect worsen again in sub-20nm space width. It has been confirmed that by using cycle etch process to remove deposition with CFx based etching micro-loading effect could be suppressed. Finally, Si etching process condition using combination of results above could provide finer line and space without "line pattern collapse" in sub-20nm.

  7. Feedback control of chlorine inductively coupled plasma etch processing

    International Nuclear Information System (INIS)

    Lin Chaung; Leou, K.-C.; Shiao, K.-M.

    2005-01-01

    Feedback control has been applied to poly-Si etch processing using a chlorine inductively coupled plasma. Since the positive ion flux and ion energy incident upon the wafer surface are the key factors that influence the etch rate, the ion current and the root mean square (rms) rf voltage on the wafer stage, which are measured using an impedance meter connected to the wafer stage, are adopted as the controlled variables to enhance etch rate. The actuators are two 13.56 MHz rf power generators, which adjust ion density and ion energy, respectively. The results of closed-loop control show that the advantages of feedback control can be achieved. For example, with feedback control, etch rate variation under the transient chamber wall condition is reduced roughly by a factor of 2 as compared to the open-loop case. In addition, the capability of the disturbance rejection was also investigated. For a gas pressure variation of 20%, the largest etch rate variation is about 2.4% with closed-loop control as compared with as large as about 6% variation using open-loop control. Also the effect of ion current and rms rf voltage on etch rate was studied using 2 2 factorial design whose results were used to derive a model equation. The obtained formula was used to adjust the set point of ion current and rf voltage so that the desired etch rate was obtained

  8. Study on morphology of high-aspect-ratio grooves fabricated by using femtosecond laser irradiation and wet etching

    International Nuclear Information System (INIS)

    Chen, Tao; Pan, An; Li, Cunxia; Si, Jinhai; Hou, Xun

    2015-01-01

    Highlights: • We studied morphologies of silicon grooves fabricated by laser irradiation and wet etching. • We found nano-ripple structures formed on the groove sidewall. • Formations of nano-ripples were due to the formation of standing wave and nanoplanes. • Remaining debris on the groove bottom was removed by KOH etching. - Abstract: Morphologies of high-aspect-ratio silicon grooves fabricated by using femtosecond laser irradiation and selective chemical etching of hydrofluoric acid (HF) were studied. Oxygen was deeply doped into silicon under femtosecond laser irradiation in air, and then the oxygen-doped regions were removed by HF etching to form high-aspect-ratio grooves. After HF etching, periodic nano-ripples which were induced in silicon by femtosecond laser were observed on the groove sidewalls. The ripple orientation was perpendicular or parallel to the laser propagation direction (z direction), which depended on the relative direction between the laser polarization direction and the scanning direction. The formation of nano-ripples with orientations perpendicular to z direction could be attributed to the standing wave generated by the interference of the incident light and the reflected light in z direction. The formation of nano-ripples with orientations parallel to z direction could be attributed to the formation of self-organized periodic nanoplanes (bulk nanogratings) induced by femtosecond laser inside silicon. Materials in the tail portion of laser-induced oxygen doping (LIOD) regions were difficult to be etched by HF solution due to low oxygen concentration. The specimen was etched further in KOH solution to remove remaining materials in LIOD regions and all-silicon grooves were fabricated

  9. Pulsed high-density plasmas for advanced dry etching processes

    International Nuclear Information System (INIS)

    Banna, Samer; Agarwal, Ankur; Cunge, Gilles; Darnon, Maxime; Pargon, Erwine; Joubert, Olivier

    2012-01-01

    Plasma etching processes at the 22 nm technology node and below will have to satisfy multiple stringent scaling requirements of microelectronics fabrication. To satisfy these requirements simultaneously, significant improvements in controlling key plasma parameters are essential. Pulsed plasmas exhibit considerable potential to meet the majority of the scaling challenges, while leveraging the broad expertise developed over the years in conventional continuous wave plasma processing. Comprehending the underlying physics and etching mechanisms in pulsed plasma operation is, however, a complex undertaking; hence the full potential of this strategy has not yet been realized. In this review paper, we first address the general potential of pulsed plasmas for plasma etching processes followed by the dynamics of pulsed plasmas in conventional high-density plasma reactors. The authors reviewed more than 30 years of academic research on pulsed plasmas for microelectronics processing, primarily for silicon and conductor etch applications, highlighting the potential benefits to date and challenges in extending the technology for mass-production. Schemes such as source pulsing, bias pulsing, synchronous pulsing, and others in conventional high-density plasma reactors used in the semiconductor industry have demonstrated greater flexibility in controlling critical plasma parameters such as ion and radical densities, ion energies, and electron temperature. Specifically, plasma pulsing allows for independent control of ion flux and neutral radicals flux to the wafer, which is key to eliminating several feature profile distortions at the nanometer scale. However, such flexibility might also introduce some difficulty in developing new etching processes based on pulsed plasmas. Therefore, the main characteristics of continuous wave plasmas and different pulsing schemes are compared to provide guidelines for implementing different schemes in advanced plasma etching processes based on

  10. Single step sequential polydimethylsiloxane wet etching to fabricate a microfluidic channel with various cross-sectional geometries

    Science.gov (United States)

    Wang, C.-K.; Liao, W.-H.; Wu, H.-M.; Lo, Y.-H.; Lin, T.-R.; Tung, Y.-C.

    2017-11-01

    Polydimethylsiloxane (PDMS) has become a widely used material to construct microfluidic devices for various biomedical and chemical applications due to its desirable material properties and manufacturability. PDMS microfluidic devices are usually fabricated using soft lithography replica molding methods with master molds made of photolithogrpahy patterned photoresist layers on silicon wafers. The fabricated microfluidic channels often have rectangular cross-sectional geometries with single or multiple heights. In this paper, we develop a single step sequential PDMS wet etching process that can be used to fabricate microfluidic channels with various cross-sectional geometries from single-layer PDMS microfluidic channels. The cross-sections of the fabricated channel can be non-rectangular, and varied along the flow direction. Furthermore, the fabricated cross-sectional geometries can be numerically simulated beforehand. In the experiments, we fabricate microfluidic channels with various cross-sectional geometries using the developed technique. In addition, we fabricate a microfluidic mixer with alternative mirrored cross-sectional geometries along the flow direction to demonstrate the practical usage of the developed technique.

  11. 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.

  12. Glass frit bonding with controlled width and height using a two-step wet silicon etching procedure

    Science.gov (United States)

    Yifang, Liu; Daner, Chen; Liwei, Lin; Gaofeng, Zheng; Jianyi, Zheng; Lingyun, Wang; Daoheng, Sun

    2016-03-01

    A simple and versatile two-step silicon wet etching technique for the control of the width and height of the glass frit bonding layer has been developed to improve bonding strength and reliability in wafer-level microelectromechanical systems (MEMS) packaging processes. The height of the glass frit bonding layer is set by the design of a vertical reference wall which regulates the distance between the silicon wafer and the encapsulation capping substrate. On the other hand, the width of the bonding layer is constrained between two micro grooves which are used to accommodate the spillages of extra glass frit during the bonding process. An optimized thermal bonding process, including the formation of glass liquid, removal of gas bubbles under vacuum and the filling of voids under normal atmospheric condition has been developed to suppress the formation of the bubbles/voids. The stencil printing and pre-sintering processes for the glass frit have been characterized before the thermal bonding process under different magnitudes of bonding pressure. The bonding gap thickness is found to be equal to the height of the reference wall of 10 μm in the prototype design. The bubbles/voids are found to be suppressed effectively and the bonding strength increases from 10.2 to 19.1 MPa as compared with a conventional thermal annealing process in air. Experimentally, prototype samples are measured to have passed the high hermetic sealing leakage tests of 5  ×  10-8 atm cc s-1.

  13. Dry Phosphorus silicate glass etching and surface conditioning and cleaning for multi-crystalline silicon solar cell processing

    International Nuclear Information System (INIS)

    Kagilik, Ahmed S.

    2014-01-01

    As an alternative to the wet chemical etching method, dry chemical etching processes for Phosphorus silicate glass [PSG} layer removal using Trifluormethane/Sulfur Hexafluoride (CHF 3 / SF 6 ) gas mixture in commercial silicon-nitride plasma enhanced chemical vapour deposition (SiN-PECVD) system is applied. The dependence of the solar cell performance on the etching temperature is investigated and optimized. It is found that the SiN-PECVD system temperature variation has a significant impact on the whole solar cell characteristics. A dry plasma cleaning treatment of the Si wafer surface after the PSG removal step is also investigated and developed. The cleaning step is used to remove the polymer film which is formed during the PSG etching using both oxygen and hydrogen gases. By applying an additional cleaning step, the polymer film deposited on the silicon wafer surface after PSG etching is eliminated. The effect of different plasma cleaning conditions on solar cell performance is investigated. After optimization of the plasma operating conditions, the performance of the solar cell is improved and the overall gain in efficiency of 0.6% absolute is yielded compared to a cell without any further cleaning step. On the other hand, the best solar cell characteristics can reach values close to that achieved by the conventional wet chemical etching processes demonstrating the effectiveness of the additional O 2 /H 2 post cleaning treatment.(author)

  14. Advanced Simulation Technology to Design Etching Process on CMOS Devices

    Science.gov (United States)

    Kuboi, Nobuyuki

    2015-09-01

    Prediction and control of plasma-induced damage is needed to mass-produce high performance CMOS devices. In particular, side-wall (SW) etching with low damage is a key process for the next generation of MOSFETs and FinFETs. To predict and control the damage, we have developed a SiN etching simulation technique for CHxFy/Ar/O2 plasma processes using a three-dimensional (3D) voxel model. This model includes new concepts for the gas transportation in the pattern, detailed surface reactions on the SiN reactive layer divided into several thin slabs and C-F polymer layer dependent on the H/N ratio, and use of ``smart voxels''. We successfully predicted the etching properties such as the etch rate, polymer layer thickness, and selectivity for Si, SiO2, and SiN films along with process variations and demonstrated the 3D damage distribution time-dependently during SW etching on MOSFETs and FinFETs. We confirmed that a large amount of Si damage was caused in the source/drain region with the passage of time in spite of the existing SiO2 layer of 15 nm in the over etch step and the Si fin having been directly damaged by a large amount of high energy H during the removal step of the parasitic fin spacer leading to Si fin damage to a depth of 14 to 18 nm. By analyzing the results of these simulations and our previous simulations, we found that it is important to carefully control the dose of high energy H, incident energy of H, polymer layer thickness, and over-etch time considering the effects of the pattern structure, chamber-wall condition, and wafer open area ratio. In collaboration with Masanaga Fukasawa and Tetsuya Tatsumi, Sony Corporation. We thank Mr. T. Shigetoshi and Mr. T. Kinoshita of Sony Corporation for their assistance with the experiments.

  15. Evaluation of the soft x-ray reflectivity of micropore optics using anisotropic wet etching of silicon wafers.

    Science.gov (United States)

    Mitsuishi, Ikuyuki; Ezoe, Yuichiro; Koshiishi, Masaki; Mita, Makoto; Maeda, Yoshitomo; Yamasaki, Noriko Y; Mitsuda, Kazuhisa; Shirata, Takayuki; Hayashi, Takayuki; Takano, Takayuki; Maeda, Ryutaro

    2010-02-20

    The x-ray reflectivity of an ultralightweight and low-cost x-ray optic using anisotropic wet etching of Si (110) wafers is evaluated at two energies, C K(alpha)0.28 keV and Al K(alpha)1.49 keV. The obtained reflectivities at both energies are not represented by a simple planar mirror model considering surface roughness. Hence, an geometrical occultation effect due to step structures upon the etched mirror surface is taken into account. Then, the reflectivities are represented by the theoretical model. The estimated surface roughness at C K(alpha) (approximately 6 nm rms) is significantly larger than approximately 1 nm at Al K(alpha). This can be explained by different coherent lengths at two energies.

  16. Evaluation of the soft x-ray reflectivity of micropore optics using anisotropic wet etching of silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Mitsuishi, Ikuyuki; Ezoe, Yuichiro; Koshiishi, Masaki; Mita, Makoto; Maeda, Yoshitomo; Yamasaki, Noriko Y.; Mitsuda, Kazuhisa; Shirata, Takayuki; Hayashi, Takayuki; Takano, Takayuki; Maeda, Ryutaro

    2010-02-20

    The x-ray reflectivity of an ultralightweight and low-cost x-ray optic using anisotropic wet etching of Si (110) wafers is evaluated at two energies, C K{alpha}0.28 keV and Al K{alpha}1.49 keV. The obtained reflectivities at both energies are not represented by a simple planar mirror model considering surface roughness. Hence, an geometrical occultation effect due to step structures upon the etched mirror surface is taken into account. Then, the reflectivities are represented by the theoretical model. The estimated surface roughness at C K{alpha} ({approx}6 nm rms) is significantly larger than {approx}1 nm at Al K{alpha}. This can be explained by different coherent lengths at two energies.

  17. Improved PECVD Si x N y film as a mask layer for deep wet etching of the silicon

    Science.gov (United States)

    Han, Jianqiang; Yin, Yi Jun; Han, Dong; Dong, LiZhen

    2017-09-01

    Although plasma enhanced chemical vapor deposition (PECVD) silicon nitride (Si x N y ) films have been extensively investigated by many researchers, requirements of film properties vary from device to device. For some applications utilizing Si x N y film as the mask Layer for deep wet etching of the silicon, it is very desirable to obtain a high quality film. In this study, Si x N y films were deposited on silicon substrates by PECVD technique from the mixtures of NH3 and 5% SiH4 diluted in Ar. The deposition temperature and RF power were fixed at 400 °C and 20 W, respectively. By adjusting the SiH4/NH3 flow ratio, Si x N y films of different compositions were deposited on silicon wafers. The stoichiometry, residual stress, etch rate in 1:50 HF, BHF solution and 40% KOH solution of deposited Si x N y films were measured. The experimental results show that the optimum SiH4/NH3 flow ratio at which deposited Si x N y films can perfectly protect the polysilicon resistors on the front side of wafers during KOH etching is between 1.63 and 2.24 under the given temperature and RF power. Polysilicon resistors protected by the Si x N y films can withstand 6 h 40% KOH double-side etching at 80 °C. At the range of SiH4/NH3 flow ratios, the Si/N atom ratio of films ranges from 0.645 to 0.702, which slightly deviate the ideal stoichiometric ratio of LPCVD Si3N4 film. In addition, the silicon nitride films with the best protection effect are not the films of minimum etch rate in KOH solution.

  18. Enhancement of terahertz radiation in a Smith-Purcell backward-wave oscillator by an inverse wet-etched grating

    International Nuclear Information System (INIS)

    Kim, Jung-Il; Jeon, Seok-Gy; Kim, Geun-Ju; Kim, Jaehong

    2011-01-01

    A terahertz (THz) Smith-Purcell (SP) backward-wave oscillator with an inverse wet-etched grating based on silicon has been proposed to enhance radiation intensity. This grating strengthens the interactions between an electron beam and the evanescent wave due to the adjacent surface structure between gratings that improves the magnitude of the electric field up to 1.7 times compared to the conventional rectangular gratings. A two-dimensional particle-in-cell (PIC) simulation shows that the radiated power is increased up to 2.3 times higher at the radiated frequency of 0.66 THz for an electron-beam energy of 30 keV.

  19. Antireflective surface structures in glass by self-assembly of SiO2 nanoparticles and wet etching.

    Science.gov (United States)

    Maier, Thomas; Bach, David; Müllner, Paul; Hainberger, Rainer; Brückl, Hubert

    2013-08-26

    We describe the fabrication of an antireflective surface structure with sub-wavelength dimensions on a glass surface using scalable low-cost techniques involving sol-gel coating, thermal annealing, and wet chemical etching. The glass surface structure consists of sand dune like protrusions with 250 nm periodicity and a maximum peak-to-valley height of 120 nm. The antireflective structure increases the transmission of the glass up to 0.9% at 700 nm, and the transmission remains enhanced over a wide spectral range and for a wide range of incident angles. Our measurements reveal a strong polarization dependence of the transmission change.

  20. A plasmaless, photochemical etch process for porous organosilicate glass films

    Science.gov (United States)

    Ryan, E. Todd; Molis, Steven E.

    2017-12-01

    A plasmaless, photochemical etch process using ultraviolet (UV) light in the presence of NH3 or O2 etched porous organosilicate glass films, also called pSiCOH films, in a two-step process. First, a UV/NH3 or UV/O2 treatment removed carbon (mostly methyl groups bonded to silicon) from a pSiCOH film by demethylation to a depth determined by the treatment exposure time. Second, aqueous HF was used to selectively remove the demethylated layer of the pSiCOH film leaving the methylated layer below. UV in the presence of inert gas or H2 did not demethylate the pSiCOH film. The depth of UV/NH3 demethylation followed diffusion limited kinetics and possible mechanisms of demethylation are presented. Unlike reactive plasma processes, which contain ions that can damage surrounding structures during nanofabrication, the photochemical etch contains no damaging ions. Feasibility of the photochemical etching was shown by comparing it to a plasma-based process to remove the pSiCOH dielectric from between Cu interconnect lines, which is a critical step during air gap fabrication. The findings also expand our understanding of UV photon interactions in pSiCOH films that may contribute to plasma-induced damage to pSiCOH films.

  1. Improved Ohmic-contact to AlGaN/GaN using Ohmic region recesses by self-terminating thermal oxidation assisted wet etching technique

    Science.gov (United States)

    Liu, J.; Wang, J.; Wang, H.; Zhu, L.; Wu, W.

    2017-06-01

    Lower Ti/Al/Ni/Au Ohmic contact resistance on AlGaN/GaN with wider rapid thermal annealing (RTA) temperature window was achieved using recessed Ohmic contact structure based on self-terminating thermal oxidation assisted wet etching technique (STOAWET), in comparison with conventional Ohmic contacts. Even at lower temperature such as 650°C, recessed structure by STOAWET could still obtain Ohmic contact with contact resistance of 1.97Ω·mm, while conventional Ohmic structure mainly featured as Schottky contact. Actually, both Ohmic contact recess and mesa isolation processes could be accomplished by STOAWET in one process step and the process window of STOAWET is wide, simplifying AlGaN/GaN HEMT device process. Our experiment shows that the isolation leakage current by STOAWET is about one order of magnitude lower than that by inductivity coupled plasma (ICP) performed on the same wafer.

  2. Surface changes of biopolymers PHB and PLLA induced by Ar{sup +} plasma treatment and wet etching

    Energy Technology Data Exchange (ETDEWEB)

    Slepičková Kasálková, N. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic); Slepička, P., E-mail: petr.slepicka@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic); Sajdl, P. [Department of Power Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic); Švorčík, V. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2014-08-01

    Polymers, especially group of biopolymers find potential application in a wide range of disciplines due to their biodegradability. In biomedical applications these materials can be used as a scaffold or matrix. In this work, the influence of the Ar{sup +} plasma treatment and subsequent wet etching (acetone/water) on the surface properties of polymers were studied. Two biopolymers – polyhydroxybutyrate with 8% polyhydroxyvalerate (PHB) and poly-L-lactic acid (PLLA) were used in these experiments. Modified surface layers were analyzed by different methods. Surface wettability was characterized by determination of water contact angle. Changes in elemental composition of modified surfaces were performed by X-ray Photoelectron Spectroscopy (XPS). Surface morphology and roughness was examined using Atomic Force Microscopy (AFM). Gravimetry method was used to study the mass loss. It was found that the modification from both with plasma and wet etching leads to dramatic changes of surface properties (surface chemistry, morphology and roughness). Rate of changes of these features strongly depends on the modification parameters.

  3. Process margin enhancement for 0.25-μm metal etch process

    Science.gov (United States)

    Lee, Chung Y.; Ma, Wei Wen; Lim, Eng H.; Cheng, Alex T.; Joy, Raymond; Ross, Matthew F.; Wong, Selmer S.; Marlowe, Trey

    2000-06-01

    This study evaluates electron beam stabilization of UV6, a positive tone Deep-UV (DUV) resist from Shipley, for a 0.25 micrometer metal etch application. Results are compared between untreated resist and resist treated with different levels of electron beam stabilization. The electron beam processing was carried out in an ElectronCureTM flood electron beam exposure system from Honeywell International Inc., Electron Vision. The ElectronCureTM system utilizes a flood electron beam source which is larger in diameter than the substrate being processed, and is capable of variable energy so that the electron range is matched to the resist film thickness. Changes in the UV6 resist material as a result of the electron beam stabilization are monitored via spectroscopic ellipsometry for film thickness and index of refraction changes and FTIR for analysis of chemical changes. Thermal flow stability is evaluated by applying hot plate bakes of 150 degrees Celsius and 200 degrees Celsius, to patterned resist wafers with no treatment and with an electron beam dose level of 2000 (mu) C/cm2. A significant improvement in the thermal flow stability of the patterned UV6 resist features is achieved with the electron beam stabilization process. Etch process performance of the UV6 resist was evaluated by performing a metal pattern transfer process on wafers with untreated resist and comparing these with etch results on wafers with different levels of electron beam stabilization. The etch processing was carried out in an Applied Materials reactor with an etch chemistry including BCl3 and Cl2. All wafers were etched under the same conditions and the resist was treated after etch to prevent further erosion after etch but before SEM analysis. Post metal etch SEM cross-sections show the enhancement in etch resistance provided by the electron beam stabilization process. Enhanced process margin is achieved as a result of the improved etch resistance, and is observed in reduced resist side

  4. Uranium recovery from wet process phosphoric acid

    International Nuclear Information System (INIS)

    1980-01-01

    In the field of metallurgy, specifically processes for recovering uranium from wet process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores, problems of imbalance of ion exchange agents, contamination of recycled phosphoric acid with process organics and oxidizing agents, and loss and contamination of uranium product, are solved by removing organics from the raffinate after ion exchange conversion of uranium to uranous form and recovery thereof by ion exchange, and returning organics to the circuit to balance mono and disubstituted ester ion exchange agents; then oxidatively stripping uranium from the agent using hydrogen peroxide; then after ion exchange recovery of uranyl and scrubbing, stripping with sodium carbonate and acidifying the strip solution and using some of it for the scrubbing; regenerating the sodium loaded agent and recycling it to the uranous recovery step. Economic recovery of uranium as a by-product of phosphate fertilizer production is effected. (author)

  5. Formation of hydrogen-related traps in electron-irradiated n-type silicon by wet chemical etching

    International Nuclear Information System (INIS)

    Tokuda, Yutaka; Shimada, Hitoshi

    1998-01-01

    Interaction of hydrogen atoms and vacancy-related defects in 10 MeV electron-irradiated n-type silicon has been studied by deep-level transient spectroscopy. Hydrogen has been incorporated into electron-irradiated n-type silicon by wet chemical etching. The reduction of the concentration of the vacancy-oxygen pair and divacancy occurs by the incorporation of hydrogen, while the formation of the NH1 electron trap (E c - 0.31 eV) is observed. Further decrease of the concentration of the vacancy-oxygen pair and further increase of the concentration of the NH1 trap are observed upon subsequent below-band-gap light illumination. It is suggested that the trap NH1 is tentatively ascribed to the vacancy-oxygen pair which is partly saturated with hydrogen

  6. Polymer degradation in reactive ion etching and its possible application to all dry processes

    International Nuclear Information System (INIS)

    Hiraoka, H.; Welsh, L.W. Jr.

    1981-01-01

    Dry etching processes involving CF 4 -plasma and reactive ion etching become increasingly important for microcircuit fabrication techniques. In these techniques polymer degradation and etch resistance against reactive species like F atoms and CF 3 + ions are the key factors in the processes. It is well-known that classical electron beam resists like poly(methyl methacrylate) and poly(1-butene sulfone) are not suitable for dry etching processes because they degrade rapidly under these etching conditions. In order to find a correlation of etching rate and polymer structures the thickness loss of polymer films have been measured for a variety of polymer films in reactive ion etching conditions, where CF 3 + ions are the major reactive species with an accelerating potential of 500 volts. Because of its high CF 4 -plasma and reactive ion etch resistance, and because of its high electron beam sensitivity, poly(methacrylonitrile) provides a positive working electron beam resist uniquely suited for all dry processes. (author)

  7. Electrodeless wet etching of n-GaN assisted with ultraviolet light

    International Nuclear Information System (INIS)

    Skriniarova, J.; Novotny, I.

    2012-01-01

    In this paper we studied photo-assisted electrodeless etching (ELPEC) of n-GaN in a K_2S_2O_8/KOH solution irradiated continuously with UV light. We investigated the impact of mask material on n-GaN patterning. As mask material thin layers of Ti, Pt and Au were used. The ratio of mask covered surface area to uncovered one was 7:1, 1:2 and 1:5. The K_2S_2O_8 oxidizing agent concentration was kept in the range from 0.006 to 0.1 M, the KOH electrolyte concentration was kept in the range from 0.004 to 0.04 M. (authors)

  8. Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

    Directory of Open Access Journals (Sweden)

    Priya Varshney

    2016-10-01

    Full Text Available In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating and one-step (chemical etching and coating in a single step processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°. Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.

  9. Uniform lateral etching of tungsten in deep trenches utilizing reaction-limited NF3 plasma process

    Science.gov (United States)

    Kofuji, Naoyuki; Mori, Masahito; Nishida, Toshiaki

    2017-06-01

    The reaction-limited etching of tungsten (W) with NF3 plasma was performed in an attempt to achieve the uniform lateral etching of W in a deep trench, a capability required by manufacturing processes for three-dimensional NAND flash memory. Reaction-limited etching was found to be possible at high pressures without ion irradiation. An almost constant etching rate that showed no dependence on NF3 pressure was obtained. The effect of varying the wafer temperature was also examined. A higher wafer temperature reduced the threshold pressure for reaction-limited etching and also increased the etching rate in the reaction-limited region. Therefore, the control of the wafer temperature is crucial to controlling the etching amount by this method. We found that the uniform lateral etching of W was possible even in a deep trench where the F radical concentration was low.

  10. Optimization of silver-assisted nano-pillar etching process in silicon

    Science.gov (United States)

    Azhari, Ayu Wazira; Sopian, Kamaruzzaman; Desa, Mohd Khairunaz Mat; Zaidi, Saleem H.

    2015-12-01

    In this study, a respond surface methodology (RSM) model is developed using three-level Box-Behnken experimental design (BBD) technique. This model is developed to investigate the influence of metal-assisted chemical etching (MACE) process variables on the nanopillars profiles created in single crystalline silicon (Si) substrate. Design-Expert® software (version 7.1) is employed in formulating the RSM model based on five critical process variables: (A) concentration of silver (Ag), (B) concentration of hydrofluoric acid (HF), (C) concentration of hydrogen peroxide (H2O2), (D) deposition time, and (E) etching time. This model is supported by data from 46 experimental configurations. Etched profiles as a function of lateral etching rate, vertical etching rate, height, size and separation between the Si trenches and etching uniformity are characterized using field emission scanning electron microscope (FE-SEM). A quadratic regression model is developed to correlate critical process variables and is validated using the analysis of variance (ANOVA) methodology. The model exhibits near-linear dependence of lateral and vertical etching rates on both the H2O2 concentration and etching time. The predicted model is in good agreement with the experimental data where R2 is equal to 0.80 and 0.67 for the etching rate and lateral etching respectively. The optimized result shows minimum lateral etching with the average pore size of about 69 nm while the maximum etching rate is estimated at around 360 nm/min. The model demonstrates that the etching process uniformity is not influenced by either the etchant concentration or the etching time. This lack of uniformity could be attributed to the surface condition of the wafer. Optimization of the process parameters show adequate accuracy of the model with acceptable percentage errors of 6%, 59%, 1.8%, 38% and 61% for determination of the height, separation, size, the pore size and the etching rate respectively.

  11. Aerosol chemistry in Titan's ionosphere: simultaneous growth and etching processes

    Science.gov (United States)

    Carrasco, Nathalie; Cernogora, Guy; Jomard, François; Etcheberry, Arnaud; Vigneron, Jackie

    2016-10-01

    Since the Cassini-CAPS measurements, organic aerosols are known to be present and formed at high altitudes in the diluted and partially ionized medium that is Titan's ionosphere [1]. This unexpected chemistry can be further investigated in the laboratory with plasma experiments simulating the complex ion-neutral chemistry starting from N2-CH4 [2]. Two sorts of solid organic samples can be produced in laboratory experiments simulating Titan's atmospheric reactivity: grains in the volume and thin films on the reactor walls. We expect that grains are more representative of Titan's atmospheric aerosols, but films are used to provide optical indices for radiative models of Titan's atmosphere.The aim of the present study is to address if these two sorts of analogues are chemically equivalent or not, when produced in the same N2-CH4 plasma discharge. The chemical compositions of both these materials are measured by using elemental analysis, XPS analysis and Secondary Ion Mass Spectrometry. We find that films are homogeneous but significantly less rich in nitrogen and hydrogen than grains produced in the same experimental conditions. This surprising difference in their chemical compositions is explained by the efficient etching occurring on the films, which stay in the discharge during the whole plasma duration, whereas the grains are ejected after a few minutes [3]. The impact for our understanding of Titan's aerosols chemical composition is important. Our study shows that chemical growth and etching process are simultaneously at stake in Titan's ionosphere. The more the aerosols stay in the ionosphere, the more graphitized they get through etching process. In order to infer Titan's aerosols composition, our work highlights a need for constraints on the residence time of aerosols in Titan's ionosphere. [1] Waite et al. (2009) Science , 316, p. 870[2] Szopa et al. (2006) PSS, 54, p. 394[3] Carrasco et al. (2016) PSS, 128, p. 52

  12. Modeling and optimization of wet sizing process

    International Nuclear Information System (INIS)

    Thai Ba Cau; Vu Thanh Quang and Nguyen Ba Tien

    2004-01-01

    Mathematical simulation on basis of Stock law has been done for wet sizing process on cylinder equipment of laboratory and semi-industrial scale. The model consists of mathematical equations describing relations between variables, such as: - Resident time distribution function of emulsion particles in the separating zone of the equipment depending on flow-rate, height, diameter and structure of the equipment. - Size-distribution function in the fine and coarse parts depending on resident time distribution function of emulsion particles, characteristics of the material being processed, such as specific density, shapes, and characteristics of the environment of classification, such as specific density, viscosity. - Experimental model was developed on data collected from an experimental cylindrical equipment with diameter x height of sedimentation chamber equal to 50 x 40 cm for an emulsion of zirconium silicate in water. - Using this experimental model allows to determine optimal flow-rate in order to obtain product with desired grain size in term of average size or size distribution function. (author)

  13. Process for recovering uranium from wet process phosphoric acid (III)

    International Nuclear Information System (INIS)

    Pyrih, R.Z.; Rickard, R.S.; Carrington, O.F.

    1983-01-01

    Uranium is conventionally recovered from wet-process phosphoric acid by two liquid ion exchange steps using a mixture of mono- and disubstituted phenyl esters of orthophosphoric acid (OPPA). Efficiency of the process drops as the mono-OPPA is lost preferentially to the aqueous phase. This invention provides a process for the removal of the uranium process organics (OPPA and organic solvents) from the raffinate of the first liquid ion exchange step and their return to the circuit. The process organics are removed by a combination flotation and absorption step, which results in the recovery of the organics on beads of a hydrophobic styrene polymer

  14. Uranium recovery from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Carrington, O.F.; Pyrih, R.Z.; Rickard, R.S.

    1981-01-01

    Improvement in the process for recovering uranium from wetprocess phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange liquidliquid solvent extraction circuits in which in the first circuit (A) the uranium is reduced to the uranous form; (B) the uranous uranium is recovered by liquid-liquid solvent extraction using a mixture of mono- and di-(Alkyl-phenyl) esters of orthophosphoric acid as the ion exchange agent; and (C) the uranium oxidatively stripped from the agent with phosphoric acid containing an oxidizing agent to convert uranous to uranyl ions, and in the second circuit (D) recovering the uranyl uranium from the strip solution by liquid-liquid solvent extraction using di(2ethylhexyl)phosphoric acid in the presence of trioctylphosphine oxide as a synergist; (E) scrubbing the uranium loaded agent with water; (F) stripping the loaded agent with ammonium carbonate, and (G) calcining the formed ammonium uranyl carbonate to uranium oxide, the improvement comprising: (1) removing the organics from the raffinate of step (B) before recycling the raffinate to the wet-process plant, and returning the recovered organics to the circuit to substantially maintain the required balance between the mono and disubstituted esters; (2) using hydogren peroxide as the oxidizing agent in step (C); (3) using an alkali metal carbonate as the stripping agent in step (F) following by acidification of the strip solution with sulfuric acid; (4) using some of the acidified strip solution as the scrubbing agent in step (E) to remove phosphorus and other impurities; and (5) regenerating the alkali metal loaded agent from step (F) before recycling it to the second circuit

  15. Anti-reflection textured structures by wet etching and island lithography for surface-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Bo-Kai [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Cheng, Hsin-Hung [Department of Marine Engineering, Taipei College of Maritime Technology, Taipei 11174, Taiwan (China); Nien, Li-Wei; Chen, Miin-Jang [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Nagao, Tadaaki [Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Li, Jia-Han [Department of Engineering Science and Ocean Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Hsueh, Chun-Hway, E-mail: hsuehc@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2015-12-01

    Graphical abstract: - Highlights: • We fabricated textured SERS substrate with a high surface area and low reflectance. • Large surface area of substrate contains more gold nanodroplets to absorb analytes. • Low reflectance of textured SERS substrate enabled multiple reflections of incident laser light. • We obtained strong SERS enhancement from nanopillar-on-pyramid SERS substrate. - Abstract: A high surface area and low reflection textured surface-enhanced Raman scattering (SERS) substrate with plasmonic gold nanodroplets fabricated by wet etching and island lithography was reported in the present study. Specifically, four textured substrates, planar, pyramid, nanopillar, and nanopillar-on-pyramid, were fabricated. The fabricated structures were simulated using the finite-difference time-domain method and the results agreed with the reflection and dark-field scattering measurements. Although the SERS signals varied in different measured regions because of the random nanostructure, the SERS substrates with nanopillar-on-pyramid structure always have the stronger enhancement factor than the SERS substrates with only pyramids or nanopillars. Based on the atomic force microscope and reflection measurements, the nanopillar-on-pyramid structure provided a large surface area and multiple reflections for SERS enhancement, which was about 3 orders of magnitude larger than that of the planar substrate. Our results can be applied to fabricate the inexpensive, large surface area, and high SERS enhancement substrates.

  16. Porous siliconformation and etching process for use in silicon micromachining

    Science.gov (United States)

    Guilinger, Terry R.; Kelly, Michael J.; Martin, Jr., Samuel B.; Stevenson, Joel O.; Tsao, Sylvia S.

    1991-01-01

    A reproducible process for uniformly etching silicon from a series of micromechanical structures used in electrical devices and the like includes providing a micromechanical structure having a silicon layer with defined areas for removal thereon and an electrochemical cell containing an aqueous hydrofluoric acid electrolyte. The micromechanical structure is submerged in the electrochemical cell and the defined areas of the silicon layer thereon are anodically biased by passing a current through the electrochemical cell for a time period sufficient to cause the defined areas of the silicon layer to become porous. The formation of the depth of the porous silicon is regulated by controlling the amount of current passing through the electrochemical cell. The micromechanical structure is then removed from the electrochemical cell and submerged in a hydroxide solution to remove the porous silicon. The process is subsequently repeated for each of the series of micromechanical structures to achieve a reproducibility better than 0.3%.

  17. Growth of ZnO nanowire arrays directly onto Si via substrate topographical adjustments using both wet chemical and dry etching methods

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Nathan A., E-mail: 523615@swansea.ac.uk [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom); Evans, Jon E.; Jones, Daniel R. [Multidisciplinary Nanotechnology Centre, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Lord, Alex M. [Centre for Nanohealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Wilks, S.P. [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom)

    2015-03-15

    Highlights: • Arrays of catalyst-free ZnO NWs have been grown by CVD without seed layers on Si. • Si surface topography was altered by substrate etching, resulting in NW growth. • XPS analysis shows growth is related to topography and not surface contamination. • Using e-beam lithography with etching, selective nanowire growth is demonstrated. • Electrical measurements on the arrays show improved conduction through the Si. - Abstract: Arrays of CVD catalyst-free ZnO nanowires have been successfully grown without the use of seed layers, using both wet chemical and dry plasma etching methods to alter surface topography. XPS analysis indicates that the NW growth cannot be attributed to a substrate surface chemistry and is therefore directly related to the substrate topography. These nanowires demonstrate structural and optical properties typical of CVD ZnO nanowires. Moreover, the NW arrays exhibit a degree of vertical alignment of less than 20° from the substrate normal. Electrical measurements suggest an improved conduction path through the substrate over seed layer grown nanowires. Furthermore, the etching technique was combined with e-beam lithography to produce high resolution selective area nanowire growth. The ability to pattern uniform nanowires using mature dry etch technology coupled with the increased charge transport through the substrate demonstrates the potential of this technique in the vertical integration of nanowire arrays.

  18. Photonic jet μ-etching: from static to dynamic process

    Science.gov (United States)

    Abdurrochman, A.; Lecler, S.; Zelgowski, J.; Mermet, F.; Fontaine, J.; Tumbelaka, B. Y.

    2017-05-01

    Photonic jet etching is a direct-laser etching method applying photonic jet phenomenon to concentrate the laser beam onto the proceeded material. We call photonic jet the phenomenon of the localized sub-wavelength propagative beam generated at the shadow-side surfaces of micro-scale dielectric cylinders or spheres, when they are illuminated by an electromagnetic plane-wave or laser beam. This concentration has made possible the laser to yield sub-μ etching marks, despite the laser was a near-infrared with nano-second pulses sources. We will present these achievements from the beginning when some spherical glasses were used for static etching to dynamic etching using an optical fiber with a semi-elliptical tip.

  19. Optimization of silver-assisted nano-pillar etching process in silicon

    International Nuclear Information System (INIS)

    Azhari, Ayu Wazira; Sopian, Kamaruzzaman; Desa, Mohd Khairunaz Mat; Zaidi, Saleem H.

    2015-01-01

    Graphical abstract: - Highlights: • Statistical analysis for synthesis of nano-pillar in crystalline Si substrates is presented. • Model is in good agreement with experimental for the etching rate and lateral etching respectively. • Optimum values for all parameters in fabrication of nanostructured Si are attained. - Abstract: In this study, a respond surface methodology (RSM) model is developed using three-level Box–Behnken experimental design (BBD) technique. This model is developed to investigate the influence of metal-assisted chemical etching (MACE) process variables on the nanopillars profiles created in single crystalline silicon (Si) substrate. Design-Expert ® software (version 7.1) is employed in formulating the RSM model based on five critical process variables: (A) concentration of silver (Ag), (B) concentration of hydrofluoric acid (HF), (C) concentration of hydrogen peroxide (H 2 O 2 ), (D) deposition time, and (E) etching time. This model is supported by data from 46 experimental configurations. Etched profiles as a function of lateral etching rate, vertical etching rate, height, size and separation between the Si trenches and etching uniformity are characterized using field emission scanning electron microscope (FE-SEM). A quadratic regression model is developed to correlate critical process variables and is validated using the analysis of variance (ANOVA) methodology. The model exhibits near-linear dependence of lateral and vertical etching rates on both the H 2 O 2 concentration and etching time. The predicted model is in good agreement with the experimental data where R 2 is equal to 0.80 and 0.67 for the etching rate and lateral etching respectively. The optimized result shows minimum lateral etching with the average pore size of about 69 nm while the maximum etching rate is estimated at around 360 nm/min. The model demonstrates that the etching process uniformity is not influenced by either the etchant concentration or the etching time

  20. Optimization of silver-assisted nano-pillar etching process in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Azhari, Ayu Wazira, E-mail: ayuwazira@unimap.edu.my [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor 43650 (Malaysia); School of Environmental Engineering, Universiti Malaysia Perlis, 01000, Kangar, Perlis (Malaysia); Sopian, Kamaruzzaman [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor 43650 (Malaysia); Desa, Mohd Khairunaz Mat [School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Nibong Tebal, Pulau Pinang, 14300 (Malaysia); Zaidi, Saleem H. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor 43650 (Malaysia)

    2015-12-01

    Graphical abstract: - Highlights: • Statistical analysis for synthesis of nano-pillar in crystalline Si substrates is presented. • Model is in good agreement with experimental for the etching rate and lateral etching respectively. • Optimum values for all parameters in fabrication of nanostructured Si are attained. - Abstract: In this study, a respond surface methodology (RSM) model is developed using three-level Box–Behnken experimental design (BBD) technique. This model is developed to investigate the influence of metal-assisted chemical etching (MACE) process variables on the nanopillars profiles created in single crystalline silicon (Si) substrate. Design-Expert{sup ®} software (version 7.1) is employed in formulating the RSM model based on five critical process variables: (A) concentration of silver (Ag), (B) concentration of hydrofluoric acid (HF), (C) concentration of hydrogen peroxide (H{sub 2}O{sub 2}), (D) deposition time, and (E) etching time. This model is supported by data from 46 experimental configurations. Etched profiles as a function of lateral etching rate, vertical etching rate, height, size and separation between the Si trenches and etching uniformity are characterized using field emission scanning electron microscope (FE-SEM). A quadratic regression model is developed to correlate critical process variables and is validated using the analysis of variance (ANOVA) methodology. The model exhibits near-linear dependence of lateral and vertical etching rates on both the H{sub 2}O{sub 2} concentration and etching time. The predicted model is in good agreement with the experimental data where R{sup 2} is equal to 0.80 and 0.67 for the etching rate and lateral etching respectively. The optimized result shows minimum lateral etching with the average pore size of about 69 nm while the maximum etching rate is estimated at around 360 nm/min. The model demonstrates that the etching process uniformity is not influenced by either the etchant

  1. Deep Reactive Ion Etching (DRIE) of High Aspect Ratio SiC Microstructures using a Time-Multiplexed Etch-Passivate Process

    Science.gov (United States)

    Evans, Laura J.; Beheim, Glenn M.

    2006-01-01

    High aspect ratio silicon carbide (SiC) microstructures are needed for microengines and other harsh environment micro-electro-mechanical systems (MEMS). Previously, deep reactive ion etching (DRIE) of low aspect ratio (AR less than or = 1) deep (greater than 100 micron) trenches in SiC has been reported. However, existing DRIE processes for SiC are not well-suited for definition of high aspect ratio features because such simple etch-only processes provide insufficient control over sidewall roughness and slope. Therefore, we have investigated the use of a time-multiplexed etch-passivate (TMEP) process, which alternates etching with polymer passivation of the etch sidewalls. An optimized TMEP process was used to etch high aspect ratio (AR greater than 5) deep (less than 100 micron) trenches in 6H-SiC. Power MEMS structures (micro turbine blades) in 6H-SiC were also fabricated.

  2. Study of polycaprolactone wet electrospinning process

    Directory of Open Access Journals (Sweden)

    E. Kostakova

    2014-08-01

    Full Text Available Wet electrospinning is a useful method for 3-dimensional structure control of nanofibrous materials. This innovative technology uses a liquid collector instead of the metal one commonly used for standard electrospinning. The article compares the internal structural features of polycaprolactone (PCL nanofibrous materials prepared by both technologies. We analyze the influence of different water/ethanol compositions used as a liquid collector on the morphology of the resultant polycaprolactone nanofibrous materials. Scanning electron micro-photographs have revealed a bimodal structure in the wet electrospun materials composed of micro and nanofibers uniformly distributed across the sample bulk. We have shown that the full-faced, twofold fiber distribution is due to the solvent composition and is induced and enhanced by increasing the ethanol weight ratio. Moreover, the comparison of fibrous layers morphology obtained by wet and dry spinning have revealed that beads that frequently appeared in dry spun materials are created by Plateau-Rayleigh instability of the fraction of thicker fibers. Theoretical conditions for spontaneous and complete immersion of cylindrical fibers into a liquid collector are also derived here.

  3. Effect of the duration of a wet KCN etching step and post deposition annealing on the efficiency of Cu2ZnSnSe4 solar cells

    OpenAIRE

    Sahayaraj, Sylvester; Brammertz, Guy; Vermang, Bart; Ranjbar, Samaneh; Meuris, Marc; Vleugels, Jef; Poortmans, Jef

    2016-01-01

    The influence of the duration of the KCN etching step on the efficiency of Cu2ZnSnSe4 (CZTSe) solar cells and Post deposition annealing (PDA) has been explored. CZTSe thin film absorbers prepared by selenization at 450 degrees C were etched by 5 wt% KCN/KOH from 30s up to 360 s before solar cell processing. KCN etching times above 120 s resulted in poor efficiencies. The fill factor (FF) and short circuit current density Jsc) of these devices were affected severely. After annealing the solar ...

  4. Wet chemical etching of Al-doped ZnO film deposited by RF magnetron sputtering method on textured glass substrate for energy application

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ki Hwan; Nam, Sang Hun; Jung, Won Suk; Lee, Yong Min; Yang, Hee Su; Boo, Jin Hyo [Dept. of Chemistry, Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-03-15

    The etching of glasses in aqueous hydrofluoric acid (HF) solutions is applied in many technological fields. Particularly, the textured transparent conductive oxide materials on the glass substrate etched by HF were used to improve the current density of solar cells. In this study, the textured glass substrate has been etched by solution and the Al-doped ZnO (AZO) thin films have been prepared on this textured glass substrates by RF magnetron sputtering method. After the AZO film deposition, the surface of AZO has been etched by hydrochloric acid with different concentration and etching time. Etched AZO thin films had higher haze ratio and sheet resistance than bare AZO glass. Increases in the root-mean-square surface roughness of AZO films enhanced from 53.78 to 84.46 nm the haze ratio in above 700 nm wavelength. Our process could be applicable in texturing glass and etching AZO surface to fabricate solar cell in industrial scale. We also carried out fabricating an organic solar-cell device. Energy conversion efficiency improvement of 123% was obtained with textured AZO-based solar-cell device compared with that of nontextured solar-cell device.

  5. Real-Time Observation of Carbon Nanotube Etching Process Using Polarized Optical Microscope.

    Science.gov (United States)

    Zhao, Qiuchen; Yao, Fengrui; Wang, Zequn; Deng, Shibin; Tong, Lianming; Liu, Kaihui; Zhang, Jin

    2017-08-01

    Controllable synthesis of carbon nanotubes (CNTs) is of great importance in its further application, which attracts broad attention. As growth and etching are the two sides in the process of material crystallography and the control of the competition between them forms the foundation for modern technology of materials design and manufacture, the understanding on etching process of carbon nanotubes is still very unclear because technically it is of great challenge to characterize the dynamics in such small one-dimensional (1D) scale. Here the real-time investigation on the etching process of CNTs is reported, by the hot-wall chemical reactor equipped with a polarized optical microscope. It is discovered that the CNT etching behavior in air is totally of random, including the etching sites, termination sites, and structure dependence. Combining with the dynamic simulation, it is revealed that the random behavior reflects the unique "self-termination" phenomenon. A structure-independent etching propagation barrier of 2.4 eV is also obtained, which indicates that the etching propagation process still follows the conventional Kinetic Wulff construction theory. The results represent the new knowledge on the etching process in carbon nanotube and can contribute to its selective enrichment. Furthermore, the "self-termination" phenomenon may be a universal behavior in 1D process. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Process for recovery of uranium from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Wiewiorowski, T.K.; Thornsberry, W.L. Jr.

    1978-01-01

    Process is claimed for the recovery of uranium from wet process phosphoric acid solution in which an organic extractant, containing uranium values and dissolved iron impurities and comprising a dialkylphosphoric acid and a trialkylphosphine oxide dissolved in a water immiscible organic solvent, is contacted with a substantially iron-free dilute aqueous phosphoric acid to remove said iron impurities. The removed impurities are bled from the system by feeding the resulting iron-loaded phosphoric acid to a secondary countercurrent uranium extraction operation from which they leave as part of the uranium-depleted acid raffinate. Also, process for recovering uranium in which the extractant, after it has been stripped of uranium values by aqueous ammonium carbonate, is contacted with a dilute aqueous acid selected from the group consisting of H 2 SO 4 , HCl, HNO 3 and iron-free H 3 PO 4 to improve the extraction efficiency of the organic extractant

  7. Process for winning uranium from wet process phosphoric acid

    International Nuclear Information System (INIS)

    1980-01-01

    A process is described for winning uranium from wet process phosphoric acid by means of liquid-liquid extraction with organic phosphoric acid esters. The process is optimised by keeping the sulphate percentage in the phosphoric acid below 2% by weight, and preferably below 0.6% by weight, as compared to P 2 O 5 in the phosphoric acid. This is achieved by adding an excess of Ba and/or Ca carbonate or sulfide solution and filtering off the formed calcium and/or barium sulphate precipitates. Solid KClO 3 is then added to the filtrate to oxidise U 4+ to U 6+ . The normal extraction procedure using organic phosphoric esters as extraction liquid, can then be applied. (Th.P.)

  8. Using chemical wet-etching methods of textured AZO films on a-Si:H solar cells for efficient light trapping

    International Nuclear Information System (INIS)

    Lin, Guo-Sheng; Li, Chien-Yu; Huang, Kuo-Chan; Houng, Mau-Phon

    2015-01-01

    In this paper, Al-doped ZnO (AZO) films are deposited on glasses substrate by RF magnetron sputtering. The optical, electrical and morphological properties of AZO films textured by wet-etching with different etchants, H 3 PO 4 , HCl, and HNO 3 are studied. It is found that the textured structure could enhance the light scattering and light trapping ability of amorphous silicon solar cells. The textured AZO film etched with HNO 3 exhibits optimized optical properties (T% ≧ 80% over entire wavelength, haze ratio > 40% at 550 nm wavelength) and excellent electrical properties (ρ = 5.86 × 10 −4 Ωcm). Scanning electron microscopy and Atomic force microscopy are used to observe surface morphology and average roughness of each textured AZO films. Finally, the textured AZO films etched by H 3 PO 4 , HCl and HNO 3 were applied to front electrode layer for p–i–n amorphous silicon solar cells. The highest conversion efficiency of amorphous silicon solar cell fabricated on HNO 3 -etched AZO film was 7.08% with open-circuit voltage, short-circuit current density and fill factor of 895 mV, 14.92 mA/cm 2 and 0.56, respectively. It shows a significantly enhancement in the short-circuit current density and conversion efficiency by 16.2% and 20.2%, respectively, compared with the solar cell fabricated on as-grown AZO film. - Highlights: • The textured surface enhances light scattering and light trapping ability. • The HNO 3 -etched AZO film exhibits excellent optical and electrical properties. • The efficiency of a-Si:H solar cell fabricated on HNO 3 -etched AZO film was 7.08%. • The short-circuit current density enhances to 16.2%. • The conversion efficiency enhances to 20.2%

  9. Thermo-fluid dynamic analysis of wet compression process

    International Nuclear Information System (INIS)

    Mohan, Abhay; Kim, Heuy Dong; Chidambaram, Palani Kumar; Suryan, Abhilash

    2016-01-01

    Wet compression systems increase the useful power output of a gas turbine by reducing the compressor work through the reduction of air temperature inside the compressor. The actual wet compression process differs from the conventional single phase compression process due to the presence of latent heat component being absorbed by the evaporating water droplets. Thus the wet compression process cannot be assumed isentropic. In the current investigation, the gas-liquid two phase has been modeled as air containing dispersed water droplets inside a simple cylinder-piston system. The piston moves in the axial direction inside the cylinder to achieve wet compression. Effects on the thermodynamic properties such as temperature, pressure and relative humidity are investigated in detail for different parameters such as compression speeds and overspray. An analytical model is derived and the requisite thermodynamic curves are generated. The deviations of generated thermodynamic curves from the dry isentropic curves (PV γ = constant) are analyzed

  10. Thermo-fluid dynamic analysis of wet compression process

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Abhay; Kim, Heuy Dong [School of Mechanical Engineering, Andong National University, Andong (Korea, Republic of); Chidambaram, Palani Kumar [FMTRC, Daejoo Machinery Co. Ltd., Daegu (Korea, Republic of); Suryan, Abhilash [Dept. of Mechanical Engineering, College of Engineering Trivandrum, Kerala (India)

    2016-12-15

    Wet compression systems increase the useful power output of a gas turbine by reducing the compressor work through the reduction of air temperature inside the compressor. The actual wet compression process differs from the conventional single phase compression process due to the presence of latent heat component being absorbed by the evaporating water droplets. Thus the wet compression process cannot be assumed isentropic. In the current investigation, the gas-liquid two phase has been modeled as air containing dispersed water droplets inside a simple cylinder-piston system. The piston moves in the axial direction inside the cylinder to achieve wet compression. Effects on the thermodynamic properties such as temperature, pressure and relative humidity are investigated in detail for different parameters such as compression speeds and overspray. An analytical model is derived and the requisite thermodynamic curves are generated. The deviations of generated thermodynamic curves from the dry isentropic curves (PV{sup γ} = constant) are analyzed.

  11. High-density plasma etching of III-nitrides: Process development, device applications and damage remediation

    Science.gov (United States)

    Singh, Rajwinder

    Plasma-assisted etching is a key technology for III-nitride device fabrication. The inevitable etch damage resulting from energetic pattern transfer is a challenge that needs to be addressed in order to optimize device performance and reliability. This dissertation focuses on the development of a high-density inductively-coupled plasma (ICP) etch process for III-nitrides, the demonstration of its applicability to practical device fabrication using a custom built ICP reactor, and development of techniques for remediation of etch damage. A chlorine-based standard dry etch process has been developed and utilized in fabrication of a number of electronic and optoelectronic III-nitride devices. Annealing studies carried out at 700°C have yielded the important insight that the annealing time necessary for making good-quality metal contacts to etch processed n-GaN is very short (water, prior to metallization, removes some of the etch damage and is helpful in recovering contact quality. In-situ treatment consisting of a slow ramp-down of rf bias at the end of the etch is found to achieve the same effect as the ex-situ treatment. This insitu technique is significantly advantageous in a large-scale production environment because it eliminates a process step, particularly one involving treatment in hydrochloric acid. ICP equipment customization for scaling up the process to full 2-inch wafer size is described. Results on etching of state of the art 256 x 256 AlGaN focal plane arrays of ultraviolet photodetectors are reported, with excellent etch uniformity over the wafer area.

  12. Performance improvements of binary diffractive structures via optimization of the photolithography and dry etch processes

    Science.gov (United States)

    Welch, Kevin; Leonard, Jerry; Jones, Richard D.

    2010-08-01

    Increasingly stringent requirements on the performance of diffractive optical elements (DOEs) used in wafer scanner illumination systems are driving continuous improvements in their associated manufacturing processes. Specifically, these processes are designed to improve the output pattern uniformity of off-axis illumination systems to minimize degradation in the ultimate imaging performance of a lithographic tool. In this paper, we discuss performance improvements in both photolithographic patterning and RIE etching of fused silica diffractive optical structures. In summary, optimized photolithographic processes were developed to increase critical dimension uniformity and featuresize linearity across the substrate. The photoresist film thickness was also optimized for integration with an improved etch process. This etch process was itself optimized for pattern transfer fidelity, sidewall profile (wall angle, trench bottom flatness), and across-wafer etch depth uniformity. Improvements observed with these processes on idealized test structures (for ease of analysis) led to their implementation in product flows, with comparable increases in performance and yield on customer designs.

  13. Optical ridge waveguides preserving the thermo-optic features in LiNbO3 crystals fabricated by combination of proton implantation and selective wet etching.

    Science.gov (United States)

    Tan, Yang; Chen, Feng

    2010-05-24

    We report on a new, simple method to fabricate optical ridge waveguides in a z-cut LiNbO3 wafer by using proton implantation and selective wet etching. The measured modal field is well confined in the ridge waveguide region, which is also confirmed by the numerical simulation. With thermal annealing treatment at 400 degrees C, the propagation loss of the ridge waveguides is determined to be as low as approximately 0.9 dB/cm. In addition, the measured thermo-optic coefficients of the waveguides are in good agreement with those of the bulk, suggesting potential applications in integrated photonics.

  14. Model determination and validation for reactive wetting processes

    Energy Technology Data Exchange (ETDEWEB)

    Yost, F.G.; O`Toole, E.J.; Sackinger, P.A. [Sandia National Labs., Albuquerque, NM (United States); Swiler, T.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering

    1998-01-01

    It is shown that dissolutive wetting initially yields a metastable equilibrium. A compact model for the kinetics of approach to this metastable state is described. The technique for constructing these kinetics stems from the early work of Onsager and begins with a relationship for the entropy production. From this, a coupled set of nonlinear, ordinary differential equations can be written directly. The equations are solved numerically for the wetted area and compared with experimental data. The model captures many of the subtle complexities of dissolutive wetting such as multiple metastable states. Sessile drop experiments involving a variety of Bi-Sn alloys on solid Bi substrates were performed. Substrates prepared from small and large-grained polycrystals and single crystals were used to measure equilibrium and metastable contact angles and estimate the surface tension and equilibrium contact angle of the solid-liquid interface. The substrates were also used to investigate the coupling of the dissolution and wetting processes and to investigate the effect of substrate grain size on wetting. It was determined that the equilibrium wetting geometry is independent of linear scale and that grain size has little influence on wetting or dissolution in the Bi-Sn system. To investigate the atomic behavior of liquids at interfaces during wetting, the authors simulated wetting in the Ag-Cu system using molecular dynamics with atomic potentials and observed both atomic dynamics and structural correlations of the liquid-solid interface. The authors found that spreading is prompted by interactions between the liquid and the substrate surface that cause the liquid layer in contact with the substrate to take on some of the symmetry of the substrate surface and result in the formation of a liquid monolayer that extends beyond the major part of the liquid droplet.

  15. Continuous Process for the Etching, Rinsing and Drying of MEMS Using Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Min, Seon Ki; Han, Gap Su; You, Seong-sik [Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2015-10-15

    The previous etching, rinsing and drying processes of wafers for MEMS (microelectromechanical system) using SC-CO{sub 2} (supercritical-CO{sub 2}) consists of two steps. Firstly, MEMS-wafers are etched by organic solvent in a separate etching equipment from the high pressure dryer and then moved to the high pressure dryer to rinse and dry them using SC-CO{sub 2}. We found that the previous two step process could be applied to etch and dry wafers for MEMS but could not confirm the reproducibility through several experiments. We thought the cause of that was the stiction of structures occurring due to vaporization of the etching solvent during moving MEMS wafer to high pressure dryer after etching it outside. In order to improve the structure stiction problem, we designed a continuous process for etching, rinsing and drying MEMS-wafers using SC-CO{sub 2} without moving them. And we also wanted to know relations of states of carbon dioxide (gas, liquid, supercritical fluid) to the structure stiction problem. In the case of using gas carbon dioxide (3 MPa, 25 .deg. C) as an etching solvent, we could obtain well-treated MEMS-wafers without stiction and confirm the reproducibility of experimental results. The quantity of rinsing solvent used could be also reduced compared with the previous technology. In the case of using liquid carbon dioxide (3 MPa, 5 .deg. C), we could not obtain well-treated MEMS-wafers without stiction due to the phase separation of between liquid carbon dioxide and etching co-solvent(acetone). In the case of using SC-CO{sub 2} (7.5 Mpa, 40 .deg. C), we had as good results as those of the case using gas-CO{sub 2}. Besides the processing time was shortened compared with that of the case of using gas-CO{sub 2}.

  16. Multi-Step Deep Reactive Ion Etching Fabrication Process for Silicon-Based Terahertz Components

    Science.gov (United States)

    Jung-Kubiak, Cecile (Inventor); Reck, Theodore (Inventor); Chattopadhyay, Goutam (Inventor); Perez, Jose Vicente Siles (Inventor); Lin, Robert H. (Inventor); Mehdi, Imran (Inventor); Lee, Choonsup (Inventor); Cooper, Ken B. (Inventor); Peralta, Alejandro (Inventor)

    2016-01-01

    A multi-step silicon etching process has been developed to fabricate silicon-based terahertz (THz) waveguide components. This technique provides precise dimensional control across multiple etch depths with batch processing capabilities. Nonlinear and passive components such as mixers and multipliers waveguides, hybrids, OMTs and twists have been fabricated and integrated into a small silicon package. This fabrication technique enables a wafer-stacking architecture to provide ultra-compact multi-pixel receiver front-ends in the THz range.

  17. Design of experiment characterization of microneedle fabrication processes based on dry silicon etching

    Science.gov (United States)

    Held, J.; Gaspar, J.; Ruther, P.; Hagner, M.; Cismak, A.; Heilmann, A.; Paul, O.

    2010-02-01

    This paper reports on the characterization of dry etching-based processes for the fabrication of silicon microneedles using a design of experiment (DoE) approach. The possibility of using such microneedles as protruding microelectrodes able to electroporate adherently growing cells and record intracellular potentials motivates the systematic analysis of the influence of etching parameters on the needle shape. Two processes are characterized: a fully isotropic etch process and a three-step etching approach. In the first case, the shape of the microneedles is defined by a single etch step. For the stepped method, the structures are realized using the following sequence: a first, isotropic step defines the tip; this is followed by anisotropic etching that increases the height of the needle; a final isotropic procedure thins the microneedle and sharpens its tip. From the various process parameters tested, it is concluded that the isotropic fabrication is influenced mostly by four process parameters, whereas six parameters dominantly govern the outcome of the stepped etching technique. The dependence of the needle shape on the etch mask diameter is also investigated. Microneedles with diameters down to the sub-micrometer range and heights below 10 µm are obtained. The experimental design is performed using the D-optimal method. The resulting geometry, i.e. heights, diameters and radii of curvature measured at different positions, is extracted from scanning electron micrographs of needle cross-sections obtained from cuts by focused ion beam. The process parameters are used as inputs and the geometry features of the microneedles as outputs for the analysis of the process.

  18. Design of experiment characterization of microneedle fabrication processes based on dry silicon etching

    International Nuclear Information System (INIS)

    Held, J; Gaspar, J; Ruther, P; Paul, O; Hagner, M; Cismak, A; Heilmann, A

    2010-01-01

    This paper reports on the characterization of dry etching-based processes for the fabrication of silicon microneedles using a design of experiment (DoE) approach. The possibility of using such microneedles as protruding microelectrodes able to electroporate adherently growing cells and record intracellular potentials motivates the systematic analysis of the influence of etching parameters on the needle shape. Two processes are characterized: a fully isotropic etch process and a three-step etching approach. In the first case, the shape of the microneedles is defined by a single etch step. For the stepped method, the structures are realized using the following sequence: a first, isotropic step defines the tip; this is followed by anisotropic etching that increases the height of the needle; a final isotropic procedure thins the microneedle and sharpens its tip. From the various process parameters tested, it is concluded that the isotropic fabrication is influenced mostly by four process parameters, whereas six parameters dominantly govern the outcome of the stepped etching technique. The dependence of the needle shape on the etch mask diameter is also investigated. Microneedles with diameters down to the sub-micrometer range and heights below 10 µm are obtained. The experimental design is performed using the D-optimal method. The resulting geometry, i.e. heights, diameters and radii of curvature measured at different positions, is extracted from scanning electron micrographs of needle cross-sections obtained from cuts by focused ion beam. The process parameters are used as inputs and the geometry features of the microneedles as outputs for the analysis of the process.

  19. A Nanoscale Plasma Etching Process for Pole Tip Recession of Perpendicular Recording Magnetic Head

    OpenAIRE

    LIU, Shoubin; HE, Dayao

    2017-01-01

    The pole tip of perpendicular recording head is constructed in a stacked structure with materials of NiCoFe, NiFe, Al2O3 and AlTiC. The surfaces of different materials are set at different heights below the air-bearing surface of slider. This paper presented a plasma dry etching process for Pole Tip Recession (PTR) based on an ion beam etching system. Ar and O2 mixed plasma at small incident angles have a high removal rate to the nonmagnetic material. It was utilised to etch the reference sur...

  20. The effect of reactive ion etch (RIE) process conditions on ReRAM device performance

    Science.gov (United States)

    Beckmann, K.; Holt, J.; Olin-Ammentorp, W.; Alamgir, Z.; Van Nostrand, J.; Cady, N. C.

    2017-09-01

    The recent surge of research on resistive random access memory (ReRAM) devices has resulted in a wealth of different materials and fabrication approaches. In this work, we describe the performance implications of utilizing a reactive ion etch (RIE) based process to fabricate HfO2 based ReRAM devices, versus a more unconventional shadow mask fabrication approach. The work is the result of an effort to increase device yield and reduce individual device size. Our results show that choice of RIE etch gas (SF6 versus CF4) is critical for defining the post-etch device profile (cross-section), and for tuning the removal of metal layers used as bottom electrodes in the ReRAM device stack. We have shown that etch conditions leading to a tapered profile for the device stack cause poor electrical performance, likely due to metal re-deposition during etching, and damage to the switching layer. These devices exhibit nonlinear I-V during the low resistive state, but this could be improved to linear behavior once a near-vertical etch profile was achieved. Device stacks with vertical etch profiles also showed an increase in forming voltage, reduced switching variability and increased endurance.

  1. Using chemical wet-etching methods of textured AZO films on a-Si:H solar cells for efficient light trapping

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Guo-Sheng; Li, Chien-Yu; Huang, Kuo-Chan; Houng, Mau-Phon, E-mail: mphoung@eembox.ncku.edu.tw

    2015-06-15

    In this paper, Al-doped ZnO (AZO) films are deposited on glasses substrate by RF magnetron sputtering. The optical, electrical and morphological properties of AZO films textured by wet-etching with different etchants, H{sub 3}PO{sub 4}, HCl, and HNO{sub 3} are studied. It is found that the textured structure could enhance the light scattering and light trapping ability of amorphous silicon solar cells. The textured AZO film etched with HNO{sub 3} exhibits optimized optical properties (T% ≧ 80% over entire wavelength, haze ratio > 40% at 550 nm wavelength) and excellent electrical properties (ρ = 5.86 × 10{sup −4} Ωcm). Scanning electron microscopy and Atomic force microscopy are used to observe surface morphology and average roughness of each textured AZO films. Finally, the textured AZO films etched by H{sub 3}PO{sub 4}, HCl and HNO{sub 3} were applied to front electrode layer for p–i–n amorphous silicon solar cells. The highest conversion efficiency of amorphous silicon solar cell fabricated on HNO{sub 3}-etched AZO film was 7.08% with open-circuit voltage, short-circuit current density and fill factor of 895 mV, 14.92 mA/cm{sup 2} and 0.56, respectively. It shows a significantly enhancement in the short-circuit current density and conversion efficiency by 16.2% and 20.2%, respectively, compared with the solar cell fabricated on as-grown AZO film. - Highlights: • The textured surface enhances light scattering and light trapping ability. • The HNO{sub 3}-etched AZO film exhibits excellent optical and electrical properties. • The efficiency of a-Si:H solar cell fabricated on HNO{sub 3}-etched AZO film was 7.08%. • The short-circuit current density enhances to 16.2%. • The conversion efficiency enhances to 20.2%.

  2. Planarization of the diamond film surface by using the hydrogen plasma etching with carbon diffusion process

    International Nuclear Information System (INIS)

    Kim, Sung Hoon

    2001-01-01

    Planarization of the free-standing diamond film surface as smooth as possible could be obtained by using the hydrogen plasma etching with the diffusion of the carbon species into the metal alloy (Fe, Cr, Ni). For this process, we placed the free-standing diamond film between the metal alloy and the Mo substrate like a metal-diamond-molybdenum (MDM) sandwich. We set the sandwich-type MDM in a microwave-plasma-enhanced chemical vapor deposition (MPECVD) system. The sandwich-type MDM was heated over ca. 1000 .deg. C by using the hydrogen plasma. We call this process as the hydrogen plasma etching with carbon diffusion process. After etching the free-standing diamond film surface, we investigated surface roughness, morphologies, and the incorporated impurities on the etched diamond film surface. Finally, we suggest that the hydrogen plasma etching with carbon diffusion process is an adequate etching technique for the fabrication of the diamond film surface applicable to electronic devices

  3. A big picture prospective for wet waste processing management

    International Nuclear Information System (INIS)

    Gibson, J.D.

    1996-01-01

    This paper provides an overview of general observations made relative to the technical and economical considerations being evaluated by many commercial nuclear power plants involving their decision making process for implementation of several new wet waste management technologies. The waste management processes reviewed include the use of, Reverse Osmosis, Non-Precoat Filters, Resin Stripping ampersand Recycling, Evaporation ampersand Calcination (RVR trademark, ROVER trademark ampersand Thermax trademark), Compression Dewatering (PressPak trademark), Incineration (Resin Express trademark), Survey ampersand Free Release (Green Is Clean) and Quantum Catalytic Extraction Processing (QCEP trademark). These waste management processes are reviewed relative to their general advantages and disadvantages associated with the processing of various wet waste streams including: reactor make-up water, floor drain sludges and other liquid waste streams such as boric acid concentrates and steam generator cleaning solutions. A summary of the conclusions generally being derived by most utilities associated with the use of these waste management processes is also provided

  4. Study of etching processes in the GEM detectors

    CERN Document Server

    Zavazieva, Darina

    2016-01-01

    Gaseous Electron Multiplier (GEM) detectors are known to operate stably at high gains and high particle fluxes. Though, at very high gains and fluxes it was observed that the insulating polyimide layer between the GEM electrodes gets etched, changing the original shape of the hole, and therefore varying the gain and the energy resolution of the detector. The idea of the project to observe degradation effect of the GEM foils during the Triple GEM detector operation in extreme conditions under X-ray radiation.

  5. Biodiesel production from wet microalgae feedstock using sequential wet extraction/transesterification and direct transesterification processes.

    Science.gov (United States)

    Chen, Ching-Lung; Huang, Chien-Chang; Ho, Kao-Chia; Hsiao, Ping-Xuan; Wu, Meng-Shan; Chang, Jo-Shu

    2015-10-01

    Although producing biodiesel from microalgae seems promising, there is still a lack of technology for the quick and cost-effective conversion of biodiesel from wet microalgae. This study was aimed to develop a novel microalgal biodiesel producing method, consisting of an open system of microwave disruption, partial dewatering (via combination of methanol treatment and low-speed centrifugation), oil extraction, and transesterification without the pre-removal of the co-solvent, using Chlamydomonas sp. JSC4 with 68.7 wt% water content as the feedstock. Direct transesterification with the disrupted wet microalgae was also conducted. The biomass content of the wet microalgae increased to 56.6 and 60.5 wt%, respectively, after microwave disruption and partial dewatering. About 96.2% oil recovery was achieved under the conditions of: extraction temperature, 45°C; hexane/methanol ratio, 3:1; extraction time, 80 min. Transesterification of the extracted oil reached 97.2% conversion within 15 min at 45°C and 6:1 solvent/methanol ratio with simultaneous Chlorophyll removal during the process. Nearly 100% biodiesel conversion was also obtained while conducting direct transesterification of the disrupted oil-bearing microalgal biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Polarity-inverted lateral overgrowth and selective wet-etching and regrowth (PILOSWER) of GaN.

    Science.gov (United States)

    Jang, Dongsoo; Jue, Miyeon; Kim, Donghoi; Kim, Hwa Seob; Lee, Hyunkyu; Kim, Chinkyo

    2018-03-07

    On an SiO 2 -patterned c-plane sapphire substrate, GaN domains were grown with their polarity controlled in accordance with the pattern. While N-polar GaN was grown on hexagonally arranged circular openings, Ga-polar GaN was laterally overgrown on mask regions due to polarity inversion occurring at the boundary of the circular openings. After etching of N-polar GaN on the circular openings by H 3 PO 4 , this template was coated with 40-nm Si by sputtering and was slightly etched by KOH. After slight etching, a thin layer of Si left on the circular openings of sapphire,but not on GaN, was oxidized during thermal annealing and served as a dielectric mask during subsequent regrowth. Thus, the subsequent growth of GaN was made only on the existing Ga-polar GaN domains, not on the circular openings of the sapphire substrate. Transmission electron microscopy analysis revealed no sign of threading dislocations in this film. This approach may help fabricating an unholed and merged GaN film physically attached to but epitaxially separated from the SiO 2 -patterned sapphire.

  7. A multi-step electrochemical etching process for a three-dimensional micro probe array

    International Nuclear Information System (INIS)

    Kim, Yoonji; Youn, Sechan; Cho, Young-Ho; Park, HoJoon; Chang, Byeung Gyu; Oh, Yong Soo

    2011-01-01

    We present a simple, fast, and cost-effective process for three-dimensional (3D) micro probe array fabrication using multi-step electrochemical metal foil etching. Compared to the previous electroplating (add-on) process, the present electrochemical (subtractive) process results in well-controlled material properties of the metallic microstructures. In the experimental study, we describe the single-step and multi-step electrochemical aluminum foil etching processes. In the single-step process, the depth etch rate and the bias etch rate of an aluminum foil have been measured as 1.50 ± 0.10 and 0.77 ± 0.03 µm min −1 , respectively. On the basis of the single-step process results, we have designed and performed the two-step electrochemical etching process for the 3D micro probe array fabrication. The fabricated 3D micro probe array shows the vertical and lateral fabrication errors of 15.5 ± 5.8% and 3.3 ± 0.9%, respectively, with the surface roughness of 37.4 ± 9.6 nm. The contact force and the contact resistance of the 3D micro probe array have been measured to be 24.30 ± 0.98 mN and 2.27 ± 0.11 Ω, respectively, for an overdrive of 49.12 ± 1.25 µm.

  8. Wet-etching induced abnormal phase transition in highly strained VO{sub 2}/TiO{sub 2} (001) epitaxial film

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Hui; Chen, Shi; Chen, Yuliang; Luo, Zhenlin; Zhou, Jingtian; Zheng, Xusheng; Wang, Liangxin; Li, Bowen; Zou, Chongwen [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei (China)

    2018-01-15

    The metal-insulator transition (MIT) behavior in vanadium dioxide (VO{sub 2}) epitaxial film is known to be dramatically affected by interfacial stress due to lattice mismatching. For the VO{sub 2}/TiO{sub 2} (001) system, there exists a considerable strain in ultra-thin VO{sub 2} thin film, which shows a lower T{sub c} value close to room temperature. As the VO{sub 2} epitaxial film grows thicker layer-by-layer along the ''bottom-up'' route, the strain will be gradually relaxed and T{sub c} will increase as well, until the MIT behavior becomes the same as that of bulk material with a T{sub c} of about 68 C. Whereas, in this study, we find that the VO{sub 2}/TiO{sub 2} (001) film thinned by ''top-down'' wet-etching shows an abnormal variation in MIT, which accompanies the potential relaxation of film strain with thinning. It is observed that even when the strained VO{sub 2} film is etched up to several nanometers, the MIT persists, and T{sub c} will increase up to that of bulk material, showing the trend to a stress-free ultra-thin VO{sub 2} film. The current findings demonstrate a facial chemical-etching way to change interfacial strain and modulate the phase transition behavior of ultrathinVO{sub 2} films, which can also be applied to other strained oxide films. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Improvement of the optical quality of site-controlled InAs quantum dots by a double stack growth technique in wet-chemically etched holes

    Energy Technology Data Exchange (ETDEWEB)

    Pfau, Tino Johannes; Gushterov, Aleksander; Reithmaier, Johann-Peter [Technische Physik, INA, Universitaet Kassel (Germany); Cestier, Isabelle; Eisenstein, Gadi [Electrical Engineering Dept., Technion, Haifa (Israel); Linder, Evgany; Gershoni, David [Solid State Institute and Physics Dept., Technion, Haifa (Israel)

    2010-07-01

    The optimization of the wet-chemically etching of holes and a special MBE growth stack technique allows enlarging the site-control of low density InAs QDs on GaAs substrates up to a buffer layer thickness of 55 nm. The strain of InAs QDs, grown in the etched holes, reduces the hole closing, so that a pre-patterned surface is conserved for the second QD layer. The distance of 50 nm GaAs between the two QD layers exceeds drastically the maximum vertical alignment based on pure strain coupling (20 nm). Compared to stacks with several QD layers, this method avoids electronic coupling between the different QD layers and reduces the problems to distinguish the dots of different layers optically. Confocal microphotoluminescence reveals a significant diminution of the low temperature photoluminescence linewidth of the second InAs QD layer to an average value of 505{+-}53 {mu}eV and a minimum width of 460 {mu}eV compared to 2 to 4 meV for QDs grown on thin buffer layers. The increase of the buffer layer thickness decreases the influence of the surface defects caused by prepatterning.

  10. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  11. Fabrication of etched facets and vertical couplers in InP for packaging and on-wafer test

    NARCIS (Netherlands)

    Lemos Alvares Dos Santos, Rui; D'Agostino, D.; Soares, F. M.; Haghighi, H. Rabbani; Williams, K. A.; Leijtens, X. J. M.

    2016-01-01

    In this letter, the fabrication and the characterization of angled and straight etched facets in InP-based technology are reported. In addition, we report on etched facets combined with coupler mirrors for vertical outcoupling, realized with a wet-etching process.

  12. Wet Mechanochemical Processing of Celestine using (NH42CO3

    Directory of Open Access Journals (Sweden)

    Deniz Bingöl

    2017-06-01

    Full Text Available In this study, traditional (univariate method of processing to the wet mechanochemical treatment were applied to obtain both SrCO3 and (NH42SO4 from celestite (SrSO4-(NH42CO3-H2O mixtures in a planetary ball mill. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis were used to analyze products formed during wet milling. A hydrometallurgical process was carried out to examine milling time, ball to grinding material mass ratio, (NH42CO3 to SrSO4 mole ratio and rotational speed of the mill in a planetary mill. Under optimum conditions, a conversion approaching 100% of SrCO3 was obtained.

  13. Environmental management system case study: textile wet processes

    Energy Technology Data Exchange (ETDEWEB)

    Nasreldin, A A [Engineering Researches and Industrial Technologies Council, Sudan Academy of Sciences, Khartoum (Sudan)

    2008-10-15

    Textile industry is one of the oldest industries, it started very early in the ancient ages, its grows and improves gradually at the first and then rapidly to satisfy other different need of the mankind, even for luxury purposes, this development caused damage to environment, then its need the treatment. Textile wet processes used significant quantities of water and various kind of chemicals marketed under the name textile auxiliaries, to enhance the appearance of the fabric, serviceability, and durability. The chemical contamination of textile wet processes can be a health risk for the mill workers, consumers and for the environment as well. A number of schemes have been proposed in different countries to control the textile wet processes to create better environment and protect the ecosystem from further degradation, the developing countries need to apply their designed policies from the beginning. A theoretical study for probability of application of environmental management system in textile industry, to prevent or eliminate textile industry pollution that considered as one of the largest polluters in Sudanese environment, especially after the government (industrial ministry) support and facilitate to textile industry development. Applying environmental management system can appreciably reduce the textile industry pollution as founded from the study.(Author)

  14. Environmental management system case study: textile wet processes

    International Nuclear Information System (INIS)

    Nasreldin, A.A.

    2008-10-01

    Textile industry is one of the oldest industries, it started very early in the ancient ages, its grows and improves gradually at the first and then rapidly to satisfy other different need of the mankind, even for luxury purposes, this development caused damage to environment, then its need the treatment. Textile wet processes used significant quantities of water and various kind of chemicals marketed under the name textile auxiliaries, to enhance the appearance of the fabric, serviceability, and durability. The chemical contamination of textile wet processes can be a health risk for the mill workers, consumers and for the environment as well. A number of schemes have been proposed in different countries to control the textile wet processes to create better environment and protect the ecosystem from further degradation, the developing countries need to apply their designed policies from the beginning. A theoretical study for probability of application of environmental management system in textile industry, to prevent or eliminate textile industry pollution that considered as one of the largest polluters in Sudanese environment, especially after the government (industrial ministry) support and facilitate to textile industry development. Applying environmental management system can appreciably reduce the textile industry pollution as founded from the study.(Author)

  15. Development studies of a novel wet oxidation process

    International Nuclear Information System (INIS)

    Rogers, T.W.; Dhooge, P.M.

    1995-01-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. The objective of this project is to develop a novel catalytic wet oxidation process for the treatment of multi-component wastes. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials

  16. Development studies of a novel wet oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, T.W.; Dhooge, P.M. [Delphi Research, Inc., Albuquerque, NM (United States)

    1995-10-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. The objective of this project is to develop a novel catalytic wet oxidation process for the treatment of multi-component wastes. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials.

  17. Dominant rate process of silicon surface etching by hydrogen chloride gas

    International Nuclear Information System (INIS)

    Habuka, Hitoshi; Suzuki, Takahiro; Yamamoto, Sunao; Nakamura, Akio; Takeuchi, Takashi; Aihara, Masahiko

    2005-01-01

    Silicon surface etching and its dominant rate process are studied using hydrogen chloride gas in a wide concentration range of 1-100% in ambient hydrogen at atmospheric pressure in a temperature range of 1023-1423 K, linked with the numerical calculation accounting for the transport phenomena and the surface chemical reaction in the entire reactor. The etch rate, the gaseous products and the surface morphology are experimentally evaluated. The dominant rate equation accounting for the first-order successive reactions at silicon surface by hydrogen chloride gas is shown to be valid. The activation energy of the dominant surface process is evaluated to be 1.5 x 10 5 J mol - 1 . The silicon deposition by the gaseous by-product, trichlorosilane, is shown to have a negligible influence on the silicon etch rate

  18. Etching processes of transparent carbon nanotube thin films using laser technologies

    International Nuclear Information System (INIS)

    Lin, H.K.; Lin, R.C.; Li, C.H.

    2010-01-01

    Carbon nanotubes (CNTs) have potential as a transparent conductive material with good mechanical and electrical properties. However, carbon nanotube thin film deposition and etching processes are very difficult to pattern the electrode. In this study, transparent CNT film with a binder is coated on a PET flexible substrate. The transmittance and sheet resistance of carbon nanotube film are 84% and 1000 Ω/□, respectively. The etching process of carbon nanotube film on flexible substrates was investigated using 355 nm and 1064 nm laser sources. Experimental results show that carbon nanotube film can be ablated using laser technology. With the 355 nm UV laser, the minimum etched line width was 20 μm with a low amount of recast material of the ablated sections. The optimal conditions of laser ablation were determined for carbon nanotube film.

  19. Chemically etched fiber tips for near-field optical microscopy: a process for smoother tips.

    Science.gov (United States)

    Lambelet, P; Sayah, A; Pfeffer, M; Philipona, C; Marquis-Weible, F

    1998-11-01

    An improved method for producing fiber tips for scanning near-field optical microscopy is presented. The improvement consists of chemically etching quartz optical fibers through their acrylate jacket. This new method is compared with the previous one in which bare fibers were etched. With the new process the meniscus formed by the acid along the fiber does not move during etching, leading to a much smoother surface of the tip cone. Subsequent metallization is thus improved, resulting in better coverage of the tip with an aluminum opaque layer. Our results show that leakage can be avoided along the cone, and light transmission through the tip is spatially limited to an optical aperture of a 100-nm dimension.

  20. Etch Defect Characterization and Reduction in Hard-Mask-Based Al Interconnect Etching

    International Nuclear Information System (INIS)

    Lee, H.J.; Hung, C.L.; Leng, C.H.; Lian, N.T.; Young, L.W.

    2009-01-01

    This paper identifies the defect adders, for example, post hard-mask etch residue, post metal etch residue, and blocked etch metal island and investigates the removal characteristics of these defects within the oxide-masked Al etching process sequence. Post hard-mask etch residue containing C atom is related to the hardening of photoresist after the conventional post-RIE ashing at 275 degree C. An in situ O 2 -based plasma ashing on RIE etcher was developed to prevent the photoresist hardening from the high-ashing temperature; followed wet stripping could successfully eliminate such hardened polymeric residue. Post metal etch residue was caused from the attack of the Al sidewall by Cl atoms, and too much CHF 3 addition in the Al main etch step passivated the surface of Al resulting in poor capability to remove the Al-containing residue. The lower addition of CHF 3 in the Al main etch step would benefit from the residue removal. One possibility of blocked etch metal island creating was due to the micro masking formed on the opening of Ti N during the hard-mask patterning. We report that an additional Ti N surface pretreatment with the Ar/CHF 3 /N 2 plasmas could reduce the impact of the micro masking residues on blocked metal etch.

  1. Characterization of the CH4/H2/Ar high density plasma etching process for ZnSe

    Science.gov (United States)

    Eddy, C. R.; Leonhardt, D.; Shamamian, V. A.; Butler, J. E.

    2001-05-01

    High density plasma etching of zinc selenide using CH4/H2/Ar plasma chemistries is investigated. Mass spectrometry, using through-the-platen sampling, is used to identify and monitor etch products evolving from the surface during etching. The identifiable primary etch products are Zn, Se, ZnH2, SeH2, Zn(CH3)2, and Se(CH3)2. Their concentrations are monitored as ion and neutral fluxes (both in intensity and composition), ion energy, and substrate temperature are varied. General insights about the surface chemistry mechanisms of the etch process are given from these observations. Regions of process parameter space best suited for moderate rate, anisotropic, and low damage etching of ZnSe are proposed.

  2. A history of engraving and etching techniques: developments of manual intaglio printmaking processes, 1400-2000

    NARCIS (Netherlands)

    Stijnman, A.C.J.

    2012-01-01

    This book surveys the history of the techniques of engraving, etching and plate printing - i.e. that of manual intaglio printmaking processes - from its beginning in the 1430s until today. These developments are observed in the light of the coherence between the technique of the intaglio print (such

  3. Development of a Photoelectrochemical Etch Process to Enable Heterogeneous Substrate Integration of Epitaxial III-Nitride Semiconductors

    Science.gov (United States)

    2017-12-01

    release stack. Recently, this technique has been refined with band engineering within the release layer7 and extended to the point where it has been...liftoff. Mesas with a 200-μm diameter are lithographically defined and etched down to a depth of approximately 450 nm using a plasma etching chemistry ...etch chemistry , bonding, and other materials processing vary, but the setup created for this project can be applied to others as well. Approved

  4. A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF3/O2 and SF6/O2

    Directory of Open Access Journals (Sweden)

    Seon-Geun Oh

    2014-01-01

    Full Text Available The characteristics of the dry etching of SiNx:H thin films for display devices using SF6/O2 and NF3/O2 were investigated using a dual-frequency capacitively coupled plasma reactive ion etching (CCP-RIE system. The investigation was carried out by varying the RF power ratio (13.56 MHz/2 MHz, pressure, and gas flow ratio. For the SiNx:H film, the etch rates obtained using NF3/O2 were higher than those obtained using SF6/O2 under various process conditions. The relationships between the etch rates and the usual monitoring parameters—the optical emission spectroscopy (OES intensity of atomic fluorine (685.1 nm and 702.89 nm and the voltages VH and VL—were investigated. The OES intensity data indicated a correlation between the bulk plasma density and the atomic fluorine density. The etch rate was proportional to the product of the OES intensity of atomic fluorine (I(F and the square root of the voltages (Vh+Vl on the assumption that the velocity of the reactive fluorine was proportional to the square root of the voltages.

  5. Uranium recovery from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    McCullough, J.F.; Phillips, J.F. Jr.; Tate, L.R.

    1979-01-01

    A method of recovering uranium from wet-process phosphoric acid is claimed where the acid is treated with a mixture of an ammonium salt or ammonia, a reducing agent, and then a miscible solvent. Solids are separated from the phosphoric acid liquid phase. The solid consists of a mixture of metal phosphates and uranium. It is washed free of adhering phosphoric acid with fresh miscible solvent. The solid is dried and dissolved in acid whereupon uranium is recovered from the solution. Miscible solvent and water are distilled away from the phosphoric acid. The distillate is rectified and water discarded. All miscible solvent is recovered for recycle. 5 claims

  6. Uranium tetrafluoride production via dioxide by wet process

    International Nuclear Information System (INIS)

    Aquino, A.R. de.

    1988-01-01

    The study for the wet way obtention of uranium tetrafluoride by the reaction of hydrofluoric acid and powder uranium dioxide, is presented. From the results obtained at laboratory scale a pilot plant was planned and erected. It is presently in operation for experimental data aquisition. Time of reaction, temperature, excess of reagents and the hydrofluoric acid / uranium dioxide ratio were the main parameters studied to obtain a product with the following characteristics: - density greater than 1 g/cm 3 , conversion rate greater than 96%, and water content equal to 0,2% that allows its application to heaxafluoride convertion or to magnesiothermic process. (author) [pt

  7. Dust emission from wet, low-emission coke quenching process

    Science.gov (United States)

    Komosiński, Bogusław; Bobik, Bartłomiej; Konieczny, Tomasz; Cieślik, Ewelina

    2018-01-01

    Coke plants, which produce various types of coke (metallurgical, foundry or heating), at temperatures between 600 and 1200°C, with limited access to oxygen, are major emitters of particulates and gaseous pollutants to air, water and soils. Primarily, the process of wet quenching should be mentioned, as one of the most cumbersome. Atmospheric pollutants include particulates, tar substances, organic pollutants including B(a)P and many others. Pollutants are also formed from the decomposition of water used to quench coke (CO, phenol, HCN, H2S, NH3, cresol) and decomposition of hot coke in the first phase of quenching (CO, H2S, SO2) [1]. The development of the coke oven technology has resulted in the changes made to different types of technological installations, such as the use of baffles in quench towers, the removal of nitrogen oxides by selective NOx reduction, and the introduction of fabric filters for particulates removal. The BAT conclusions for coke plants [2] provide a methodology for the measurement of particulate emission from a wet, low-emission technology using Mohrhauer probes. The conclusions define the emission level for wet quenching process as 25 g/Mgcoke. The conducted research was aimed at verification of the presented method. For two of three quench towers (A and C) the requirements included in the BAT conclusions are not met and emissions amount to 87.34 and 61.35 g/Mgcoke respectively. The lowest particulates emission was recorded on the quench tower B and amounted to 22.5 g/Mgcoke, therefore not exceeding the requirements.

  8. Guiding gate-etch process development using 3D surface reaction modeling for 7nm and beyond

    Science.gov (United States)

    Dunn, Derren; Sporre, John R.; Deshpande, Vaibhav; Oulmane, Mohamed; Gull, Ronald; Ventzek, Peter; Ranjan, Alok

    2017-03-01

    Increasingly, advanced process nodes such as 7nm (N7) are fundamentally 3D and require stringent control of critical dimensions over high aspect ratio features. Process integration in these nodes requires a deep understanding of complex physical mechanisms to control critical dimensions from lithography through final etch. Polysilicon gate etch processes are critical steps in several device architectures for advanced nodes that rely on self-aligned patterning approaches to gate definition. These processes are required to meet several key metrics: (a) vertical etch profiles over high aspect ratios; (b) clean gate sidewalls free of etch process residue; (c) minimal erosion of liner oxide films protecting key architectural elements such as fins; and (e) residue free corners at gate interfaces with critical device elements. In this study, we explore how hybrid modeling approaches can be used to model a multi-step finFET polysilicon gate etch process. Initial parts of the patterning process through hardmask assembly are modeled using process emulation. Important aspects of gate definition are then modeled using a particle Monte Carlo (PMC) feature scale model that incorporates surface chemical reactions.1 When necessary, species and energy flux inputs to the PMC model are derived from simulations of the etch chamber. The modeled polysilicon gate etch process consists of several steps including a hard mask breakthrough step (BT), main feature etch steps (ME), and over-etch steps (OE) that control gate profiles at the gate fin interface. An additional constraint on this etch flow is that fin spacer oxides are left intact after final profile tuning steps. A natural optimization required from these processes is to maximize vertical gate profiles while minimizing erosion of fin spacer films.2

  9. Similarity ratio analysis for early stage fault detection with optical emission spectrometer in plasma etching process.

    Directory of Open Access Journals (Sweden)

    Jie Yang

    Full Text Available A Similarity Ratio Analysis (SRA method is proposed for early-stage Fault Detection (FD in plasma etching processes using real-time Optical Emission Spectrometer (OES data as input. The SRA method can help to realise a highly precise control system by detecting abnormal etch-rate faults in real-time during an etching process. The method processes spectrum scans at successive time points and uses a windowing mechanism over the time series to alleviate problems with timing uncertainties due to process shift from one process run to another. A SRA library is first built to capture features of a healthy etching process. By comparing with the SRA library, a Similarity Ratio (SR statistic is then calculated for each spectrum scan as the monitored process progresses. A fault detection mechanism, named 3-Warning-1-Alarm (3W1A, takes the SR values as inputs and triggers a system alarm when certain conditions are satisfied. This design reduces the chance of false alarm, and provides a reliable fault reporting service. The SRA method is demonstrated on a real semiconductor manufacturing dataset. The effectiveness of SRA-based fault detection is evaluated using a time-series SR test and also using a post-process SR test. The time-series SR provides an early-stage fault detection service, so less energy and materials will be wasted by faulty processing. The post-process SR provides a fault detection service with higher reliability than the time-series SR, but with fault testing conducted only after each process run completes.

  10. Influence of high frequency ex-electric field on etching process and shape of pores for nuclear track film

    International Nuclear Information System (INIS)

    Chen Hui; Wang Yulan; Xu Shiping; Wang Jianchen

    2011-01-01

    To assess the details of the chemical etching process of polyethylene terephthalate (PET), the current signals during the whole etching process were recorded with the etching apparatus. The background-current was studied, which illustrated that it was mainly determined by the electric capacity of the etching system and was influenced by the thickness of the membrane but not by the temperature. According to the record of the current change during the etching process, it was found that the process can be divided into three phases. The influences of the existence and intensity of the ex-electric field on the breakthrough time and shape of pores were also studied. The existence of ex-electric field could shorten the breakthrough time and shape the pores more close to column. And these two phenomenons could be strengthened as the intensity of the electric field rose, and yet would reach a plateau when the intensity gets near 10 V/cm. (authors)

  11. Ultraviolet Laser Damage Dependence on Contamination Concentration in Fused Silica Optics during Reactive Ion Etching Process

    Directory of Open Access Journals (Sweden)

    Laixi Sun

    2018-04-01

    Full Text Available The reactive ion etching (RIE process of fused silica is often accompanied by surface contamination, which seriously degrades the ultraviolet laser damage performance of the optics. In this study, we find that the contamination behavior on the fused silica surface is very sensitive to the RIE process which can be significantly optimized by changing the plasma generating conditions such as discharge mode, etchant gas and electrode material. Additionally, an optimized RIE process is proposed to thoroughly remove polishing-introduced contamination and efficiently prevent the introduction of other contamination during the etching process. The research demonstrates the feasibility of improving the damage performance of fused silica optics by using the RIE technique.

  12. DREM: Infinite etch selectivity and optimized scallop size distribution with conventional photoresists in an adapted multiplexed Bosch DRIE process

    DEFF Research Database (Denmark)

    Chang, Bingdong; Leussink, Pele; Jensen, Flemming

    2018-01-01

    The quest to sculpture materials as small and deep as possible is an ongoing topic in micro- and nanofabrication. For this, the Bosch process has been widely used to achieve anisotropic silicon microstructures with high aspect ratio. Reactive ion etching (RIE) lag is a phenomenon in which etch ra...

  13. Effect of deposition temperature and thermal annealing on the dry etch rate of a-C: H films for the dry etch hard process of semiconductor devices

    International Nuclear Information System (INIS)

    Lee, Seung Moo; Won, Jaihyung; Yim, Soyoung; Park, Se Jun; Choi, Jongsik; Kim, Jeongtae; Lee, Hyeondeok; Byun, Dongjin

    2012-01-01

    thermal annealing of the high density, as-deposited a-C:H films. Furthermore, not only the density itself but also the variation of density with thermal annealing need to be elucidated in order to understand the dry etch properties of annealed a-C:H films. - Highlights: ► A-C:H(amorphous carbon) films are grown for using hard mask in dry etch process by plasma-enhanced chemical vapor deposition and annealed. ► Physical, chemical and mechanical properties of grown amorphous carbon films are changed by hydrogen and hydrocarbon contents, be determined by deposition and annealing temperature. ► Dry etch rate of a-C:H films is decreased and the film density increased through thermal annealing with high density, low hydrogen content, as-deposited film.

  14. High-quality InN grown on KOH wet etched N-polar InN template by RF-MBE

    International Nuclear Information System (INIS)

    Muto, D.; Araki, T.; Kitagawa, S.; Kurouchi, M.; Nanishi, Y.; Naoi, H.; Na, H.

    2006-01-01

    We have succeeded in dramatically decreasing the density of dislocations in InN by regrowing InN films on micro-facetted N-polar InN templates. The micro-facetted N-polar InN templates were formed by wet etching in a 10 mol/l KOH solution. InN films were regrown on the micro-facetted N-polar InN templates and on flat surface N-polar InN templates for comparison by radio-frequency plasma-assisted molecular beam epitaxy. InN regrown on micro-facetted InN had considerably smaller twist distribution than that grown on the flat InN templates. From transmission electron microscopy observation, it was confirmed that the InN grown on the micro-facetted InN template had much lower density of dislocations than that grown on the flat InN template, and moreover the propagation of edge dislocations was almost completely terminated at the interface between the regrown InN and the micro-facetted InN template. Based on the results, we propose that regrowth of InN on micro-facetted InN templates is an effective way to obtain high-quality InN films. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Process of recovering uranium from wet process acid

    International Nuclear Information System (INIS)

    York, W.R.

    1983-01-01

    Entrainment of contaminated water in the organic phase and poor phase disengagement is prevented in the second cycle scrubber, in a two cycle uranium recovery process, by washing the organic solvent stream containing entrained H 3 PO 4 from the second cycle extractor, with a dilute aqueous sulfuric or nitric acid solution in an acid scrubber, prior to passing the solvent stream into the second cycle stripper. (author)

  16. Discussion about the application of treatment process for dehydrated wet waste at nuclear power station

    International Nuclear Information System (INIS)

    Li Guanghua; Wu Qiang

    2009-01-01

    In nuclear power station, the most popular treatment about low level radioactive wet waste generated during the unit operating and maintenance is embedded by cement. For radioactive waste minimization, this article introduces a new treatment process to dehydrate and compress wet waste. According to the development and application of the treatment process for the wet waste, and comparing with the formerly treatment-the cement embedding, prove that the new treatment can meet the purpose for volume reduction of wet waste. (authors)

  17. Process for recovering uranium from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Pyrih, R.Z.; Rickard, S.; Carrington, F.

    1982-01-01

    A process for recovering uranium from phosphoric acid solutions uses an acidified alkali metal carbonate solution for the second-stage strip of uranyl uranium from the ion-exchange solution. The stripped solution is then recycled to the ion-exchange circuit. In the first stripping stage the ion-exchange solution containing the recovered uranyl uranium and an inert organic diluent is stripped with ammonium carbonate, producing a slurry of ammonium uranyl tricarbonate. The second strip, with a solution of 50-200 grams per litre of sodium carbonate eliminates the problems of inadequate removal of phosphorus, iron and vanadium impurities, solids accumulation, and phase separation in the strip circuit

  18. Power generation characteristics of tubular type SOFC by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tajiri, H.; Nakayama, T. [Kyushu Electric Power Company, Inc., Fukuoka (Japan); Kuroishi, M. [TOTO Ltd., Kanagawa (Japan)] [and others

    1996-12-31

    The development of a practical solid oxide fuel cell requires improvement of a cell performance and a cell manufacturing technology suitable for the mass production. In particular tubular type SOFC is thought to be superior in its reliability because its configuration can avoid the high temperature sealing and reduce the thermal stress resulting from the contact between cells. The authors have fabricated a tubular cell with an air electrode support by a wet processing technique, which is suitable for mass production in improving a power density. To enhance the power output of the module, the Integrated Tubular-Type (ITT) cell has been developed. This paper reports the performance of the single cells with various active anode areas and the bundle with series-connected 9-ITT cells with an active anode area of 840 cm{sup 2}.

  19. Two-Phase Phenomena In Wet Flue Gas Desulfurization Process

    International Nuclear Information System (INIS)

    Minzer, U.; Moses, E.J.; Toren, M.; Blumenfeld, Y.

    1998-01-01

    In order to reduce sulfur oxides discharge, Israel Electric Corporation (IEC) is building a wet Flue Gas Desulfurization (FGD) facility at Rutenberg B power station. The primary objective of IEC is to minimize the occurrence of stack liquid discharge and avoid the discharge of large droplets, in order to prevent acid rain around the stack. Liquid discharge from the stack is the integrated outcome of two-phase processes, which are discussed in this work. In order to estimate droplets discharge the present investigation employs analytical models, empirical tests, and numerical calculations of two-phase phenomena. The two-phase phenomena are coupled and therefore cannot be investigated separately. The present work concerns the application of Computational Fluid Dynamic (CFD) as an engineering complementary tool in the IEC investigation

  20. Development studies for a novel wet oxidation process. Phase 2

    International Nuclear Information System (INIS)

    1994-07-01

    DETOX SM is a catalyzed wet oxidation process which destroys organic materials in an acidic water solution of iron at 373 to 473 K. The solution can be used repeatedly to destroy great amounts of organic materials. Since the process is conducted in a contained vessel, air emissions from the process can be well controlled. The solution is also capable of dissolving and concentrating many heavy and radioactive metals for eventual stabilization and disposal. The Phase 2 effort for this project is site selection and engineering design for a DETOX demonstration unit. Site selection was made using a set of site selection criteria and evaluation factors. A survey of mixed wastes at DOE sites was conducted using the Interim Mixed Waste Inventory Report. Sites with likely suitable waste types were identified. Potential demonstration sites were ranked based on waste types, interest, regulatory needs, scheduling, ability to provide support, and available facilities. Engineering design for the demonstration unit is in progress and is being performed by Jacobs Applied Technology. The engineering design proceeded through preliminary process flow diagrams (PFDs), calculation of mass and energy balances for representative waste types, process and instrumentation diagrams (P and IDs), preparation of component specifications, and a firm cost estimate for fabrication of the demonstration unit

  1. Six-month evaluation of adhesives interface created by a hydrophobic adhesive to acid-etched ethanol-wet bonded dentine with simplified dehydration protocols.

    Science.gov (United States)

    Sadek, Fernanda T; Mazzoni, Annalisa; Breschi, Lorenzo; Tay, Franklin R; Braga, Roberto R

    2010-04-01

    To evaluate the efficacy of simplified dehydration protocols, in the absence of tubular occlusion, on bond strength and interfacial nanoleakage of a hydrophobic experimental adhesive blend to acid-etched, ethanol-dehydrated dentine immediately and after 6 months. Molars were randomly assigned to 6 treatment groups (n=5). Under pulpal pressure simulation, dentine crowns were acid-etched with 35% H(3)PO(4) and rinsed with water. Adper Scotchbond Multi-Purpose was used for the control group. The remaining groups had their dentine surface dehydrated with ethanol solutions: group 1=50%, 70%, 80%, 95% and 3x100%, 30s for each application; group 2 the same ethanol sequence with 15s for each solution; groups 3, 4 and 5 used 100% ethanol only, applied in seven, three or one 30s step, respectively. After dehydration, a primer (50% BisGMA+TEGDMA, 50% ethanol) was used, followed by the neat comonomer adhesive application. Resin composite build-ups were then prepared using an incremental technique. Specimens were stored for 24h, sectioned into beams and stressed to failure after 24h or after 6 months of artificial ageing. Interfacial silver leakage evaluation was performed for both storage periods (n=5 per subgroup). Group 1 showed higher bond strengths at 24h or after 6 months of ageing (45.6+/-5.9(a)/43.1+/-3.2(a)MPa) and lower silver impregnation. Bond strength results were statistically similar to control group (41.2+/-3.3(ab)/38.3+/-4.0(ab)MPa), group 2 (40.0+/-3.1(ab)/38.6+/-3.2(ab)MPa), and group 3 at 24h (35.5+/-4.3(ab)MPa). Groups 4 (34.6+/-5.7(bc)/25.9+/-4.1(c)MPa) and 5 (24.7+/-4.9(c)/18.2+/-4.2(c)MPa) resulted in lower bond strengths, extensive interfacial nanoleakage and more prominent reductions (up to 25%) in bond strengths after 6 months of ageing. Simplified dehydration protocols using one or three 100% ethanol applications should be avoided for the ethanol-wet bonding technique in the absence of tubular occlusion, as they showed decreased bond strength, more

  2. Plasma etching of patterned tungsten

    International Nuclear Information System (INIS)

    Franssila, S.

    1993-01-01

    Plasma etching of tungsten is discussed from the viewpoint of thin film structure and integrated circuit process engineering. The emphasis is on patterned tungsten etching for silicon device and X-ray mask fabrication. After introducing tungsten etch chemistries and mechanisms, microstructural aspects of tungsten films (crystal structure, grain size, film density, defects, impurities) in relation to etching are discussed. Approaches to etch process optimization are presented, and the current state-of-the-art of patterned tungsten etching is reviewed. (orig.)

  3. Endpoint in plasma etch process using new modified w-multivariate charts and windowed regression

    Science.gov (United States)

    Zakour, Sihem Ben; Taleb, Hassen

    2017-09-01

    Endpoint detection is very important undertaking on the side of getting a good understanding and figuring out if a plasma etching process is done in the right way, especially if the etched area is very small (0.1%). It truly is a crucial part of supplying repeatable effects in every single wafer. When the film being etched has been completely cleared, the endpoint is reached. To ensure the desired device performance on the produced integrated circuit, the high optical emission spectroscopy (OES) sensor is employed. The huge number of gathered wavelengths (profiles) is then analyzed and pre-processed using a new proposed simple algorithm named Spectra peak selection (SPS) to select the important wavelengths, then we employ wavelet analysis (WA) to enhance the performance of detection by suppressing noise and redundant information. The selected and treated OES wavelengths are then used in modified multivariate control charts (MEWMA and Hotelling) for three statistics (mean, SD and CV) and windowed polynomial regression for mean. The employ of three aforementioned statistics is motivated by controlling mean shift, variance shift and their ratio (CV) if both mean and SD are not stable. The control charts show their performance in detecting endpoint especially W-mean Hotelling chart and the worst result is given by CV statistic. As the best detection of endpoint is given by the W-Hotelling mean statistic, this statistic will be used to construct a windowed wavelet Hotelling polynomial regression. This latter can only identify the window containing endpoint phenomenon.

  4. Investigating the process of white etching crack initiation in bearing steel

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Benjamin; Greco, Aaron

    2016-04-01

    White etching cracks (WECs) have been identified as a dominant mode of premature failure within wind turbine gearbox bearings. Though WECs have been reported in the field for over a decade, the conditions leading to WECs, and the process by which this failure culminates, are both highly debated. In previously published work, the generation of WECs on a benchtop scale was linked to sliding at the surface of the test sample, it was also postulated that the generation of WECs was dependent on the cumulative energy that had been applied to the sample over the entirety of the test. In this paper, a three ring on roller bench top test rig is used to systematically alter the cumulative energy that a sample experiences through changes in normal load, sliding, and run time, in an attempt to correlate cumulative energy with the formation of WECs. It was determined that, in the current test setup, the presence of WECs can be predicted by this energy criterion. The authors then used this information to study the process by which WECs initiate. Lastly, it was found that, under the current testing conditions, the formation of a dark etching microstructure precedes the formation of a crack, and a crack precedes the formation of white etching microstructure.

  5. Technology of uranium recovery from wet-process phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Katsutoshi [Saga Univ. (Japan). Faculty of Science and Engineering; Nakashio, Fumiyuki

    1982-12-01

    Rock phosphate contains from 0.005 to 0.02 wt.% of uranium. Though the content is a mere 5 to 10 % of that in uranium ore, the total recovery of uranium is significant since it is used for fertilizer manufacture in a large quantity. Wet-process phosphoric acid is produced by the reaction of rock phosphate with sulfuric acid. The recovery of uranium from this phosphoric acid is mostly by solvent extraction at present. According to U/sup 4 +/ or UO/sub 2//sup 2 +/ as the form of its existence, the technique of solvent extraction differs. The following matters are described: processing of rock phosphate; recovery techniques including the extraction by OPPA-octyl pyrophosphoric acid for U/sup 4 +/, and by mixed DEHPA-Di-(2)-ethylhexyl phosphoric acid and TOPO-tryoctyl phosphine oxide for UO/sub 2//sup 2 +/, and by OPAP-octylphenyl acid phosphate for U/sup 4 +/; the recent progress of the technology as seen in patents.

  6. Process for recovering yttrium and lanthanides from wet-process phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, J.A.; Weterings, C.A.

    1983-06-28

    Process for recovering yttrium and lanthanides from wet-process phosphoric acid by adding a flocculant to the phosphoric acid, separating out the resultant precipitate and then recovering yttrium and lanthanides from the precipitate. Uranium is recovered from the remaining phosphoric acid.

  7. Development studies for a novel wet oxidation process

    International Nuclear Information System (INIS)

    Dhooge, P.M.; Hakim, L.B.

    1994-01-01

    A catalytic wet oxidation process (DETOX), which uses an acidic iron solution to oxidize organic compounds to carbon dioxide, water, and other simple products, was investigated as a potential method for the treatment of multicomponent hazardous and mixed wastes. The organic compounds picric acid, poly(vinyl chloride), tetrachlorothiophene, pentachloropyridine, Aroclor 1260 (a polychlorinated biphenyl), and hexachlorobenzene were oxidized in 125 ml reaction vessels. The metals arsenic, barium, beryllium, cadmium, cerium (as a surrogate for plutonium), chromium, lead, mercury, neodymium (as a surrogate for uranium), nickel, and vanadium were tested in the DETOX solution. Barium, beryllium, cerium, chromium, mercury, neodymium, nickel, and vanadium were all found to be very soluble (>100 g/l) in the DETOX chloride-based solution. Arsenic, barium, cadmium, and lead solubilities were lower. Lead could be selectively precipitated from the DETOX solution. Chromium(VI) was reduced to relatively non-toxic chromium(III) by the solution. Six soils were contaminated with arsenic, barium, beryllium, chromium, lead, and neodymium oxides at approximately 0.1% by weight, and benzene, trichloroethene, mineral oil, and Aroclor 1260 at approximately 5% by weight total, and 5.g amounts treated with the DETOX solution in unstirred 125. ml reaction bombs. It is felt that soil treatment in a properly designed system is entirely possible despite incomplete oxidation of the less volatile organic materials in these unstirred tests

  8. Porous Gold Films Fabricated by Wet-Chemistry Processes

    Directory of Open Access Journals (Sweden)

    Aymeric Pastre

    2016-01-01

    Full Text Available Porous gold films presented in this paper are formed by combining gold electroless deposition and polystyrene beads templating methods. This original approach allows the formation of conductive films (2 × 106 (Ω·cm−1 with tailored and interconnected porosity. The porous gold film was deposited up to 1.2 μm on the silicon substrate without delamination. An original zirconia gel matrix containing gold nanoparticles deposited on the substrate acts both as an adhesion layer through the creation of covalent bonds and as a seed layer for the metallic gold film growth. Dip-coating parameters and gold electroless deposition kinetics have been optimized in order to create a three-dimensional network of 20 nm wide pores separated by 20 nm thick continuous gold layers. The resulting porous gold films were characterized by GIXRD, SEM, krypton adsorption-desorption, and 4-point probes method. The process is adaptable to different pore sizes and based on wet-chemistry. Consequently, the porous gold films presented in this paper can be used in a wide range of applications such as sensing, catalysis, optics, or electronics.

  9. Catalyst and processing effects on metal-assisted chemical etching for the production of highly porous GaN

    International Nuclear Information System (INIS)

    Geng, Xuewen; Grismer, Dane A; Bohn, Paul W; Duan, Barrett K; Zhao, Liancheng

    2013-01-01

    Metal-assisted chemical etching is a facile method to produce micro-/nanostructures in the near-surface region of gallium nitride (GaN) and other semiconductors. Detailed studies of the production of porous GaN (PGaN) using different metal catalysts and GaN doping conditions have been performed in order to understand the mechanism by which metal-assisted chemical etching is accomplished in GaN. Patterned catalysts show increasing metal-assisted chemical etching activity to n-GaN in the order Ag < Au < Ir < Pt. In addition, the catalytic behavior of continuous films is compared to discontinuous island films. Continuous metal films strongly shield the surface, hindering metal-assisted chemical etching, an effect which can be overcome by using discontinuous films or increasing the irradiance of the light source. With increasing etch time or irradiance, PGaN morphologies change from uniform porous structures to ridge and valley structures. The doping type plays an important role, with metal-assisted chemical etching activity increasing in the order p-GaN < intrinsic GaN < n-GaN. Both the catalyst identity and the doping type effects are explained by the work functions and the related band offsets that affect the metal-assisted chemical etching process through a combination of different barriers to hole injection and the formation of hole accumulation/depletion layers at the metal–semiconductor interface. (paper)

  10. Characterization of the high density plasma etching process of CCTO thin films for the fabrication of very high density capacitors

    International Nuclear Information System (INIS)

    Altamore, C; Tringali, C; Sparta', N; Marco, S Di; Grasso, A; Ravesi, S

    2010-01-01

    In this work the feasibility of CCTO (Calcium Copper Titanate) patterning by etching process is demonstrated and fully characterized in a hard to etch materials etcher. CCTO sintered in powder shows a giant relative dielectric constant (10 5 ) measured at 1 MHz at room temperature. This feature is furthermore coupled with stability from 10 1 Hz to 10 6 Hz in a wide temperature range (100K - 600K). In principle, this property can allow to fabricate very high capacitance density condenser. Due to its perovskite multi-component structure, CCTO can be considered a hard to etch material. For high density capacitor fabrication, CCTO anisotropic etching is requested by using high density plasma. The behavior of etched CCTO was studied in a HRe- (High Density Reflected electron) plasma etcher using Cl 2 /Ar chemistry. The relationship between the etch rate and the Cl 2 /Ar ratio was also studied. The effects of RF MHz, KHz Power and pressure variation, the impact of HBr addiction to the Cl 2 /Ar chemistry on the CCTO etch rate and on its selectivity to Pt and photo resist was investigated.

  11. Characterization of the high density plasma etching process of CCTO thin films for the fabrication of very high density capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Altamore, C; Tringali, C; Sparta' , N; Marco, S Di; Grasso, A; Ravesi, S [STMicroelectronics, Industial and Multi-segment Sector R and D, Catania (Italy)

    2010-02-15

    In this work the feasibility of CCTO (Calcium Copper Titanate) patterning by etching process is demonstrated and fully characterized in a hard to etch materials etcher. CCTO sintered in powder shows a giant relative dielectric constant (10{sup 5}) measured at 1 MHz at room temperature. This feature is furthermore coupled with stability from 10{sup 1} Hz to 10{sup 6} Hz in a wide temperature range (100K - 600K). In principle, this property can allow to fabricate very high capacitance density condenser. Due to its perovskite multi-component structure, CCTO can be considered a hard to etch material. For high density capacitor fabrication, CCTO anisotropic etching is requested by using high density plasma. The behavior of etched CCTO was studied in a HRe- (High Density Reflected electron) plasma etcher using Cl{sub 2}/Ar chemistry. The relationship between the etch rate and the Cl{sub 2}/Ar ratio was also studied. The effects of RF MHz, KHz Power and pressure variation, the impact of HBr addiction to the Cl{sub 2}/Ar chemistry on the CCTO etch rate and on its selectivity to Pt and photo resist was investigated.

  12. Tuning of structural, light emission and wetting properties of nanostructured copper oxide-porous silicon matrix formed on electrochemically etched copper-coated silicon substrates

    Science.gov (United States)

    Naddaf, M.

    2017-01-01

    Matrices of copper oxide-porous silicon nanostructures have been formed by electrochemical etching of copper-coated silicon surfaces in HF-based solution at different etching times (5-15 min). Micro-Raman, X-ray diffraction and X-ray photoelectron spectroscopy results show that the nature of copper oxide in the matrix changes from single-phase copper (I) oxide (Cu2O) to single-phase copper (II) oxide (CuO) on increasing the etching time. This is accompanied with important variation in the content of carbon, carbon hydrides, carbonyl compounds and silicon oxide in the matrix. The matrix formed at the low etching time (5 min) exhibits a single broad "blue" room-temperature photoluminescence (PL) band. On increasing the etching time, the intensity of this band decreases and a much stronger "red" PL band emerges in the PL spectra. The relative intensity of this band with respect to the "blue" band significantly increases on increasing the etching time. The "blue" and "red" PL bands are attributed to Cu2O and porous silicon of the matrix, respectively. In addition, the water contact angle measurements reveal that the hydrophobicity of the matrix surface can be tuned from hydrophobic to superhydrophobic state by controlling the etching time.

  13. Development of the PNC wet process producing uranium tetrafluoride

    International Nuclear Information System (INIS)

    Takada, Shingo

    1979-01-01

    Pilot plant operation for the industrialization of the PNC (Power Reactor and Nuclear Fuel Development Corp.) wet process, which consists of ore leaching, solvent extraction (Amex Chloride Conversion), electrolytic reduction, UF 4 hydrate precipitation and dehydration, has been carried out for over ten years with several technical developments and improvements. In this paper these results of investigation on hydrofluorination step, dehydration step and reactability of UF 4 to UF 6 are reported. A new hydrofluorination equipment for continuous precipitation of crystal hydrate (particle size of 50 -- 100 mu ) was developed, and this made it possible to simplify the procedures of liquid-solid separation, drying and granulation. The water molecule of product (UF 4 .1 -- 1.2H 2 O) is composed of 70 -- 80% molecule dehydrated at 150 -- 200 0 C and 20 -- 30% dehydrated at about 350 0 C. The reactor-grade UF 4 containing less than 0.1% H 2 O, about 1% UO 2 and about 0.3% UO 2 F 2 by weight was obtained under the conditions of retention time of 1 hour at 350 0 C in an atmosphere of nitrogen by batch-wise operation of 3-inch diameter fluidized-bed dehydrator. From batch-wise experimental operations of 3-inch diameter fluidized-bed reactor, high fluorine efficiencies over 99.9% (less than 0.1% of fluorine unreacted), were attained at 380 0 C with 41% fluorine in the inlet fluidizing gas under the continuous operation of UF 4 feed velocity of 0.1 kg/h.cm 2 . (author)

  14. GPU based 3D feature profile simulation of high-aspect ratio contact hole etch process under fluorocarbon plasmas

    Science.gov (United States)

    Chun, Poo-Reum; Lee, Se-Ah; Yook, Yeong-Geun; Choi, Kwang-Sung; Cho, Deog-Geun; Yu, Dong-Hun; Chang, Won-Seok; Kwon, Deuk-Chul; Im, Yeon-Ho

    2013-09-01

    Although plasma etch profile simulation has been attracted much interest for developing reliable plasma etching, there still exist big gaps between current research status and predictable modeling due to the inherent complexity of plasma process. As an effort to address this issue, we present 3D feature profile simulation coupled with well-defined plasma-surface kinetic model for silicon dioxide etching process under fluorocarbon plasmas. To capture the realistic plasma surface reaction behaviors, a polymer layer based surface kinetic model was proposed to consider the simultaneous polymer deposition and oxide etching. Finally, the realistic plasma surface model was used for calculation of speed function for 3D topology simulation, which consists of multiple level set based moving algorithm, and ballistic transport module. In addition, the time consumable computations in the ballistic transport calculation were improved drastically by GPU based numerical computation, leading to the real time computation. Finally, we demonstrated that the surface kinetic model could be coupled successfully for 3D etch profile simulations in high-aspect ratio contact hole plasma etching.

  15. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    Science.gov (United States)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M. P.; Hihn, J. Y.

    2015-11-01

    Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  16. Effect of Drug Active Substance Particles on Wet Granulation Process.

    Czech Academy of Sciences Publication Activity Database

    Bělohlav, Z.; Břenková, L.; Hanika, Jiří; Durdil, P.; Rapek, P.; Tomášek, V.

    2007-01-01

    Roč. 85, A7 (2007) , s. 974-980 ISSN 0263-8762 Institutional research plan: CEZ:AV0Z40720504 Keywords : wet granulation * control * active substance Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.837, year: 2007

  17. Multivariate modelling of the tablet manufacturing process with wet granulation for tablet optimization and in-process control

    NARCIS (Netherlands)

    Westerhuis, J.A; Coenegracht, P.M J; Lerk, C.F

    1997-01-01

    The process of tablet manufacturing with granulation is described as a two-step process. The first step comprises wet granulation of the powder mixture, and in the second step the granules are compressed into tablets. For the modelling of the pharmaceutical process of wet granulation and tableting,

  18. Process for recovering a uranium containing concentrate and purified phosphoric acid from a wet process phosphoric acid containing uranium

    International Nuclear Information System (INIS)

    Weterings, C.A.M.; Janssen, J.A.

    1985-01-01

    A process is claimed for recovering from a wet process phosphoric acid which contains uranium, a uranium containing concentrate and a purified phosphoric acid. The wet process phosphoric acid is treated with a precipitant in the presence of a reducing agent and an aliphatic ketone

  19. Process for recovering a uranium containing concentrate and purified phosphoric acid from a wet process phosphoric acid containing uranium

    Energy Technology Data Exchange (ETDEWEB)

    Weterings, C.A.M.; Janssen, J.A.

    1985-04-30

    A process is claimed for recovering from a wet process phosphoric acid which contains uranium, a uranium containing concentrate and a purified phosphoric acid. The wet process phosphoric acid is treated with a precipitant in the presence of a reducing agent and an aliphatic ketone.

  20. Feature scale modeling for etching and deposition processes in semiconductor manufacturing

    International Nuclear Information System (INIS)

    Pyka, W.

    2000-04-01

    Simulation of etching and deposition processes as well as three-dimensional geometry generation are important issues in state of the art TCAD applications. Three-dimensional effects are gaining importance for semiconductor devices and for their interconnects. Therefore a strictly physically based simulation of their topography is required. Accurate investigation of single etching and deposition processes has become equally important as process integration. Within this context several aspects of three-dimensional topography simulation have been covered by this thesis and new and interesting results have been achieved in various areas. The algorithmic core of the cell-based structuring element surface propagation method has been optimized and has been eliminated from its position as factor which predominantly determines the required CPU time. In parallel with investigated optimization techniques and required by various process models, the implementation of the surface normal calculation and the special handling of voids and unconnected parts of the geometry has been completed in three dimensions. A process-step-based solid modeling tool which incorporates layout data as well as aerial image simulation has been supplied. It can be coupled with the topography simulation and includes simple geometrically based models for CMP and oxidation. In the presented combination, the tool makes use of the design information stored in the layout file, combines it with the manufacturing recipe, and hence is extremely helpful for the automatic generation of three-dimensional structures. Its usefulness has been proven with several interconnect examples. Regarding topography models, resist development not only turned out to be very helpful for predicting exposed and etched resist profiles within a rigorous lithography simulation, but, by means of benchmark examples, also demonstrated the extraordinary stability of the proposed cellular surface movement algorithm. With respect to

  1. Silicon dioxide etching process for fabrication of micro-optics employing pulse-modulated electron-beam-excited plasma

    International Nuclear Information System (INIS)

    Takeda, Keigo; Ohta, Takayuki; Ito, Masafumi; Hori, Masaru

    2006-01-01

    Silicon dioxide etching process employing a pulse-modulated electron-beam-excited plasma (EBEP) has been developed for a fabrication process of optical micro-electro-mechanical systems (MEMSs). Nonplanar dielectric materials were etched by using self-bias induced by the electron beam generating the plasma. In order to investigate the effect of pulse modulation on electron beam, plasma diagnostics were carried out in the EBEP employing C 4 F 8 gas diluted with Ar gas by using a Langmuir single probe and time resolved optical emission spectroscopy. It was found that the pulse-modulated EBEP has an excellent potential to reduce the plasma-induced thermal damage on a photoresist film on a substrate to get the uniform etching and the anisotropic SiO 2 etching in comparison with the conventional EBEP. The pulse-modulated EBEP enabled us to get the high etch rate of SiO 2 of 375 nm/min without any additional bias power supply. Furthermore, the microfabrication on the core area of optical fiber was realized. These results indicate that the pulse-modulated EBEP will be a powerful tool for the application to optical MEMS process

  2. Selective dry etching of silicon containing anti-reflective coating

    Science.gov (United States)

    Sridhar, Shyam; Nolan, Andrew; Wang, Li; Karakas, Erdinc; Voronin, Sergey; Biolsi, Peter; Ranjan, Alok

    2018-03-01

    Multi-layer patterning schemes involve the use of Silicon containing Anti-Reflective Coating (SiARC) films for their anti-reflective properties. Patterning transfer completion requires complete and selective removal of SiARC which is very difficult due to its high silicon content (>40%). Typically, SiARC removal is accomplished through a non-selective etch during the pattern transfer process using fluorine containing plasmas, or an ex-situ wet etch process using hydrofluoric acid is employed to remove the residual SiARC, post pattern transfer. Using a non-selective etch may result in profile distortion or wiggling, due to distortion of the underlying organic layer. The drawbacks of using wet etch process for SiARC removal are increased overall processing time and the need for additional equipment. Many applications may involve patterning of active structures in a poly-Si layer with an underlying oxide stopping layer. In such applications, SiARC removal selective to oxide using a wet process may prove futile. Removing SiARC selectively to SiO2 using a dry etch process is also challenging, due to similarity in the nature of chemical bonds (Si - O) in the two materials. In this work, we present highly selective etching of SiARC, in a plasma driven by a surface wave radial line slot antenna. The first step in the process involves an in-situ modification of the SiARC layer in O2 plasma followed by selective etching in a NF3/H2 plasma. Surface treatment in O2 plasma resulted in enhanced etching of the SiARC layer. For the right processing conditions, in-situ NF3/H2 dry etch process demonstrated selectivity values greater than 15:1 with respect to SiO2. The etching chemistry, however, was sensitive to NF3:H2 gas ratio. For dilute NF3 in H2, no SiARC etching was observed. Presumably, this is due to the deposition of ammonium fluorosilicate layer that occurs for dilute NF3/H2 plasmas. Additionally, challenges involved in selective SiARC removal (selective to SiO2, organic

  3. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y., E-mail: jean-yves.hihn@univ-fcomte.fr

    2015-11-15

    Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  4. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    International Nuclear Information System (INIS)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y.

    2015-01-01

    Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  5. Grafting on nuclear tracks using the active sites that remain after the etching process

    International Nuclear Information System (INIS)

    Mazzei, R.; Bermudez, G. Garcia; Chappa, V.C.; Grosso, M.F. del; Fernandez, A.

    2006-01-01

    Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam

  6. Grafting on nuclear tracks using the active sites that remain after the etching process

    Energy Technology Data Exchange (ETDEWEB)

    Mazzei, R. [Unidad de Aplicaciones Tecnologicas y Agropecuarias, CNEA, 1429 Buenos Aires (Argentina) and Universidad Tecnologica Nacional, Buenos Aires (Argentina)]. E-mail: mazzei@cae.cnea.gov.ar; Bermudez, G. Garcia [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, 1653 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Chappa, V.C. [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Grosso, M.F. del [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); U. A. de Materiales, CNEA, 1429 Buenos Aires (Argentina); Fernandez, A. [Universidad Tecnologica Nacional, Buenos Aires (Argentina)

    2006-09-15

    Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam.

  7. Etching of Niobium Sample Placed on Superconducting Radio Frequency Cavity Surface in Ar/CL2 Plasma

    International Nuclear Information System (INIS)

    Upadhyay, Janardan; Phillips, Larry; Valente, Anne-Marie

    2011-01-01

    Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. It has been proven with flat samples that the bulk Niobium (Nb) removal rate and the surface roughness after the plasma etchings are equal to or better than wet etching processes. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders serve the purpose of diagnostic ports for the measurement of the plasma parameters and for the holding of the Nb sample to be etched. The plasma properties at RF (100 MHz) and MW (2.45 GHz) frequencies are being measured with the help of electrical and optical probes at different pressures and RF power levels inside of this cavity. The niobium coupons placed on several holders around the cell are being etched simultaneously. The etching results will be presented at this conference.

  8. Etching of Niobium Sample Placed on Superconducting Radio Frequency Cavity Surface in Ar/CL2 Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Janardan Upadhyay, Larry Phillips, Anne-Marie Valente

    2011-09-01

    Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. It has been proven with flat samples that the bulk Niobium (Nb) removal rate and the surface roughness after the plasma etchings are equal to or better than wet etching processes. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders serve the purpose of diagnostic ports for the measurement of the plasma parameters and for the holding of the Nb sample to be etched. The plasma properties at RF (100 MHz) and MW (2.45 GHz) frequencies are being measured with the help of electrical and optical probes at different pressures and RF power levels inside of this cavity. The niobium coupons placed on several holders around the cell are being etched simultaneously. The etching results will be presented at this conference.

  9. Low-frequency magnetization processes in chemically etched Co-based amorphous ribbons

    International Nuclear Information System (INIS)

    Betancourt, I.; Martinez, L.A.; Valenzuela, R.

    2005-01-01

    In this report we present a study of the magnetization processes for Co-based amorphous ribbons at low frequencies (10 Hz-13 MHz) as a function of decreasing thicknesses attained by chemical etching. Reversible domain-wall bulging, characterized by initial permeability and relaxation frequency, was monitored by means of inductance measurements. The real part of inductance (proportional to initial permeability) exhibited a decreasing trend with diminishing ribbon thickness, together with an increasing tendency for the relaxation frequency. For high amplitude of the ac field (leading to domain-wall unpinning), reduced ribbon thickness showed a deleterious-enhancement effect on irreversible domain-wall displacement, which was observed for both real and imaginary inductance spectroscopic plots. Results are interpreted in terms of reduced domain-wall pinning distances resulting from thinner alloy samples

  10. XAFS studies of monodisperse Au nanoclusters formation in the etching process

    International Nuclear Information System (INIS)

    Yang, Lina; Huang, Ting; Liu, Wei; Bao, Jie; Huang, Yuanyuan; Cao, Yuanjie; Yao, Tao; Sun, Zhihu; Wei, Shiqiang

    2016-01-01

    Understanding the formation mechanism of gold nanoclusters is essential to the development of their synthetic chemistry. Here, by using x-ray absorption fine-structure (XAFS) spectroscopy, UV-Vis and MS spectra, the formation process of monodisperse Au 13 nanoclusters is investigated. We find that a critical step involving the formation of smaller Au 8 -Au 11 metastable intermediate clusters induced by the HCl + HSR etching of the polydisperse Au n precursor clusters occurs firstly. Then these intermediate species undergo a size-growth to Au 13 cores, followed by a slow structure rearrangement to reach the final stable structure. This work enriches the understanding of cluster formation chemistry and may guide the way towards the design and the controllable synthesis of nanoclusters. (paper)

  11. Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour.

    Science.gov (United States)

    Nagai, Masatsugu; Nakanishi, Kazuhiro; Takahashi, Hiraku; Kato, Hiromitsu; Makino, Toshiharu; Yamasaki, Satoshi; Matsumoto, Tsubasa; Inokuma, Takao; Tokuda, Norio

    2018-04-27

    Diamond possesses excellent physical and electronic properties, and thus various applications that use diamond are under development. Additionally, the control of diamond geometry by etching technique is essential for such applications. However, conventional wet processes used for etching other materials are ineffective for diamond. Moreover, plasma processes currently employed for diamond etching are not selective, and plasma-induced damage to diamond deteriorates the device-performances. Here, we report a non-plasma etching process for single crystal diamond using thermochemical reaction between Ni and diamond in high-temperature water vapour. Diamond under Ni films was selectively etched, with no etching at other locations. A diamond-etching rate of approximately 8.7 μm/min (1000 °C) was successfully achieved. To the best of our knowledge, this rate is considerably greater than those reported so far for other diamond-etching processes, including plasma processes. The anisotropy observed for this diamond etching was considerably similar to that observed for Si etching using KOH.

  12. Silicon integrated circuit process

    International Nuclear Information System (INIS)

    Lee, Jong Duck

    1985-12-01

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  13. Silicon integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Duck

    1985-12-15

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  14. Finite element simulation of dynamic wetting flows as an interface formation process

    KAUST Repository

    Sprittles, J.E.; Shikhmurzaev, Y.D.

    2013-01-01

    A mathematically challenging model of dynamic wetting as a process of interface formation has been, for the first time, fully incorporated into a numerical code based on the finite element method and applied, as a test case, to the problem

  15. Design of an oval-form cathode for the precision etching process of e-paper surface

    International Nuclear Information System (INIS)

    Pa, P.S.

    2009-01-01

    A newly designed oval-form cathode using electroetching for indium-tin-oxide (ITO) microstructure removal from the surface of e-paper polymer PET films is presented. Through ultra-precise microstructural etching, the semiconductor industry can effectively reclaim defective products, thereby reducing production costs. The design features for the ITO removal process and the tool design of oval-form cathodes are of significant interest. A smaller oval-form cathode minor axis, a higher cathode rotational speed, a higher concentration, or a higher electrolyte temperature corresponds to a higher ITO etching rate.

  16. Novel back-channel-etch process flow based a-IGZO TFTs for circuit and display applications on PEN foil

    NARCIS (Netherlands)

    Nag, M.; Rockele, M.; Steudel, S.; Chasin, A.; Myny, K.; Bhoolokam, A.; Willegems, M.; Smout, S.; Vicca, P.; Ameys, M.; Ke, T.H.; Schols, S.; Genoe, J.; Steen, J.L. P.J. van der; Groeseneken, G.; Heremans, P.

    2014-01-01

    In this study, we report high-quality amorphous indiunrv-galiium-zinc-oxide (a-IGZO) thinfilm transistors (TFTs) fabricated on a polyethylene naphthalate foil using a new back-channel-etch (BCE) process flow. The BCE flow allows a better scalability of TFTs for high-resolution backplanes and related

  17. Core-shell polymer nanorods by a two-step template wetting process

    International Nuclear Information System (INIS)

    Dougherty, S; Liang, J

    2009-01-01

    One-dimensional core-shell polymer nanowires offer many advantages and great potential for many different applications. In this paper we introduce a highly versatile two-step template wetting process to fabricate two-component core-shell polymer nanowires with controllable shell thickness. PLLA and PMMA were chosen as model polymers to demonstrate the feasibility of this process. Solution wetting with different concentrations of polymer solutions was used to fabricate the shell layer and melt wetting was used to fill the shell with the core polymer. The shell thickness was analyzed as a function of the polymer solution concentration and viscosity, and the core-shell morphology was observed with TEM. This paper demonstrates the feasibility of fabricating polymer core-shell nanostructures using our two-step template wetting process and opens the arena for optimization and future experiments with polymers that are desirable for specific applications.

  18. Normally-off AlGaN/GaN-based MOS-HEMT with self-terminating TMAH wet recess etching

    Science.gov (United States)

    Son, Dong-Hyeok; Jo, Young-Woo; Won, Chul-Ho; Lee, Jun-Hyeok; Seo, Jae Hwa; Lee, Sang-Heung; Lim, Jong-Won; Kim, Ji Heon; Kang, In Man; Cristoloveanu, Sorin; Lee, Jung-Hee

    2018-03-01

    Normally-off AlGaN/GaN-based MOS-HEMT has been fabricated by utilizing damage-free self-terminating tetramethyl ammonium hydroxide (TMAH) recess etching. The device exhibited a threshold voltage of +2.0 V with good uniformity, extremely small hysteresis of ∼20 mV, and maximum drain current of 210 mA/mm. The device also exhibited excellent off-state performances, such as breakdown voltage of ∼800 V with off-state leakage current as low as ∼10-12 A and high on/off current ratio (Ion/Ioff) of 1010. These excellent device performances are believed to be due to the high quality recessed surface, provided by the simple self-terminating TMAH etching.

  19. Preliminary comparison of three processes of AlN oxidation: dry, wet and mixed ones

    Directory of Open Access Journals (Sweden)

    Korbutowicz R.

    2016-03-01

    Full Text Available Three methods of AlN layers oxidation: dry, wet and mixed (wet with oxygen were compared. Some physical parameters of oxidized thin films of aluminum nitride (AlN layers grown on silicon Si(1 1 1 were investigated by means Energy-Dispersive X-ray Spectroscopy (EDS and Spectroscopic Ellipsometry (SE. Three series of the thermal oxidations processes were carried out at 1012 °C in pure nitrogen as carrying gas and various gas ambients: (a dry oxidation with oxygen, (b wet oxidation with water steam and (c mixed atmosphere with various process times. All the research methods have shown that along with the rising of the oxidation time, AlN layer across the aluminum oxide nitride transforms to aluminum oxide. The mixed oxidation was a faster method than the dry or wet ones.

  20. Di- and tri-carboxylic-acid-based etches for processing high temperature superconducting thin films and related materials

    International Nuclear Information System (INIS)

    Ginley, D.S.; Barr, L.; Ashby, C.I.H.; Plut, T.A.; Urea, D.; Siegal, M.P.; Martens, J.S.; Johansson, M.E.

    1994-01-01

    The development of passive and active electronics from high-temperature superconducting thin films depends on the development of process technology capable of producing appropriate feature sizes without degrading the key superconducting properties. We present a new class of chelating etches based on di- and tri-carboxylic acids that are compatible with positive photoresists and can produce sub-micron feature sizes while typically producing increases the microwave surface resistance at 94 GHz by less than 10%. This simple etching process works well for both the Y--Ba--Cu--O and Tl--Ba--Ca--Cu--O systems. In addition, we demonstrate that the use of chelating etches with an activator such as HF allows the etching of related oxides such as LaAlO 3 , which is a key substrate material, and Pb(Zr 0.53 Ti 0.47 )O 3 (PZT) which is a key ferroelectric material for HTS and other applications such as nonvolatile memories

  1. Investigations on diamond nanostructuring of different morphologies by the reactive-ion etching process and their potential applications.

    Science.gov (United States)

    Kunuku, Srinivasu; Sankaran, Kamatchi Jothiramalingam; Tsai, Cheng-Yen; Chang, Wen-Hao; Tai, Nyan-Hwa; Leou, Keh-Chyang; Lin, I-Nan

    2013-08-14

    We report the systematic studies on the fabrication of aligned, uniform, and highly dense diamond nanostructures from diamond films of various granular structures. Self-assembled Au nanodots are used as a mask in the self-biased reactive-ion etching (RIE) process, using an O2/CF4 process plasma. The morphology of diamond nanostructures is a close function of the initial phase composition of diamond. Cone-shaped and tip-shaped diamond nanostructures result for microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) films, whereas pillarlike and grasslike diamond nanostructures are obtained for Ar-plasma-based and N2-plasma-based ultrananocrystalline diamond (UNCD) films, respectively. While the nitrogen-incorporated UNCD (N-UNCD) nanograss shows the most-superior electron-field-emission properties, the NCD nanotips exhibit the best photoluminescence properties, viz, different applications need different morphology of diamond nanostructures to optimize the respective characteristics. The optimum diamond nanostructure can be achieved by proper choice of granular structure of the initial diamond film. The etching mechanism is explained by in situ observation of optical emission spectrum of RIE plasma. The preferential etching of sp(2)-bonded carbon contained in the diamond films is the prime factor, which forms the unique diamond nanostructures from each type of diamond films. However, the excited oxygen atoms (O*) are the main etching species of diamond film.

  2. Investigation of near dry EDM compared with wet and dry EDM processes

    International Nuclear Information System (INIS)

    Gholipoor, Ahad; Baseri, Hamid; Shabgard, Mohammad Reza

    2015-01-01

    Material removal rate (MRR), tool wear ratio (TWR) and surface roughness (SR) obtained by near-dry EDM process were compared with wet and dry EDM at three levels of discharge energy in drilling of SPK steel. Surface integrity machined by this process was studied and compared with wet and dry EDM processes, by scanning electron microscopy (SEM). The results showed that at high level of discharge energy, wet EDM has the most MRR, TWR and SR, and dry EDM has the least MRR, TWR and SR, while at low discharge energy levels, near-dry EDM process has the most MRR and the least SR. SEM micrographs showed that the quality of surface obtained by near-dry EDM process is better than others and the machined surfaces by near-dry EDM process have lower micro-cracks and craters, relatively.

  3. Investigation of near dry EDM compared with wet and dry EDM processes

    Energy Technology Data Exchange (ETDEWEB)

    Gholipoor, Ahad [Islamic Azad University of Tabriz, Tabriz (Iran, Islamic Republic of); Baseri, Hamid [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shabgard, Mohammad Reza [University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2015-05-15

    Material removal rate (MRR), tool wear ratio (TWR) and surface roughness (SR) obtained by near-dry EDM process were compared with wet and dry EDM at three levels of discharge energy in drilling of SPK steel. Surface integrity machined by this process was studied and compared with wet and dry EDM processes, by scanning electron microscopy (SEM). The results showed that at high level of discharge energy, wet EDM has the most MRR, TWR and SR, and dry EDM has the least MRR, TWR and SR, while at low discharge energy levels, near-dry EDM process has the most MRR and the least SR. SEM micrographs showed that the quality of surface obtained by near-dry EDM process is better than others and the machined surfaces by near-dry EDM process have lower micro-cracks and craters, relatively.

  4. Study for process and equipment design of wet gelation stages in vibropacking process

    International Nuclear Information System (INIS)

    Tanimoto, Ryoji; Kikuchi, Toshiaki; Tanaka, Hirokazu; Amino, Masaki; Yanai, Minoru

    2004-02-01

    Process and layout design of external wet gelation stages in vibropacking process was examined for the feasibility study of commercialized FBR cycle system. In this study, following process stages for the oxide core fuel production line were covered, that is, solidification, washing, drying, calcination, reduction, sintering stages including interim storage of sintering particles and reagent recovery stage. The main results obtained by this study are as follows: (1) Based on the process examination results conducted previously, process-flow, mass-balance and number of production line/equipment were clarified. The process is covered from the receive tank of feed solution to the interim storage equipment. Reagent recovery process-flow, mass-balance were also clarified. And preliminary design of the main equipment was reexamined. (2) Normal operation procedure and the procedure after process failure were summarized along with a remote automated operation procedure. Operation sequence of each production line was mapped out by using a time-chart. (3) Design outline of reagent recovery equipments, installed to recover waste liquid from the wet gelation stages in the view of environmental impact were examined. Effective techniques such as collection of solvent, residue waste treatment method were examined its applicability and selected. Schematic block diagram was presented. (4) Analytical items and analyzing apparatus were extracted taking into account of quality control and process management. Analytical sample taking position and frequency of sampling were also examined. (5) A schematic layout drawing of main manufacturing process and reagent recovery process was presented taking into account of material handling. (6) A feature of the operating rate at each process stage was examined by analyzing failure rate reliability of each component. applying the reliability-centred method. (RCM), the operating rate was evaluated and annual maintenance period was estimated using

  5. Controlled ion track etching

    Science.gov (United States)

    George, J.; Irkens, M.; Neumann, S.; Scherer, U. W.; Srivastava, A.; Sinha, D.; Fink, D.

    2006-03-01

    It is a common practice since long to follow the ion track-etching process in thin foils via conductometry, i.e . by measurement of the electrical current which passes through the etched track, once the track breakthrough condition has been achieved. The major disadvantage of this approach, namely the absence of any major detectable signal before breakthrough, can be avoided by examining the track-etching process capacitively. This method allows one to define precisely not only the breakthrough point before it is reached, but also the length of any non-transient track. Combining both capacitive and conductive etching allows one to control the etching process perfectly. Examples and possible applications are given.

  6. Development studies of a novel wet oxidation process

    International Nuclear Information System (INIS)

    Rogers, T.W.; Dhooge, P.M.

    1995-01-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. There is a need for non-combustion processes with a wide application range to treat the large majority of these waste forms. The non-combustion process should also be safe, effective, cost-competitive, permit-able, and preferrably mobile. This paper describes the DETOX process of organic waste oxidation

  7. Measurement of the oxidation-extraction of uranium from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    Lawes, B.C.

    1985-01-01

    The present invention relates to processes for the recovery of uranium from wet-process phosphoric acid and more particularly to the oxidation-extraction steps in the DEPA-TOPO process for such recovery. A more efficient use of oxidant is obtained by monitoring the redox potential during the extraction step

  8. Multiplexed FBG and etched fiber sensors for process and health monitoring of 2-&3-D RTM components

    OpenAIRE

    Keulen, Casey J.; Yıldız, Mehmet; Yildiz, Mehmet; Suleman, Afzal

    2011-01-01

    This paper presents research being conducted on the use of a combination of fiber optic sensors for process and health monitoring of resin transfer molded (RTM) composite structures. A laboratory scale RTM apparatus has been designed and built with the capability of visually monitoring the resin filling process and embedding fiber optic sensors into the composite. Fiber Bragg gratings (FBG) and etched fiber sensors (EFS) have been multiplexed and embedded in quasi-2-D panels and 3-D hollow se...

  9. The roles of wetting liquid in the transfer process of single layer graphene onto arbitrary substrates.

    Science.gov (United States)

    Kim, Ju Hun; Yi, Junghwa; Jin, Hyeong Ki; Kim, Un Jeong; Park, Wanjun

    2013-11-01

    Wet transfer is crucial for most device structures of the proposed applications employing single layer graphene in order to take advantage of the unique physical, chemical, bio-chemical and electrical properties of the graphene. However, transfer methodologies that can be used to obtain continuous film without voids, wrinkles and cracks are limited although film perfectness critically depends on the relative surface tension of wetting liquids on the substrate. We report the importance of wetting liquid in the transfer process with a systematic study on the parameters governing film integrity in single layer graphene grown via chemical vapor deposition. Two different suspension liquids (in terms of polar character) are tested for adequacy of transfer onto SiO2 and hexamethyldisiloxane (HMDS). We found that the relative surface tension of the wetting liquid on the surfaces of the substrate is related to transfer quality. In addition, dimethyl sulfoxide (DMSO) is introduced as a good suspension liquid to HMDS, a mechanically flexible substrate.

  10. New development on electrochemical etching processes at the Atomic Energy Organization of Iran

    CERN Document Server

    Sohrabi, M

    1999-01-01

    Some highlights of new developments made in our laboratory at the Atomic Energy Organization of Iran on chemical and electrochemical etching (ECE) of polymer track detectors like polycarbonate (PC) are presented. They include introduction of new ECE chamber systems and methods for production of ECE signs and symbols, and a new versatile ECE chamber (VECE) system for multi-purpose, multi-size, and/or multi-shape detector processing; determination of photoneutron doses in and around high-energy X-ray beams of a 20 MV medical accelerator; verification of the Smythe and Mason equations for ECE of tracks in polymers; ECE of alpha and recoil tracks in PC using PMW, PEW and PEMW etchants; introduction of a novel method using ethylene diamine for treatment of PC detectors with its applications, for example in precision removal of surface layers of PC (e.g. bulk removal rates of about 0.04, 0.15, 0.36, 0.66, and 1.33 mm min sup - sup 1 for 60%, 65%, 70%, 75% and 80% ethylene diamine solution (v/v) in water respectivel...

  11. 3-Dimensional Microorifice Fabricated Utilizing Single Undercut Etching Process for Producing Ultrasmall Water and Chitosan Droplets

    Directory of Open Access Journals (Sweden)

    Che-Hsin Lin

    2013-01-01

    Full Text Available This research reports a microfluidic device for producing small droplets via a microorifice and a T-junction structure. The orifice is fabricated using an isotropic undercut etching process of amorphous glass materials. Since the equivalent hydraulic diameter of the produced microorifice can be as small as 1.1 μm, the microdevice can easily produce droplets of the size smaller than 10 μm in diameter. In addition, a permanent hydrophobic coating technique is also applied to modify the main channel to be hydrophobic to enhance the formation of water-based droplets. Experimental results show that the developed microfluidic chip with the ultrasmall orifice can steadily produce water-in-oil droplets with different sizes. Uniform water-in-oil droplets with the size from 60 μm to 6.5 μm in diameter can be formed by adjusting the flow rate ratio of the continuous phase and the disperse phases from 1 to 7. Moreover, curable linear polymer of chitosan droplets with the size smaller than 100 μm can also be successfully produced using the developed microchip device. The microfluidic T-junction with a micro-orifice developed in the present study provides a simple yet efficient way to produce various droplets of different sizes.

  12. Thermal stability study of Cr/Au contact formed on n-type Ga-polar GaN, N-polar GaN, and wet-etched N-polar GaN surfaces

    International Nuclear Information System (INIS)

    Choi, Yunju; Kim, Yangsoo; Ahn, Kwang-Soon; Kim, Hyunsoo

    2014-01-01

    Highlights: • The Cr/Au contact on n-type Ga-polar (0 0 0 1) GaN, N-polar (0 0 0 −1) GaN, and wet-etched N-polar GaN were investigated. • Thermal annealing led to a significant degradation of contact formed on N-polar n-GaN samples. • Contact degradation was shown to be closely related to the increase in the electrical resistivity of n-GaN. • Out-diffusion of Ga and N atoms was clearly observed in N-polar samples. - Abstract: The electrical characteristics and thermal stability of a Cr/Au contact formed on n-type Ga-polar (0 0 0 1) GaN, N-polar GaN, and wet-etched N-polar GaN were investigated. As-deposited Cr/Au showed a nearly ohmic contact behavior for all samples, i.e., the specific contact resistance was 3.2 × 10 −3 , 4.3 × 10 −4 , and 1.1 × 10 −3 Ω cm 2 for the Ga-polar, flat N-polar, and roughened N-polar samples, respectively. However, thermal annealing performed at 250 °C for 1 min in a N 2 ambient led to a significant degradation of contact, i.e., the contact resistance increased by 186, 3260, and 2030% after annealing for Ga-polar, flat N-polar, and roughened N-polar samples, respectively. This could be due to the different disruption degree of Cr/Au and GaN interface after annealing, i.e., the insignificant interfacial reaction occurred in the Ga-polar sample, while out-diffusion of Ga and N atoms was clearly observed in N-polar samples

  13. Thermal stability study of Cr/Au contact formed on n-type Ga-polar GaN, N-polar GaN, and wet-etched N-polar GaN surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yunju [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Suncheon Center, Korea Basic Science Institute, Suncheon 540-742 (Korea, Republic of); Kim, Yangsoo [Suncheon Center, Korea Basic Science Institute, Suncheon 540-742 (Korea, Republic of); Ahn, Kwang-Soon, E-mail: kstheory@ynu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 712-749 (Korea, Republic of); Kim, Hyunsoo, E-mail: hskim7@jbnu.ac.kr [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2014-10-30

    Highlights: • The Cr/Au contact on n-type Ga-polar (0 0 0 1) GaN, N-polar (0 0 0 −1) GaN, and wet-etched N-polar GaN were investigated. • Thermal annealing led to a significant degradation of contact formed on N-polar n-GaN samples. • Contact degradation was shown to be closely related to the increase in the electrical resistivity of n-GaN. • Out-diffusion of Ga and N atoms was clearly observed in N-polar samples. - Abstract: The electrical characteristics and thermal stability of a Cr/Au contact formed on n-type Ga-polar (0 0 0 1) GaN, N-polar GaN, and wet-etched N-polar GaN were investigated. As-deposited Cr/Au showed a nearly ohmic contact behavior for all samples, i.e., the specific contact resistance was 3.2 × 10{sup −3}, 4.3 × 10{sup −4}, and 1.1 × 10{sup −3} Ω cm{sup 2} for the Ga-polar, flat N-polar, and roughened N-polar samples, respectively. However, thermal annealing performed at 250 °C for 1 min in a N{sub 2} ambient led to a significant degradation of contact, i.e., the contact resistance increased by 186, 3260, and 2030% after annealing for Ga-polar, flat N-polar, and roughened N-polar samples, respectively. This could be due to the different disruption degree of Cr/Au and GaN interface after annealing, i.e., the insignificant interfacial reaction occurred in the Ga-polar sample, while out-diffusion of Ga and N atoms was clearly observed in N-polar samples.

  14. Performance of wet process method alternatives : terminal or continuous blend

    OpenAIRE

    Fontes, Liseane P. T. L.; Pereira, Paulo A. A.; Pais, Jorge C.; Trichês, Glicério

    2006-01-01

    This study presents the results of the research to investigate asphalt rubber mixtures produced with asphalt rubber binder obtained from two different processes; (i) terminal blend (produced in refinery); (ii) continuous blend (produced in laboratory). The experiment included the evaluation of fatigue and permanent deformation resistance of two gap graded mixtures (Caltrans ARHM -GG; ADOT AR-A C) and a dense gradation Asphalt Institute (AI) mix type IV) Two asphalt rubbers from terminal blend...

  15. Ex-situ XPS-investigation of the interface between PE-CVD SiO{sub 2} and wet chemically etched MO-CVD epitaxial layers of In{sub 0.53}Ga{sub 0.47}As

    Energy Technology Data Exchange (ETDEWEB)

    Procop, M. [Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Wandel, K. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Festkoerperphysik; Verucchi, R. [Modena Univ. (Italy). Ist. di Fisica

    1995-11-01

    The As rich SiO{sub 2}/In{sub 0.53}Ga{sub 0.47}As interface which is produced by wet chemical etching before SiO{sub 2} deposition to improve the electronic properties of the interface has been studied. SiO{sub 2}-layers of about 10 to 20 nm thickness have been deposited in a plasma enhanced chemical vapour deposition (PECVD) reactor and then thinned down to about 4 to 3 nm by 1.5 keV Ar ion beam bombardment at grazing incidence (85 ) in the XPS analysis chamber. The photoelectron spectra show that an additional broadening of the In and As lines due to a possible ion beam damage can be neglected in case of a qualitative interpretation of the interface spectra. Moreover, TRIM simulations of the collision cascade reveal low damage production in the SiO{sub 2}/In{sub 0.53}Ga{sub 0.47}As interface region. Therefore such ex-situ XPS experiments allow a supervision of the interface chemistry after the fabrication process and an optimisation of the technology with regard to the etching solution and deposition conditions. The conservation or removal of the elemental arsenic and the oxidation of the semiconductor due to the SiO{sub 2} deposition are well reflected in the photoelectron spectra. (orig.)

  16. Dry etching technology for semiconductors

    CERN Document Server

    Nojiri, Kazuo

    2015-01-01

    This book is a must-have reference to dry etching technology for semiconductors, which will enable engineers to develop new etching processes for further miniaturization and integration of semiconductor integrated circuits.  The author describes the device manufacturing flow, and explains in which part of the flow dry etching is actually used. The content is designed as a practical guide for engineers working at chip makers, equipment suppliers and materials suppliers, and university students studying plasma, focusing on the topics they need most, such as detailed etching processes for each material (Si, SiO2, Metal etc) used in semiconductor devices, etching equipment used in manufacturing fabs, explanation of why a particular plasma source and gas chemistry are used for the etching of each material, and how to develop etching processes.  The latest, key technologies are also described, such as 3D IC Etching, Dual Damascene Etching, Low-k Etching, Hi-k/Metal Gate Etching, FinFET Etching, Double Patterning ...

  17. Surface Modification of Ti-35Nb-10Ta-1.5Fe by the Double Acid-Etching Process

    OpenAIRE

    Joan Lario; Angélica Amigó; Francisco Segovia; Vicente Amigó

    2018-01-01

    Surface topography and composition influence the osteoblastic proliferation and osseointegration rates, which favor the biomechanical stability of bone anchoring and implants. In recent years, beta titanium alloys have been developed, and are composed of biocompatible elements, have low elastic modulus, high corrosion resistance, and mechanical properties to improve the long performance behavior of biomaterials. In the present research, the influence of the acid-etching process was studied in...

  18. Dry-plasma-free chemical etch technique for variability reduction in multi-patterning (Conference Presentation)

    Science.gov (United States)

    Kal, Subhadeep; Mohanty, Nihar; Farrell, Richard A.; Franke, Elliott; Raley, Angelique; Thibaut, Sophie; Pereira, Cheryl; Pillai, Karthik; Ko, Akiteru; Mosden, Aelan; Biolsi, Peter

    2017-04-01

    Scaling beyond the 7nm technology node demands significant control over the variability down to a few angstroms, in order to achieve reasonable yield. For example, to meet the current scaling targets it is highly desirable to achieve sub 30nm pitch line/space features at back-end of the line (BEOL) or front end of line (FEOL); uniform and precise contact/hole patterning at middle of line (MOL). One of the quintessential requirements for such precise and possibly self-aligned patterning strategies is superior etch selectivity between the target films while other masks/films are exposed. The need to achieve high etch selectivity becomes more evident for unit process development at MOL and BEOL, as a result of low density films choices (compared to FEOL film choices) due to lower temperature budget. Low etch selectivity with conventional plasma and wet chemical etch techniques, causes significant gouging (un-intended etching of etch stop layer, as shown in Fig 1), high line edge roughness (LER)/line width roughness (LWR), non-uniformity, etc. In certain circumstances this may lead to added downstream process stochastics. Furthermore, conventional plasma etches may also have the added disadvantage of plasma VUV damage and corner rounding (Fig. 1). Finally, the above mentioned factors can potentially compromise edge placement error (EPE) and/or yield. Therefore a process flow enabled with extremely high selective etches inherent to film properties and/or etch chemistries is a significant advantage. To improve this etch selectivity for certain etch steps during a process flow, we have to implement alternate highly selective, plasma free techniques in conjunction with conventional plasma etches (Fig 2.). In this article, we will present our plasma free, chemical gas phase etch technique using chemistries that have high selectivity towards a spectrum of films owing to the reaction mechanism ( as shown Fig 1). Gas phase etches also help eliminate plasma damage to the

  19. Dry Etching

    DEFF Research Database (Denmark)

    Stamate, Eugen; Yeom, Geun Young

    2016-01-01

    generation) to 2,200 × 2,500 mm (eighth generation), and the substrate size is expected to increase further within a few years. This chapter aims to present relevant details on dry etching including the phenomenology, materials to be etched with the different recipes, plasma sources fulfilling the dry...

  20. Multivariate statistical modelling of the pharmaceutical process of wet granulation and tableting

    NARCIS (Netherlands)

    Westerhuis, Johannes Arnold

    1997-01-01

    Wet granulation in high-shear mixers is a process of particle size enlargement much used in the pharmaceutical industry to improve the tableting properties of powder mixtures, such as flowability and compactibility, necessary for the large scale production of pharmaceutical talbets. ... Zie: Summary

  1. Comparison of torque measurements and near-infrared spectroscopy in characterization of a wet granulation process

    DEFF Research Database (Denmark)

    Jørgensen, Anna Cecilia; Luukkonen, Pirjo; Rantanen, Jukka

    2004-01-01

    The purpose of this study was to compare impeller torque measurements and near-infrared (NIR) spectroscopy in the characterization of the water addition phase of a wet granulation process. Additionally, the effect of hydrate formation during granulation on the impeller torque was investigated....... Anhydrous theophylline, alpha-lactose monohydrate, and microcrystalline cellulose (MCC) were used as materials for the study. The materials and mixtures of them were granulated using purified water in a small-scale high-shear mixer. The impeller torque was registered and NIR spectra of wet samples were...... recorded at-line. The torque and the NIR baseline-corrected water absorbances increased with increasing water content. A plateau in the NIR baseline-corrected water absorbances was observed for wet masses containing MCC. This was at the region of optimal water amount for granulation according to the torque...

  2. Value-added and Supporting - Inhibiting Factors for the Wet Processing of Coffee

    OpenAIRE

    Hariyati, Yuli

    2014-01-01

    Coffee is one of the annual crops which are widely favored by coffee enjoyers. SidomulyoVillage is one of the fourth largest coffee producing villages in District of Silo with a land area of 180 ha in 2009. Coffee experiences a process of harvest and post harvest; one of the activities of post-harvest is coffee processing. Coffee processing is divided into two; wet processing and dry processing. The majority of farmers in SidomulyoVillage do dry processing; about 75% of farmers do dry process...

  3. Dry etching for microelectronics

    CERN Document Server

    Powell, RA

    1984-01-01

    This volume collects together for the first time a series of in-depth, critical reviews of important topics in dry etching, such as dry processing of III-V compound semiconductors, dry etching of refractory metal silicides and dry etching aluminium and aluminium alloys. This topical format provides the reader with more specialised information and references than found in a general review article. In addition, it presents a broad perspective which would otherwise have to be gained by reading a large number of individual research papers. An additional important and unique feature of this book

  4. Etching in microsystem technology

    CERN Document Server

    Kohler, Michael

    2008-01-01

    Microcomponents and microdevices are increasingly finding application in everyday life. The specific functions of all modern microdevices depend strongly on the selection and combination of the materials used in their construction, i.e., the chemical and physical solid-state properties of these materials, and their treatment. The precise patterning of various materials, which is normally performed by lithographic etching processes, is a prerequisite for the fabrication of microdevices.The microtechnical etching of functional patterns is a multidisciplinary area, the basis for the etching p

  5. Combination of gettering and etching in multicrystalline silicon used in solar cells processing

    International Nuclear Information System (INIS)

    Dimassi, W.; Bouaicha, M.; Nouri, H.; Ben Nasrallah, S.; Bessais, B.

    2006-01-01

    Undesired impurities can be removed away from multicrystalline silicon (mc-Si) wafers by combining porous silicon (PS) formation and heat treatments. The gettering procedure used in this work is based on the formation of a PS film at both back and front sides of the mc-Si wafers, followed by a heat treatment. The latter was achieved in an infrared furnace at different temperatures and during various periods. We show that when the based material undergoes such a gettering, the electrical properties (short-circuit current, open-circuit voltage, serial and shunt resistances) and the electronic parameters (diffusion length and grain boundary recombination velocity) of the corresponding solar cells can be improved only if some regions of the wafers are etched. Compared to reference cells based on untreated wafers, the diffusion length and grain boundary recombination velocity of solar cells fabricated from gettered and etched samples was improved by about 30% and reduced by a factor of 10, respectively

  6. Overview Of Dry-Etch Techniques

    Science.gov (United States)

    Salzer, John M.

    1986-08-01

    With pattern dimensions shrinking, dry methods of etching providing controllable degrees of anisotropy become a necessity. A number of different configurations of equipment - inline, hex, planar, barrel - have been offered, and within each type, there are numerous significant variations. Further, each specific type of machine must be perfected over a complex, interactive parameter space to achieve suitable removal of various materials. Among the most critical system parameters are the choice of cathode or anode to hold the wafers, the chamber pressure, the plasma excitation frequency, and the electrode and magnetron structures. Recent trends include the use of vacuum load locks, multiple chambers, multiple electrodes, downstream etching or stripping, and multistep processes. A major percentage of etches in production handle the three materials: polysilicon, oxide and aluminum. Recent process developments have targeted refractory metals, their silicides, and with increasing emphasis, silicon trenching. Indeed, with new VLSI structures, silicon trenching has become the process of greatest interest. For stripping, dry processes provide advantages other than anisotropy. Here, too, new configurations and methods have been introduced recently. While wet processes are less than desirable from a number of viewpoints (handling, safety, disposal, venting, classes of clean room, automatability), dry methods are still being perfected as a direct, universal replacement. The paper will give an overview of these machine structures and process solutions, together with examples of interest. These findings and the trends discussed are based on semiannual survey of manufacturers and users of the various types of equipment.

  7. Oxidation-extraction of uranium from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    Lawes, B.C.

    1985-01-01

    The invention involves an improvement to the reductive stripping process for recovering uranium values from wet-process phosphoric acid solution, where uranium in the solution is oxidized to uranium (VI) oxidation state and then extracted from the solution by contact with a water immiscible organic solvent, by adding sufficient oxidant, hydrogen peroxide, to obtain greater than 90 percent conversion of the uranium to the uranium (VI) oxidation state to the phosphoric acid solution and simultaneously extracting the uranium (VI)

  8. Texture-Etched SnO2 Glasses Applied to Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Bing-Rui Wu

    2014-01-01

    Full Text Available Transparent electrodes of tin dioxide (SnO2 on glasses were further wet-etched in the diluted HCl:Cr solution to obtain larger surface roughness and better light-scattering characteristic for thin-film solar cell applications. The process parameters in terms of HCl/Cr mixture ratio, etching temperature, and etching time have been investigated. After etching process, the surface roughness, transmission haze, and sheet resistance of SnO2 glasses were measured. It was found that the etching rate was increased with the additions in etchant concentration of Cr and etching temperature. The optimum texture-etching parameters were 0.15 wt.% Cr in 49% HCl, temperature of 90°C, and time of 30 sec. Moreover, silicon thin-film solar cells with the p-i-n structure were fabricated on the textured SnO2 glasses using hot-wire chemical vapor deposition. By optimizing the texture-etching process, the cell efficiency was increased from 4.04% to 4.39%, resulting from the increment of short-circuit current density from 14.14 to 15.58 mA/cm2. This improvement in cell performances can be ascribed to the light-scattering effect induced by surface texturization of SnO2.

  9. Single-Run Single-Mask Inductively-Coupled-Plasma Reactive-Ion-Etching Process for Fabricating Suspended High-Aspect-Ratio Microstructures

    Science.gov (United States)

    Yang, Yao-Joe; Kuo, Wen-Cheng; Fan, Kuang-Chao

    2006-01-01

    In this work, we present a single-run single-mask (SRM) process for fabricating suspended high-aspect-ratio structures on standard silicon wafers using an inductively coupled plasma-reactive ion etching (ICP-RIE) etcher. This process eliminates extra fabrication steps which are required for structure release after trench etching. Released microstructures with 120 μm thickness are obtained by this process. The corresponding maximum aspect ratio of the trench is 28. The SRM process is an extended version of the standard process proposed by BOSCH GmbH (BOSCH process). The first step of the SRM process is a standard BOSCH process for trench etching, then a polymer layer is deposited on trench sidewalls as a protective layer for the subsequent structure-releasing step. The structure is released by dry isotropic etching after the polymer layer on the trench floor is removed. All the steps can be integrated into a single-run ICP process. Also, only one mask is required. Therefore, the process complexity and fabrication cost can be effectively reduced. Discussions on each SRM step and considerations for avoiding undesired etching of the silicon structures during the release process are also presented.

  10. Municipal solid waste processing and separation employing wet torrefaction for alternative fuel production and aluminum reclamation.

    Science.gov (United States)

    Mu'min, Gea Fardias; Prawisudha, Pandji; Zaini, Ilman Nuran; Aziz, Muhammad; Pasek, Ari Darmawan

    2017-09-01

    This study employs wet torrefaction process (also known as hydrothermal) at low temperature. This process simultaneously acts as waste processing and separation of mixed waste, for subsequent utilization as an alternative fuel. The process is also applied for the delamination and separation of non-recyclable laminated aluminum waste into separable aluminum and plastic. A 2.5-L reactor was used to examine the wet torrefaction process at temperatures below 200°C. It was observed that the processed mixed waste was converted into two different products: a mushy organic part and a bulky plastic part. Using mechanical separation, the two products can be separated into a granular organic product and a plastic bulk for further treatment. TGA analysis showed that no changes in the plastic composition and no intrusion from plastic fraction to the organic fraction. It can be proclaimed that both fractions have been completely separated by wet torrefaction. The separated plastic fraction product obtained from the wet torrefaction treatment also contained relatively high calorific value (approximately 44MJ/kg), therefore, justifying its use as an alternative fuel. The non-recyclable plastic fraction of laminated aluminum was observed to be delaminated and separated from its aluminum counterpart at a temperature of 170°C using an additional acetic acid concentration of 3%, leaving less than 25% of the plastic content in the aluminum part. Plastic products from both samples had high calorific values of more than 30MJ/kg, which is sufficient to be converted and used as a fuel. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Metal-assisted etch combined with regularizing etch

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Joanne; Miller, Jeff; Jura, Michael; Black, Marcie R.; Forziati, Joanne; Murphy, Brian; Magliozzi, Lauren

    2018-03-06

    In an aspect of the disclosure, a process for forming nanostructuring on a silicon-containing substrate is provided. The process comprises (a) performing metal-assisted chemical etching on the substrate, (b) performing a clean, including partial or total removal of the metal used to assist the chemical etch, and (c) performing an isotropic or substantially isotropic chemical etch subsequently to the metal-assisted chemical etch of step (a). In an alternative aspect of the disclosure, the process comprises (a) performing metal-assisted chemical etching on the substrate, (b) cleaning the substrate, including removal of some or all of the assisting metal, and (c) performing a chemical etch which results in regularized openings in the silicon substrate.

  12. Enhancement of a-IGZO TFT Device Performance Using a Clean Interface Process via Etch-Stopper Nano-layers

    Science.gov (United States)

    Chung, Jae-Moon; Zhang, Xiaokun; Shang, Fei; Kim, Ji-Hoon; Wang, Xiao-Lin; Liu, Shuai; Yang, Baoguo; Xiang, Yong

    2018-05-01

    To overcome the technological and economic obstacles of amorphous indium-gallium-zinc-oxide (a-IGZO)-based display backplane for industrial production, a clean etch-stopper (CL-ES) process is developed to fabricate a-IGZO-based thin film transistor (TFT) with improved uniformity and reproducibility on 8.5th generation glass substrates (2200 mm × 2500 mm). Compared with a-IGZO-based TFT with back-channel-etched (BCE) structure, a newly formed ES nano-layer ( 100 nm) and a simultaneous etching of a-IGZO nano-layer (30 nm) and source-drain electrode layer are firstly introduced to a-IGZO-based TFT device with CL-ES structure to improve the uniformity and stability of device for large-area display. The saturation electron mobility of 8.05 cm2/V s and the V th uniformity of 0.72 V are realized on the a-IGZO-based TFT device with CL-ES structure. In the negative bias temperature illumination stress and positive bias thermal stress reliability testing under a ± 30 V bias for 3600 s, the measured V th shift of CL-ES-structured device significantly decreased to - 0.51 and + 1.94 V, which are much lower than that of BCE-structured device (- 3.88 V, + 5.58 V). The electrical performance of the a-IGZO-based TFT device with CL-ES structure implies that the economic transfer from a silicon-based TFT process to the metal oxide semiconductor-based process for LCD fabrication is highly feasible.

  13. Enhancement of a-IGZO TFT Device Performance Using a Clean Interface Process via Etch-Stopper Nano-layers.

    Science.gov (United States)

    Chung, Jae-Moon; Zhang, Xiaokun; Shang, Fei; Kim, Ji-Hoon; Wang, Xiao-Lin; Liu, Shuai; Yang, Baoguo; Xiang, Yong

    2018-05-29

    To overcome the technological and economic obstacles of amorphous indium-gallium-zinc-oxide (a-IGZO)-based display backplane for industrial production, a clean etch-stopper (CL-ES) process is developed to fabricate a-IGZO-based thin film transistor (TFT) with improved uniformity and reproducibility on 8.5th generation glass substrates (2200 mm × 2500 mm). Compared with a-IGZO-based TFT with back-channel-etched (BCE) structure, a newly formed ES nano-layer (~ 100 nm) and a simultaneous etching of a-IGZO nano-layer (30 nm) and source-drain electrode layer are firstly introduced to a-IGZO-based TFT device with CL-ES structure to improve the uniformity and stability of device for large-area display. The saturation electron mobility of 8.05 cm 2 /V s and the V th uniformity of 0.72 V are realized on the a-IGZO-based TFT device with CL-ES structure. In the negative bias temperature illumination stress and positive bias thermal stress reliability testing under a ± 30 V bias for 3600 s, the measured V th shift of CL-ES-structured device significantly decreased to - 0.51 and + 1.94 V, which are much lower than that of BCE-structured device (- 3.88 V, + 5.58 V). The electrical performance of the a-IGZO-based TFT device with CL-ES structure implies that the economic transfer from a silicon-based TFT process to the metal oxide semiconductor-based process for LCD fabrication is highly feasible.

  14. Molecular dynamic simulation study of plasma etching L10 FePt media in embedded mask patterning (EMP) process

    OpenAIRE

    Jianxin Zhu; P. Quarterman; Jian-Ping Wang

    2017-01-01

    Plasma etching process of single-crystal L10-FePt media [H. Wang et al., Appl. Phys. Lett. 102(5) (2013)] is studied using molecular dynamic simulation. Embedded-Atom Method [M. S. Daw and M. I. Baskes, Phy. Rev. B 29, 6443 (1984); X. W. Zhou, R. A. Johnson and H. N. G. Wadley, Phy. Rev. B 69, 144113 (2004)] is used to calculate the interatomic potential within atoms in FePt alloy, and ZBL potential [J.F. Ziegler, J. P. Biersack and U. Littmark, “The Stopping and Range of Ions in Matter,” Vol...

  15. Effect of the electronic structure of the etched CdTe single crystals on the exciton radiation processes

    International Nuclear Information System (INIS)

    Tkachuk, P.M.; Tkachuk, V.Yi.; Mel'nichuk, S.V.; Kurik, M.V.

    2005-01-01

    Under optical excitation the structure of the radiation beyond fundamental absorption of the orientated CdTe single crystals caused by LO-phonon scattering processes of the electron-hole states is observed. Crystals have been doped with impurity of Cl as a result of the surface preparing by etching in Br-methanol. Electronic structure of the single crystals surface layer is identified on the basis of two-phonon radiation absorption investigation. Taking into account the modes selection rules the one and two phonon scattering mechanisms for two crystals surface orientations are determined

  16. Real-time control of ion density and ion energy in chlorine inductively coupled plasma etch processing

    International Nuclear Information System (INIS)

    Chang, C.-H.; Leou, K.-C.; Lin Chaung; Lin, T.-L.; Tseng, C.-W.; Tsai, C.-H.

    2003-01-01

    In this study, we have experimentally demonstrated the real-time closed-loop control of both ion density and ion energy in a chlorine inductively coupled plasma etcher. To measure positive ion density, the trace rare gases-optical emission spectroscopy is used to measure the chlorine positive ion density. An rf voltage probe is adopted to measure the root-mean-square rf voltage on the electrostatic chuck which is linearly dependent on sheath voltage. One actuator is a 13.56 MHz rf generator to drive the inductive coil seated on a ceramic window. The second actuator is also a 13.56 MHz rf generator to power the electrostatic chuck. The closed-loop controller is designed to compensate for process drift, process disturbance, and pilot wafer effect and to minimize steady-state error of plasma parameters. This controller has been used to control the etch process of unpatterned polysilicon. The experimental results showed that the closed-loop control had a better repeatability of plasma parameters compared with open-loop control. The closed-loop control can eliminate the process disturbance resulting from reflected power. In addition, experimental results also demonstrated that closed-loop control has a better reproducibility in etch rate as compared with open-loop control

  17. Highly selective SiO2 etching over Si3N4 using a cyclic process with BCl3 and fluorocarbon gas chemistries

    Science.gov (United States)

    Matsui, Miyako; Kuwahara, Kenichi

    2018-06-01

    A cyclic process for highly selective SiO2 etching with atomic-scale precision over Si3N4 was developed by using BCl3 and fluorocarbon gas chemistries. This process consists of two alternately performed steps: a deposition step using BCl3 mixed-gas plasma and an etching step using CF4/Ar mixed-gas plasma. The mechanism of the cyclic process was investigated by analyzing the surface chemistry at each step. BCl x layers formed on both SiO2 and Si3N4 surfaces in the deposition step. Early in the etching step, the deposited BCl x layers reacted with CF x radicals by forming CCl x and BF x . Then, fluorocarbon films were deposited on both surfaces in the etching step. We found that the BCl x layers formed in the deposition step enhanced the formation of the fluorocarbon films in the CF4 plasma etching step. In addition, because F radicals that radiated from the CF4 plasma reacted with B atoms while passing through the BCl x layers, the BCl x layers protected the Si3N4 surface from F-radical etching. The deposited layers, which contained the BCl x , CCl x , and CF x components, became thinner on SiO2 than on Si3N4, which promoted the ion-assisted etching of SiO2. This is because the BCl x component had a high reactivity with SiO2, and the CF x component was consumed by the etching reaction with SiO2.

  18. Optimized piranha etching process for SU8-based MEMS and MOEMS construction

    International Nuclear Information System (INIS)

    Holmes, Matthew; Keeley, Jared; Hurd, Katherine; Hawkins, Aaron; Schmidt, Holger

    2010-01-01

    We demonstrate the optimization of the concentration, temperature and cycling of a piranha (H 2 O 2 :H 2 SO 4 ) mixture that produces high yields while quickly etching hollow structures made using a highly crosslinked SU8 polymer sacrificial core. The effects of the piranha mixture on the thickness, refractive index and roughness of common micro-electromechanical systems and micro-opto-electromechanical systems fabrication materials (SiN, SiO 2 and Si) were determined. The effectiveness of the optimal piranha mixture was demonstrated in the construction of hollow anti-resonant reflecting optical waveguides

  19. Optimized piranha etching process for SU8-based MEMS and MOEMS construction

    Science.gov (United States)

    Holmes, Matthew; Keeley, Jared; Hurd, Katherine; Schmidt, Holger; Hawkins, Aaron

    2010-11-01

    We demonstrate the optimization of the concentration, temperature and cycling of a piranha (H2O2:H2SO4) mixture that produces high yields while quickly etching hollow structures made using a highly crosslinked SU8 polymer sacrificial core. The effects of the piranha mixture on the thickness, refractive index and roughness of common micro-electromechanical systems and micro-opto-electromechanical systems fabrication materials (SiN, SiO2 and Si) were determined. The effectiveness of the optimal piranha mixture was demonstrated in the construction of hollow anti-resonant reflecting optical waveguides.

  20. Optimized piranha etching process for SU8-based MEMS and MOEMS construction

    OpenAIRE

    Holmes, Matthew; Keeley, Jared; Hurd, Katherine; Schmidt, Holger; Hawkins, Aaron

    2010-01-01

    We demonstrate the optimization of the concentration, temperature and cycling of a piranha (H2O2:H2SO4) mixture that produces high yields while quickly etching hollow structures made using a highly crosslinked SU8 polymer sacrificial core. The effects of the piranha mixture on the thickness, refractive index and roughness of common micro-electromechanical systems and micro-opto-electromechanical systems fabrication materials (SiN, SiO2 and Si) were determined. The effectiveness of the optimal...

  1. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    Energy Technology Data Exchange (ETDEWEB)

    Bjerre, A B; Skammelsen Schmidt, A

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates `losses` of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation.

  2. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    International Nuclear Information System (INIS)

    Bjerre, A.B.; Skammelsen Schmidt, A.

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates 'losses' of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation

  3. Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik; Michael-Lindhard, Jonas; Hübner, Jörg

    2015-01-01

    This article describes the realization of complex high-aspect ratio silicon structures with feature dimensions from 100 lm to 100nm by deep reactive ion etching using the Bosch process. As the exact shape of the sidewall profiles can be crucial for the proper functioning of a device, the authors...... of the sacrificial structures was accomplished by thermal oxidation and subsequent selective wet etching. The effects of the dimensions and relative placement of sacrificial walls and pillars on the etching result were determined through systematic experiments. The authors applied this process for exact sidewall...

  4. Fatty acid composition of maize germ oil from high-oil hybrids wet-milling processing

    Directory of Open Access Journals (Sweden)

    Jovanović Petar Lj.

    2005-01-01

    Full Text Available Maize germ was obtained by wet-milling laboratory processing of domestic high-oil maize hybrids. After separation, the germ was subjected to extraction of maize oil. Fatty acid composition of maize germ oil was determined by gas chromatography. The results showed very high levels of unsaturated fatty acids and a constant sum of oleic and linoleic acids in oils of different maize hybrids.

  5. Solid waste management practices in wet coffee processing industries of Gidabo watershed, Ethiopia.

    Science.gov (United States)

    Ulsido, Mihret D; Li, Meng

    2016-07-01

    The financial and social contributions of coffee processing industries within most coffee export-based national economies like Ethiopia are generally high. The type and amount of waste produced and the waste management options adopted by these industries can have negative effects on the environment. This study investigated the solid waste management options adopted in wet coffee processing industries in the Gidabo watershed of Ethiopia. A field observation and assessment were made to identify whether the operational characteristics of the industries have any effect on the waste management options that were practiced. The investigation was conducted on 125 wet coffee processing industries about their solid waste handling techniques. Focus group discussion, structured questionnaires, key informant interview and transect walks are some of the tools employed during the investigation. Two major types of wastes, namely hull-bean-pulp blended solid waste and wastewater rich in dissolved and suspended solids were generated in the industries. Wet mills, on average, released 20.69% green coffee bean, 18.58% water and 60.74% pulp by weight. Even though these wastes are rich in organic matter and recyclables; the most favoured solid waste management options in the watershed were disposal (50.4%) and industrial or household composting (49.6%). Laxity and impulsive decision are the driving motives behind solid waste management in Gidabo watershed. Therefore, to reduce possible contamination of the environment, wastes generated during the processing of red coffee cherries, such as coffee wet mill solid wastes, should be handled properly and effectively through maximisation of their benefits with minimised losses. © The Author(s) 2016.

  6. Extraction of uranium from wet process phosphoric acid in centrifugal and mixer-settler batteries

    International Nuclear Information System (INIS)

    Poczynajlo, A.; Giers, M.

    1986-01-01

    Five stage countercurrent batteries were comparatively applied for the extraction of uranium from wet phosphoric acid (Chemical Works, Police) in semitechnical scale. As an extractant phase the 0.16 M equimolar solution of mono- and dinonylphenyolphosphoric acids in kerosene was used. The optimum hydrodynamic and extraction conditions for the batteries were found. Process efficiencies of the apparatus were also determined. 5 refs., 5 figs., 2 tabs. (author)

  7. Pretreatment of phosphoric acid for uranium recovery by the wet phosphoric acid process

    International Nuclear Information System (INIS)

    Chern, S.L.P.; Chen, Y.C.L.; Chang, S.S.H.; Kuo, T.S.; Ting, G.C.M.

    1980-01-01

    The proposal deals with reprocessing of phosphoric acid arising from uranium separation according to the wet phosphoric acid process and being intended for recycling. In detail, the sludge will be removed by means of an inclined separating device containing corrugated plates, then the organic impurities are washed out with kerosene in suitable facilities, and the crude phase remaining in the settling tank will be separated from the kerosene in a separating centrifuge. The method has only got low cost of installation. (UWI) [de

  8. Prediction of UV spectra and UV-radiation damage in actual plasma etching processes using on-wafer monitoring technique

    International Nuclear Information System (INIS)

    Jinnai, Butsurin; Fukuda, Seiichi; Ohtake, Hiroto; Samukawa, Seiji

    2010-01-01

    UV radiation during plasma processing affects the surface of materials. Nevertheless, the interaction of UV photons with surface is not clearly understood because of the difficulty in monitoring photons during plasma processing. For this purpose, we have previously proposed an on-wafer monitoring technique for UV photons. For this study, using the combination of this on-wafer monitoring technique and a neural network, we established a relationship between the data obtained from the on-wafer monitoring technique and UV spectra. Also, we obtained absolute intensities of UV radiation by calibrating arbitrary units of UV intensity with a 126 nm excimer lamp. As a result, UV spectra and their absolute intensities could be predicted with the on-wafer monitoring. Furthermore, we developed a prediction system with the on-wafer monitoring technique to simulate UV-radiation damage in dielectric films during plasma etching. UV-induced damage in SiOC films was predicted in this study. Our prediction results of damage in SiOC films shows that UV spectra and their absolute intensities are the key cause of damage in SiOC films. In addition, UV-radiation damage in SiOC films strongly depends on the geometry of the etching structure. The on-wafer monitoring technique should be useful in understanding the interaction of UV radiation with surface and in optimizing plasma processing by controlling UV radiation.

  9. Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A. [Institute of Nuclear Physics, Ibrahimov Str., 1, 050032 Almaty (Kazakhstan); The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan); Güven, Olgun [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey); Zdorovets, Maxim V. [Institute of Nuclear Physics, Ibrahimov Str., 1, 050032 Almaty (Kazakhstan); The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan); Taltenov, Abzal A. [The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan)

    2015-12-15

    In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H{sub 2}O{sub 2} under UV irradiation (H{sub 2}O{sub 2}/UV) and Fenton system under visible light (Fenton/H{sub 2}O{sub 2}/Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H{sub 2}O{sub 2}/UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H{sub 2}O{sub 2}/Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

  10. Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

    International Nuclear Information System (INIS)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Zdorovets, Maxim V.; Taltenov, Abzal A.

    2015-01-01

    In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H 2 O 2 under UV irradiation (H 2 O 2 /UV) and Fenton system under visible light (Fenton/H 2 O 2 /Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H 2 O 2 /UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H 2 O 2 /Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

  11. Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

    Science.gov (United States)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Zdorovets, Maxim V.; Taltenov, Abzal A.

    2015-12-01

    In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H2O2 under UV irradiation (H2O2/UV) and Fenton system under visible light (Fenton/H2O2/Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H2O2/UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H2O2/Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

  12. Deep reactive ion etching of fused silica using a single-coated soft mask layer for bio-analytical applications

    International Nuclear Information System (INIS)

    Ray, Tathagata; Zhu, Haixin; Meldrum, Deirdre R

    2010-01-01

    In this note, we present our results from process development and characterization of reactive ion etching (RIE) of fused silica using a single-coated soft masking layer (KMPR® 1025, Microchem Corporation, Newton, MA). The effects of a number of fluorine-radical-based gaseous chemistries, the gas flow rate, RF power and chamber pressure on the etch rate and etching selectivity of fused silica were studied using factorial experimental designs. RF power and pressure were found to be the most important factors in determining the etch rate. The highest fused silica etch rate obtained was about 933 Å min −1 by using SF 6 -based gas chemistry, and the highest etching selectivity between the fused silica and KMPR® 1025 was up to 1.2 using a combination of CF 4 , CHF 3 and Ar. Up to 30 µm deep microstructures have been successfully fabricated using the developed processes. The average area roughness (R a ) of the etched surface was measured and results showed it is comparable to the roughness obtained using a wet etching technique. Additionally, near-vertical sidewalls (with a taper angle up to 85°) have been obtained for the etched microstructures. The processes developed here can be applied to any application requiring fabrication of deep microstructures in fused silica with near-vertical sidewalls. To our knowledge, this is the first note on deep RIE of fused silica using a single-coated KMPR® 1025 masking layer and a non-ICP-based reactive ion etcher. (technical note)

  13. Effective treatment of oily scum via catalytic wet persulfate oxidation process activated by Fe2.

    Science.gov (United States)

    Yuan, Xingzhong; Guan, Renpeng; Wu, Zhibin; Jiang, Longbo; Li, Yifu; Chen, Xiaohong; Zeng, Guangming

    2018-04-05

    Oily scum, a hazardous by-product of petroleum industry, need to be deposed urgently to reduce environmental risks. This paper introduces catalytic wet persulfate oxidation (CWPO) process in the treatment of oily scum to realize risk relief. Under the activation of heat and Fe 2+ , persulfate (PS) was decomposed into sulfate radicals and hydroxyl radicals, which played a major role on the degradation of petroleum hydrocarbons. The effects of wet air oxidation (WAO) and CWPO process on the degradation of oily scum were compared. In CWPO process, the total petroleum hydrocarbons (TPHs) content of oily scum was decreased from 92.63% to 16.75%, which was still up to 70.19% in WAO process. The degradation rate of TPHs in CWPO process was about 3.38 times higher than that in WAO process. The great performance of CWPO process was also confirmed by elemental analysis, which indicated that the C and H contents of oily scum were reduced significantly by CWPO process. These results indicated that CWPO process has high potential on the degradation of oily scum for environmental protection. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Enhanced Control of Mercury and other HAPs by Innovative Modifications to Wet FGD Processes

    International Nuclear Information System (INIS)

    Hargrove, O.W.; Carey, T.R.; Richardson, C.F.; Skarupa, R.C.; Meserole, F.B.; Rhudy, R.G.; Brown, Thomas D.

    1997-01-01

    The overall objective of this project was to learn more about controlling emissions of hazardous air pollutants (HAPs) from coal-fired power plants that are equipped with wet flue gas desulfurization (FGD) systems. The project was included by FETC as a Phase I project in its Mega-PRDA program. Phase I of this project focused on three research areas. These areas in order of priority were: (1) Catalytic oxidation of vapor-phase elemental mercury; (2) Enhanced particulate-phase HAPs removal by electrostatic charging of liquid droplets; and (3) Enhanced mercury removal by addition of additives to FGD process liquor. Mercury can exist in two forms in utility flue gas--as elemental mercury and as oxidized mercury (predominant form believed to be HgCl 2 ). Previous test results have shown that wet scrubbers effectively remove the oxidized mercury from the gas but are ineffective in removing elemental mercury. Recent improvements in mercury speciation techniques confirm this finding. Catalytic oxidation of vapor-phase elemental mercury is of interest in cases where a wet scrubber exists or is planned for SO 2 control. If a loW--cost process could be developed to oxidize all of the elemental mercury in the flue gas, then the maximum achievable mercury removal across the existing or planned wet scrubber would increase. Other approaches for improving control of HAPs included a method for improving particulate removal across the FGD process and the use of additives to increase mercury solubility. This paper discusses results related only to catalytic oxidation of elemental mercury

  15. Method for the recovery of uranium from phosphoric acid, originating from the wet-process of uraniferous phosphate ores

    International Nuclear Information System (INIS)

    Pyrih, R.Z.; Rickard, R.S.; Carrington, O.F.

    1978-01-01

    Improvement in the process for recoverying uranium from wet-process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange circuits is described. (Auth.)

  16. Simulation of biodiesel production using hydro-esterification process from wet microalgae

    Directory of Open Access Journals (Sweden)

    Pradana Yano Surya

    2018-01-01

    Full Text Available Recently, algae have received a lot of attention as a new biomass source for the production of renewable energy, such as biodiesel. Conventionally, biodiesel is made through esterification or transesterification of oils where the process involves a catalyst and alcohol to be reacted in a reactor. However, this process is energy intensive for drying and extraction step. To overcome this situation, we studied simulation of a new route of hydro-esterification process which is combine hydrolysis and esterification processes for biodiesel production from wet microalgae. Firstly, wet microalgae treated by hydrolyzer to produce fatty acids (FAs, separated with separator, and then mixed with methanol and esterified at subcritical condition to produce fatty acid methyl esters (FAMEs while H2SO4 conducted as the catalyst. Energy and material balance of conventional and hydrolysis-esterification process was evaluated by Aspen Plus. Simulation result indicated that conventional route is energy demanding process, requiring 4.40 MJ/L biodiesel produced. In contrast, the total energy consumption of hydrolysis-esterification method can be reduced significantly into 2.43 MJ/L biodiesel. Based on the energy consumption comparison, hydro-esterification process is less costly than conventional process for biodiesel production.

  17. Precise thickness control in recess etching of AlGaN/GaN hetero-structure using photocarrier-regulated electrochemical process

    Science.gov (United States)

    Kumazaki, Yusuke; Uemura, Keisuke; Sato, Taketomo; Hashizume, Tamotsu

    2017-05-01

    The photocarrier-regulated electrochemical (PREC) process was developed for fabricating recessed-gate AlGaN/GaN high-electron-mobility transistors (HEMTs) for normally off operation. The PREC process is based on photo-assisted electrochemical etching using low-energy chemical reactions. The fundamental photo-electrochemical measurements on AlGaN/GaN heterostructures revealed that the photo-carriers generated in the top AlGaN layer caused homogeneous etching of AlGaN with a smooth surface, but those generated in the GaN layer underneath caused inhomogeneous etching that roughens the surface. The concept of the PREC process is to supply the photo-carriers generated only in the AlGaN layer by selecting proper conditions on light wavelength and voltage. The phenomenon of self-termination etching has been observed during the PREC process, where the etching depth was controlled by light intensity. The recessed-gate AlGaN/GaN HEMT fabricated with the PREC process showed positive threshold voltage and improvement in transconductance compared to planar-gate AlGaN/GaN HEMTs.

  18. Recovering of uranium from phosphoric acid produced by the wet process

    International Nuclear Information System (INIS)

    Barreiro, A.J.; Lyon, W.L.; Holleman, R.A.; Randell, C.C.

    1977-01-01

    Process for recovering uranium as from an aqueous solution of phosphoric acid arising from a wet process, with a scrubbing agent essentially composed of a hydrocarbon whose boiling point is situated between 150 0 C and 300 0 C, which reacts with the contaminents formed in the sludge in the phosphoric acid, in an efficient enough quantity to wash the contamination products forming the phosphoric acid sludge, give a sludge phase and a purified phosphoric acid phase, after which the sludge phase is extracted [fr

  19. Semitechnical studies of uranium recovery from wet process phosphoric acid by liquid-liquid-extraction method

    International Nuclear Information System (INIS)

    Poczynajlo, A.; Wlodarski, R.; Giers, M.

    1987-01-01

    A semitechnical installation for uranium recovery from wet process phosphoric acid has been built. The installation is based on technological process comprising 2 extraction cycles, the first with a mixture of mono- and dinonylphenylphosphoric acids (NPPA) and the second with a synergic mixture of di-/2-ethylhexyl/-phosphoric acid (D2EHPA) and trioctylphosphine oxide (TOPO). The installation was set going and the studies on the concentration distributions of uranium and other components of phosphoric acid have been performed for all technological circuits. 23 refs., 15 figs., 3 tabs. (author)

  20. Calculating Soil Wetness, Evapotranspiration and Carbon Cycle Processes Over Large Grid Areas Using a New Scaling Technique

    Science.gov (United States)

    Sellers, Piers

    2012-01-01

    Soil wetness typically shows great spatial variability over the length scales of general circulation model (GCM) grid areas (approx 100 km ), and the functions relating evapotranspiration and photosynthetic rate to local-scale (approx 1 m) soil wetness are highly non-linear. Soil respiration is also highly dependent on very small-scale variations in soil wetness. We therefore expect significant inaccuracies whenever we insert a single grid area-average soil wetness value into a function to calculate any of these rates for the grid area. For the particular case of evapotranspiration., this method - use of a grid-averaged soil wetness value - can also provoke severe oscillations in the evapotranspiration rate and soil wetness under some conditions. A method is presented whereby the probability distribution timction(pdf) for soil wetness within a grid area is represented by binning. and numerical integration of the binned pdf is performed to provide a spatially-integrated wetness stress term for the whole grid area, which then permits calculation of grid area fluxes in a single operation. The method is very accurate when 10 or more bins are used, can deal realistically with spatially variable precipitation, conserves moisture exactly and allows for precise modification of the soil wetness pdf after every time step. The method could also be applied to other ecological problems where small-scale processes must be area-integrated, or upscaled, to estimate fluxes over large areas, for example in treatments of the terrestrial carbon budget or trace gas generation.

  1. Introducing etch kernels for efficient pattern sampling and etch bias prediction

    Science.gov (United States)

    Weisbuch, François; Lutich, Andrey; Schatz, Jirka

    2018-01-01

    Successful patterning requires good control of the photolithography and etch processes. While compact litho models, mainly based on rigorous physics, can predict very well the contours printed in photoresist, pure empirical etch models are less accurate and more unstable. Compact etch models are based on geometrical kernels to compute the litho-etch biases that measure the distance between litho and etch contours. The definition of the kernels, as well as the choice of calibration patterns, is critical to get a robust etch model. This work proposes to define a set of independent and anisotropic etch kernels-"internal, external, curvature, Gaussian, z_profile"-designed to represent the finest details of the resist geometry to characterize precisely the etch bias at any point along a resist contour. By evaluating the etch kernels on various structures, it is possible to map their etch signatures in a multidimensional space and analyze them to find an optimal sampling of structures. The etch kernels evaluated on these structures were combined with experimental etch bias derived from scanning electron microscope contours to train artificial neural networks to predict etch bias. The method applied to contact and line/space layers shows an improvement in etch model prediction accuracy over standard etch model. This work emphasizes the importance of the etch kernel definition to characterize and predict complex etch effects.

  2. Prevalence of Salmonella in poultry processing environments in wet markets in Penang and Perlis, Malaysia.

    Science.gov (United States)

    Nidaullah, Hafiz; Abirami, Nadarajan; Shamila-Syuhada, Ahamed Kamal; Chuah, Li-Oon; Nurul, Huda; Tan, Teik Pei; Abidin, Farah Wahida Zainal; Rusul, Gulam

    2017-03-01

    The aim of this study was to determine the prevalence of various Salmonella serotypes in chickens, carcass contact surfaces as well as environmental samples collected from wet markets and small scale processing plant. A total of 182 poultry and environmental samples were collected at random on separate occasions from wet markets and small scale processing plant, during the period of October 2014 to July 2015 in Penang and Perlis, Malaysia. The samples were analyzed for the presence of Salmonella using ISO 6579:2002 conventional culture-based method. Presumptive Salmonella colonies were subjected to various biochemical tests (such as triple sugar iron and lysine iron test), serologically confirmed using polyvalent O and H antisera and further serotyped at Public Health Laboratory, Ministry of Health, Perak, Malaysia. Salmonella serotypes were isolated from 161 out of 182 samples (88.46%) with 100% prevalence in the whole chicken carcass and chicken cuts - as well as transport crate, cage, drum, knife, chopping board, display table, floor, bench wash water, wash water, and drain water. Salmonella was isolated from 91.67%, 83.33%, and 66.67% of defeathering machines, drain swabs, and apron, respectively. 17 serotypes were isolated in this study with Salmonella Albany (57/161), Salmonella Corvallis (42/161), and Salmonella Brancaster (37/161) being the predominant serovars. The most carcass contact and environmental samples collected along the wet market chicken processing line were consistently contaminated with Salmonella . This indicates that Salmonella has established itself in poultry processing environments by colonizing the surfaces of the equipment and survives in these environments by establishing biofilms. Our results highlight the need of implementing strict hygiene and sanitation standards to reduce the incidence of Salmonella . The prevalence of Salmonella in poultry can be reduced effectively by identifying and eliminating the sources and contamination

  3. Prevalence of Salmonella in poultry processing environments in wet markets in Penang and Perlis, Malaysia

    Directory of Open Access Journals (Sweden)

    Hafiz Nidaullah

    2017-03-01

    Full Text Available Aim: The aim of this study was to determine the prevalence of various Salmonella serotypes in chickens, carcass contact surfaces as well as environmental samples collected from wet markets and small scale processing plant. Materials and Methods: A total of 182 poultry and environmental samples were collected at random on separate occasions from wet markets and small scale processing plant, during the period of October 2014 to July 2015 in Penang and Perlis, Malaysia. The samples were analyzed for the presence of Salmonella using ISO 6579:2002 conventional culture-based method. Presumptive Salmonella colonies were subjected to various biochemical tests (such as triple sugar iron and lysine iron test, serologically confirmed using polyvalent O and H antisera and further serotyped at Public Health Laboratory, Ministry of Health, Perak, Malaysia. Results: Salmonella serotypes were isolated from 161 out of 182 samples (88.46% with 100% prevalence in the whole chicken carcass and chicken cuts - as well as transport crate, cage, drum, knife, chopping board, display table, floor, bench wash water, wash water, and drain water. Salmonella was isolated from 91.67%, 83.33%, and 66.67% of defeathering machines, drain swabs, and apron, respectively. 17 serotypes were isolated in this study with Salmonella Albany (57/161, Salmonella Corvallis (42/161, and Salmonella Brancaster (37/161 being the predominant serovars. Conclusion: The most carcass contact and environmental samples collected along the wet market chicken processing line were consistently contaminated with Salmonella. This indicates that Salmonella has established itself in poultry processing environments by colonizing the surfaces of the equipment and survives in these environments by establishing biofilms. Our results highlight the need of implementing strict hygiene and sanitation standards to reduce the incidence of Salmonella. The prevalence of Salmonella in poultry can be reduced effectively

  4. Prevalence of Salmonella in poultry processing environments in wet markets in Penang and Perlis, Malaysia

    Science.gov (United States)

    Nidaullah, Hafiz; Abirami, Nadarajan; Shamila-Syuhada, Ahamed Kamal; Chuah, Li-Oon; Nurul, Huda; Tan, Teik Pei; Abidin, Farah Wahida Zainal; Rusul, Gulam

    2017-01-01

    Aim: The aim of this study was to determine the prevalence of various Salmonella serotypes in chickens, carcass contact surfaces as well as environmental samples collected from wet markets and small scale processing plant. Materials and Methods: A total of 182 poultry and environmental samples were collected at random on separate occasions from wet markets and small scale processing plant, during the period of October 2014 to July 2015 in Penang and Perlis, Malaysia. The samples were analyzed for the presence of Salmonella using ISO 6579:2002 conventional culture-based method. Presumptive Salmonella colonies were subjected to various biochemical tests (such as triple sugar iron and lysine iron test), serologically confirmed using polyvalent O and H antisera and further serotyped at Public Health Laboratory, Ministry of Health, Perak, Malaysia. Results: Salmonella serotypes were isolated from 161 out of 182 samples (88.46%) with 100% prevalence in the whole chicken carcass and chicken cuts - as well as transport crate, cage, drum, knife, chopping board, display table, floor, bench wash water, wash water, and drain water. Salmonella was isolated from 91.67%, 83.33%, and 66.67% of defeathering machines, drain swabs, and apron, respectively. 17 serotypes were isolated in this study with Salmonella Albany (57/161), Salmonella Corvallis (42/161), and Salmonella Brancaster (37/161) being the predominant serovars. Conclusion: The most carcass contact and environmental samples collected along the wet market chicken processing line were consistently contaminated with Salmonella. This indicates that Salmonella has established itself in poultry processing environments by colonizing the surfaces of the equipment and survives in these environments by establishing biofilms. Our results highlight the need of implementing strict hygiene and sanitation standards to reduce the incidence of Salmonella. The prevalence of Salmonella in poultry can be reduced effectively by identifying

  5. Preliminary Evaluation of Cesium Distribution for Wet Sieving Process Planned for Soil Decontamination in Japan - 13104

    Energy Technology Data Exchange (ETDEWEB)

    Enokida, Y.; Tanada, Y.; Hirabayashi, D. [Graduate School of Engineering, 1 Furo-cho Nagoya-shi, Aichi-ken, 4648603 (Japan); Sawada, K. [EcoTopia Science Institute, Nagoya University, 1 Furo-cho Nagoya-shi, Aichi-ken, 4648603 (Japan)

    2013-07-01

    For the purpose of decontaminating radioactive cesium from a huge amount of soil, which has been estimated to be 1.2x10{sup 8} m{sup 3} by excavating to a 5-cm depth from the surface of Fukushima Prefecture where a severe nuclear accident occurred at TEPCO's power generating site and has emitted a significant amount of radioactive materials, mainly radioactive cesium, a wet sieving process was selected as one of effective methods available in Japan. Some private companies have demonstrated this process for soil treatment in the Fukushima area by testing at their plants. The results were very promising, and a full-fledged application is expected to follow. In the present study, we spiked several aqueous samples containing soil collected from an industrial wet sieving plant located near our university for the recycling of construction wastes with non-radioactive cesium hydroxide. The present study provides scientific data concerning the effectiveness in volume reduction of the contaminated soil by a wet sieving process as well as the cesium distribution between the liquid phase and clay minerals for each sub-process of the full-scale one, but a simulating plant equipped with a process of coagulating sedimentation and operational safety fundamentals for the plant. Especially for the latter aspect, the study showed that clay minerals of submicron size strongly bind a high content of cesium, which was only slightly removed by coagulation with natural sedimentation (1 G) nor centrifugal sedimentation (3,700 G) and some of the cesium may be transferred to the effluent or recycled water. By applying ultracentrifugation (257,000 G), most of submicron clay minerals containing cesium was removed, and the cesium amount which might be transferred to the effluent or recycled water, could be reduced to less than 2.3 % of the original design by the addition of a cesium barrier consisting of ultracentrifugation or a hollow fiber membrane. (authors)

  6. FY 1999 report on the results of the R and D of the substituting gas system and the substituting process of the etching gas used in the electronic device production process; 1999 nendo denshi device seizo process de shiyosuru etching gas no daitai gas system oyobi daitai process no kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    As to the dry etching process and the wiring process where PFC gas and electric power are required most in the electronic device production process, an investigational study was conducted with the aim of PFC saving and energy saving, and the FY 1999 results were summed up. In the study, high efficiency etching process analysis equipment was developed, and three kinds of PFC gas quantitative analysis method were comparatively studied. Relating to the substitution of global environmental warming gas, it was found that C{sub x}F{sub y} type gas was effective which includes no oxygen, has a lot of carbon element numbers, and has double unsaturated bond. Further, in the study of the technology of PFC decomposition by plasma, it was indicated that PFC of 98.7% at maximum in exhaust gas could be removed on ideal conditions. In the dry etching technology by non-PFC gas of the organic insulating film, it was found out that NH{sub 3} base gas is more excellent in both shape and speed of etching than the existing O{sub 2} base one. As to the future wiring technology, new concepts of the optical wiring inside chip, etc. were proposed. (NEDO)

  7. Finite element simulation of dynamic wetting flows as an interface formation process

    KAUST Repository

    Sprittles, J.E.

    2013-01-01

    A mathematically challenging model of dynamic wetting as a process of interface formation has been, for the first time, fully incorporated into a numerical code based on the finite element method and applied, as a test case, to the problem of capillary rise. The motivation for this work comes from the fact that, as discovered experimentally more than a decade ago, the key variable in dynamic wetting flows - the dynamic contact angle - depends not just on the velocity of the three-phase contact line but on the entire flow field/geometry. Hence, to describe this effect, it becomes necessary to use the mathematical model that has this dependence as its integral part. A new physical effect, termed the \\'hydrodynamic resist to dynamic wetting\\', is discovered where the influence of the capillary\\'s radius on the dynamic contact angle, and hence on the global flow, is computed. The capabilities of the numerical framework are then demonstrated by comparing the results to experiments on the unsteady capillary rise, where excellent agreement is obtained. Practical recommendations on the spatial resolution required by the numerical scheme for a given set of non-dimensional similarity parameters are provided, and a comparison to asymptotic results available in limiting cases confirms that the code is converging to the correct solution. The appendix gives a user-friendly step-by-step guide specifying the entire implementation and allowing the reader to easily reproduce all presented results, including the benchmark calculations. © 2012 Elsevier Inc.

  8. Development of etched nuclear tracks

    International Nuclear Information System (INIS)

    Somogyi, G.

    1980-01-01

    The theoretical description of the evolution of etched tracks in solid state nuclear track detectors is considered for different initial conditions, for the cases of constant and varying track etch rates, isotropic and anisotropic bulk etching as well as for thick and thin detectors. It is summarized how one can calculate the main parameters of etch-pit geometry, the track length, the axes of a surface track opening, track profile and track contour. The application of the theory of etch-track evolution is demonstrated with selected practical problems. Attention is paid to certain questions related to the determination of unknown track parameters and calculation of surface track sizes. Finally, the theory is extended to the description of the perforation and etch-hole evolution process in thin detectors, which is of particular interest for track radiography and nuclear filter production. (orig.)

  9. Development of etched nuclear tracks

    International Nuclear Information System (INIS)

    Somogyi, G.

    1979-01-01

    The theoretical description of the evolution of etched tracks in solid state nuclear track detectors is considered for different initial conditions, for the cases of constant and varying track etch rates, isotopic and unisotropic bulk etching as well as for thick and thin detectors. It is summarized how the main parameters of etch-pit geometry, the track length, the axes of a surface track opening, the track profile and the track contour can be calculated. The application of the theory of etch-track evolution is demonstrated with selected practical problems. Attention is paid to certain questions related to the determination of unknown track parameters and calculation of surface track sizes. Finally, the theory is extended to the description of the perforation and etch-hole evolution process in thin detectors, which is of particular interest for track radiography and nuclear filter production. (author)

  10. Uranium recovery from wet-process phosphoric acid with octylphenyl acid phosphate. Progress report

    International Nuclear Information System (INIS)

    Arnold, W.D.; McKamey, D.R.; Baes, C.F.

    1980-01-01

    Studies were continued of a process for recovering uranium from wet-process phosphoric acid with octylphenyl acid phosphate (OPAP), a mixture of mono- and dioctylphenyl phosphoric acids. The mixture contained at least nine impurities, the principal one being octyl phenol, and also material that readily hydrolyzed to octyl phenol and orthophosphoric acid. The combination of mono- and dioctylphenyl phosphoric acids was the principal uranium extractant, but some of the impurities also extracted uranium. Hydrolysis of the extractant had little effect on uranium extraction, as did the presence of moderate concentrations of octyl phenol and trioctylphenyl phosphate. Diluent choice among refined kerosenes, naphthenic mixtures, and paraffinic hydrocarbons also had little effect on uranium extraction, but extraction was much lower when an aromatic diluent was used. Purified OPAP fractions were sparingly soluble in aliphatic hydrocarbon diluents. The solubility was increased by the presence of impurities such as octyl phenol, and by the addition of water or an acidic solution to the extractant-diluent mixture. In continuous stability tests, extractant loss by distribution to the aqueous phase was much less to wet-process phosphoric acid than to reagent grade acid. Uranium recovery from wet-process acid decreased steadily because of the combined effects of extractant poisoning and precipitation of the extractant as a complex with ferric iron. Unaccountable losses of organic phase volume occurred in the continuous tests. While attempts to recover the lost organic phase were unsuccessful, the test results indicate it was not lost by entrainment or dissolution in the phosphoric acid solutions. 21 figures, 8 tables

  11. Double-layer optical fiber coating analysis in MHD flow of an elastico-viscous fluid using wet-on-wet coating process

    Directory of Open Access Journals (Sweden)

    Zeeshan Khan

    Full Text Available Modern optical fibers require a double-layer coating on the glass fiber in order to provide protection from signal attenuation and mechanical damage. The most important plastic resins used in wires and optical fibers are plastic polyvinyl chloride (PVC and low and high density polyethylene (LDPE/HDPE, nylon and Polysulfone. One of the most important things which affect the final product after processing is the design of the coating die. In the present study, double-layer optical fiber coating is performed using melt polymer satisfying Oldroyd 8-constant fluid model in a pressure type die with the effect of magneto-hydrodynamic (MHD. Wet-on-wet coating process is applied for double-layer optical fiber coating. The coating process in the coating die is modeled as a simple two-layer Couette flow of two immiscible fluids in an annulus with an assigned pressure gradient. Based on the assumptions of fully developed laminar and MHD flow, the Oldroyd 8-constant model of non-Newtonian fluid of two immiscible resin layers is modeled. The governing nonlinear equations are solved analytically by the new technique of Optimal Homotopy Asymptotic Method (OHAM. The convergence of the series solution is established. The results are also verified by the Adomian Decomposition Method (ADM. The effect of important parameters such as magnetic parameter Mi, the dilatant constant α, the Pseodoplastic constant β, the radii ratio δ, the pressure gradient Ω, the speed of fiber optics V, and the viscosity ratio κ on the velocity profiles, thickness of coated fiber optics, volume flow rate, and shear stress on the fiber optics are investigated. At the end the result of the present work is also compared with the experimental results already available in the literature by taking non-Newtonian parameters tends to zero. Keywords: Non-Newtonian fluid, Oldroyd 8-constant fluid, MHD flow, Double-layer fiber coating, OHAM, ADM, Wet-on-wet coating process

  12. Investigation on the effect of seawater to hydraulic property and wetting process of bentonite

    International Nuclear Information System (INIS)

    Hasegawa, Takuma

    2004-01-01

    On high-level waste disposal, bentonite is one of the most promising material for buffer and backfill material. The hydraulic properties and wetting process of bentonite are important not only for barrier performance assessment but also for prediction of waste disposal environment, such as resaturation time and thermal distribution. In Japan, we should consider the effect of seawater for bentonite, because radioactive waste will be disposed of in coastal area and in marine sediment where seawater remained. However, it is not enough to understand the effect of seawater. Therefore, experimental study was conducted to investigate the effect of seawater on the hydraulic conductivity and wetting process of bentonite. The effect of seawater on hydraulic conductivity is significant for Na-bentonite, the hydraulic conductivity of Na-bentonite in seawater is one order to magnitude higher than that in distilled water. On the other hand, the hydraulic conductivity of Ca-bentonite is not influenced by seawater. The hydraulic conductivity of bentonite decreases as effective montmorillonite density increases. The effective montmorillonite density is ratio between the weight of montmorillonite and volume of porosity and montmorillonite. The hydraulic conductivity of bentonite is close related to swelling property since the hydraulic conductivity decrease as the swelling pressure increase. Wetting process of compacted bentonite could be evaluated by diffusion phenomena since infiltration rate and change of saturation rate and represented by diffusion equation. The effect of seawater on water diffusivity is significant for Na-type bentonite with low effective montmorillonite density. Except for that condition, the water diffusivity of bentonite is almost constant and is not influenced by effective montmorillonite density and seawater. (author)

  13. In situ reflectivity investigations of solid/liquid interface during laser backside etching

    International Nuclear Information System (INIS)

    Boehme, R.; Otto, T.; Zimmer, K.

    2006-01-01

    In situ reflectivity measurements of the solid/liquid interface with a pump-probe setup were performed during laser-induced backside wet etching (LIBWE) of fused silica with KrF excimer laser using toluene as absorbing liquid. The intensity, the temporal shape, and the duration of the reflected light measured in dependence on the laser fluence are discussed referring to the surface modification and the bubble formation. The vaporisation of the superheated liquid at the solid interface causes a considerable increase of the reflectivity and gives information about the bubble lifetime. The alterations of the reflectivity after bubbles collapse can be explained with the changed optical properties due to surface modifications of the solid surface. Comparative studies of the reflectivity at different times and the etch rate behaviour in dependence on the laser fluence show that the in situ measured surface modification begins just at the etch threshold fluence and correlates further with etch rate behaviour and the etched surface appearance. The already observed surface modification at LIBWE due to a carbon deposition and structural changes of the near surface region are approved by the changes of the interface reflectivity and emphasizes the importance of the modified surface region in the laser-induced backside wet etching process

  14. Process options for treatment of organic containing ILWs by wet oxidation

    International Nuclear Information System (INIS)

    Holman, D.J.

    1989-01-01

    The process chemistry, applications and experience with several wet oxidation options are reviewed along with criteria for the selection of viable systems and plant designs, covering a range of organic wastes, including solvents, cellulosic filters, chelant decontamination reagents and ion exchange resins. The use of hydrogen peroxide to treat water-cooled reactor residues containing mixed inorganic and organic filter materials with ion exchange resins is examined in further detail along with treatment of secondary arisings. The technical and financial justifications for treatment are examined along with the engineering requirements to retro-fit the required plant to an existing cement encapsulation facility. (author)

  15. Rapid, cool sintering of wet processed yttria-stabilized zirconia ceramic electrolyte thin films

    OpenAIRE

    Park, Jun-Sik; Kim, Dug-Joong; Chung, Wan-Ho; Lim, Yonghyun; Kim, Hak-Sung; Kim, Young-Beom

    2017-01-01

    Here we report a photonic annealing process for yttria-stabilized zirconia films, which are one of the most well-known solid-state electrolytes for solid oxide fuel cells (SOFCs). Precursor films were coated using a wet-chemical method with a simple metal-organic precursor solution and directly annealed at standard pressure and temperature by two cycles of xenon flash lamp irradiation. The residual organics were almost completely decomposed in the first pre-annealing step, and the fluorite cr...

  16. Rapid prototyping of 2D glass microfluidic devices based on femtosecond laser assisted selective etching process

    Science.gov (United States)

    Kim, Sung-Il; Kim, Jeongtae; Koo, Chiwan; Joung, Yeun-Ho; Choi, Jiyeon

    2018-02-01

    Microfluidics technology which deals with small liquid samples and reagents within micro-scale channels has been widely applied in various aspects of biological, chemical, and life-scientific research. For fabricating microfluidic devices, a silicon-based polymer, PDMS (Polydimethylsiloxane), is widely used in soft lithography, but it has several drawbacks for microfluidic applications. Glass has many advantages over PDMS due to its excellent optical, chemical, and mechanical properties. However, difficulties in fabrication of glass microfluidic devices that requires multiple skilled steps such as MEMS technology taking several hours to days, impedes broad application of glass based devices. Here, we demonstrate a rapid and optical prototyping of a glass microfluidic device by using femtosecond laser assisted selective etching (LASE) and femtosecond laser welding. A microfluidic droplet generator was fabricated as a demonstration of a microfluidic device using our proposed prototyping. The fabrication time of a single glass chip containing few centimeter long and complex-shaped microfluidic channels was drastically reduced in an hour with the proposed laser based rapid and simple glass micromachining and hermetic packaging technique.

  17. Noncontact COS charge analysis for in-line monitoring of wet cleaning processes

    Science.gov (United States)

    Zhang, Xiafang; Juang, Min; Tai, Sung-Shan; Chen, Kuo-in; Wossen, Ejigu; Horner, Gregory

    1998-08-01

    Contamination levels in chemical cleaning equipment and wafer cleanliness in general are very critical to semiconductor manufacturers. In this work, a Keithley Instruments non contact electrical tester (Quantox) is used to measure the mobile ion (Qm) contamination in a variety of cleaning processes. Results show that photoresist strip cleaning process has a higher mobile ion concentration than standard pre-diffusion cleaning process. RCA1, RCA2 and HF solutions mapping measured by the Quantox indicates some negative static charges on the surface after cleaning. This negative field appears to assist Qm removal during wet chemical cleaning. The dependence of flatband voltage and other oxide charges on various cleaning processes has also been investigated using the Quantox. The data suggests that a dipole layer has been formed by a surface reaction during chemical cleaning.

  18. The extraction of uranium from wet process phosphoric acid using a liquid surfactant membrane system

    International Nuclear Information System (INIS)

    Dickens, N.; Davies, G.A.

    1984-01-01

    A liquid membrane extraction process is examined for the extraction of uranium from wet process phosphoric acid. Uranium is present in the acid in concentrations up to 100 ppm which in principle makes it ideal for treatment with a membrane process. The membrane system studied is based on extraction using DEHPA-TOPO reagents which are contained within the organic phase of a water in oil emulsion. Formulations of the emulsion membrane system have been studied, the limitations of acid temperature, P 2 O 5 concentration and solid dispersed impurities in the acid have been studied in laboratory batch experiments and in a continuous pilot plant unit capable of treating 5l of concentrated acid per minute. Data from the pilot plant work has been used to develop a flowsheet for a commercial unit based on this process. (author)

  19. Culture-Dependent and -Independent Methods to Investigate the Predominant Microorganisms Associated with Wet Processed Coffee.

    Science.gov (United States)

    Feng, Xiaomin; Dong, Honghong; Yang, Pan; Yang, Ruijuan; Lu, Jun; Lv, Jie; Sheng, Jun

    2016-08-01

    The fermentation process of Yunnan arabica coffee is a typical wet fermentation. Its excellent quality is closely related to microbes in the process of fermentation. The purpose of this study was to isolate and identify the microorganisms in the wet method of coffee processing in Yunnan Province, China. Microbial community structure and dominant bacterial species were evaluated by traditional cultivated separation method and PCR-DGGE technology, and were further analyzed in combination with the changes of organic acid content, activity of pectinase, and physical parameters (pH and temperature). A large number of microorganisms which can produce pectinase were found. Among them, Enterobacter cowanii, Pantoea agglomerans, Enterobacteriaceae bacterium, and Rahnella aquatilis were the predominant gram-negative bacteria, Bacillus cereus was the predominant gram-positive bacterium, Pichia kluyveri, Hanseniaspora uvarum, and Pichia fermentans were the predominant yeasts, and all those are pectinase-producing microorganisms. As for the contents of organic acids, oxalic was the highest, followed by acetic and lactic acids. Butyrate and propionate, which were unfavorable during the fermentation period, were barely discovered.

  20. Process analysis and modeling of a single-step lutein extraction method for wet microalgae.

    Science.gov (United States)

    Gong, Mengyue; Wang, Yuruihan; Bassi, Amarjeet

    2017-11-01

    Lutein is a commercial carotenoid with potential health benefits. Microalgae are alternative sources for the lutein production in comparison to conventional approaches using marigold flowers. In this study, a process analysis of a single-step simultaneous extraction, saponification, and primary purification process for free lutein production from wet microalgae biomass was carried out. The feasibility of binary solvent mixtures for wet biomass extraction was successfully demonstrated, and the extraction kinetics of lutein from chloroplast in microalgae were first evaluated. The effects of types of organic solvent, solvent polarity, cell disruption method, and alkali and solvent usage on lutein yields were examined. A mathematical model based on Fick's second law of diffusion was applied to model the experimental data. The mass transfer coefficients were used to estimate the extraction rates. The extraction rate was found more significantly related with alkali ratio to solvent than to biomass. The best conditions for extraction efficiency were found to be pre-treatment with ultrasonication at 0.5 s working cycle per second, react 0.5 h in 0.27 L/g solvent to biomass ratio, and 1:3 ether/ethanol (v/v) with 1.25 g KOH/L. The entire process can be controlled within 1 h and yield over 8 mg/g lutein, which is more economical for scale-up.

  1. Design Of A Small-Scale Hulling Machine For Improved Wet-Processed Coffee.

    Directory of Open Access Journals (Sweden)

    Adeleke

    2017-08-01

    Full Text Available The method of primary processing of coffee is a vital determinant of quality and price. Wet processing method produces higher quality beans but is very labourious. This work outlines the design of a small scale cost-effective ergonomic and easily maintained and operated coffee hulling machine that can improve quality and productivity of green coffee beans. The machine can be constructed from locally available materials at a relatively low cost of about NGN 140000.00 with cheap running cost. The beaters are made from rubber strip which can deflect when in contact with any obstruction causing little or no stresses on drum members and reducing the risk of damage to both the beans and machine. The machine is portable and detachable which make it fit to be owned by a group of farmers who can move it from one farm to the other making affordability and running cost easier. The easily affordable and relatively low running cost may be further reduced by the fact that the machine is powered by 3.0 Hp petrol engine which is suitable for other purposes among the rural dwellers. The eventual construction of the machine will encourage more farmers to go into wet processing of coffee and reduce the foreign exchange hitherto lost to this purpose.

  2. Wet separation processes as method to separate limestone and oil shale

    Science.gov (United States)

    Nurme, Martin; Karu, Veiko

    2015-04-01

    Biggest oil shale industry is located in Estonia. Oil shale usage is mainly for electricity generation, shale oil generation and cement production. All these processes need certain quality oil shale. Oil shale seam have interlayer limestone layers. To use oil shale in production, it is needed to separate oil shale and limestone. A key challenge is find separation process when we can get the best quality for all product types. In oil shale separation typically has been used heavy media separation process. There are tested also different types of separation processes before: wet separation, pneumatic separation. Now oil shale industry moves more to oil production and this needs innovation methods for separation to ensure fuel quality and the changes in quality. The pilot unit test with Allmineral ALLJIG have pointed out that the suitable new innovation way for oil shale separation can be wet separation with gravity, where material by pulsating water forming layers of grains according to their density and subsequently separates the heavy material (limestone) from the stratified material (oil shale)bed. Main aim of this research is to find the suitable separation process for oil shale, that the products have highest quality. The expected results can be used also for developing separation processes for phosphorite rock or all others, where traditional separation processes doesn't work property. This research is part of the study Sustainable and environmentally acceptable Oil shale mining No. 3.2.0501.11-0025 http://mi.ttu.ee/etp and the project B36 Extraction and processing of rock with selective methods - http://mi.ttu.ee/separation; http://mi.ttu.ee/miningwaste/

  3. Fiscal 2000 achievement report on the investigation of alternative gas system and process technologies for dry etching in electronic device manufacturing; 2000 nendo denshi device seizo process de shiyosuru etching gas no daitai gas system oyobi daitai process no kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Efforts are made to develop technologies for saving PFC (perfluoro-compound) and conserving energy in semiconductor manufacturing processes, in particular, in the layer insulation film (SiO{sub 2}) dry etching process. Activities are conducted in the five fields of (1) research and development of technologies for reducing the amount of etching gas consumption, (2) development of a dry etching technology using alternative gas, (3) development of a dry etching technology using a low dielectric constant layer insulation film, (4) research and development of novel wiring structures and a method for fabricating the same, and (5) re-entrusted studies. Conducted in field (5) are studies of novel alternative gas - solid sources to substitute PFC, theory design technologies for low dielectric constant organic macromolecules, low dielectric constant material film fabrication by CVD (chemical vapor deposition), and technology for optical wiring inside chips. In field (2), studies are conducted of low GWP (global warming potential) alternative PFC gas aided etching and decomposition prevention technologies for reduction in PFC emissions, and it is made clear that C{sub 4}F{sub 6} performs excellently as an etchant. (NEDO)

  4. A systematic study of the controlled generation of crystalline iron oxide nanoparticles on graphene using a chemical etching process

    Directory of Open Access Journals (Sweden)

    Peter Krauß

    2017-09-01

    Full Text Available Chemical vapor deposition (CVD of carbon precursors employing a metal catalyst is a well-established method for synthesizing high-quality single-layer graphene. Yet the main challenge of the CVD process is the required transfer of a graphene layer from the substrate surface onto a chosen target substrate. This process is delicate and can severely degrade the quality of the transferred graphene. The protective polymer coatings typically used generate residues and contamination on the ultrathin graphene layer. In this work, we have developed a graphene transfer process which works without a coating and allows the transfer of graphene onto arbitrary substrates without the need for any additional post-processing. During the course of our transfer studies, we found that the etching process that is usually employed can lead to contamination of the graphene layer with the Faradaic etchant component FeCl3, resulting in the deposition of iron oxide FexOy nanoparticles on the graphene surface. We systematically analyzed the removal of the copper substrate layer and verified that crystalline iron oxide nanoparticles could be generated in controllable density on the graphene surface when this process is optimized. It was further confirmed that the FexOy particles on graphene are active in the catalytic growth of carbon nanotubes when employing a water-assisted CVD process.

  5. Examining Wetting and Dewetting Processes in Thin-films on Crystalline Substrates at the Nanoscale

    Science.gov (United States)

    Hihath, Sahar

    Controlling the wetting and dewetting of ultra-thin films on solid substrates is important for a variety of technological and fundamental research applications. These applications include film deposition for semiconductor manufacturing, the growth of nanowires through nanoparticle-based catalysis sites, to making ordered arrays of nanoscale particles for electronic and optical devices. However, despite the importance of these processes, the underlying mechanisms by which a film wets a surface or dewets from it is still often unclear and widely debated. In this dissertation we examine wetting and dewetting processes in three materials systems that are relevant for device applications with the ultimate goal of understanding what mechanisms drive the wetting (or dewetting) process in each case. First, we examine the formation of wetting layers between nanoparticle films and highly conductive GaAs substrates for spintronic applications. In this case, the formation of a wetting layer is important for nanoparticle adhesion on the substrate surface. Wetting layers can be made by annealing these systems, which causes elemental diffusion from nanoparticles into the substrate, thereby adhesion between the nanoparticles and the substrate. Here we investigate the feasibility of forming a wetting layer underneath nanoparticles post-annealing in a system of Fe3O4 nanoparticles on a (100) GaAs substrate by studying the interface structure and composition via Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDXS). Electron Energy-Loss fine structures of the Fe-L 3,2 and O-K absorption edges were quantitatively analyzed to gain insight about the compositional gradient of the interface between the nanoparticles and the GaAs substrate. Additionally, real-space density functional theory calculations of the dynamical form factor was performed to confirm the

  6. Rapid, cool sintering of wet processed yttria-stabilized zirconia ceramic electrolyte thin films.

    Science.gov (United States)

    Park, Jun-Sik; Kim, Dug-Joong; Chung, Wan-Ho; Lim, Yonghyun; Kim, Hak-Sung; Kim, Young-Beom

    2017-09-29

    Here we report a photonic annealing process for yttria-stabilized zirconia films, which are one of the most well-known solid-state electrolytes for solid oxide fuel cells (SOFCs). Precursor films were coated using a wet-chemical method with a simple metal-organic precursor solution and directly annealed at standard pressure and temperature by two cycles of xenon flash lamp irradiation. The residual organics were almost completely decomposed in the first pre-annealing step, and the fluorite crystalline phases and good ionic conductivity were developed during the second annealing step. These films showed properties comparable to those of thermally annealed films. This process is much faster than conventional annealing processes (e.g. halogen furnaces); a few seconds compared to tens of hours, respectively. The significance of this work includes the treatment of solid-state electrolyte oxides for SOFCs and the demonstration of the feasibility of other oxide components for solid-state energy devices.

  7. Development of an improved two-cycle process for recovering uranium from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    Chen, H.M.; Chen, H.J.; Tsai, Y.M.; Lee, T.W.; Ting, G.

    1987-01-01

    An improved two-cycle separation process for the recovery of uranium from wet-process phosphoric acid by extraction with bis(2-ethylhexyl)phosphoric acid (D2EHPA) plus dibutyl butylphosphonate (DBBP) in kerosene has been developed and demonstrated successfully in bench-scale, continuous mixer-settler tests. The sulfuric acid and water scrubbing steps for the recycled extraction in the second cycle solve the problems of the contamination and dilution of the phosphoric acid by the ammonium ion and water and also avoid the formation of undesirable phosphatic precipitates during the subsequent extraction of uranium by recycled organic extractant

  8. Mechanistic modelling of fluidized bed drying processes of wet porous granules

    DEFF Research Database (Denmark)

    Mortier, Séverine Thérèse F.C.; De Beer, Thomas; Gernaey, Krist

    2011-01-01

    depending on the geometry of the gas inlet, the gas velocity, characteristics of the particles, the dryer design, etc. Computational Fluid Dynamics (CFD) allows to model this behaviour. Moreover, turbulence can be modelled using several approaches: Reynolds-averaged Navier–Stokes Equations (RANS) or Large...... are powerful tools to gain process insight and eventually develop well-controlled processes. The level of detail embedded in such a model depends on the goal of the model. Several models have therefore been proposed in the literature and are reviewed here. The drying behaviour of one single granule, a porous...... particle, can be described using the continuum approach, the pore network modelling method and the shrinkage of the diameter of the wet core approach. As several granules dry at a drying rate dependent on the gas temperature, gas velocity, porosity, etc., the moisture content of a batch of granules...

  9. Wet and dry deposition and resuspension of AFCT/TFCT fuel processing radionuclides. Final report

    International Nuclear Information System (INIS)

    Slinn, W.G.N.; Katen, P.C.; Wolf, M.A.; Loveland, W.D.; Radke, L.F.; Miller, E.L.; Ghannam, L.J.; Reynolds, B.W.; Vickers, D.

    1979-09-01

    After short summary and introductory chapters, Chapter IV contains a critical analysis of available parameterizations for resuspension and for wet and dry removal processes and recommends interim parameterizations for use in radiation dose calculations. Chapter V describes methods and experimental results from field studies of in-cloud vs below-cloud scavenging, precipitation efficiency, and modifications of aerosols by clouds. In Chapter VI are contained descriptions of methods and results from four different approaches to the problem of measuring the dry deposition velocities of submicron aerosol particles depositing on vegetation. Chapter VII describes experimental results from a study of resuspension and weathering of tracer aerosol particles deposited on soil, grass and gravel; typical resuspension rates were found to be of the order of 10 -8 s -1 and it is recommended that the concept of weathering be reassessed. In Chapter VIII, National Weather Service data are used to obtain Lagrangian statistics for use in a regional-scale study of wet and dry removal. Chapter IX develops new concepts in reservoir models for application at regional to global scales. In the final chapter are some comments about the results found in this study and recommendations for future research

  10. Study of Thermal Electrical Modified Etching for Glass and Its Application in Structure Etching

    Directory of Open Access Journals (Sweden)

    Zhan Zhan

    2017-02-01

    Full Text Available In this work, an accelerating etching method for glass named thermal electrical modified etching (TEM etching is investigated. Based on the identification of the effect in anodic bonding, a novel method for glass structure micromachining is proposed using TEM etching. To validate the method, TEM-etched glasses are prepared and their morphology is tested, revealing the feasibility of the new method for micro/nano structure micromachining. Furthermore, two kinds of edge effect in the TEM and etching processes are analyzed. Additionally, a parameter study of TEM etching involving transferred charge, applied pressure, and etching roughness is conducted to evaluate this method. The study shows that TEM etching is a promising manufacture method for glass with low process temperature, three-dimensional self-control ability, and low equipment requirement.

  11. Etch bias inversion during EUV mask ARC etch

    Science.gov (United States)

    Lajn, Alexander; Rolff, Haiko; Wistrom, Richard

    2017-07-01

    The introduction of EUV lithography to high volume manufacturing is now within reach for 7nm technology node and beyond (1), at least for some steps. The scheduling is in transition from long to mid-term. Thus, all contributors need to focus their efforts on the production requirements. For the photo mask industry, these requirements include the control of defectivity, CD performance and lifetime of their masks. The mask CD performance including CD uniformity, CD targeting, and CD linearity/ resolution, is predominantly determined by the photo resist performance and by the litho and etch processes. State-of-the-art chemically amplified resists exhibit an asymmetric resolution for directly and indirectly written features, which usually results in a similarly asymmetric resolution performance on the mask. This resolution gap may reach as high as multiple tens of nanometers on the mask level in dependence of the chosen processes. Depending on the printing requirements of the wafer process, a reduction or even an increase of this gap may be required. A potential way of tuning via the etch process, is to control the lateral CD contribution during etch. Aside from process tuning knobs like pressure, RF powers and gases, which usually also affect CD linearity and CD uniformity, the simplest knob is the etch time itself. An increased over etch time results in an increased CD contribution in the normal case. , We found that the etch CD contribution of ARC layer etch on EUV photo masks is reduced by longer over etch times. Moreover, this effect can be demonstrated to be present for different etch chambers and photo resists.

  12. High-etch-rate bottom-antireflective coating and gap-fill materials using dextrin derivatives in via first dual-Damascene lithography process

    Science.gov (United States)

    Takei, Satoshi; Sakaida, Yasushi; Shinjo, Tetsuya; Hashimoto, Keisuke; Nakajima, Yasuyuki

    2008-03-01

    The present paper describes a novel class of bottom antireflective coating (BARC) and gap fill materials using dextrin derivatives. The general trend of interconnect fabrication for such a high performance LSI is to apply cupper (Cu)/ low-dielectric-constant (low-k) interconnect to reduce RC delay. A via-first dual damascene process is one of the most promising processes to fabricate Cu/ low-k interconnect due to its wide miss-alignment margin. The sacrificial materials containing dextrin derivatives under resist for lithography were developed in via-first dual damascene process. The dextrin derivatives in this study was obtained by the esterification of the hydroxyl groups of dextrin resulting in improved solubility in the resist solvents such as propylene glycol monomethylether, propylene glycol monomethylether acetate, and ethyl lactate due to avoid the issue of defects that were caused by incompatability. The etch rate of our developed BARC and gap fill materials using dextrin derivatives was more than two times faster than one of the ArF resists evaluated in a CF4 gas condition using reactive ion etching. The improved etch performance was also verified by comparison with poly(hydroxystyrene), acrylate-type materials and latest low-k materials as a reference. In addition to superior etch performance, these materials showed good resist profiles and via filling performance without voids in via holes.

  13. Biogenic amine profile in unripe Arabica coffee beans processed according to dry and wet methods.

    Science.gov (United States)

    Dias, Eduardo C; Pereira, Rosemary G F A; Borém, Flávio M; Mendes, Eulália; de Lima, Renato R; Fernandes, José O; Casal, Susana

    2012-04-25

    Immature coffee fruit processing contributes to a high amount of defective beans, which determines a significant amount of low-quality coffee sold in the Brazilian internal market. Unripe bean processing was tested, taking the levels of bioactive amines as criteria for evaluating the extent of fermentation and establishing the differences between processing methods. The beans were processed by the dry method after being mechanically depulped immediately after harvest or after a 12 h resting period in a dry pile or immersed in water. Seven bioactive amines were quantified: putrescine, spermine, spermidine, serotonin, cadaverine, histamine, and tyramine, with global amounts ranging from 71.8 to 80.3 mg/kg. The levels of spermine and spermidine were lower in the unripe depulped coffee than in the natural coffee. The specific conditions of dry and wet processing also influenced cadaverine levels, and histamine was reduced in unripe depulped coffee. A resting period of 12 h does not induce significant alteration on the beans and can be improved if performed in water. These results confirm that peeling immature coffee can decrease fermentation processes while providing more uniform drying, thus reducing the number of defects and potentially increasing beverage quality.

  14. Wet-Lay Process - A Novel Approach to Scalable Fabrication of Tissue Scaffolds and Reinforcement Membranes

    Science.gov (United States)

    Wood, Andrew

    Fibrous materials received a great deal of interest in the fields of tissue engineering and regenerative medicine due to the beneficial cell-interactions and tunable properties for various biomedical applications. These materials are highly advantageous as they provide a large surface area for cellular attachment, proliferation, high porosity values for cellular in-growth, and the ability to modify the membrane to achieve desired responses to both mechanical loading as well as environmental stimuli. A prominent method currently used to fabricate such membranes is electrospinning which uses electrostatic forces to produce fibers on the range of nanometers giving them high morphological saliency to the native extra cellular matrix (ECM). These fibers are also advantageous mechanically with strength and flexibility due to their larger aspect ratio when compared to larger diameter micro/macro fibers. While this spinning technique has many advantages and has seen the most quantity of research in recent years, it does have its own set of drawbacks. Among them is the use cytotoxic solvents during processing which must be fully removed before implantation. In addition, since the fiber produced have smaller diameters, the resulting average pore-size of the scaffold is decreased which in turn hinders cellular penetration into the bulk scaffold. In this work, we have proposed and characterized a novel method called wet-lay process for the rapid fabrication of fibrous membranes for tissue scaffolds. Wet-laying is a method common to textiles and paper industry but unexplored for tissue scaffolds. Short fibers are first suspended in an aqueous bath and homogeneously dispersed using shear force. After draining away the aqueous solution, a nonwoven fibro-porous membrane is deposited onto the draining screen. The implementation of wet-laid membranes into weak hydrogel matrices has shown a reinforcement effect for the composite. Further analyses were carried out to determine the

  15. Obtaining and characterization catalyst Ki/Al_2O_3 by physical dispersion process via wet

    International Nuclear Information System (INIS)

    Silva, M.C. da; Dantas, J.; Costa, A.C.F.M.; Costa, N.C.O.; Freitas, N.L. de

    2014-01-01

    The aim of this study is the Obtention and characterization of catalysts being supported alumina impregnated with KI by physical dispersion in wet via attritor mill in periods of 30 and 60 minutes. Before and after impregnation the catalysts were characterized by XRD, X ray fluorescence, particle size distribution, textural analysis (BET). The results show the presence of the stable crystalline phase Al_2O_3 in all samples after impregnation and the second phase formed from KI and K_2O. There was a decrease in the agglomerates incorporated with the potassium due to the milling process. It was observed that the highest specific surface area was obtained by the impregnated sample into a 60 min. (author)

  16. Fabrication of Aligned Polyaniline Nanofiber Array via a Facile Wet Chemical Process.

    Science.gov (United States)

    Sun, Qunhui; Bi, Wu; Fuller, Thomas F; Ding, Yong; Deng, Yulin

    2009-06-17

    In this work, we demonstrate for the first time a template free approach to synthesize aligned polyaniline nanofiber (PN) array on a passivated gold (Au) substrate via a facile wet chemical process. The Au surface was first modified using 4-aminothiophenol (4-ATP) to afford the surface functionality, followed subsequently by an oxidation polymerization of aniline (AN) monomer in an aqueous medium using ammonium persulfate as the oxidant and tartaric acid as the doping agent. The results show that a vertically aligned PANI nanofiber array with individual fiber diameters of ca. 100 nm, heights of ca. 600 nm and a packing density of ca. 40 pieces·µm(-2) , was synthesized. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Experimental Investigation of the Productivity of a Wet Separation Process of Traditional and Bio-Plastics

    Directory of Open Access Journals (Sweden)

    Monica Moroni

    2018-05-01

    Full Text Available The separation process within a mechanical recycling plant plays a major role in the context of the production of high-quality secondary raw materials and the reduction of extensive waste disposal in landfills. Traditional plants for plastic separation employ dry or wet processes that rely on the different physical properties among the polymers. The hydraulic separator is a device employing a wet technology for particle separation. It allows the separation of two-polymer mixtures into two products, one collected within the instrument and the other one expelled through its outlet ducts. Apparatus performance were analyzed as a function of fluid and solid flow rates, flow patterns developing within the apparatus, in addition to the density, shape, and size of the polymers. For the hydraulic configurations tested, a two-way coupling takes place where the fluid exerts an influence on the plastic particles and the opposite occurs too. The interaction between the solid and liquid phases determines whether a certain polymer settles within the device or is expelled from the apparatus. Tests carried out with samples of increasing volumes of solid particles demonstrate that there are no significant differences in the apparatus effectiveness as far as a two-way interaction takes place. Almost pure concentrates of Polyethylene Terephthalate (PET, Polyvinyl Chloride (PVC, and Polycarbonate (PC can be obtained from a mixture of traditional polymers. Tests conducted on Polylactic Acid (PLA and Mater-Bi® samples showed that the hydraulic separator can be effectively employed to separate bio-plastics from conventional plastics with remarkable grade and recovery.

  18. Artificial Intelligence Tools for Scaling Up of High Shear Wet Granulation Process.

    Science.gov (United States)

    Landin, Mariana

    2017-01-01

    The results presented in this article demonstrate the potential of artificial intelligence tools for predicting the endpoint of the granulation process in high-speed mixer granulators of different scales from 25L to 600L. The combination of neurofuzzy logic and gene expression programing technologies allowed the modeling of the impeller power as a function of operation conditions and wet granule properties, establishing the critical variables that affect the response and obtaining a unique experimental polynomial equation (transparent model) of high predictability (R 2 > 86.78%) for all size equipment. Gene expression programing allowed the modeling of the granulation process for granulators of similar and dissimilar geometries and can be improved by implementing additional characteristics of the process, as composition variables or operation parameters (e.g., batch size, chopper speed). The principles and the methodology proposed here can be applied to understand and control manufacturing process, using any other granulation equipment, including continuous granulation processes. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  19. Treatment of toxic and hazardous organic wastes by wet oxidation process with oxygenated water at low temperature

    International Nuclear Information System (INIS)

    Piccinno, T.; Salluzzo, A.; Nardi, L.; Gili, M.; Luce, A.; Troiani, F.; Cornacchia, G.

    1989-11-01

    The wet oxidation process using air or molecular oxygen is a well-known process from long time. It is suitable to oxidize several types of waste refractory to the usual biological, thermal and chemical treatments. The drastic operating conditions (high pressures and temperatures) prevented its industrial development. In the last years a new interest was assigned to the process for the treatment of nuclear wastes (organic resins and exhaust organic wastes); the treatment is carried out at widely reduced operating conditions (atmospheric pressure and boiling temperature) by means of metallic catalysts and hydrogen peroxide. With some limits, the wet oxidation with hydrogen peroxide at low temperature can be applied to conventional waste waters containing toxic organic compounds. In the present report are summarized the activities developed at ENEA Fuel Cycle Department by the task force 'Deox' constituted by laboratory and plant specialists in order to verify the application of the wet oxidation process to the treatment of the toxic wastes. (author)

  20. Influence of etching process parameters on the antireflection property of Si SWSs by thermally dewetted Ag and Ag/SiO{sub 2} nanopatterns

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Jung Woo; Yu, Jae Su [Department of Electronics and Radio Engineering, Kyung Hee University, 446-701 Yongin (Korea, Republic of); Song, Young Min; Lee, Yong Tak [Department of Information and Communications, Gwangju Institute of Science and Technology, 500-712 Gwangju (Korea, Republic of)

    2011-08-15

    The etching parameter dependent antireflection characteristics of disordered Si subwavelength structures (SWSs) by inductively coupled plasma (ICP) etching in a mixture gas of SiCl{sub 4}/Ar using thermally dewetted Ag and Ag/SiO{sub 2} nanopatterns are investigated. The average size and period of Si SWSs are closely correlated with thermal dewetting conditions. For desirable Ag nanoparticle patterns, the profile of Si SWSs is optimized by changing the ICP etching process parameters to obtain the lowest reflectance spectrum. The most tapered SWS with the highest height leads to a relatively low reflectance. The Ag nanopatterns result in more tapered and rough surface SWSs compared to the Ag/SiO{sub 2} nanopatterns, indicating a slightly reduced reflectance. The Si SWS etched using Ag nanopatterns by SiCl{sub 4}/Ar of 5 sccm/10 sccm at 50 W RF power, 200 W ICP power, and 10 mTorr process pressure exhibits a very low total reflectance of <{proportional_to}2.4% in the wavelength range of 400-1000 nm, maintaining a specular reflectance of <16% at 350-1100 nm up to the incident angle of {theta}{sub i} = 50 . (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Periodic arrays of deep nanopores made in silicon with reactive ion etching and deep UV lithography

    International Nuclear Information System (INIS)

    Woldering, Leon A; Tjerkstra, R Willem; Vos, Willem L; Jansen, Henri V; Setija, Irwan D

    2008-01-01

    We report on the fabrication of periodic arrays of deep nanopores with high aspect ratios in crystalline silicon. The radii and pitches of the pores were defined in a chromium mask by means of deep UV scan and step technology. The pores were etched with a reactive ion etching process with SF 6 , optimized for the formation of deep nanopores. We have realized structures with pitches between 440 and 750 nm, pore diameters between 310 and 515 nm, and depth to diameter aspect ratios up to 16. To the best of our knowledge, this is the highest aspect ratio ever reported for arrays of nanopores in silicon made with a reactive ion etching process. Our experimental results show that the etching rate of the nanopores is aspect-ratio-dependent, and is mostly influenced by the angular distribution of the etching ions. Furthermore we show both experimentally and theoretically that, for sub-micrometer structures, reducing the sidewall erosion is the best way to maximize the aspect ratio of the pores. Our structures have potential applications in chemical sensors, in the control of liquid wetting of surfaces, and as capacitors in high-frequency electronics. We demonstrate by means of optical reflectivity that our high-quality structures are very well suited as photonic crystals. Since the process studied is compatible with existing CMOS semiconductor fabrication, it allows for the incorporation of the etched arrays in silicon chips

  2. Kinetic-limited etching of magnesium doping nitrogen polar GaN in potassium hydroxide solution

    International Nuclear Information System (INIS)

    Jiang, Junyan; Zhang, Yuantao; Chi, Chen; Yang, Fan; Li, Pengchong; Zhao, Degang; Zhang, Baolin; Du, Guotong

    2016-01-01

    Graphical abstract: - Highlights: • Effects of Mg doping on wet etching of N-polar GaN are illustrated and analysed. • Etching process model of Mg-doped N-polar GaN in KOH solution is purposed. • It is found that Mg doping can induce tensile strain in N-polar GaN film. • N-polar p-GaN film with a hole concentration of 2.4 × 10"1"7 cm"−"3 is obtained. - Abstract: KOH based wet etchings were performed on both undoped and Mg-doped N-polar GaN films grown by metal-organic chemical vapor deposition. It is found that the etching rate for Mg-doped N-polar GaN gets slow obviously compared with undoped N-polar GaN. X-ray photoelectron spectroscopy analysis proved that Mg oxide formed on N-polar GaN surface is insoluble in KOH solution so that kinetic-limited etching occurs as the etching process goes on. The etching process model of Mg-doped N-polar GaN in KOH solution is tentatively purposed using a simplified ideal atomic configuration. Raman spectroscopy analysis reveals that Mg doping can induce tensile strain in N-polar GaN films. Meanwhile, p-type N-polar GaN film with a hole concentration of 2.4 × 10"1"7 cm"−"3 was obtained by optimizing bis-cyclopentadienyl magnesium flow rates.

  3. Kinetic-limited etching of magnesium doping nitrogen polar GaN in potassium hydroxide solution

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Junyan; Zhang, Yuantao; Chi, Chen; Yang, Fan; Li, Pengchong [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Qianjin Street 2699, Changchun 130012 (China); Zhao, Degang [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Science, PO Box 912, Beijing 100083 (China); Zhang, Baolin; Du, Guotong [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Qianjin Street 2699, Changchun 130012 (China)

    2016-01-01

    Graphical abstract: - Highlights: • Effects of Mg doping on wet etching of N-polar GaN are illustrated and analysed. • Etching process model of Mg-doped N-polar GaN in KOH solution is purposed. • It is found that Mg doping can induce tensile strain in N-polar GaN film. • N-polar p-GaN film with a hole concentration of 2.4 × 10{sup 17} cm{sup −3} is obtained. - Abstract: KOH based wet etchings were performed on both undoped and Mg-doped N-polar GaN films grown by metal-organic chemical vapor deposition. It is found that the etching rate for Mg-doped N-polar GaN gets slow obviously compared with undoped N-polar GaN. X-ray photoelectron spectroscopy analysis proved that Mg oxide formed on N-polar GaN surface is insoluble in KOH solution so that kinetic-limited etching occurs as the etching process goes on. The etching process model of Mg-doped N-polar GaN in KOH solution is tentatively purposed using a simplified ideal atomic configuration. Raman spectroscopy analysis reveals that Mg doping can induce tensile strain in N-polar GaN films. Meanwhile, p-type N-polar GaN film with a hole concentration of 2.4 × 10{sup 17} cm{sup −3} was obtained by optimizing bis-cyclopentadienyl magnesium flow rates.

  4. Nanostructuring of Mo/Si multilayers by means of reactive ion etching using a three-level mask

    International Nuclear Information System (INIS)

    Dreeskornfeld, L.; Haindl, G.; Kleineberg, U.; Heinzmann, U.; Shi, F.; Volland, B.; Rangelow, I.W.; Majkova, E.; Luby, S.; Kostic,; Matay, L.; Hrkut, P.; Hudek, P.; Lee, H.-Y.

    2004-01-01

    Recently, Mo/Si multilayer reflectors have been gaining industry interest as a promising choice for the next generation extreme ultraviolet mask material for printing sub 70 nm feature size devices. A reactive ion etching system with optimized hardware using CHF 3 /Ar process regime shows the capability for highly anisotropic etching of sub congruent with 400 nm feature sizes in Mo/Si test multilayers with ten periods and a bilayer thickness of 7.8 nm which were prepared by e-beam evaporation. A three-level-mask technique consisting of a top resist mask layer poly-methyl-meth-acrylate, a middle hard amorphous Si mask layer and a bottom-level polyimide layer is used to create the etch mask. The etch characteristics of the polyimide film is shown to be one of the major factors determining the success of the described multilayer etching process. The developed etching technology demonstrates superior process performance without facets, excellent uniformity and good profile control. No contamination, degeneration or defect generation in the unetched multilayer structure could be detected. This non-conventional process results in minimum deposition during the etching thus eliminating the need for a dry or wet cleaning. Sidewall angles in Mo/Si multilayers of 85 deg. , without undercut, bowing and ripples resulting in smooth sidewalls are achieved

  5. Development of wet-proofed catalyst and catalytic exchange process for tritium extraction

    Energy Technology Data Exchange (ETDEWEB)

    Song, Myung Jae; Son, Soon Hwan; Chung, Yang Gun; Lee, Gab Bock [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1996-12-31

    To apply a liquid phase catalytic exchange(LPCE) process for the tritium extraction from tritiated heavy water, the wet proofed catalyst to allow the hydrogen isotopic exchange reaction between liquid water and hydrogen gas was developed. A styrene divinyl benzene copolymer was selected as am effective catalyst support and prepared by suspension copolymerization. After post-treatment, final catalyst supports were dipped in chloroplatinic acid solution. The catalyst support had a good physical properties at a particular preparation condition. The catalytic performance was successfully verified through hydrogen isotopic exchange reaction in the exchange column. A mathematical model for the tritium removal process consisted of LPCE front-ended process and cryogenic distillation process was established using the NTU-HTU method for LPCE column and the FUG method for cryogenic distillation column, respectively. A computer program was developed using the model and then used to investigate optimum design variables which affect the size of columns and tritium inventory (author). 84 refs., 113 figs.

  6. Microstructural evolution of all-wet-processed CIGS films using Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hee Soo; Choi, Eunmi; Kim, Areum; Pyo, Sung Gyu [School of Integrative Engineering, Chung-Ang University, 221 Heukseok-Dong, Seoul, 156-756 (Korea, Republic of); Yoon, Sung Pil [Fuel Cell Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of)

    2014-08-15

    We report a wet process deposition in order to identify a cost-effective processing scheme for CuIn{sub 1-x}Ga{sub x}Se{sub 2} (CIGS) layers on molybdenum/soda lime glass substrates from a Cu-In-Ga precursor solution. We employed a spin coater at various settings to evaluate the uniformity of the resulting CIGS solar cell layer. After the CIGS precursor film was deposited, we applied a selenization process. In the selenization process, we used a controlled temperature RTA system and compared it to a noncontrolled temperature system. We investigated the morphological properties for different selenization temperature treatments. We used Raman mapping to detect binary compounds and found the binary compound effect on the film. Raman mapping results show that the density of the binary compound in the CIGS layer increased with selenization temperature, and at 600 C, the density of the binary compounds was highest. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Single Mode Optical Fiber based Refractive Index Sensor using Etched Cladding

    OpenAIRE

    Kumar, Ajay; Gupta, Geeta; Mallik, Arun; Bhatnagar, Anuj

    2011-01-01

    The use of optical fiber for sensor applications is a topic of current interest. We report the fabrication of etched single mode optical fiber based refractive index sensor. Experiments are performed to determine the etch rate of fiber in buffered hydrofluoric acid, which can be high or low depending upon the temperature at which etching is carried out. Controlled wet etching of fiber cladding is performed using these measurements and etched fiber region is tested for refractive index sensing...

  8. A Self-Aligned a-IGZO Thin-Film Transistor Using a New Two-Photo-Mask Process with a Continuous Etching Scheme

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2014-08-01

    Full Text Available Minimizing the parasitic capacitance and the number of photo-masks can improve operational speed and reduce fabrication costs. Therefore, in this study, a new two-photo-mask process is proposed that exhibits a self-aligned structure without an etching-stop layer. Combining the backside-ultraviolet (BUV exposure and backside-lift-off (BLO schemes can not only prevent the damage when etching the source/drain (S/D electrodes but also reduce the number of photo-masks required during fabrication and minimize the parasitic capacitance with the decreasing of gate overlap length at same time. Compared with traditional fabrication processes, the proposed process yields that thin-film transistors (TFTs exhibit comparable field-effect mobility (9.5 cm2/V·s, threshold voltage (3.39 V, and subthreshold swing (0.3 V/decade. The delay time of an inverter fabricated using the proposed process was considerably decreased.

  9. A Self-Aligned a-IGZO Thin-Film Transistor Using a New Two-Photo-Mask Process with a Continuous Etching Scheme.

    Science.gov (United States)

    Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der

    2014-08-11

    Minimizing the parasitic capacitance and the number of photo-masks can improve operational speed and reduce fabrication costs. Therefore, in this study, a new two-photo-mask process is proposed that exhibits a self-aligned structure without an etching-stop layer. Combining the backside-ultraviolet (BUV) exposure and backside-lift-off (BLO) schemes can not only prevent the damage when etching the source/drain (S/D) electrodes but also reduce the number of photo-masks required during fabrication and minimize the parasitic capacitance with the decreasing of gate overlap length at same time. Compared with traditional fabrication processes, the proposed process yields that thin-film transistors (TFTs) exhibit comparable field-effect mobility (9.5 cm²/V·s), threshold voltage (3.39 V), and subthreshold swing (0.3 V/decade). The delay time of an inverter fabricated using the proposed process was considerably decreased.

  10. Laboratory-scale dry/wet-milling process for the extraction of starch and gluten from wheat

    NARCIS (Netherlands)

    Steeneken, P.A.M.; Helmens, H.J.

    2009-01-01

    A laboratory-scale process is presented for the manufacture of starch and gluten from wheat. Main feature of this process is that whole wheat kernels are crushed dry between smooth rolls prior to wet disintegration in excess water in such way that gluten formation is prevented and fibres can be

  11. Fabrication of Light Extraction Efficiency of Organic Light-Emitting Diodes with 3D Aspherical Microlens by Using Dry Etching Process

    Directory of Open Access Journals (Sweden)

    Y. C. Chen

    2013-01-01

    Full Text Available organic light-emitting diode (OLED can enable a greater artificial contrast ratio and viewing angle compared to liquid crystal display (LCD because OLED pixels directly emit light. There is a shortcoming that the internal quantum efficiency can reach values close to 100%, but about 80% light disperses because of the difference among the refractive indices of the substrate, anode, indium tin oxide (ITO film, and air. In this paper, three dimensions aspherical microlens arrays (3D A-MLAs with substrate modifications are developed to simulate the optical luminous field by using FRED software. This study modified parameters of 3D A-MLAs such as the diameter, fill-factor, aspect ratio, dry etching parameters, and electroforming rates of microlens to improve the extraction efficiency of the OLED. In dry etching, not only the aspect ratio with better extraction rate can be obtained by reactive ion etching (RIE dry etching, but also an undercutting phenomenon can be avoided. The dimensions of 3D A-MLAs can be accurately controlled in the electroforming process used to make a nickel-cobalt (Ni-Co metal mold to achieve the designed dimensions. According to the measured results, the average luminance efficacy of the OLEDs with 3D A-MLAs can be enhanced.

  12. Influence of chemistry on wetting dynamics of nanotextured hydrophobic surfaces.

    Science.gov (United States)

    Di Mundo, Rosa; Palumbo, Fabio; d'Agostino, Riccardo

    2010-04-06

    In this work, the role of a chemical parameter, such as the degree of fluorination, on the wetting behavior of nanotextured hydrophobic surfaces is investigated. Texture and chemistry tuning of the surfaces has been accomplished with single batch radiofrequency low-pressure plasma processes. Polystyrene substrates have been textured by CF(4) plasma etching and subsequently covered by thin films with a tunable F-to-C ratio, obtained in discharges fed with C(4)F(8)-C(2)H(4). Measurements of wetting dynamics reveal a regime transition from adhesive-hydrophobic to slippery-superhydrophobic, i.e., from wet to non wet states, as the F-to-C rises at constant topography. Such achievements are strengthened by calculation of the solid fraction of surface water contact area applying Cassie-Baxter advancing and receding equations to water contact angle data of textured and flat reference surfaces.

  13. INVESTIGATION ON UTILITY OF PLASTIC WASTE AS AN ADDITIVE FOR BITUMINOUS CONCRETE USING WET PROCESS OF MIXING

    Directory of Open Access Journals (Sweden)

    Anurag Virendra Tiwari

    2017-12-01

    Full Text Available Purpose. Plastic waste has become a major environmental issue of concern due to its exponential growth due to rapid urbanization. The paper investigates utility of plastic waste as an additive for bituminous concrete using wet process of mixing. Methodology. The methodology for the present paper has been designed with complex research consisting of Marshall mix design of the bituminous mix added with plastic waste for modifying bitumen using wet process of mixing, performing the tests on the samples and analyzing the results in the form of table and figures. In the present paper LDPE and HDPE type of plastic waste are used to modify the bitumen. Finding. The results show that addition of 6 percent of bitumen improves the Marshall properties of the mix. Use of plastic to modify the bitumen not only makes the road surface more durable but also it is an eco-friendly way of proper disposal of plastic waste. Originality. The processes used for mixing the plastic waste to the bitumen are dry process and wet process. Dry process of mixing the plastic waste to the bituminous mix is most common and lot of study is carried out on its application. In the present paper wet process of mixing has not yet been studied much. Practical Value. The practical application of utilizing the plastic waste to modify bitumen in the bituminous mix improves the stability values resulting in the more durable road surface. Also the method ensures the proper disposal of plastic waste in eco-friendly way.

  14. Development of a novel wet oxidation process for hazardous and mixed wastes

    International Nuclear Information System (INIS)

    Dhooge, P.M.

    1994-01-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. The over all objective of the effort described here is to develop a novel catalytic wet oxidation process for the treatment of these multi-component wastes, with the aim of providing a versatile, non-thermal method which will destroy hazardous organic compounds while simultaneously containing and concentrating toxic and radioactive metals for recovery or disposal in a readily stabilized matrix. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials. The metal catalysts are in the form of salts dissolved in a dilute acid solution. A typical catalyst composition is 60% ferric chloride, 3--4% hydrochloric acid, 0.13% platinum ions, and 0.13% ruthenium ions in a water solution. The catalyst solution is maintained at 423--473 K. Wastes are introduced into contact with the solution, where their organic portion is oxidized to carbon dioxide and water. If the organic portion is chlorinated, hydrogen chloride will be produced as a product. The process is a viable alternative to incineration for the treatment of organic mixed wastes. Estimated costs for waste treatment using the process are from $2.50/kg to $25.00/kg, depending on the size of the unit and the amount of waste processed. Process units can be mobile for on-site treatment of wastes. Results from phase 1 and 2, design and engineering studies, are described

  15. Inductively coupled plasma etching of GaAs low loss waveguides for a traveling waveguide polarization converter, using chlorine chemistry

    Science.gov (United States)

    Lu, J.; Meng, X.; Springthorpe, A. J.; Shepherd, F. R.; Poirier, M.

    2004-05-01

    A traveling waveguide polarization converter [M. Poirier et al.] has been developed, which involves long, low loss, weakly confined waveguides etched in GaAs (epitaxially grown by molecular beam epitaxy), with electroplated ``T electrodes'' distributed along the etched floor adjacent to the ridge walls, and airbridge interconnect metallization. This article describes the development of the waveguide fabrication, based on inductively coupled plasma (ICP) etching of GaAs using Cl2 chemistry; the special processes required to fabricate the electrodes and metallization [X. Meng et al.], and the device characteristics [M. Poirier et al.], are described elsewhere. The required waveguide has dimensions nominally 4 μm wide and 2.1 μm deep, with dimensional tolerances ~0.1 μm across the wafer and wafer to wafer. A vertical etch profile with very smooth sidewalls and floors is required to enable the plated metal electrodes to be fabricated within 0.1 μm of the ridge. The ridges were fabricated using Cl2 ICP etching and a photoresist mask patterned with an I-line stepper; He backside cooling, combined with an electrostatic chuck, was employed to ensure good heat transfer to prevent resist reticulation. The experimental results showed that the ridge profile is very sensitive to ICP power and platen rf power. High ICP power and low platen power tend to result in more isotropic etching, whereas increasing platen power increases the photoresist etch rate, which causes rougher ridge sidewalls. No strong dependence of GaAs etch rate and ridge profile were observed with small changes in process temperature (chuck temperature). However, when the chuck temperature was decreased from 25 to 0 °C, etch uniformity across a 3 in. wafer improved from 6% to 3%. Photoresist and polymer residues present after the ICP etch were removed using a combination of wet and dry processes. .

  16. Inductively coupled plasma etching of GaAs low loss waveguides for a traveling waveguide polarization converter, using chlorine chemistry

    International Nuclear Information System (INIS)

    Lu, J.; Meng, X.; SpringThorpe, A.J.; Shepherd, F.R.; Poirier, M.

    2004-01-01

    A traveling waveguide polarization converter [M. Poirier et al.] has been developed, which involves long, low loss, weakly confined waveguides etched in GaAs (epitaxially grown by molecular beam epitaxy), with electroplated 'T electrodes' distributed along the etched floor adjacent to the ridge walls, and airbridge interconnect metallization. This article describes the development of the waveguide fabrication, based on inductively coupled plasma (ICP) etching of GaAs using Cl 2 chemistry; the special processes required to fabricate the electrodes and metallization [X. Meng et al.], and the device characteristics [M. Poirier et al.], are described elsewhere. The required waveguide has dimensions nominally 4 μm wide and 2.1 μm deep, with dimensional tolerances ∼0.1 μm across the wafer and wafer to wafer. A vertical etch profile with very smooth sidewalls and floors is required to enable the plated metal electrodes to be fabricated within 0.1 μm of the ridge. The ridges were fabricated using Cl 2 ICP etching and a photoresist mask patterned with an I-line stepper; He backside cooling, combined with an electrostatic chuck, was employed to ensure good heat transfer to prevent resist reticulation. The experimental results showed that the ridge profile is very sensitive to ICP power and platen rf power. High ICP power and low platen power tend to result in more isotropic etching, whereas increasing platen power increases the photoresist etch rate, which causes rougher ridge sidewalls. No strong dependence of GaAs etch rate and ridge profile were observed with small changes in process temperature (chuck temperature). However, when the chuck temperature was decreased from 25 to 0 deg. C, etch uniformity across a 3 in. wafer improved from 6% to 3%. Photoresist and polymer residues present after the ICP etch were removed using a combination of wet and dry processes

  17. Nano integrated circuit process

    International Nuclear Information System (INIS)

    Yoon, Yung Sup

    2004-02-01

    This book contains nine chapters, which are introduction of manufacture of semiconductor chip, oxidation such as Dry-oxidation, wet oxidation, oxidation model and oxide film, diffusion like diffusion process, diffusion equation, diffusion coefficient and diffusion system, ion implantation, including ion distribution, channeling, multiimplantation and masking and its system, sputtering such as CVD and PVD, lithography, wet etch and dry etch, interconnection and flattening like metal-silicon connection, silicide, multiple layer metal process and flattening, an integrated circuit process, including MOSFET and CMOS.

  18. Nano integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yung Sup

    2004-02-15

    This book contains nine chapters, which are introduction of manufacture of semiconductor chip, oxidation such as Dry-oxidation, wet oxidation, oxidation model and oxide film, diffusion like diffusion process, diffusion equation, diffusion coefficient and diffusion system, ion implantation, including ion distribution, channeling, multiimplantation and masking and its system, sputtering such as CVD and PVD, lithography, wet etch and dry etch, interconnection and flattening like metal-silicon connection, silicide, multiple layer metal process and flattening, an integrated circuit process, including MOSFET and CMOS.

  19. A catalytic wet oxidation process for mixed waste volume reduction/recycling

    International Nuclear Information System (INIS)

    Dhooge, Patrick M.

    1992-01-01

    Mixed wastes have presented a challenge to treatment and destruction technologies. A recently developed catalytic wet oxidation method has promising characteristics for volume reduction and recycling of mixed wastes. The process utilizes iron (III) as an oxidant in the presence of homogeneous cocatalysts which increase organics' oxidation rates and the rate of oxidation of iron (II) by oxygen. The reaction is conducted in an aqueous mineral acid solution at temperatures of 373 - 573 deg K. The mineral acid should solvate a number of heavy metals, including U and Pu. Studies of reaction rates show that the process can oxidize a wide range of organic compounds including aromatics and chlorinated hydrocarbons. Rate constants in the range of 10 -7 to 10 -4 sec -1 , depending on the cocatalyst, acidity, type of anions, type of organic, temperature, and time. Activation energies ranged from 25. to 32. KJ/mole. Preliminary measurements of the extent of oxidation which could be obtained ranged from 80% for trichloroethylene to 99.8% for 1,2,4-trimethylbenzene; evidence was obtained that absorption by the fluorocarbon liners of the reaction bombs allowed some of the organics to escape exposure to the catalyst solution. The results indicate that complete oxidation of the organics used here, and presumably many others, can be achieved. (author)

  20. Neutral wetting brush layers for block copolymer thin films using homopolymer blends processed at high temperatures

    International Nuclear Information System (INIS)

    Ceresoli, M; Palermo, M; Ferrarese Lupi, F; Seguini, G; Perego, M; Zuccheri, G; Phadatare, S D; Antonioli, D; Gianotti, V; Sparnacci, K; Laus, M

    2015-01-01

    Binary homopolymer blends of two hydroxyl-terminated polystyrene (PS-OH) and polymethylmethacrylate (PMMA-OH) homopolymers (Mn ∼ 16000 g mol"−"1) were grafted on SiO_2 substrates by high-temperature (T > 150 °C), short-time (t < 600 s) thermal treatments. The resulting brush layer was tested to screen preferential interactions of the SiO_2 substrate with the different symmetric and asymmetric PS-b-PMMA block copolymers deposited on top of the grafted molecules. By properly adjusting the blend composition and the processing parameters, an efficient surface neutralization path was identified, enabling the formation, in the block copolymer film, of homogeneous textures of lamellae or cylinders perpendicularly oriented with respect to the substrate. A critical interplay between the phase segregation of the homopolymer blends and their grafting process on the SiO_2 was observed. In fact, the polar SiO_2 is preferential for the PMMA-rich phase that forms a homogeneous layer on the substrate, while the PS-rich phase is located at the polymer-air interface. During the thermal treatment, phase segregation and grafting proceed simultaneously. Complete wetting of the PS rich phase on the PMMA rich phase leads to the formation of a PS/PMMA bilayer. In this case, the progressive diffusion of PS chains toward the polymer-SiO_2 interface during the thermal treatment allows tuning of the brush layer composition. (paper)

  1. Dynamics of liquid nitrogen cooling process of solid surface at wetting contact coefficient

    International Nuclear Information System (INIS)

    Smakulski, P; Pietrowicz, S

    2015-01-01

    Liquid cryogens cooling by direct contact is very often used as a method for decreasing the temperature of electronic devices or equipment i.e. HTS cables. Somehow, cooldown process conducted in that way could not be optimized, because of cryogen pool boiling characteristic and low value of the heat transfer coefficient. One of the possibilities to increase the efficiency of heat transfer, as well as the efficiency of cooling itself, it is to use a spray cooling method. The paper shows dynamics analysis of liquid nitrogen cooling solid surface process. The model of heat transfer for the single droplet of liquid nitrogen, which hits on a flat and smooth surface with respect to the different Weber numbers, is shown. Temperature profiles in calculation domains are presented, as well as the required cooling time. The numerical calculations are performed for different initial and boundary conditions, to study how the wetting contact coefficient is changing, and how it contributed to heat transfer between solid and liquid cryogen. (paper)

  2. Isolating GaSb Membranes Grown Metamorphically on GaAs Substrates Using Highly Selective Substrate Removal Etch Processes

    Science.gov (United States)

    Renteria, E. J.; Muniz, A. J.; Addamane, S. J.; Shima, D. M.; Hains, C. P.; Balakrishnan, G.

    2015-05-01

    The etch rates of NH4OH:H2O2 and C6H8O7:H2O2 for GaAs and GaSb have been investigated to develop a selective etch for GaAs substrates and to isolate GaSb epilayers grown on GaAs. The NH4OH:H2O2 solution has a greater etch rate differential for the GaSb/GaAs material system than C6H8O7:H2O2 solution. The selectivity of NH4OH:H2O2 for GaAs/GaSb under optimized etch conditions has been observed to be as high as 11,000 ± 2000, whereas that of C6H8O7:H2O2 has been measured up to 143 ± 2. The etch contrast has been verified by isolating 2- μm-thick GaSb epilayers that were grown on GaAs substrates. GaSb membranes were tested and characterized with high- resolution x-ray diffraction and atomic force microscopy.

  3. Preface: Special Topic on Atomic and Molecular Layer Processing: Deposition, Patterning, and Etching

    Science.gov (United States)

    Engstrom, James R.; Kummel, Andrew C.

    2017-02-01

    Thin film processing technologies that promise atomic and molecular scale control have received increasing interest in the past several years, as traditional methods for fabrication begin to reach their fundamental limits. Many of these technologies involve at their heart phenomena occurring at or near surfaces, including adsorption, gas-surface reactions, diffusion, desorption, and re-organization of near-surface layers. Moreover many of these phenomena involve not just reactions occurring under conditions of local thermodynamic equilibrium but also the action of energetic species including electrons, ions, and hyperthermal neutrals. There is a rich landscape of atomic and molecular scale interactions occurring in these systems that is still not well understood. In this Special Topic Issue of The Journal of Chemical Physics, we have collected recent representative examples of work that is directed at unraveling the mechanistic details concerning atomic and molecular layer processing, which will provide an important framework from which these fields can continue to develop. These studies range from the application of theory and computation to these systems to the use of powerful experimental probes, such as X-ray synchrotron radiation, probe microscopies, and photoelectron and infrared spectroscopies. The work presented here helps in identifying some of the major challenges and direct future activities in this exciting area of research involving atomic and molecular layer manipulation and fabrication.

  4. Process Analytical Technology for High Shear Wet Granulation: Wet Mass Consistency Reported by In-Line Drag Flow Force Sensor Is Consistent With Powder Rheology Measured by At-Line FT4 Powder Rheometer.

    Science.gov (United States)

    Narang, Ajit S; Sheverev, Valery; Freeman, Tim; Both, Douglas; Stepaniuk, Vadim; Delancy, Michael; Millington-Smith, Doug; Macias, Kevin; Subramanian, Ganeshkumar

    2016-01-01

    Drag flow force (DFF) sensor that measures the force exerted by wet mass in a granulator on a thin cylindrical probe was shown as a promising process analytical technology for real-time in-line high-resolution monitoring of wet mass consistency during high shear wet granulation. Our previous studies indicated that this process analytical technology tool could be correlated to granulation end point established independently through drug product critical quality attributes. In this study, the measurements of flow force by a DFF sensor, taken during wet granulation of 3 placebo formulations with different binder content, are compared with concurrent at line FT4 Powder Rheometer characterization of wet granules collected at different time points of the processing. The wet mass consistency measured by the DFF sensor correlated well with the granulation's resistance to flow and interparticulate interactions as measured by FT4 Powder Rheometer. This indicated that the force pulse magnitude measured by the DFF sensor was indicative of fundamental material properties (e.g., shear viscosity and granule size/density), as they were changing during the granulation process. These studies indicate that DFF sensor can be a valuable tool for wet granulation formulation and process development and scale up, as well as for routine monitoring and control during manufacturing. Copyright © 2016. Published by Elsevier Inc.

  5. Conceptual Biorefinery Design and Research Targeted for 2022: Hydrothermal Liquefacation Processing of Wet Waste to Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Snowden-Swan, Lesley J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhu, Yunhua [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bearden, Mark D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Seiple, Timothy E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Susanne B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schmidt, Andrew J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Billing, Justin M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hallen, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hart, Todd R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Jian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Albrecht, Karl O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fox, Samuel P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Maupin, Gary D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elliott, Douglas C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-12-28

    The Department of Energy Bioenergy Technologies Office (BETO) invests in research and development of new pathways for commercially viable conversion of biomass into drop-in ready transportation fuels, fuel blendstocks and products. The primary emphasis has been on terrestrial and algae feedstocks, but more recently BETO has begun to explore the potential of wet wastes for biofuel production, with focus on wastewater residuals, manure, food waste, and fats, oils and grease. A recent resource analysis estimates that 77 million dry tons per year of these wastes are generated annually, 65% of which are underutilized for any beneficial purpose. Approximately 14 million dry tons of the total resource is wastewater residuals (sludge and biosolids) generated at the nation’s wastewater treatment plants (WWTPs). Conversion of this resource into transportation fuels could significantly contribute to the creation of a new domestic bioenergy and bioproduct industry, while providing an economically and environmentally sustainable alternative for current waste disposal practices. Hydrothermal liquefaction (HTL) is a process that uses hot, pressurized water in the condensed phase to convert biomass to a thermally stable oil product, also known as “biocrude”, which can then be thermo-catalytically upgraded to hydrocarbon fuel blendstocks. HTL is conceptually simple, has a high carbon efficiency, and can be applied to a wide range of wet feedstocks at similar processing conditions. The purpose of this report is to document the conceptual design, economics and supporting data for a sludge-to-fuel pathway via HTL and biocrude upgrading. The configuration includes a HTL plant that is co-located with a WWTP and a larger scale biocrude upgrading plant for production of hydrocarbon fuel blendstocks. Experimental data from bench scale testing of a 1:1 mixture of primary:secondary sludges are used to establish the economic and technical assumptions for the analysis. The design

  6. Utilization and application of wet potato processing coproducts for finishing cattle.

    Science.gov (United States)

    Nelson, M L

    2010-04-01

    Wet coproducts fed to beef cattle include processing coproducts of the fruit, vegetable, juice, and brewing industries. Considerations for their utilization in beef cattle diets include quantity available, feeding value, quality of animal products produced, economics (e.g., transportation of water), storage and preservation, consumer perception, nuisance concerns, contaminants, and interactions with other diet ingredients. Potato (Solanum tuberosum) coproducts from processing for frozen food products may be quantitatively most important because the 11.3 million t of potatoes (fresh weight) processed in the United States and Canada in 2008 resulted in an estimated 4.3 million t (as-is basis) of coproduct. Chemical composition and feeding value of potato coproducts depends on the coproduct type. The names of coproducts vary among potato processors and some processors combine the different coproducts into one product commonly called slurry. The 4 main potato coproducts are 1) potato peels; 2) screen solids (small potatoes and pieces); 3) fried product (fries, hash browns, batter, crumbles); and 4) material from the water recovery systems (oxidation ditch, belt solids, filter cake). The coproducts, except the fried products, ensile rapidly, reaching pH 5 in 7 d or less. Dry matter content varies from 10 to 30% and on a DM basis varies in CP (5 to 27%), starch (3 to 56%), NDF (4 to 41%), and ether extract (3 to 37%) content among potato coproducts. Type of coproduct and frying greatly affect the energy value (0.6 to 1.6 Mcal of NE(g)/kg of DM). Composition, quality, and shelf life of beef was not affected by potato coproduct feeding in contrast to perceptions of some purveyors and chefs. Potato coproducts are quantitatively important energy sources in beef cattle diets, which, in turn, solve a potentially massive disposal problem for the food processing industry.

  7. III-Nitride Blue Laser Diode with Photoelectrochemically Etched Current Aperture

    Science.gov (United States)

    Megalini, Ludovico

    distance. In this dissertation it is presented the first nitride blue edge emitting LD with a photoelectrochemical etched current aperture (CA-LD) into the device active region. Photoelectrochemical etching (PECE) has emerged as a powerful wet etching technique for III-nitride compounds. Beyond the advantages of wet etching technique, PECE offers bandgap selectivity, which is particularly desirable because it allows more freedom in designing new and advanced devices with higher performances. In the first part of this thesis a review of PECE is presented, and it is shown how it can be used to achieve a selective and controllable deep undercut of the active region of LEDs and LDs, in particular the selective PECE of MQW active region of (10-10) m-plane and (20-2-1) plane structures is reported. In the second part of this thesis, the fabrication flow process of the CA-LD is described. The performance of these devices is compared with that of shallow etched ridge LDs with a nominally identical epitaxial structure and active region width and it is experimentally shown that the CA-LD design has superior performance. CW operation of a (20-2-1) CA-LD with a 1.5 microm wide active region is demonstrated. Finally, in the third and last part of this thesis, the CA-LD performance is discussed in more details, in particular, an analysis of optical scattering losses caused by the rough edges of the remnant PEC etched active region is presented.

  8. Fabrication of combined-scale nano- and microfluidic polymer systems using a multilevel dry etching, electroplating and molding process

    DEFF Research Database (Denmark)

    Tanzi, Simone; Østergaard, Peter Friis; Matteucci, Marco

    2012-01-01

    Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions to fabric......Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions...

  9. Quantitative analysis of precipitation over Fukushima to understand the wet deposition process in March 2011

    Science.gov (United States)

    Yatagai, A.; Onda, Y.; Watanabe, A.

    2012-04-01

    The Great East Japan Earthquake caused a severe accident at the Fukushima-Daiichi nuclear power plant (NPP), leading to the emission of large amounts of radioactive pollutants into the environment. The transport and diffusion of these radioactive pollutants in the atmosphere caused a disaster for residents in and around Fukushima. Studies have sought to understand the transport, diffusion, and deposition process, and to understand the movement of radioactive pollutants through the soil, vegetation, rivers, and groundwater. However, a detailed simulation and understanding of the distribution of radioactive compounds depend on a simulation of precipitation and on the information on the timing of the emission of these radioactive pollutants from the NPP. Past nuclear expansion studies have demonstrated the importance of wet deposition in distributing pollutants. Hence, this study examined the quantitative precipitation pattern in March 2011 using rain-gauge observations and X-band radar data from Fukushima University. We used the AMeDAS rain-gauge network data of 1) the Japan Meteorological Agency (1273 stations in Japan) and 2) the Water Information System (47 stations in Fukushima prefecture) and 3) the rain-gauge data of the Environmental Information Network of NTT Docomo (30 stations in Fukushima) to construct 0.05-degree mesh data using the same method used to create the APHRODITE daily grid precipitation data (Yatagai et al., 2009). Since some AMeDAS data for the coastal region were lost due to the earthquake, the complementary network of 2) and 3) yielded better precipitation estimates. The data clarified that snowfall was observed on the night of Mar 15 into the morning of Mar 16 throughout Fukushima prefecture. This had an important effect on the radioactive contamination pattern in Fukushima prefecture. The precipitation pattern itself does not show one-on-one correspondence with the contamination pattern. While the pollutants transported northeast of the

  10. Polymeric supported sorbents for decreasing hazardous metal ions content in wet process phosphoric acid

    International Nuclear Information System (INIS)

    El-Zahhar, A.A.; El-Naggar, H.A.; Ahmed, M.

    2005-01-01

    Procedure for preparation of polymeric supported silica, and their usage for decreasing hazardous metal ion content in wet process phosphoric acid was developed. The procedure is based firstly on extraction silica from rice straw by alkaline treatment , secondly supporting the produced silica on binding polyacrylonitrile (PAN). The produced polymer based sorbent was used for decreasing hazardous metal ions (especially iron) present as inorganic impurities in crud Egyptian phosphoric acid (green acid). Different factors affecting the sorption equilibrium ( contact time, temperature , sorbent mass and batch factor ) were studied. Studying the sorption isotherm revealed that the adsorption data could favorably fit the Langmuir adsorption isotherm. In the dynamic study , the sorption capacity at (Cξ/Cο = 50%) was found to be 28.5 mg/g and the loaded column could be regenerated using 50ml of 0.15 M HNO 3 . The regenerated column could undergo sorption regeneration cycles up to four cycles without significant decrease in the sorption capacity , weight loss or change in the physical properties of the sorbent

  11. Kinetic parameters of biomass growth in a UASB reactor treating wastewater from coffee wet processing (WCWP

    Directory of Open Access Journals (Sweden)

    Claudio Milton Montenegro Campos

    2014-10-01

    Full Text Available This study evaluated the treatment of wastewater from coffee wet processing (WCWP in an anaerobic treatment system at a laboratory scale. The system included an acidification/equalization tank (AET, a heat exchanger, an Upflow Anaerobic Sludge Blanket Reactor (UASB, a gas equalization device and a gas meter. The minimum and maximum flow rates and volumetric organic loadings rate (VOLR were 0.004 to 0.037 m 3 d -1 and 0.14 to 20.29 kgCOD m -3 d -1 , respectively. The kinetic parameters measured during the anaerobic biodegradation of the WCWP, with a minimal concentration of phenolic compounds of 50 mg L - ¹, were: Y = 0.37 mgTVS (mgCODremoved -1 , Kd = 0.0075 d-1 , Ks = 1.504mg L -1 , μmax = 0.2 d -1 . The profile of sludge in the reactor showed total solids (TS values from 22,296 to 55,895 mg L -1 and TVS 11,853 to 41,509 mg L -1 , demonstrating a gradual increase of biomass in the reactor during the treatment, even in the presence of phenolic compounds in the concentration already mentioned.

  12. New procedure for extraction of algal lipids from wet biomass: a green clean and scalable process.

    Science.gov (United States)

    Dejoye Tanzi, Celine; Abert Vian, Maryline; Chemat, Farid

    2013-04-01

    A new procedure, called Simultaneous Distillation and Extraction Process (SDEP), for lipid extraction from wet microalgae (Nannochloropsis oculata and Dunaliella salina) was reported. This method does not require a pre-drying of the biomass and employs alternative solvents such as d-limonene, α-pinene and p-cymene. This procedure has been compared with Soxhlet extraction (Sox) and Bligh & Dyer method (B&D). For N. oculata, results showed that SDEP-cymene provided similar lipid yields to B&D (21.45% and 23.78%), while SDEP-limonene and pinene provided lower yields (18.73% and 18.75% respectively). For D. salina, SDEP-pinene provided the maximum lipid yield (3.29%) compared to the other solvents, which is quite close to B&D result (4.03%). No significant differences in terms of distribution of lipid classes and fatty acid composition have been obtained for different techniques. Evaluation of energy consumption indicates a substantial saving in the extraction cost by SDEP compared to the conventional extraction technique, Soxhlet. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Liquid-liquid extraction for purification of wet process phosphoric acid

    International Nuclear Information System (INIS)

    Lotfollahi, Mohammad Nader; Bakshi, Mahdi

    2006-01-01

    The Wet Process Phosphoric Acid (WPA) is used to produce fertilizers and alimentary supplies for cattle. In each of these applications, the impurities contained in acid must be in standard range. In this paper purification of WPA by solvent extraction is performed and the effect of the mass ratio of solvent to feed on extraction efficiency is studied. The working solvents are Methyl Iso Butyl Ketone (MIBK), Iso Amyl Alcohol (IAA) and the mixture of them. The results show that the IAA is better than other solvents in extraction of WPA. This solvent can extract 82.2% of acid after two extraction stages but MIBK can extract only 73.5% of acid after three extraction stages. For all of these solvents, the Pb and Cd concentrations go down to trace. The experimental results show that the maximum separation of Mg with MIBK is 87.5% which occurs at the mass ratio of solvent to feed eual to 4. In the case of IAA solvent the percent is 91.7% and the ratio is 8

  14. Anodic processes in the chemical and electrochemical etching of Si crystals in acid-fluoride solutions: Pore formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ulin, V. P.; Ulin, N. V.; Soldatenkov, F. Yu., E-mail: f.soldatenkov@mail.ioffe.ru [Ioffe Physical–Technical Institute (Russian Federation)

    2017-04-15

    The interaction of heavily doped p- and n-type Si crystals with hydrofluoric acid in the dark with and without contact with metals having greatly differing work functions (Ag and Pd) is studied. The dependences of the dissolution rates of Si crystals in HF solutions that contain oxidizing agents with different redox potentials (FeCl{sub 3}, V{sub 2}O{sub 5} and CrO{sub 3}) on the type and level of silicon doping are determined. Analysis of the experimental data suggests that valence-band holes in silicon are not directly involved in the anodic reactions of silicon oxidation and dissolution and their generation in crystals does not limit the rate of these processes. It is also shown that the character and rate of the chemical process leading to silicon dissolution in HF-containing electrolytes are determined by the interfacial potential attained at the semiconductor–electrolyte interface. The mechanism of electrochemical pore formation in silicon crystals is discussed in terms of selfconsistent cooperative reactions of nucleophilic substitution between chemisorbed fluorine anions and coordination- saturated silicon atoms in the crystal subsurface layer. A specific feature of these reactions for silicon crystals is that vacant nonbonding d{sup 2}sp{sup 3} orbitals of Si atoms, associated with sixfold degenerate states corresponding to the Δ valley of the conduction band, are involved in the formation of intermediate complexes. According to the suggested model, the pore-formation process spontaneously develops in local regions of the interface under the action of the interfacial potential in the adsorption layer and occurs as a result of the detachment of (SiF{sub 2}){sub n} polymer chains from the crystal. Just this process leads to the preferential propagation of pores along the <100> crystallographic directions. The thermodynamic aspects of pore nucleation and the effect of the potential drop across the interface, conduction type, and free-carrier concentration

  15. Surface etching technologies for monocrystalline silicon wafer solar cells

    Science.gov (United States)

    Tang, Muzhi

    With more than 200 GW of accumulated installations in 2015, photovoltaics (PV) has become an important green energy harvesting method. The PV market is dominated by solar cells made from crystalline silicon wafers. The engineering of the wafer surfaces is critical to the solar cell cost reduction and performance enhancement. Therefore, this thesis focuses on the development of surface etching technologies for monocrystalline silicon wafer solar cells. It aims to develop a more efficient alkaline texturing method and more effective surface cleaning processes. Firstly, a rapid, isopropanol alcohol free texturing method is successfully demonstrated to shorten the process time and reduce the consumption of chemicals. This method utilizes the special chemical properties of triethylamine, which can form Si-N bonds with wafer surface atoms. Secondly, a room-temperature anisotropic emitter etch-back process is developed to improve the n+ emitter passivation. Using this method, 19.0% efficient screen-printed aluminium back surface field solar cells are developed that show an efficiency gain of 0.15% (absolute) compared with conventionally made solar cells. Finally, state-of-the-art silicon surface passivation results are achieved using hydrogen plasma etching as a dry alternative to the classical hydrofluoric acid wet-chemical process. The effective native oxide removal and the hydrogenation of the silicon surface are shown to be the reasons for the excellent level of surface passivation achieved with this novel method.

  16. Isolating GaSb membranes grown metamorphically on GaAs substrates using highly selective substrate removal etch processes

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering. Center for High Technology Materials; Balakrishnan, Ganesh [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering. Center for High Technology Materials

    2017-02-24

    The etch rates of NH4OH:H2O2 and C6H8O7:H2O2 for GaAs and GaSb have been investigated to develop a selective etch for GaAs substrates and to isolate GaSb epilayers grown on GaAs. The NH4OH:H2O2 solution has a greater etch rate differential for the GaSb/GaAs material system than C6H8O7:H2O2 solution. The selectivity of NH4OH:H2O2 for GaAs/GaSb under optimized etch conditions has been observed to be as high as 11471 ± 1691 whereas that of C6H8O7:H2O2 has been measured up to 143 ± 2. The etch contrast has been verified by isolating 2 μm thick GaSb epi-layers that were grown on GaAs substrates. GaSb membranes were tested and characterized with high-resolution X-Ray diffraction (HR-XRD) and atomic force microscopy (AFM).

  17. Formation of nanogaps in InAs nanowires by selectively etching embedded InP segments.

    Science.gov (United States)

    Schukfeh, M I; Storm, K; Hansen, A; Thelander, C; Hinze, P; Beyer, A; Weimann, T; Samuelson, L; Tornow, M

    2014-11-21

    We present a method to fabricate nanometer scale gaps within InAs nanowires by selectively etching InAs/InP heterostructure nanowires. We used vapor-liquid-solid grown InAs nanowires with embedded InP segments of 10-60 nm length and developed an etching recipe to selectively remove the InP segment. A photo-assisted wet etching process in a mixture of acetic acid and hydrobromic acid gave high selectivity, with accurate removal of InP segments down to 20 nm, leaving the InAs wire largely unattacked, as verified using scanning electron and transmission electron microscopy. The obtained nanogaps in InAs wires have potential as semiconducting electrodes to investigate electronic transport in nanoscale objects. We demonstrate this functionality by dielectrophoretically trapping 30 nm diameter gold nanoparticles into the gap.

  18. Formation of nanogaps in InAs nanowires by selectively etching embedded InP segments

    International Nuclear Information System (INIS)

    Schukfeh, M I; Hansen, A; Tornow, M; Storm, K; Thelander, C; Samuelson, L; Hinze, P; Weimann, T; Beyer, A

    2014-01-01

    We present a method to fabricate nanometer scale gaps within InAs nanowires by selectively etching InAs/InP heterostructure nanowires. We used vapor–liquid–solid grown InAs nanowires with embedded InP segments of 10–60 nm length and developed an etching recipe to selectively remove the InP segment. A photo-assisted wet etching process in a mixture of acetic acid and hydrobromic acid gave high selectivity, with accurate removal of InP segments down to 20 nm, leaving the InAs wire largely unattacked, as verified using scanning electron and transmission electron microscopy. The obtained nanogaps in InAs wires have potential as semiconducting electrodes to investigate electronic transport in nanoscale objects. We demonstrate this functionality by dielectrophoretically trapping 30 nm diameter gold nanoparticles into the gap. (paper)

  19. Influence of predictive contamination to agricultural products due to dry and wet processes during an accidental release of radionuclides

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Jeong, Hyo Joon; Han, Moon Hee; Lee, Chang Woo

    2003-01-01

    The influence of predictive contamination to agricultural products due to the wet processes as well as dry processes from radioactive air concentration during a nuclear emergency is comprehensively analyzed. The previous dynamic food chain model DYNACON considering Korean agricultural and environmental conditions, in which the initial input parameter was radionuclide concentrations on the ground, is improved so as to evaluate radioactive contamination to agricultural products from either radioactive air concentrations or radionuclide concentrations on the ground. As for the results, wet deposition is a more dominant mechanism than dry deposition in contamination on the ground. While, the contamination levels of agricultural products are strongly dependent on radionuclide and precipitation when the deposition of radionuclides occurs. It means that the contamination levels of agricultural products are determined from which is the more dominant process between deposition on the ground and interception to agricultural plants

  20. Nanorods on surface of GaN-based thin-film LEDs deposited by post-annealing after photo-assisted chemical etching

    Science.gov (United States)

    Chen, Lung-Chien; Lin, Wun-Wei; Liu, Te-Yu

    2017-01-01

    This study investigates the optoelectronic characteristics of gallium nitride (GaN)-based thin-film light-emitting diodes (TF-LEDs) that are formed by a two-step transfer process that involves wet etching and post-annealing. In the two-step transfer process, GaN LEDs were stripped from sapphire substrates by the laser lift-off (LLO) method using a KrF laser and then transferred onto ceramic substrates. Ga-K nanorods were formed on the surface of the GaN-based TF-LEDs following photo-assisted chemical etching and photo-enhanced post-annealing at 100 °C for 1 min. As a result, the light output power of GaN-based TF-LEDs with wet etching and post-annealing was over 72% more than that of LEDs that did not undergo these treatments.

  1. Dry etching technologies for reflective multilayer

    Science.gov (United States)

    Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Kase, Yoshihisa; Yoshimori, Tomoaki; Muto, Makoto; Nonaka, Mikio; Iwami, Munenori

    2012-11-01

    We have developed a highly integrated methodology for patterning Extreme Ultraviolet (EUV) mask, which has been highlighted for the lithography technique at the 14nm half-pitch generation and beyond. The EUV mask is characterized as a reflective-type mask which is completely different compared with conventional transparent-type of photo mask. And it requires not only patterning of absorber layer without damaging the underlying multi reflective layers (40 Si/Mo layers) but also etching multi reflective layers. In this case, the dry etch process has generally faced technical challenges such as the difficulties in CD control, etch damage to quartz substrate and low selectivity to the mask resist. Shibaura Mechatronics ARESTM mask etch system and its optimized etch process has already achieved the maximal etch performance at patterning two-layered absorber. And in this study, our process technologies of multi reflective layers will be evaluated by means of optimal combination of process gases and our optimized plasma produced by certain source power and bias power. When our ARES™ is used for multilayer etching, the user can choose to etch the absorber layer at the same time or etch only the multilayer.

  2. A wet-chemical approach to perovskite and fluorite-type nanoceramics: synthesis and processing

    NARCIS (Netherlands)

    Veldhuis, Sjoerd

    2015-01-01

    In thesis the low-temperature, wet-chemical approach to various functional inorganic oxide materials is described. The main focus of this research is to control the material’s synthesis from liquid precursor to metal oxide powder or thin film; while understanding its formation mechanism. In

  3. Monitoring of multiple solvent induced form changes during high shear wet granulation and drying processes using online Raman spectroscopy.

    Science.gov (United States)

    Reddy, Jay Poorna; Jones, John W; Wray, Patrick S; Dennis, Andrew B; Brown, Jonathan; Timmins, Peter

    2018-04-25

    Form changes during drug product processing can be a risk to the final product quality in terms of chemical stability and bioavailability. In this study, online Raman spectroscopy was used to monitor the form changes in real time during high shear wet granulation of Compound A, a highly soluble drug present at a high drug load in an extended release formulation. The effect of water content, temperature, wet massing time and drying technique on the degree of drug transformation were examined. A designed set of calibration standards were employed to develop quantitative partial least square regression models to predict the concentration of each drug form during both wet granulation and the drying process. Throughout all our experiments we observed complex changes of the drug form during granulation, manifest as conversions between the initial non-solvated form of Compound A, the hemi-hydrate form and the "apparent" amorphous form (dissolved drug). The online Raman data demonstrate that the non-solvated form converts to an "apparent" amorphous form (dissolved drug) due to drug dissolution with no appearance of the hemi-hydrate form during water addition stage. The extent of conversion of the non-solvated form was governed by the amount of water added and the rate of conversion was accelerated at higher temperatures. Interestingly, in the wet massing zone, the formation of the hemi-hydrate form was observed at a rate equivalent to the rate of depletion of the non-solvated form with no change in the level of the "apparent amorphous" form generated. The level of hemi-hydrate increased with an increase in wet massing time. The drying process had a significant effect on the proportion of each form. During tray drying, changes in drug form continued for hours. In contrast fluid bed drying appeared to lock the final proportions of drug form product attained during granulation, with comparatively small changes observed during drying. In conclusion, it was possible to

  4. Temperature dependence on plasma-induced damage and chemical reactions in GaN etching processes using chlorine plasma

    Science.gov (United States)

    Liu, Zecheng; Ishikawa, Kenji; Imamura, Masato; Tsutsumi, Takayoshi; Kondo, Hiroki; Oda, Osamu; Sekine, Makoto; Hori, Masaru

    2018-06-01

    Plasma-induced damage (PID) on GaN was optimally reduced by high-temperature chlorine plasma etching. Energetic ion bombardments primarily induced PID involving stoichiometry, surface roughness, and photoluminescence (PL) degradation. Chemical reactions under ultraviolet (UV) irradiation and chlorine radical exposure at temperatures higher than 400 °C can be controlled by taking into account the synergism of simultaneous photon and radical irradiations to effectively reduce PID.

  5. ABB wet flue gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Niijhawan, P.

    1994-12-31

    The wet limestone process for flue gas desulfurization (FGD) is outlined. The following topics are discussed: wet flue gas desulfurization, wet FGD characteristics, wet scrubbers, ABB wet FGD experience, wet FGD forced oxidation, advanced limestone FGD systems, key design elements, open spray tower design, spray tower vs. packed tower, important performance parameters, SO{sub 2} removal efficiency, influence by L/G, limestone utilization, wet FGD commercial database, particulate removal efficiencies, materials of construction, nozzle layout, spray nozzles, recycle pumps, mist elimination, horizontal flow demister, mist eliminator washing, reagent preparation system, spray tower FGDS power consumption, flue gas reheat options, byproduct conditioning system, and wet limestone system.

  6. Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

    Science.gov (United States)

    Li, Kun-Dar; Miao, Jin-Ru

    2018-02-01

    To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, and preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

  7. Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

    Directory of Open Access Journals (Sweden)

    Kun-Dar Li

    2018-02-01

    Full Text Available To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, and preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

  8. Influence of radioactive contamination to agricultural products due to dry and wet deposition processes during a nuclear emergency

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Han, Moon Hee; Choi, Yong Ho; Lee, Chang Woo

    2002-01-01

    Combined with deposition model onto the ground of radionuclides, the influence of radioactive contamination to agricultural products was analyzed due to wet deposition as well as dry deposition from radioactive air concentration during a nuclear emergency. The previous dynamic food chain model, in which initial input parameter is only radionuclide concentrations on the ground, was improved for the evaluating of radioactive contamination to agricultural products from either radionuclide concentrations in air or radionuclide concentrations on the ground. As the results, in case of deposition onto the ground, wet deposition was more dominant process than dry deposition. While the contamination levels of agricultural products were dependent on the a variety of factors such as radionuclides and rainfall rate. It means that the contamination levels of agricultural products are determined from which is more dominant process between deposition on the ground and interception onto agricultural plants

  9. Kinetic-limited etching of magnesium doping nitrogen polar GaN in potassium hydroxide solution

    Science.gov (United States)

    Jiang, Junyan; Zhang, Yuantao; Chi, Chen; Yang, Fan; Li, Pengchong; Zhao, Degang; Zhang, Baolin; Du, Guotong

    2016-01-01

    KOH based wet etchings were performed on both undoped and Mg-doped N-polar GaN films grown by metal-organic chemical vapor deposition. It is found that the etching rate for Mg-doped N-polar GaN gets slow obviously compared with undoped N-polar GaN. X-ray photoelectron spectroscopy analysis proved that Mg oxide formed on N-polar GaN surface is insoluble in KOH solution so that kinetic-limited etching occurs as the etching process goes on. The etching process model of Mg-doped N-polar GaN in KOH solution is tentatively purposed using a simplified ideal atomic configuration. Raman spectroscopy analysis reveals that Mg doping can induce tensile strain in N-polar GaN films. Meanwhile, p-type N-polar GaN film with a hole concentration of 2.4 ÿ 1017 cm⿿3 was obtained by optimizing bis-cyclopentadienyl magnesium flow rates.

  10. Selective photochemical dry etching of compound semiconductors

    International Nuclear Information System (INIS)

    Ashby, C.I.H.

    1988-01-01

    When laser-driven etching of a semiconductor requires direct participation of photogenerated carriers, the etching quantum yield will be sensitive to the electronic properties of a specific semiconductor material. The band-gap energy of the semiconductor determines the minimum photon energy needed for carrier-driven etching since sub-gap photons do not generate free carriers. However, only those free carriers that reach the reacting surface contribute to etching and the ultimate carrier flux to the surface is controlled by more subtle electronic properties than the lowest-energy band gap. For example, the initial depth of carrier generation and the probability of carrier recombination between the point of generation and the surface profoundly influence the etching quantum yield. Appropriate manipulation of process parameters can provide additional reaction control based on such secondary electronic properties. Applications to selective dry etching of GaAs and related materials are discussed

  11. Plasma etching of electrospun polymeric nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Verdonck, Patrick [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil)]. E-mail: verdonck@imec.be; Braga Caliope, Priscila [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); Moral Hernandez, Emilio del [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); Silva, Ana Neilde R. da [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); FATEC-SP, Pca Fernando Prestes, 30 Sao Paulo, SP (Brazil)

    2006-10-25

    Electrospun polymeric nanofibres have several applications because of their high surface area to volume and high length to diameter ratios. This paper investigates the influence of plasma etching on these fibres and the etching mechanisms. For the characterization, SEM analysis was performed to determine the forms and shapes of the fibres and SEM photos were analysed by the technique of mathematical morphology, in order to determine the area on the sample occupied by the fibres and the frequency distribution of the nanofibre diameters. The results showed that the oxygen plasma etches the nanofibres much faster when ion bombardment is present. The form of the fibres is not altered by the etching, indicating the possibility of transport of oxygen atoms over the fibre surface. The most frequent diameter, somewhat surprisingly, is not significantly dependent on the etching process, and remains of the order of 80 nm, indicating that fibres with smaller diameters are etched at high rates.

  12. Obtaining porous silicon suitable for sensor technology using MacEtch nonelectrolytic etching

    Directory of Open Access Journals (Sweden)

    Iatsunskyi I. R.

    2013-12-01

    Full Text Available The author suggests to use the etching method MacEtch (metal-assisted chemical etching for production of micro- and nanostructures of porous silicon. The paper presents research results on the morphology structures obtained at different parameters of deposition and etching processes. The research has shown that, depending on the parameters of deposition of silver particles and silicon wafers etching, the obtained surface morphology may be different. There may be both individual crater-like pores and developed porous or macroporous surface. These results indicate that the MacEtch etching is a promising method for obtaining micro-porous silicon nanostructures suitable for effective use in gas sensors and biological object sensors.

  13. A double stage dry-wet-fermentation process for a fast and safe digestion of different kinds of organic material

    International Nuclear Information System (INIS)

    Busch, G.; Sieber, M.; Buschmann, J.; Burkhardat, M.

    2009-01-01

    The fermentation of organic material is a four-step-process. It is admissible to merge the first two steps (hydrolysis and acidification) to hydrolysis in general and the last two steps (aceto genesis and methano genesis) to methano genesis. The Brandenburg University of Technology in Cottbus has devised a double stage dry-wet-fermentation process for fast and safe anaerobic degradation. Using these processes, it is possible to decompose different kinds of organic material like renewable material (e. g. maize silage), waste (e. g. household-waste) and industrial material (e. g. glycerine). (Author)

  14. Reduction of Residual Stresses in Sapphire Cover Glass Induced by Mechanical Polishing and Laser Chamfering Through Etching

    Directory of Open Access Journals (Sweden)

    Shih-Jeh Wu

    2016-10-01

    Full Text Available Sapphire is a hard and anti-scratch material commonly used as cover glass of mobile devices such as watches and mobile phones. A mechanical polishing using diamond slurry is usually necessary to create mirror surface. Additional chamfering at the edge is sometimes needed by mechanical grinding. These processes induce residual stresses and the mechanical strength of the sapphire work piece is impaired. In this study wet etching by phosphate acid process is applied to relief the induced stress in a 1” diameter sapphire cover glass. The sapphire is polished before the edge is chamfered by a picosecond laser. Residual stresses are measured by laser curvature method at different stages of machining. The results show that the wet etching process effectively relief the stress and the laser machining does not incur serious residual stress.

  15. Etching Behavior of Aluminum Alloy Extrusions

    Science.gov (United States)

    Zhu, Hanliang

    2014-11-01

    The etching treatment is an important process step in influencing the surface quality of anodized aluminum alloy extrusions. The aim of etching is to produce a homogeneously matte surface. However, in the etching process, further surface imperfections can be generated on the extrusion surface due to uneven materials loss from different microstructural components. These surface imperfections formed prior to anodizing can significantly influence the surface quality of the final anodized extrusion products. In this article, various factors that influence the materials loss during alkaline etching of aluminum alloy extrusions are investigated. The influencing variables considered include etching process parameters, Fe-rich particles, Mg-Si precipitates, and extrusion profiles. This study provides a basis for improving the surface quality in industrial extrusion products by optimizing various process parameters.

  16. Copper-assisted, anti-reflection etching of silicon surfaces

    Science.gov (United States)

    Toor, Fatima; Branz, Howard

    2014-08-26

    A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

  17. Plasma etching of niobium-SiO/sub x/ layers

    International Nuclear Information System (INIS)

    Schelle, D.; Tiller, H.J.

    1986-01-01

    CF 4 -plasma etching of niobium and SiO/sub x/ layers has been investigated in a r.f. diode reactor. Etch rates increase linearly with increasing power density and also increase with pressure. The etch rate ratio can be changed using different etch gases or operating in different plasma modes (PE or IEPE). Changing from the ion enhanced plasma etching mode (IEPE) to plasma etching mode (PE) the etch rate ratio is changing by a factor of ten. On the basis of etch rate dependences on process parametes and thermodynamic data it has been suggested the generation of fluorine radicals as the rate limiting step. A general etching model has been proposed, which explains qualitatively and quantitatively (on account of data from literature) the measured results. (author)

  18. Complex three-dimensional structures in Si{1 0 0} using wet bulk micromachining

    International Nuclear Information System (INIS)

    Pal, Prem; Sato, Kazuo

    2009-01-01

    Complex three-dimensional structures for microelectromechanical systems (MEMS) are fabricated in Si{1 0 0} wafers using wet bulk micromachining. The structures are divided into two categories: fixed and freestanding. The fabrication processes for both types utilize single wafers with sequentially deposited nitride and oxide layers, local oxidation of silicon (LOCOS) and two steps of wet anisotropic etching. The fixed structures contain perfectly sharp edges. Thermally deposited oxide is used as the material for the freestanding structures. Wet etching is performed in tetramethyl ammonium hydroxide (TMAH) with and without Triton X-100 (C 14 H 22 O(C 2 H 4 O) n , n = 9–10). For the fixed structures, both etching steps are performed either in 25 wt% TMAH + Triton or pure TMAH or both, depending upon the type of the structures. In the case of freestanding systems, TMAH + Triton is utilized first, followed by pure TMAH. The fabrication methods enable densely arrayed structures, allowing the manufacture of corrugated diaphragms, compact size liquid (or gas) flow delivery systems, newly shaped mold for soft MEMS structures (e.g. PDMS (polydimethylsiloxane)) and other applications. The present research is an approach to fabricate advanced MEMS structures, extending the range of 3D structures fabricated by silicon anisotropic etching

  19. Preparation of composite micro/nano structure on the silicon surface by reactive ion etching: Enhanced anti-reflective and hydrophobic properties

    Science.gov (United States)

    Zeng, Yu; Fan, Xiaoli; Chen, Jiajia; He, Siyu; Yi, Zao; Ye, Xin; Yi, Yougen

    2018-05-01

    A silicon substrate with micro-pyramid structure (black silicon) is prepared by wet chemical etching and then subjected to reactive ion etching (RIE) in the mixed gas condition of SF6, CHF3 and He. We systematically study the impacts of flow rates of SF6, CHF3 and He, the etching pressure and the etching time on the surface morphology and reflectivity through various characterizations. Meanwhile, we explore and obtain the optimal combination of parameters for the preparation of composite structure that match the RIE process based on the basis of micro-pyramid silicon substrate. The composite sample prepared under the optimum parameters exhibits excellent anti-reflective performance, hydrophobic, self-cleaning and anti-corrosive properties. Based on the above characteristics, the composite micro/nano structure can be applied to solar cells, photodetectors, LEDs, outdoor devices and other important fields.

  20. Plasma etching: Yesterday, today, and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, Vincent M.; Kornblit, Avinoam [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204 (United States)

    2013-09-15

    The field of plasma etching is reviewed. Plasma etching, a revolutionary extension of the technique of physical sputtering, was introduced to integrated circuit manufacturing as early as the mid 1960s and more widely in the early 1970s, in an effort to reduce liquid waste disposal in manufacturing and achieve selectivities that were difficult to obtain with wet chemistry. Quickly, the ability to anisotropically etch silicon, aluminum, and silicon dioxide in plasmas became the breakthrough that allowed the features in integrated circuits to continue to shrink over the next 40 years. Some of this early history is reviewed, and a discussion of the evolution in plasma reactor design is included. Some basic principles related to plasma etching such as evaporation rates and Langmuir–Hinshelwood adsorption are introduced. Etching mechanisms of selected materials, silicon, silicon dioxide, and low dielectric-constant materials are discussed in detail. A detailed treatment is presented of applications in current silicon integrated circuit fabrication. Finally, some predictions are offered for future needs and advances in plasma etching for silicon and nonsilicon-based devices.

  1. Plasma etching: Yesterday, today, and tomorrow

    International Nuclear Information System (INIS)

    Donnelly, Vincent M.; Kornblit, Avinoam

    2013-01-01

    The field of plasma etching is reviewed. Plasma etching, a revolutionary extension of the technique of physical sputtering, was introduced to integrated circuit manufacturing as early as the mid 1960s and more widely in the early 1970s, in an effort to reduce liquid waste disposal in manufacturing and achieve selectivities that were difficult to obtain with wet chemistry. Quickly, the ability to anisotropically etch silicon, aluminum, and silicon dioxide in plasmas became the breakthrough that allowed the features in integrated circuits to continue to shrink over the next 40 years. Some of this early history is reviewed, and a discussion of the evolution in plasma reactor design is included. Some basic principles related to plasma etching such as evaporation rates and Langmuir–Hinshelwood adsorption are introduced. Etching mechanisms of selected materials, silicon, silicon dioxide, and low dielectric-constant materials are discussed in detail. A detailed treatment is presented of applications in current silicon integrated circuit fabrication. Finally, some predictions are offered for future needs and advances in plasma etching for silicon and nonsilicon-based devices

  2. Effect of surfactants or a water soluble polymer on the crystal transition of clarithromycin during a wet granulation process.

    Science.gov (United States)

    Nozawa, Kenji; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2015-11-10

    To generate products containing a stable form of clarithromycin (CAM) (form II) regardless of the initial crystal form of CAM or type of granulation solvent, the effects of five surfactants, or a water-soluble polymer (macrogol 400) were determined on the crystal transition of CAM. The metastable form (form I) was kneaded with water, after adding surfactants, or a water-soluble polymer. Form II was also kneaded with ethanol, after adding the same additives. The resulting samples were analyzed by powder X-ray diffraction. Form I was completely converted to form II by a wet granulation using water with additives bearing polyoxyethylene chains such as polysorbate 80 (PS80), polyoxyl 40 stearate or macrogol 400. The granulation of the form II using ethanol with these additives did not result in a crystal transition to form I. Furthermore, CAM tablets were manufactured using granules with PS80, and these crystal forms and dissolution behaviors were investigated. As a result, the wet granulation of CAM with PS80 gave CAM tablets containing only form II and PS80 did not have any adverse effects on tablet characteristics. Therefore, these data suggests that the crystal form of CAM can be controlled to be form II using a wet granulation process with additives bearing polyoxyethylene chains regardless of the initial crystal form of CAM or type of granulation solvent. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Wet Gas Airfoil Analyses

    OpenAIRE

    Larsen, Tarjei Thorrud

    2011-01-01

    Subsea wet gas compression renders new possibilities for cost savings and enhanced gas recovery on existing gas wells. Technology like this opens to make traditional offshore processing plants redundant. With new technology, follows new challenges. Multiphase flows is regarded as a complex field of study, and increased knowledge on the fundamental mechanisms regarding wet gas flow is of paramount importance to the efficiency and stability of the wet gas compressor. The scope of this work was ...

  4. Breakage and drying behaviour of granules in a continuous fluid bed dryer: Influence of process parameters and wet granule transfer.

    Science.gov (United States)

    De Leersnyder, F; Vanhoorne, V; Bekaert, H; Vercruysse, J; Ghijs, M; Bostijn, N; Verstraeten, M; Cappuyns, P; Van Assche, I; Vander Heyden, Y; Ziemons, E; Remon, J P; Nopens, I; Vervaet, C; De Beer, T

    2018-03-30

    Although twin screw granulation has already been widely studied in recent years, only few studies addressed the subsequent continuous drying which is required after wet granulation and still suffers from a lack of detailed understanding. The latter is important for optimisation and control and, hence, a cost-effective practical implementation. Therefore, the aim of the current study is to increase understanding of the drying kinetics and the breakage and attrition phenomena during fluid bed drying after continuous twin screw granulation. Experiments were performed on a continuous manufacturing line consisting of a twin-screw granulator, a six-segmented fluid bed dryer, a mill, a lubricant blender and a tablet press. Granulation parameters were fixed in order to only examine the effect of drying parameters (filling time, drying time, air flow, drying air temperature) on the size distribution and moisture content of granules (both of the entire granulate and of size fractions). The wet granules were transferred either gravimetrically or pneumatically from the granulator exit to the fluid bed dryer. After a certain drying time, the moisture content reached an equilibrium. This drying time was found to depend on the applied airflow, drying air temperature and filling time. The moisture content of the granules decreased with an increasing drying time, airflow and drying temperature. Although smaller granules dried faster, the multimodal particle size distribution of the granules did not compromise uniform drying of the granules when the target moisture content was achieved. Extensive breakage of granules was observed during drying. Especially wet granules were prone to breakage and attrition during pneumatic transport, either in the wet transfer line or in the dry transfer line. Breakage and attrition of granules during transport and drying should be anticipated early on during process and formulation development by performing integrated experiments on the granulator

  5. Fabrication of a vertical sidewall using double-sided anisotropic etching of 〈1 0 0〉 oriented silicon

    International Nuclear Information System (INIS)

    Kim, Hyun-Seok; Bang, Yong-Seung; Song, Eun-Seok; Kim, Yong-Kweon; Kim, Jung-Mu; Ji, Chang-Hyeon

    2012-01-01

    A double-sided wet etch process has been proposed to fabricate vertical structures in 〈1 0 0〉 oriented silicon substrate. Both sides of a {1 0 0} silicon wafer have been patterned identically along the 〈1 1 0〉 direction, and etched using potassium hydroxide (KOH) solution. By precisly controlling the etch time, using etch-timer structure and additive control, structures with smooth and vertical {1 1 0} sidewalls have been fabricated at the edges of a rectangular opening without undercut. Rectangular through-holes, bridges and cantilevers have been constructed using the proposed process. The measured average surface roughness of the vertical sidewall was 481 nm, which has been further reduced to 217 nm and 218 nm by postetching using a KOH–IPA and TMAH–Triton mixture, respectively. Slanted {4 1 1} planes exposed at the concave corners during the vertical etch process have been successfully removed or diminished by the postetching process. A bridge structure with a high aspect ratio of 39:1 has been fabricated, and cantilevers without undercutting were successfully constructed by applying the compensation technique. The proposed process can potentially be utilized in place of the deep reactive ion etching process for the fabrication of structures having vertical through-holes, such as through-silicon vias, high aspect ratio springs and filters for microfluidic applications. (paper)

  6. TOPICAL REVIEW: Black silicon method X: a review on high speed and selective plasma etching of silicon with profile control: an in-depth comparison between Bosch and cryostat DRIE processes as a roadmap to next generation equipment

    Science.gov (United States)

    Jansen, H V; de Boer, M J; Unnikrishnan, S; Louwerse, M C; Elwenspoek, M C

    2009-03-01

    An intensive study has been performed to understand and tune deep reactive ion etch (DRIE) processes for optimum results with respect to the silicon etch rate, etch profile and mask etch selectivity (in order of priority) using state-of-the-art dual power source DRIE equipment. The research compares pulsed-mode DRIE processes (e.g. Bosch technique) and mixed-mode DRIE processes (e.g. cryostat technique). In both techniques, an inhibitor is added to fluorine-based plasma to achieve directional etching, which is formed out of an oxide-forming (O2) or a fluorocarbon (FC) gas (C4F8 or CHF3). The inhibitor can be introduced together with the etch gas, which is named a mixed-mode DRIE process, or the inhibitor can be added in a time-multiplexed manner, which will be termed a pulsed-mode DRIE process. Next, the most convenient mode of operation found in this study is highlighted including some remarks to ensure proper etching (i.e. step synchronization in pulsed-mode operation and heat control of the wafer). First of all, for the fabrication of directional profiles, pulsed-mode DRIE is far easier to handle, is more robust with respect to the pattern layout and has the potential of achieving much higher mask etch selectivity, whereas in a mixed-mode the etch rate is higher and sidewall scalloping is prohibited. It is found that both pulsed-mode CHF3 and C4F8 are perfectly suited to perform high speed directional etching, although they have the drawback of leaving the FC residue at the sidewalls of etched structures. They show an identical result when the flow of CHF3 is roughly 30 times the flow of C4F8, and the amount of gas needed for a comparable result decreases rapidly while lowering the temperature from room down to cryogenic (and increasing the etch rate). Moreover, lowering the temperature lowers the mask erosion rate substantially (and so the mask selectivity improves). The pulsed-mode O2 is FC-free but shows only tolerable anisotropic results at -120 °C. The

  7. Isolation, selection and evaluation of yeasts for use in fermentation of coffee beans by the wet process.

    Science.gov (United States)

    de Melo Pereira, Gilberto Vinícius; Soccol, Vanete Thomaz; Pandey, Ashok; Medeiros, Adriane Bianchi Pedroni; Andrade Lara, João Marcos Rodrigues; Gollo, André Luiz; Soccol, Carlos Ricardo

    2014-10-01

    During wet processing of coffee, the ripe cherries are pulped, then fermented and dried. This study reports an experimental approach for target identification and selection of indigenous coffee yeasts and their potential use as starter cultures during the fermentation step of wet processing. A total of 144 yeast isolates originating from spontaneously fermenting coffee beans were identified by molecular approaches and screened for their capacity to grow under coffee-associated stress conditions. According to ITS-rRNA gene sequencing, Pichia fermentans and Pichia kluyveri were the most frequent isolates, followed by Candida Candida glabrata, quercitrusa, Saccharomyces sp., Pichia guilliermondii, Pichia caribbica and Hanseniaspora opuntiae. Nine stress-tolerant yeast strains were evaluated for their ability to produce aromatic compounds in a coffee pulp simulation medium and for their pectinolytic activity. P. fermentans YC5.2 produced the highest concentrations of flavor-active ester compounds (viz., ethyl acetate and isoamyl acetate), while Saccharomyces sp. YC9.15 was the best pectinase-producing strain. The potential impact of these selected yeast strains to promote flavor development in coffee beverages was investigated for inoculating coffee beans during wet fermentation trials at laboratory scale. Inoculation of a single culture of P. fermentans YC5.2 and co-culture of P. fermentans YC5.2 and Saccharomyces sp. YC9.15 enhanced significantly the formation of volatile aroma compounds during the fermentation process compared to un-inoculated control. The sensory analysis indicated that the flavor of coffee beverages was influenced by the starter cultures, being rated as having the higher sensory scores for fruity, buttery and fermented aroma. This demonstrates a complementary role of yeasts associated with coffee quality through the synthesis of yeast-specific volatile constituents. The yeast strains P. fermentans YC5.2 and Saccharomyces sp. YC9.15 have a great

  8. Black silicon method X: a review on high speed and selective plasma etching of silicon with profile control: an in-depth comparison between Bosch and cryostat DRIE processes as a roadmap to next generation equipment

    International Nuclear Information System (INIS)

    Jansen, H V; De Boer, M J; Unnikrishnan, S; Louwerse, M C; Elwenspoek, M C

    2009-01-01

    An intensive study has been performed to understand and tune deep reactive ion etch (DRIE) processes for optimum results with respect to the silicon etch rate, etch profile and mask etch selectivity (in order of priority) using state-of-the-art dual power source DRIE equipment. The research compares pulsed-mode DRIE processes (e.g. Bosch technique) and mixed-mode DRIE processes (e.g. cryostat technique). In both techniques, an inhibitor is added to fluorine-based plasma to achieve directional etching, which is formed out of an oxide-forming (O 2 ) or a fluorocarbon (FC) gas (C 4 F 8 or CHF 3 ). The inhibitor can be introduced together with the etch gas, which is named a mixed-mode DRIE process, or the inhibitor can be added in a time-multiplexed manner, which will be termed a pulsed-mode DRIE process. Next, the most convenient mode of operation found in this study is highlighted including some remarks to ensure proper etching (i.e. step synchronization in pulsed-mode operation and heat control of the wafer). First of all, for the fabrication of directional profiles, pulsed-mode DRIE is far easier to handle, is more robust with respect to the pattern layout and has the potential of achieving much higher mask etch selectivity, whereas in a mixed-mode the etch rate is higher and sidewall scalloping is prohibited. It is found that both pulsed-mode CHF 3 and C 4 F 8 are perfectly suited to perform high speed directional etching, although they have the drawback of leaving the FC residue at the sidewalls of etched structures. They show an identical result when the flow of CHF 3 is roughly 30 times the flow of C 4 F 8 , and the amount of gas needed for a comparable result decreases rapidly while lowering the temperature from room down to cryogenic (and increasing the etch rate). Moreover, lowering the temperature lowers the mask erosion rate substantially (and so the mask selectivity improves). The pulsed-mode O 2 is FC-free but shows only tolerable anisotropic results at

  9. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Stefanie M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Lauermann, Iver, E-mail: Iver.lauermann@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Aziz, Emad F., E-mail: Emad.Aziz@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

    2010-02-15

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  10. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    International Nuclear Information System (INIS)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-01-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  11. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Science.gov (United States)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-02-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  12. Combined wet-chemical process to synthesize 65PMN-35PT nanosized powders

    International Nuclear Information System (INIS)

    Santos, Luis P.S.; Longo, Elson; Leite, Edson R.; Camargo, Emerson R.

    2004-01-01

    Columbite MgNb 2 O 6 precursors were synthesized by a wet-chemical method by means of the dissolution of Nb 2 O 5 .5H 2 O and magnesium carbonate in a solution of oxalic acid. Pure 65PMN-35PT powders could be obtained by the columbite method with the use of the partial oxalate and oxidant peroxo methods. Powders were characterized by X-ray diffraction and FT-Raman spectroscopy showing that pure 65PMN-35PT are obtained when the powders are calcined up to 800 deg. C, without any trace of Pb-Nb pyrochlore. Cubic Pb 1,86 Mg 0.24 Nb 1.76 O 6.5 pyrochlore phase is formed by lead loss in the powders calcined at 900 deg. C and higher temperatures as undoubtedly characterized by Raman spectroscopy

  13. Tailoring Wet Explosion Process Parameters for the Pretreatment of Cocksfoot Grass for High Sugar Yields

    DEFF Research Database (Denmark)

    Njoku, Stephen Ikechukwu; Ahring, Birgitte Kiær; Uellendahl, Hinrich

    2013-01-01

    The pretreatment of lignocellulosic biomass is crucial for efficient subsequent enzymatic hydrolysis and ethanol fermentation. In this study, wet explosion (WEx) pretreatment was applied to cocksfoot grass and pretreatment conditions were tailored for maximizing the sugar yields using response...... glucose release with low formation of by-products. Under these conditions, the cellulose and hemicellulose sugar recovery was 94 % and 70 %, respectively. The efficiency of the enzymatic hydrolysis of cellulose under these conditions was 91 %. On the other hand, the release of pentose sugars was higher...... when applying less severe pretreatment conditions C (160 °C, 5 min, 0.2 % dilute sulfuric acid). Therefore, the choice of the most suitable pretreatment conditions is depending on the main target product, i.e., hexose or pentose sugars....

  14. A compact process for the treatment of olive mill wastewater by combining wet hydrogen peroxide catalytic oxidation and biological techniques

    International Nuclear Information System (INIS)

    Azabou, Samia; Najjar, Wahiba; Bouaziz, Mohamed; Ghorbel, Abdelhamid; Sayadi, Sami

    2010-01-01

    A system based on combined actions of catalytic wet oxidation and microbial technologies for the treatment of highly polluted OMW containing polyphenols was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process has been investigated in the semi-batch mode at atmospheric pressure, using aluminium-iron-pillared inter layer clay ((Al-Fe)PILC), under two different catalytic processes: ((Al-Fe)PILC/H 2 O 2 /ultraviolet radiations) at 25 deg. C and ((Al-Fe)PILC/H 2 O 2 ) at 50 deg. C. The results show that raw OMW was resistant to the photocatalytic process. However ((Al-Fe)PILC/H 2 O 2 ), system operating at 50 deg. C reduced considerably the COD, colour and total phenolic contents, and thus decreased the inhibition of the marine photobacteria Vibrio fischeri luminescence by 70%. This study also examined the feasibility of coupling WHPCO and anaerobic digestion treatment. Biomethanisation experiments performed with raw OMW or pre-treated OMW proved that pre-treatments with ((Al-Fe)PILC/H 2 O 2 ) system, for more than 2 h, resulted in higher methane production. Both untreated OMW as well as 2-h pre-treated OMW revealed as toxic to anaerobic bacteria.

  15. Density improvement of Li{sub 2}TiO{sub 3} pebbles fabricated by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, K; Kawamura, H [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Fuchinoue, K; Sawada, H; Watarumi, K

    1998-03-01

    Lithium titanate (Li{sub 2}TiO{sub 3}) has attracted the attention of many researchers from a point of tritium recovery at low temperature, chemical stability, etc.. The application of small Li{sub 2}TiO{sub 3} sphere has been proposed in some designs of fusion blanket. On the other hand, the wet process is most advantageous as the fabrication method of Li{sub 2}TiO{sub 3} pebbles from a point of mass production, and of reprocessing necessary for effective use of resources and reduction of radioactive wastes. In the preliminary fabrication test, density of Li{sub 2}TiO{sub 3} pebbles was about 40%T.D.. Therefore, in this study, density improvement tests and preliminary characterization of Li{sub 2}TiO{sub 3} pebbles by wet process were performed, noting the aging condition and sintering condition in the fabrication process of the gel-spheres. This study yielded Li{sub 2}TiO{sub 3} pebbles in target range of 80-85%T.D.. (author)

  16. Characterization of silicon isotropic etch by inductively coupled plasma etcher for microneedle array fabrication

    International Nuclear Information System (INIS)

    Ji, J; Tay, F E H; Miao Jianmin; Sun Jianbo

    2006-01-01

    This work investigates the isotropic etching properties in inductively coupled plasma (ICP) etcher for microneedle arrays fabrication. The effects of process variables including powers, gas and pressure on needle structure generation are characterized by factorial design of experiment (DOE). The experimental responses of vertical etching depth, lateral etching length, ratio of vertical etching depth to lateral etching length and photoresist etching rate are reported. The relevance of the etching variables is also presented. The obtained etching behaviours for microneedle structure generation will be applied to develop recipes to fabricate microneedles in designed dimensions

  17. Characterization of silicon isotropic etch by inductively coupled plasma etcher for microneedle array fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Ji, J [Mechanical Engineering National University of Singapore, 119260, Singapore (Singapore); Tay, F E H [Mechanical Engineering National University of Singapore, 119260, Singapore (Singapore); Miao Jianmin [MicroMachines Center, School of Mechanical and Aerospace Engineering, Nanyang Technologica l University, 50 Nanyang Avenue, 639798 (Singapore); Sun Jianbo [MicroMachines Center, School of Mechanical and Aerospace Engineering, Nanyang Technologica l University, 50 Nanyang Avenue, 639798 (Singapore)

    2006-04-01

    This work investigates the isotropic etching properties in inductively coupled plasma (ICP) etcher for microneedle arrays fabrication. The effects of process variables including powers, gas and pressure on needle structure generation are characterized by factorial design of experiment (DOE). The experimental responses of vertical etching depth, lateral etching length, ratio of vertical etching depth to lateral etching length and photoresist etching rate are reported. The relevance of the etching variables is also presented. The obtained etching behaviours for microneedle structure generation will be applied to develop recipes to fabricate microneedles in designed dimensions.

  18. Etching characteristics of a CR-39 track detector at room temperature in different etching solutions

    International Nuclear Information System (INIS)

    Dajko, G.

    1991-01-01

    Investigations were carried out to discover how the etching characteristics of CR-39 detectors change with varying conditions of the etching process. Measurements were made at room temperature in pure NaOH and KOH solutions; in different alcoholic KOH solutions (PEW solution, i.e. potassium hydroxide, ethyl alcohol, water); and in NaOH and KOH solutions containing different additives. The bulk etching rate of the detector (V B ) and the V (= V T /V B ) function, i.e. track to bulk etch rates ratio, for 6.1 MeV α-particles, were measured systematically. (author)

  19. Reactive ion etching of microphotonic structures

    International Nuclear Information System (INIS)

    Du, J.; Glasscock, J.; Vanajek, J.; Savvides, N.

    2004-01-01

    Full text: Fabrication of microphotonic structures such as planar waveguides and other periodic structures based on silicon technology has become increasingly important due to the potential for integration of planar optical devices. We have fabricated various periodic microstructures on silicon wafers using standard optical lithography and reactive ion etching (RIE). For optical applications the surface roughness and the sidewall angle or steepness of microstructures are the most critical factors. In particular, sidewall roughness of the etched waveguide core accounts for most of the optical propagation loss. We show that by varying the main RIE parameters such as gas pressure, RF power and CF 4 /Ar/O 2 gas composition it is possible to produce microstructures with near-vertical sidewalls and very smooth surfaces. In addition to plasma etching conditions, poor edge quality of the mask often causes sidewall roughness. We employed Ni/Cr metal masks in these experiments for deep etching, and used Ar + ion milling instead of wet chemical etching to open the mask. This improves the edge quality of the mask and ultimately results in smooth sidewalls

  20. Latent structure analysis in the pharmaceutical process of tablets prepared by wet granulation.

    Science.gov (United States)

    Uehara, Naoto; Hayashi, Yoshihiro; Mochida, Hiroshi; Otoguro, Saori; Onuki, Yoshinori; Obata, Yasuko; Takayama, Kozo

    2016-01-01

    Granule characteristics are some of the important intermediate qualities that determine tablet properties. However, the relationships between granule and tablet characteristics are poorly understood. The aim of this study was to elucidate relationships among formulation factors, granule characteristics, and tablet properties using a non-linear response surface method (RSM) incorporating a thin-plate spline interpolation (RSM-S) and a Bayesian network (BN). Tablets containing lactose (Lac), cornstarch (CS), and microcrystalline cellulose (MCC) were prepared by wet granulation. Ten formulations were prepared by an extreme vertices design. The angle of repose (Y 1 ), compressibility (Y 2 ), cohesion force (Y 3 ), internal friction angle (Y 4 ), and mean particle size (Y 5 ) were measured as granule characteristics. Tensile strength (TS) and disintegration time (DT) were measured as tablet properties. RSM-S results showed that TS increased with increasing amounts of MCC and Lac. DT decreased with increasing amounts of MCC and CS. The optimal BN models were predicted using four evaluation indices -Y 3 was shown to be the most important factor for TS, whereas Y 2 , Y 3 , and Y 4 were relatively important for predicting DT. Moreover, tablets with excellent tablet properties (i.e. high TS and low DT) were produced by relatively high Y 1 , low Y 2 , high Y 3 , high Y 4 , and middle Y 5 values, and resulted from the middle of MCC, middle-to-low CS, low Lac, and middle-to-low magnesium stearate (Mg-St) amounts. The RSM-S and BN techniques are useful for revealing complex relationships among formulation factors, granule characteristics, and tablet properties.

  1. Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion.

    Directory of Open Access Journals (Sweden)

    R Zahran

    Full Text Available Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF acid, many questions remain unresolved, including the optimal etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5-7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time.

  2. Synthesis of Monodispersed Spherical Single Crystalline Silver Particles by Wet Chemical Process; Shisshiki kagakuho ni yoru tanbunsankyujo tankesshoginryushi no gose

    Energy Technology Data Exchange (ETDEWEB)

    Ueyama, Ryousuke.; Harada, Masahiro.; Ueyama, Tamotsu.; Harada, Akio. [Daiken Chemistry Industry Corporation, Osaka (Japan); Yamamoto, Takashi. [National Defence Academy, Kanagawa (Japan). Dept. of Electrical Engineering; Shiosaki, Tadashi. [Nara Institute of Science and Technology, Nara (Japan). Graduate School of Materials Science; Kuribayashi, Kiyoshi. [Teikyo University of Science and Technology, Yamanashi (Japan). Dept. of Materials

    1999-01-01

    Ultrafine silver monodispersed particle were prepared by wet chemical process. To decrease the reduction speed, an important factor in generating monodispersed particles is to control the following three factors: synthesis temperature, concentration of aggregation-relaxing agent added, and concentration of silver nitrate solution. Synthesis of monodispersed spherical Ag particles, used as metal powders for electrode, became possible using the nucleus grouwth reaction method. This process also allowed the control of the diameter of the powder particles. The silver particles were distributed in ta narrow particle diameter range with on average of 0.5 {mu}m. Transmission electron microscopy (TEM) revealed that single-crystalline silver particles were prepared by the present method. (author)

  3. Intensification of mass transfer in wet textile processes by power ultrasound

    NARCIS (Netherlands)

    Moholkar, V.S.; Nierstrasz, Vincent; Warmoeskerken, Marinus

    2003-01-01

    In industrial textile pre-treatment and finishing processes, mass transfer and mass transport are often rate-limiting. As a result, these processes require a relatively long residence time, large amounts of water and chemicals, and are also energy-consuming. In most of these processes, diffusion and

  4. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, R J; Johnson, Jr, A B; Lund, A L; Gilbert, E R [and others

    1996-07-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl{sub x}, UAl{sub x}-Al and U{sub 3}O{sub 8}-Al cermets, U-5% fissium, UMo, UZrH{sub x}, UErZrH, UO{sub 2}-stainless steel cermet, and U{sub 3}O{sub 8}-stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified.

  5. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Guenther, R.J.; Johnson, A.B. Jr.; Lund, A.L.; Gilbert, E.R.

    1994-11-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl x , UAl x -Al and U 3 O 8 -Al cermets, U-5% fissium, UMo, UZrH x , UErZrH, UO 2 -stainless steel cermet, and U 3 O 8 -stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified

  6. Optical and Electrical Performance of ZnO Films Textured by Chemical Etching

    Directory of Open Access Journals (Sweden)

    Shiuh-Chuan HER

    2015-11-01

    Full Text Available Zinc oxide (ZnO films were prepared by radio frequency (RF magnetron sputtering on the glass substrate as transparent conductive oxide films. For silicon solar cells, a proper surface texture is essential to introduce light scattering and subsequent light trapping to enhance the current generation. In this study, the magnetron-sputtered ZnO films were textured by wet-chemical etching in diluted hydrochloric acid (HCl for better light scattering. The diffuse transmittance of the surface textured ZnO films was measured to evaluate the light scattering. The influence of hydrochloric acid concentration on the morphology, optical and electrical properties of the surface-textured ZnO film was investigated. The ZnO film etched in 0.05M HCl solution for 30 s exhibited average diffuse transmittance in the visible wavelength range of 9.52 % and good resistivity of 1.10 x 10-3 W×cm while the as-deposited ZnO film had average diffuse transmittance of 0.51 % and relatively high resistivity of 5.84 x 10-2 W×cm. Experimental results illustrated that the optical and electrical performance of ZnO films can be significantly improved by introducing the surface texture through the wet-chemical etching process.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9624

  7. Semiconductor structure and recess formation etch technique

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Sun, Min; Palacios, Tomas Apostol

    2017-02-14

    A semiconductor structure has a first layer that includes a first semiconductor material and a second layer that includes a second semiconductor material. The first semiconductor material is selectively etchable over the second semiconductor material using a first etching process. The first layer is disposed over the second layer. A recess is disposed at least in the first layer. Also described is a method of forming a semiconductor structure that includes a recess. The method includes etching a region in a first layer using a first etching process. The first layer includes a first semiconductor material. The first etching process stops at a second layer beneath the first layer. The second layer includes a second semiconductor material.

  8. Application of advanced oxidation processes for cleaning of industrial water generated in wet dedusting of shaft furnace gases.

    Science.gov (United States)

    Czaplicka, Marianna; Kurowski, Ryszard; Jaworek, Katarzyna; Bratek, Łukasz

    2013-01-01

    The paper presents results of studies into advanced oxidation processes in 03 and 03/UV systems. An advanced oxidation process (AOP) was conducted to reduce the load of impurities in circulating waters from wet de-dusting of shaft furnace gases. Besides inorganic impurities, i.e. mainly arsenic compounds (16 g As L(-1) on average), lead, zinc, chlorides and sulphates, the waters also contain some organic material. The organic material is composed of a complex mixture that contains, amongst others, aliphatic compounds, phenol and its derivatives, pyridine bases, including pyridine, and its derivatives. The test results show degradation of organic and inorganic compounds during ozonation and photo-oxidation processes. Analysis of the solutions from the processes demonstrated that the complex organic material in the industrial water was oxidized in ozonation and in photo-oxidation, which resulted in formation of aldehydes and carboxylic acids. Kinetic degradation of selected pollutants is presented. Obtained results indicated that the O3/UV process is more effective in degradation of organic matter than ozonation. Depending on the process type, precipitation of the solid phase was observed. The efficiency of solid-phase formation was higher in photo-oxidation with ozone. It was found that the precipitated solid phase is composed mainly of arsenic, iron and oxygen.

  9. Si etching with reactive neutral beams of very low energy

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Yasuhiro [Organization for Research and Development of Innovative Science and Technology, Kansai University, 3-3-35 Yamate-chou, Suita, Osaka 565-0871 (Japan); Hamagaki, Manabu; Mise, Takaya [RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198 (Japan); Iwata, Naotaka; Hara, Tamio [Toyota Technological Institute, 2-12-1 Hisakata, Tenpaku-ku, Nagoya 468-8511 (Japan)

    2014-12-14

    A Si etching process has been investigated with reactive neutral beams (NBs) extracted using a low acceleration voltage of less than 100 V from CF{sub 4} and Ar mixed plasmas. The etched Si profile shows that the etching process is predominantly anisotropic. The reactive NB has a constant Si etching rate in the acceleration voltage range from 20 V to 80 V. It is considered that low-energy NBs can trigger Si etching because F radicals adsorb onto the Si surface and weaken Si–Si bonds. The etching rate per unit beam flux is 33 times higher than that with Ar NB. These results show that the low-energy reactive NB is useful for damage-free high speed Si etching.

  10. Enhanced ferro-actuator with a porosity-controlled membrane using the sol-gel process and the HF etching method

    International Nuclear Information System (INIS)

    Kim, KiSu; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2016-01-01

    In this paper, we propose a ferro-actuator using a porous polyvinylidene difluoride (PVDF) membrane. In detail, we fabricated the silica-embedded PVDF membrane using a sol-gel process with PVDF solution and tetraethyl orthosilicate (TEOS) solution, where the size of the silica was determined by the ratio of the PVDF and TEOS solutions. Using hydrofluoric acid (HF) etching, the silica were removed from the silica-embedded PVDF membrane, and porous PVDF membranes with different porosities were obtained. Finally, through absorption of a ferrofluid on the porous PVDF membrane, the proposed ferro-actuator using porous PVDF membranes with different porosities was fabricated. We executed the characterization and actuation test as follows. First, the silica size of the silica-embedded PVDF membrane and the pore size of the porous PVDF membrane were analyzed using scanning electron microscopy (SEM) imaging. Second, energy-dispersive x-ray spectroscopy analysis showed that the silica had clearly been removed from the silica-embedded PVDF membrane by HF etching. Third, through x-ray photoelectron spectroscopy and vibrating sample magnetometer (VSM) of the ferro-actuators, we found that more ferrofluids were absorbed by the porous PVDF membrane when the pore of the membrane was smaller and uniformly distributed. Finally, we executed tip displacement and a blocking force test of the proposed ferro-actuator using the porous PVDF membrane. Similar to the VSM result, the ferro-actuator that used a porous PVDF membrane with smaller pores exhibited better actuation performance. The ferro-actuator that used a porous PVDF membrane displayed a tip displacement that was about 7.2-fold better and a blocking force that was about 6.5-fold better than the ferro-actuator that used a pure PVDF membrane. Thus, we controlled the pore size of the porous PVDF membrane and enhanced the actuation performance of the ferro-actuator using a porous PVDF membrane. (technical note)

  11. Development of a novel wet oxidation process for hazardous and mixed wastes

    International Nuclear Information System (INIS)

    Dhooge, P.M.

    1994-01-01

    This article describes and evaluates the DETOX sm process for processing of mixed wastes. Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides, often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. The DETOX sm process, patented by Delphi Research, uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials. Included are the following subject areas: project description (phases I-IV); results of all phases; and future work. 5 figs., 1 tab

  12. [Wet work].

    Science.gov (United States)

    Kieć-Swierczyńska, Marta; Chomiczewska, Dorota; Krecisz, Beata

    2010-01-01

    Wet work is one of the most important risk factors of occupational skin diseases. Exposure of hands to the wet environment for more than 2 hours daily, wearing moisture-proof protective gloves for a corresponding period of time or necessity to wash hands frequently lead to the disruption of epidermal stratum corneum, damage to skin barrier function and induction of irritant contact dermatitis. It may also promote penetration of allergens into the skin and increase the risk of sensitization to occupational allergens. Exposure to wet work plays a significant role in occupations, such as hairdressers and barbers, nurses and other health care workers, cleaning staff, food handlers and metalworkers. It is more common among women because many occupations involving wet work are female-dominated. The incidence of wet-work-induced occupational skin diseases can be reduced by taking appropriate preventive measures. These include identification of high-risk groups, education of workers, organization of work enabling to minimize the exposure to wet work, use of personal protective equipment and skin care after work.

  13. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T., E-mail: aruna_reddy@nal.res.in; Basu, Bharathibai J.

    2013-07-15

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  14. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    International Nuclear Information System (INIS)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T.; Basu, Bharathibai J.

    2013-01-01

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  15. Effect of nitrogen doping on wetting and photoactive properties of laser processed zinc oxide-graphene oxide nanocomposite layers

    Energy Technology Data Exchange (ETDEWEB)

    György, E., E-mail: egyorgy@icmab.es [Consejo Superior de Investigaciones Cientificas, Instituto de Ciencia de Materiales de Barcelona (CSIC-ICMAB), Campus UAB, 08193 Bellaterra (Spain); National Institute for Lasers, Plasma and Radiation Physics, P. O. Box MG 36, 76900 Bucharest V (Romania); Pérez del Pino, A. [Consejo Superior de Investigaciones Cientificas, Instituto de Ciencia de Materiales de Barcelona (CSIC-ICMAB), Campus UAB, 08193 Bellaterra (Spain); Logofatu, C. [National Institute for Materials Physics, P. O. Box MG. 7, 77125 Bucharest (Romania); Duta, A.; Isac, L. [Transilvania University of Brasov, Research Centre for Renewable Energy Systems and Recycling, Eroilor 29, 500036, Brasov (Romania)

    2014-07-14

    Zinc oxide-graphene oxide nanocomposite layers were submitted to laser irradiation in air or controlled nitrogen atmosphere using a frequency quadrupled Nd:YAG (λ = 266 nm, τ{sub FWHM} ≅ 3 ns, ν = 10 Hz) laser source. The experiments were performed in air at atmospheric pressure or in nitrogen at a pressure of 2 × 10{sup 4} Pa. The effect of the irradiation conditions, incident laser fluence value, and number of subsequent laser pulses on the surface morphology of the composite material was systematically investigated. The obtained results reveal that nitrogen incorporation improves significantly the wetting and photoactive properties of the laser processed layers. The kinetics of water contact angle variation when the samples are submitted to laser irradiation in nitrogen are faster than that of the samples irradiated in air, the surfaces becoming super-hydrophilic under UV light irradiation.

  16. Comparative study of the different industrial manufacturing routes for UO2 pellet specifications through the wet process

    International Nuclear Information System (INIS)

    Palheiros, Franklin; Gonzaga, Reinaldo; Soares, Alexandre

    2009-01-01

    In the fuel cycle, converting UF 6 to UO 2 powder is an intermediate step for fabrication of pellets for fuel assemblies to be used in nuclear power plants. The basic proposal common to the different powder fabrication processes is to provide raw material capable of being processed into the form of pellets. The wet processes is the most often used industrially and are divided in two categories: the ADU (Ammonium Diuranate) and AUC (Ammonium Uranyl Carbonate) processes, whose names originate in the precipitate obtained in aqueous solution during the intermediate steps of UO 2 powder fabrication. It has known that the powder characteristics have a considerable influence in the UO 2 pellet manufacturing and quality characteristics. INB has used the AUC process to produce UO 2 pellets and supply fuel to Angra 1 and 2 Nuclear Power Plants. Despite of this process is characterized by the precipitation of a different intermediate precipitate compared to the ADU route (i.e., (NH 4 ) 4 UO 2 (CO 3 ) 3 , in the AUC process, and (NH 4 ) 2 U 2 O 7 in ADU process) leading to some slight differences in the final pellet microstructure, it has been considered that the models that predict the pellet behavior during irradiation in a nuclear reactor are basically the same compared to those used to predict the pellets form the ADU process. In order to evaluate how different the pellets originated from these two industrial routes are, this paper aims to compare the INB production historical data (Angra 1, Cycles 14 and 15) with the key parameters of a common product specification from the ADU process. (author)

  17. Direct uranium extraction from dihydrate and hemi-dihydrate wet process phosphoric acids by liquid emulsion membrane

    International Nuclear Information System (INIS)

    El-Hazek, N.T.; El Sayed, M.S.

    2003-01-01

    A new liquid emulsion membrane (LEM) process for uranium extraction from either dihydrate 28-30% P 2 O 5 (DH) or hemi-dihydrate 42-45% P 2 O 5 (HDH) wet process phosphoric acid is proposed. In this process, the organic component of the LEM is composed of a synergistic mixture of 0.1M di-2-ethyl hexyl phosphoric acid (DEHPA) and 0.025M trioctyl phosphine oxide (TOPO) with 4% Span 80. The internal or the strip acid phase is composed of 0.5M citric acid. The prepared LEM was proved to be stable in 42-45% P 2 O 5 acid concentration range and can, therefore, be applied to the phosphoric acid produced by the hemi-dihydrate process. After breakdown of the loaded emulsion, the uranyl citrate in the internal strip phase is separated by adding methanol followed by its calcination to the orange oxide. Most of the reagents used are recycled. The proposed process is characterized by simplicity, practically closed operation cycle in addition to lower capital and operating costs. (author)

  18. Metal-assisted chemical etching of CIGS thin films for grain size analysis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Chaowei [Research and Development Centre, Hanergy Thin Film Power Group Limited, Chengdu (China); Loi, Huu-Ha; Duong, Anh; Parker, Magdalena [Failure Analysis Department, MiaSole Hi-Tech Corp., Santa Clara, CA (United States)

    2016-09-15

    Grain size of the CIGS absorber is an important monitoring factor in the CIGS solar cell manufacturing. Electron backscatter diffraction (EBSD) analysis is commonly used to perform CIGS grain size analysis in the scanning electron microscope (SEM). Although direct quantification on SEM image using the average grain intercept (AGI) method is faster and simpler than EBSD, it is hardly applicable on CIGS thin films. The challenge is that, not like polycrystalline silicon, to define grain boundaries by selective chemical etching is not easily realizable for the multi-component CIGS alloy. In this Letter, we present direct quantification of CIGS thin film grain size using the AGI method by developing metal-assisted wet chemical etching process to define CIGS grain boundaries. The calculated value is similar to EBSD result. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Investigation of Plasma Etching for Superconducting RF Cavities Surface Preparation. Final Report

    International Nuclear Information System (INIS)

    Vuskovic, Leposava

    2009-01-01

    Our results show that plasma-treated samples are comparable or superior to a BCP sample, both in the size of features and sharpness of the boundaries between individual features at the surface. Plasma treatment of bulk Nb cavities is a promising technique for microwave cavities preparation used in particle acceleration application. Etching rates are sufficiently high to enable efficient removal of mechanically damaged surface layer with high reproducibility. No impurities are deposited on the bulk Nb surface during plasma treatment. Surface topology characteristic are promising for complex cavity geometry, since discharge conforms the profile of the reaction chamber. In view of these experimental results, we propose plasma treatment for producing microwave cavities with high Q factor instead of using bulk Nb treated with wet etching process.

  20. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  1. Study Of The Wet Multipass Drawing Process Applied On High Strength Thin Steel Wires

    Science.gov (United States)

    Thimont, J.; Felder, E.; Bobadilla, C.; Buessler, P.; Persem, N.; Vaubourg, JP.

    2011-05-01

    Many kinds of high strength thin steel wires are involved in so many applications. Most of the time, these wires are made of a pearlitic steel grade. The current developments mainly concern the wire last drawing operation: after a patenting treatment several reduction passes are performed on a slip-type multipass drawing machine. This paper focuses on modeling this multipass drawing process: a constitutive law based on the wire microstructure evolutions is created, a mechanical study is performed, a set of experiments which enables determining the process friction coefficients is suggested and finally the related analytical model is introduced. This model provides several general results about the process and can be used in order to set the drawing machines.

  2. Catalytic Hydrothermal Conversion of Wet Biomass Feedstocks and Upgrading – Process Design and Optimization

    DEFF Research Database (Denmark)

    Hoffmann, Jessica; Toor, Saqib; Rosendahl, Lasse

    Liquid biofuels will play a major role for a more sustainable energy system of the future. The CatLiq® process is a 2nd generation biomass conversion process that is based on hydrothermal liquefaction. Hydrothermal liquefaction offers a very efficient and feedstock flexible way of converting...... biomass to bio-oil. Bio-oils from hydrothermal liquefaction are characterised by their high feedstock flexibility. Upgrading of complete bio-oils derived from hydrothermal conversion has not yet been extensively studied. Purpose of this work is to reduce the oxygen content of the bio-oil to improve...

  3. Conversion of a wet waste feedstock to biocrude by hydrothermal processing in a continuous-flow reactor: grape pomace

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Schmidt, Andrew J.; Hart, Todd R.; Billing, Justin M.

    2017-05-13

    Wet waste feedstocks present an apt opportunity for biomass conversion to fuels by hydrothermal processing. In this study, grape pomace slurries from two varieties, Montepulciano and cabernet sauvignon, have been converted into a biocrude by hydrothermal liquefaction (HTL) in a bench-scale, continuous-flow reactor system. Carbon conversion to gravity-separable biocrude product up to 56 % was accomplished at relatively low temperature (350 C) in a pressurized (sub-critical liquid water) environment (20 MPa) when using grape pomace feedstock slurry with a 16.8 wt% concentration of dry solids processed at a liquid hourly space velocity of 2.1 h-1. Direct oil recovery was achieved without the use of a solvent and biomass trace mineral components were removed by processing steps so that they did not cause processing difficulties. In addition, catalytic hydrothermal gasification (CHG) was effectively applied for HTL byproduct water cleanup using a Ru on C catalyst in a fixed bed producing a gas composed of methane and carbon dioxide from water soluble organics. Conversion of 99.8% of the chemical oxygen demand (COD) left in the aqueous phase was demonstrated. As a result, high conversion of grape pomace to liquid and gas fuel products was found with residual organic contamination in byproduct water reduced to <150 mg/kg COD.

  4. On the Rust Products Formed on Weathering and Carbon Steels Exposed to Chloride in Dry-Wet Cyclical Processes

    International Nuclear Information System (INIS)

    Garcia, K. E.; Morales, A. L.; Barrero, C. A.; Greneche, J. M.

    2005-01-01

    The rust products formed on weathering and carbon steels exposed to dry-wet cyclical processes in different chloride-rich solutions are carefully examined by means of different techniques. Special emphasis is given to the methodology of analysis of the data using 300 K and 77 K Moessbauer spectrometry and X-ray diffraction. The rust that is loosely bound to the metal surface and that it is lost during the corrosion process, for both types of steel, was found to be composed of lepidocrocite, superparamagnetic goethite, hematite, and traces of akaganeite. On the other hand, the adherent rust, which is differentiated as scraped and hit according to the way it is obtained, from both steels was found to be composed of akaganeite, spinel phase, goethite exhibiting broad distribution of particle sizes and lepidocrocite. The relative abundances of rust components for both steels were very similar, suggesting similar corrosion processes. Mass loss measurements show that the corrosion rates increases with increasing the chloride concentration. The presence of large quantities of spinel phase and akaganeite are a consequence of a corrosion process under the influence of very high chloride concentrations. Our results are useful for assessing the behavior of weathering steels where the levels of chlorides are high or in contact with sea water.

  5. Campylobacter in Broiler Chicken and Broiler Meat in Sri Lanka : Influence of Semi-Automated vs. Wet Market Processing on Campylobacter Contamination of Broiler Neck Skin Samples

    NARCIS (Netherlands)

    Kottawatta, Kottawattage S A; van Bergen, Marcel A P; Abeynayake, Preeni; Wagenaar, Jaap A; Veldman, Kees T; Kalupahana, Ruwani S

    2017-01-01

    Broiler meat can become contaminated with Campylobacter of intestinal origin during processing. The present study aimed to identify the prevalence of Campylobacter in broiler flocks and meat contamination at retail shops, and determine the influence of semi-automated and wet market processing on

  6. Recovery of uranium from wet process by the chloridic leaching of phosphate rocks

    International Nuclear Information System (INIS)

    Santana, A.O.; Paula, H.C.B.; Dantas, C.C.

    1984-01-01

    Uranium was recovered from chloridic leach liquor of phosphate rocks by solvent extraction on a laboratory scale. The extractor system is a mixture of di-(2-ethylhexyl) phosphoric acid (D 2 EHPA) and tributyl-phosphate (TBP) in a varsol diluent. The uranium concentration is 150 ppm in the rocks and 12 ppm in the leach liquor. The phosphate rocks are leached on a semi-industrial scale for dicalcium phosphate production. The recovery process comprises the following steps: extraction, reextraction, iron removal and uranium precipitation. (orig./EF)

  7. Recovery of uranium from wet process by the chloridic leaching of phosphate rocks

    Energy Technology Data Exchange (ETDEWEB)

    Santana, A O; Paula, H C.B.; Dantas, C C

    1984-03-01

    Uranium was recovered from chloridic leach liquor of phosphate rocks by solvent extraction on a laboratory scale. The extractor system is a mixture of di-(2-ethylhexyl) phosphoric acid (D/sub 2/EHPA) and tributyl-phosphate (TBP) in a varsol diluent. The uranium concentration is 150 ppm in the rocks and 12 ppm in the leach liquor. The phosphate rocks are leached on a semi-industrial scale for dicalcium phosphate production. The recovery process comprises the following steps: extraction, reextraction, iron removal and uranium precipitation.

  8. Etching method employing radiation

    International Nuclear Information System (INIS)

    Chapman, B.N.; Winters, H.F.

    1982-01-01

    This invention provides a method for etching a silicon oxide, carbide, nitride, or oxynitride surface using an electron or ion beam in the presence of a xenon or krypton fluoride. No additional steps are required after exposure to radiation

  9. Extraction-wet oxidation process using sulphuric acid for treatment of TBP-dodecane wastes

    International Nuclear Information System (INIS)

    Deshingkar, D.S.; Kartha, P.K.S.

    1998-03-01

    In the nuclear fuel reprocessing plants, 30% n-tributyl phosphate in hydrocarbon diluent is used for extraction of uranium and plutonium from the spent fuel by Purex process. When TBP-dodecane can no longer be purified from its degradation products, it is discarded as alpha bearing, intermediate level wastes containing plutonium and ruthenium-106. To overcome shortcomings of extraction-pyrolysis and saponification processes, studies were undertaken to find the suitability of H 2 SO 4 as an alternative extractant for TBP. Oxidation of TBP to H 3 PO 4 using H 2 O 2 was also explored as H 3 PO 4 can be treated by known procedures for removal of plutonium and ruthenium-106. The experiments were conducted with aged spent solvent wastes discharged from reprocessing plant at Trombay using H 2 SO 4 and H 2 SO 4 - H 3 PO 4 mixture. The decontamination factors (DFs) for alpha activity were found to be satisfactory. The DFs for ruthenium were lower as compared to those obtained in experiments with simulated degraded waste. The gas chromatographic analysis of separated diluent revealed high branched alkane content and low n-dodecane content of separated diluent. It is very much different from that of diluent currently in use. Hence incineration of separated diluent is recommended. (author)

  10. Outstanding field emission properties of wet-processed titanium dioxide coated carbon nanotube based field emission devices

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jinzhuo; Ou-Yang, Wei, E-mail: ouyangwei@phy.ecnu.edu.cn; Chen, Xiaohong; Guo, Pingsheng; Piao, Xianqing; Sun, Zhuo [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Xu, Peng; Wang, Miao [Department of Physics, Zhejiang University, 38 ZheDa Road, Hangzhou 310027 (China); Li, Jun [Department of Electronic Science and Technology, Tongji University, 4800 Caoan Road, Shanghai 201804 (China)

    2015-02-16

    Field emission devices using a wet-processed composite cathode of carbon nanotube films coated with titanium dioxide exhibit outstanding field emission characteristics, including ultralow turn on field of 0.383 V μm{sup −1} and threshold field of 0.657 V μm{sup −1} corresponding with a very high field enhancement factor of 20 000, exceptional current stability, and excellent emission uniformity. The improved field emission properties are attributed to the enhanced edge effect simultaneously with the reduced screening effect, and the lowered work function of the composite cathode. In addition, the highly stable electron emission is found due to the presence of titanium dioxide nanoparticles on the carbon nanotubes, which prohibits the cathode from the influence of ions and free radical created in the emission process as well as residual oxygen gas in the device. The high-performance solution-processed composite cathode demonstrates great potential application in vacuum electronic devices.

  11. Influence factors on etching rate of PET nuclear pore membrane

    International Nuclear Information System (INIS)

    Zuo Zhenzhong; Wu Zhendong; Liang Haiying; Ju Wei; Chen Dongfeng; Fu Yuanyong; Qu Guopu

    2014-01-01

    Background: The nuclear pore membrane is a kind of liquid filtration material manufactured by irradiation and chemical etching. Various conditions in etch process have a great influence on etch rate. Purpose: The influence factors of concentration and temperature of etch solution and the irradiation energy of heavy ions on etch rate was studied. Methods: Four layers of PET (polyethylene terephthalate) films were stacked together and were irradiated with 140-MeV 32 S ions at room temperature under vacuum conditions. Utilizing conductivity measurement technique, the electrical current changes through the u:radiated PET film were monitored during etching, from which the breakthrough time and therefore the track etching rate was calculated. Results: The results show that there is an exponential correlation between etch rate and temperature, and a linear correlation between etch rate and concentration. The track etching rate increases linearly with energy loss rate. Empirical formula for the bulk etching rate as a function of etchant concentration and temperature was also established via fitting of measurements. Conclusion: It is concluded that by using 1.6-MeV·u -1 32 S ions, PET nuclear pore membrane with cylindrical pore shape can be prepared at 85℃ with etchant concentration of l mol·L -1 . (authors)

  12. Plasma Etching of Tapered Features in Silicon for MEMS and Wafer Level Packaging Applications

    International Nuclear Information System (INIS)

    Ngo, H-D; Hiess, Andre; Seidemann, Volker; Studzinski, Daniel; Lange, Martin; Leib, Juergen; Shariff, Dzafir; Ashraf, Huma; Steel, Mike; Atabo, Lilian; Reast, Jon

    2006-01-01

    This paper is a brief report of plasma etching as applied to pattern transfer in silicon. It will focus more on concept overview and strategies for etching of tapered features of interest for MEMS and Wafer Level Packaging (WLP). The basis of plasma etching, the dry etching technique, is explained and plasma configurations are described elsewhere. An important feature of plasma etching is the possibility to achieve etch anisotropy. The plasma etch process is extremely sensitive to many variables such as mask material, mask openings and more important the plasma parameters

  13. High rate dry etching of InGaZnO by BCl3/O2 plasma

    Science.gov (United States)

    Park, Wanjae; Whang, Ki-Woong; Gwang Yoon, Young; Hwan Kim, Jeong; Rha, Sang-Ho; Seong Hwang, Cheol

    2011-08-01

    This paper reports the results of the high-rate dry etching of indium gallium zinc oxide (IGZO) at room temperature using BCl3/O2 plasma. We achieved an etch rate of 250 nm/min. We inferred from the x-ray photoelectron spectroscopy analysis that BOx or BOClx radicals generated from BCl3/O2 plasma cause the etching of the IGZO material. O2 initiates the etching of IGZO, and Ar removes nonvolatile byproducts from the surface during the etching process. Consequently, a smooth etched surface results when these gases are added to the etch gas.

  14. Hybrid mask for deep etching

    KAUST Repository

    Ghoneim, Mohamed T.

    2017-08-10

    Deep reactive ion etching is essential for creating high aspect ratio micro-structures for microelectromechanical systems, sensors and actuators, and emerging flexible electronics. A novel hybrid dual soft/hard mask bilayer may be deposited during semiconductor manufacturing for deep reactive etches. Such a manufacturing process may include depositing a first mask material on a substrate; depositing a second mask material on the first mask material; depositing a third mask material on the second mask material; patterning the third mask material with a pattern corresponding to one or more trenches for transfer to the substrate; transferring the pattern from the third mask material to the second mask material; transferring the pattern from the second mask material to the first mask material; and/or transferring the pattern from the first mask material to the substrate.

  15. Etching of germanium-tin using ammonia peroxide mixture

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yuan; Ong, Bin Leong; Wang, Wei; Gong, Xiao; Liang, Gengchiau; Yeo, Yee-Chia, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Zhang, Zheng; Pan, Jisheng [Institute of Material Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03, Innovis, Singapore 138634 (Singapore); Tok, Eng-Soon [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

    2015-12-28

    The wet etching of germanium-tin (Ge{sub 1-x}Sn{sub x}) alloys (4.2% < x < 16.0%) in ammonia peroxide mixture (APM) is investigated. Empirical fitting of the data points indicates that the etch depth of Ge{sub 1-x}Sn{sub x} is proportional to the square root of the etch time t and decreases exponentially with increasing x for a given t. In addition, X-ray photoelectron spectroscopy results show that increasing t increases the intensity of the Sn oxide peak, whereas no obvious change is observed for the Ge oxide peak. This indicates that an accumulation of Sn oxide on the Ge{sub 1-x}Sn{sub x} surface decreases the amount of Ge atoms exposed to the etchant, which accounts for the decrease in etch rate with increasing etch time. Atomic force microscopy was used to examine the surface morphologies of the Ge{sub 0.918}Sn{sub 0.082} samples. Both root-mean-square roughness and undulation periods of the Ge{sub 1-x}Sn{sub x} surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge{sub 1-x}Sn{sub x} using APM and may be used for the fabrication of Ge{sub 1-x}Sn{sub x}-based electronic and photonic devices.

  16. Dry etching of thin chalcogenide films

    Energy Technology Data Exchange (ETDEWEB)

    Petkov, Kiril [Acad. J. Malinowski Central Laboratory of Photoprocesses, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 109, 1113 Sofia (Bulgaria); Vassilev, Gergo; Vassilev, Venceslav, E-mail: kpetkov@clf.bas.b [Department of Semiconductors, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsky Blvd., 1756 Sofia (Bulgaria)

    2010-04-01

    Fluorocarbon plasmas (pure and mixtures with Ar) were used to investigate the changes in the etching rate depending on the chalcogenide glasses composition and light exposure. The experiments were performed on modified commercial HZM-4 vacuum equipment in a diode electrode configuration. The surface microstructure of thin chalcogenide layers and its change after etching in CCl{sub 2}F{sub 2} and CF{sub 4} plasmas were studied by SEM. The dependence of the composition of As-S-Ge, As-Se and multicomponent Ge-Se-Sb-Ag-I layers on the etching rate was discussed. The selective etching of some glasses observed after light exposure opens opportunities for deep structure processing applications.

  17. Chemical etching of GaAs with a novel low energy ion beam source: a low damage process for device fabrication

    International Nuclear Information System (INIS)

    Beckerman, J.; Jackman, R.B.

    1993-01-01

    If the advantages of physics (anisotropy) can be combined with the advantages of chemistry (damage-free perturbation of the lattice) then an excellent, near damage-free, etching reaction can result. In this context, the promise for ultra-low energy ( -1 . The source does, however, give rise to a coating, derived from the source liner, which must be washed from all etched samples. The presence of such a coating is likely to be the origin of the slow etch rate achieved. After removal of the coating, smooth, mirror-like etched surfaces are apparent. These surfaces perform very well when Schottky diodes are constructed from them showing no deviation from the behaviour of control samples. (author)

  18. Recent studies of uranium recovery from wet-process phosphoric acid with octylphenyl acid phosphate

    International Nuclear Information System (INIS)

    Arnold, W.D.

    1978-01-01

    Commercial OPAP is a complex mixture that contains at least 11 components. Octyl phenol is the principal impurity. Commercial OPAP contains readily-hydrolyzable material. The concentrations of octyl phenol and an unidentified impurity increase in the hydrolyzed product. Uranium extraction power is decreased slightly by hydrolysis of the reagent. Four major problems were encountered in continuous stability tests: (1) Microemulsion or micelle formation--loss of organic phase into phosphoric acid. We do not have a solution to this problem at this time. It could involve alteration of the organic, e.g., adding a modifier, changing the reagent structure, or changing the diluent. (2) Reagent poisoning--reduction of uranium extraction and interference with organic titrations by material extracted from the acid. Additional work is needed to identify the poisoning material or materials. It can then be removed if it originates in the phosphate rock, or avoided if it originates in chemicals added during processing. (3) Crystallization with iron--loss of both major components of the reagent as a complex with ferric iron. We believe this problem can be controlled by controlling the ferric iron concentration in the phosphoric acid. (4) MOPPA distribution loss--a selective loss to the aqueous phase. We believe this can be minimized by controlling the iron concentration of the phosphoric acid. The iron concentration will need to be kept low enough to avoid reagent crystallization and high enough to avoid MOPPA distribution loss. 15 figs

  19. Unexpected 226Ra build-up in wet-process phosphoric-acid plants

    International Nuclear Information System (INIS)

    Lardinoye, M.H.; Weterings, K.; Berg, W.B. van de

    1982-01-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filters. This higher radiation level is caused by radium which is present in very low concentrations in the phosphates used for fertilizer production. Detectable radiation levels around vessels and piping in other phosphoric-acid works have since been determined. In all factories the filter part and especially the washing-acid section showed the highest radiation level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of barium sulphate and calcium sulphate with a higher radium concentration is formed. The radium ions appeared to be incorporated in the barium sulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal contamination in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning the equipment in which the radioactive scaling is formed. (author)

  20. Unexpected /sup 226/Ra build-up in wet-process phosphoric-acid plants

    Energy Technology Data Exchange (ETDEWEB)

    Lardinoye, M.H.; Weterings, K. (Stamicarbon B.V., Geleen (Netherlands)); van de Berg, W.B. (Unie van Kunstmestfabrieken, Utrecht (Netherlands))

    1982-04-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filters. This higher radiation level is caused by radium which is present in very low concentrations in the phosphates used for fertilizer production. Detectable radiation levels around vessels and piping in other phosphoric-acid works have since been determined. In all factories the filter part and especially the washing-acid section showed the highest radiation level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of barium sulphate and calcium sulphate with a higher radium concentration is formed. The radium ions appeared to be incorporated in the barium sulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal contamination in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning the equipment in which the radioactive scaling is formed.

  1. Unexpected 226Ra build-up in wet-process phosphoric-acid plants.

    Science.gov (United States)

    Lardinoye, M H; Weterings, K; van de Berg, W B

    1982-04-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filtres. This higher radiation level is caused by radium, which, as a decay product in the 238U series, is present in very low concentrations (1-50 pCi 226R/g) in the phosphates used for fertilizer production. Specific research later on established that there were detectable radiation levels around vessels and piping in other phosphoric-acid works as well. It turned out that in all factories the filter part, and especially the washing-acid section showed the highest radiation-level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of bariumsulphate and calciumsulphate with a higher radiumconcentration (+/- 0.1 Ci/g) is formed. The radium ions appeared to be incorporated in the bariumsulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal pollution, for example in cleaning operations by radio-active intake or inhallation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning (every 1-3 yr) the equipment in which the radio-active scaling is formed.

  2. Unexpected /sup 226/Ra build-up in wet-process phosphoric-acid plants

    Energy Technology Data Exchange (ETDEWEB)

    Lardinoye, M.H.; Weterings, K.; van de Berg, W.B.

    1982-04-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filtres. This higher radiation level is caused by radium, which, as a decay product in the /sup 238/U series, is present in very low concentrations (1-50 pCi 226R/g) in the phosphates used for fertilizer production. Specific research later on established that there were detectable radiation levels around vessels and piping in other phosphoric-acid works as well. It turned out that in all factories the filter part, and especially the washing-acid section showed the highest radiation-level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of bariumsulfate and calciumsulfate with a higher radium concentration (+/- 0.1 Ci/g) is formed. The radium ions appeared to be incorporated in the bariumsulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal pollution, for example in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning (every 1-3 yr) the equipment in which the radioactive scaling is formed.

  3. Two step esterification-transesterification process of wet greasy sewage sludge for biodiesel production.

    Science.gov (United States)

    Urrutia, C; Sangaletti-Gerhard, N; Cea, M; Suazo, A; Aliberti, A; Navia, R

    2016-01-01

    Sewage sludge generated in municipal wastewater treatment plants was used as a feedstock for biodiesel production via esterification/transesterification in a two-step process. In the first esterification step, greasy and secondary sludge were tested using acid and enzymatic catalysts. The results indicate that both catalysts performed the esterification of free fatty acids (FFA) simultaneously with the transesterification of triacylglycerols (TAG). Acid catalyst demonstrated better performance in FFA esterification compared to TAG transesterification, while enzymatic catalyst showed the ability to first hydrolyze TAG in FFA, which were esterified to methyl esters. In addition, FAME concentration using greasy sludge were higher (63.9% and 58.7%), compared with those of secondary sludge (11% and 16%), using acid and enzymatic catalysts, respectively. Therefore, only greasy sludge was used in the second step of alkaline transesterification. The alkaline transesterification of the previously esterified greasy sludge reached a maximum FAME concentration of 65.4% when using acid catalyst. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Device fabrication by plasma etching

    International Nuclear Information System (INIS)

    Mogab, C.J.

    1980-01-01

    Plasma etching as applied to many of the materials encountered in the fabrication of LSI's is complicated by loading effect-the dependence of etch rate on the integrated surface area to be etched. This problem is alleviated by appropriate choice of etchant and etching conditions. Appropriate choice of system parameters, generally most concerned with the inherent lifetime of etchant species, may also result in improvement of etch rate uniformity on a wafer-by-wafer basis

  5. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    OpenAIRE

    Ajay Kumar; Dr. Pramod Kumar

    2014-01-01

    This paper presents a description of etching process for fabrication single mode optical fiber sensors. The process of fabrication demonstrates an optimized etching based method to fabricate single mode fiber (SMF) optic sensors in specified constant time and temperature. We propose a single mode optical fiber based temperature sensor, where the temperature sensing region is obtained by etching its cladding diameter over small length to a critical value. It is observed that th...

  6. 3D memory: etch is the new litho

    Science.gov (United States)

    Petti, Christopher

    2018-03-01

    This paper discusses the process challenges and limitations for 3D NAND processes, focusing on vertical 3D architectures. The effect of deep memory hole etches on die cost is calculated, with die cost showing a minimum at a given number of layers because of aspect-ratio dependent etch effects. Techniques to mitigate these etch effects are summarized, as are other etch issues, such as bowing and twisting. Metal replacement gate processes and their challenges are also described. Lastly, future directions of vertical 3D NAND technologies are explored.

  7. Campylobacter in Broiler Chicken and Broiler Meat in Sri Lanka: Influence of Semi-Automated vs. Wet Market Processing on Campylobacter Contamination of Broiler Neck Skin Samples

    Directory of Open Access Journals (Sweden)

    Kottawattage S. A. Kottawatta

    2017-11-01

    Full Text Available Broiler meat can become contaminated with Campylobacter of intestinal origin during processing. The present study aimed to identify the prevalence of Campylobacter in broiler flocks and meat contamination at retail shops, and determine the influence of semi-automated and wet market processing on Campylobacter contamination of neck skin samples. Samples were collected from semi-automated plants (n = 102 and wet markets (n = 25. From each batch of broilers, pooled caecal samples and neck skin samples were tested for Campylobacter. Broiler meat purchased from retail outlets (n = 37 was also tested. The prevalence of Campylobacter colonized broiler flocks was 67%. The contamination of meat at retail was 59%. Both semi-automated and wet market processing resulted to contaminate the broiler neck skins to the levels of 27.4% and 48%, respectively. When Campylobacter-free broiler flocks were processed in semi-automated facilities 15% (5/33 of neck skin samples became contaminated by the end of processing whereas 25% (2/8 became contaminated after wet market processing. Characterization of isolates revealed a higher proportion of C. coli compared to C. jejuni. Higher proportions of isolates were resistant to important antimicrobials. This study shows the importance of Campylobacter in poultry industry in Sri Lanka and the need for controlling antimicrobial resistance.

  8. Campylobacter in Broiler Chicken and Broiler Meat in Sri Lanka: Influence of Semi-Automated vs. Wet Market Processing on Campylobacter Contamination of Broiler Neck Skin Samples.

    Science.gov (United States)

    Kottawatta, Kottawattage S A; Van Bergen, Marcel A P; Abeynayake, Preeni; Wagenaar, Jaap A; Veldman, Kees T; Kalupahana, Ruwani S

    2017-11-29

    Broiler meat can become contaminated with Campylobacter of intestinal origin during processing. The present study aimed to identify the prevalence of Campylobacter in broiler flocks and meat contamination at retail shops, and determine the influence of semi-automated and wet market processing on Campylobacter contamination of neck skin samples. Samples were collected from semi-automated plants ( n = 102) and wet markets ( n = 25). From each batch of broilers, pooled caecal samples and neck skin samples were tested for Campylobacter . Broiler meat purchased from retail outlets ( n = 37) was also tested. The prevalence of Campylobacter colonized broiler flocks was 67%. The contamination of meat at retail was 59%. Both semi-automated and wet market processing resulted to contaminate the broiler neck skins to the levels of 27.4% and 48%, respectively. When Campylobacter -free broiler flocks were processed in semi-automated facilities 15% (5/33) of neck skin samples became contaminated by the end of processing whereas 25% (2/8) became contaminated after wet market processing. Characterization of isolates revealed a higher proportion of C. coli compared to C. jejuni . Higher proportions of isolates were resistant to important antimicrobials. This study shows the importance of Campylobacter in poultry industry in Sri Lanka and the need for controlling antimicrobial resistance.

  9. Potential radiological impacts of recovery of uranium from wet-process phosphoric acid. Final report to the Environmental Protection Agency

    International Nuclear Information System (INIS)

    Davis, W. Jr.; Haywood, F.F.; Danek, J.L.; Moore, R.E.; Wagner, E.B.; Rupp, E.M.

    1979-01-01

    A study was made to determine the radiological impacts associated with recovery of uranium from wet-process (WP) phosphoric acid in central Florida. Removal of U and other radionuclides from phosphoric acid prevents their distribution on farm lands and urban gardens and grasses via fertilizers; this results in a positive impact (decreased dose commitment) on the associated populations. This study considers the potential negative impacts of current and project recovery processes in a site-specific manner using detailed state-of-the-art methodologies. Positive impacts are treated in a generic sense using U.S. average values for important variables such as average and maximum fertilizer application rates and quantities of radionuclides in fertilizer. Three model plants to recover U from WP phosphoric acid were selected and source terms for release of radionuclides are developed for all three and for two treatment methods for airborne particulates. Costs for radwaste treatment were developed. Field measurements were conducted at the only commercial uranium recovery plant in operation. Radiological doses to the population surrounding release points during plant operation were estimated

  10. The influence of Chromium supplied by tanning and wet finishing processes on the formation of cr(vi in leather

    Directory of Open Access Journals (Sweden)

    W. F. Fuck

    2011-06-01

    Full Text Available Chromium used in leather manufacturing can be oxidized from the trivalent to the hexavalent state, causing environmental concerns. In this study, the influence of Cr(III from tanning, deacidification pH, fatliquors, chrome retanning and vegetable retanning on the formation of Cr(VI in leather was analyzed by comparing natural and aged samples. In wet-blue leather, even after aging and in fatliquored leathers that did not suffer the aging process, the presence of Cr(VI was always below the detection limit of 3 mg/kg. Considering the presence of Cr(VI, the supply of chromium during the retanning step had a more significant effect than during the tanning. In the fatliquoring process with sulfites, fish and synthetic fatliquor leather samples contained Cr(VI when aged, and the highest concentration detected was 26.7 mg/kg. The evaluation of Cr(VI formation led to recommendations for regulation in the leather industry.

  11. Metallographic examination of TD-nickel base alloys. [thermal and chemical etching technique evaluation

    Science.gov (United States)

    Kane, R. D.; Petrovic, J. J.; Ebert, L. J.

    1975-01-01

    Techniques are evaluated for chemical, electrochemical, and thermal etching of thoria dispersed (TD) nickel alloys. An electrochemical etch is described which yielded good results only for large grain sizes of TD-nickel. Two types of thermal etches are assessed for TD-nickel: an oxidation etch and vacuum annealing of a polished specimen to produce an etch. It is shown that the first etch was somewhat dependent on sample orientation with respect to the processing direction, the second technique was not sensitive to specimen orientation or grain size, and neither method appear to alter the innate grain structure when the materials were fully annealed prior to etching. An electrochemical etch is described which was used to observe the microstructures in TD-NiCr, and a thermal-oxidation etch is shown to produce better detail of grain boundaries and to have excellent etching behavior over the entire range of grain sizes of the sample.

  12. Fabrication Process Changes for Performance Improvement of a RF MEMS Resonator: Conformable Contact Lithography, Moire Alignment, and Chlorine Dry Etching

    National Research Council Canada - National Science Library

    Sakai, Mark

    2005-01-01

    .... A CCL process utilizing moire alignment marks is described. An automated moire-based alignment system using Labview software is presented which demonstrates sub-100 nm alignment accuracy for a single alignment mark...

  13. Low-k SiOCH Film Etching Process and Its Diagnostics Employing Ar/C5F10O/N2 Plasma

    Science.gov (United States)

    Nagai, Mikio; Hayashi, Takayuki; Hori, Masaru; Okamoto, Hidekazu

    2006-09-01

    We proposed an environmental harmonic etching gas of C5F10O (CF3CF2CF2OCFCF2), and demonstrated the etching of low-k SiOCH films employing a dual-frequency capacitively coupled etching system. Dissociative ionization cross sections for the electron impact ionizations of C5F10O and c-C4F8 gases have been measured by quadrupole mass spectroscopy (QMS). The dissociative ionization cross section of CF3+ from C5F10O gas was much higher than those of other ionic species, and 10 times higher than that of CF3+ from C4F8 gas. CF3+ is effective for increasing the etching rate of SiO2. As a result, the etching rate of SiOCH films using Ar/C5F10O/N2 plasma was about 1000 nm/min, which is much higher than that using Ar/C4F8/N2 plasma. The behaviours of fluorocarbon radicals in Ar/C5F10O/N2 plasma, which were measured by infrared diode laser absorption spectroscopy, were similar to those in Ar/C4F8/N2 plasma. The densities of CF and CF3 radicals were markedly decreased with increasing N2 flow rate. Etching rate was controlled by N2 flow rate. A vertical profile of SiOCH with a high etching rate and less microloading was realized using Ar/C5F10O/N2 plasma chemistry.

  14. Characterization of a calcium phosphate cement based on alpha-tricalcium phosphate obtained by wet precipitation process

    International Nuclear Information System (INIS)

    Thurmer, M.B.; Diehl, C.E.; Vieira, R.S.; Coelho, W.T.G.; Santos, L.A.

    2012-01-01

    There are several systems of calcium phosphate cements being studied. Those based on alpha-tricalcium phosphate are of particular interest. After setting they produce calcium deficient hydroxyapatite similar to bone like hydroxyapatite. This work aims to obtain alpha-tricalcium phosphate powders by the wet precipitation process, using calcium nitrate and phosphoric acid as reagents. This powder was characterized by infrared spectroscopy, X-ray diffraction and particle size distribution. In order to prepare the calcium phosphate cement, the powder was mixed with an accelerator in an aqueous solution. The mechanical properties of the cement were assessed and it was evaluated by means of apparent density, X-ray diffraction and scanning electron microscopy. The described method produced crystalline alpha-tricalcium phosphate as the major phase. The calcium phosphate cement showed high values of compression strength (50 MPa). The soaking of the cement in a simulated body fluid (SBF) formed a layer of hydroxyapatite like crystals in the surface of the samples. (author)

  15. Wetting properties of hybrid structure with hydrophilic ridges and hydrophobic channels

    Science.gov (United States)

    Lee, Dong-Ki; Choi, Su Young; Park, Min Soo; Cho, Young Hak

    2018-02-01

    In the present study, we fabricated a hybrid structure where the upper surface of the ridge is hydrophilic and the inner surface of the channel is hydrophobic. Laser-induced backside wet etching (LIBWE) process was performed to machine the hybrid structure on a Pyrex glass substrate. Wetting properties were evaluated from static contact angles (CAs) measurement in parallel and orthogonal directions. The water droplet on the hybrid structure was in the Cassie-Baxter state and showed anisotropic wetting property along groove lines. Moisture condensation studies under humid condition indicated that water droplets grew and coalesced on the ridge with hydrophilicity. Furthermore, water-oil separation was tested using a microfluidic chip with the developed hybrid structure. In case of hybrid microfluidic chip, the water could not flow into channel but the hexadecane could flow due to the capillary pressure difference.

  16. Cracking of GaN on sapphire from etch-process-induced nonuniformity in residual thermal stress

    International Nuclear Information System (INIS)

    Lacroix, Yves; Chung, Sung-Hoon; Sakai, Shiro

    2001-01-01

    An experiment was performed to explain the appearance of cracks along mesa structures during the processing of GaN device layers grown on sapphire substrates. Micro-Raman spectroscopy was used to measure the position-dependent stress in the GaN layer. We show evidence that the stress at the interface with the substrate may be larger along the mesa structures than that of the as-grown layer, and that this increase in stress can be enough to induce cracks along mesa structures during processing. We report on the formation of cracks that propagate guided by the nonuniformity of the stress induced by the formation of mesa structures in the GaN layer, independent of crystal direction. The understanding of cracking mechanisms has implications in GaN-based device structures that require heteroepitaxial growth of layers with different lattice size and thermal expansion coefficients. [copyright] 2001 American Institute of Physics

  17. The chemical and electrochemical anisotropic etching of silicon

    International Nuclear Information System (INIS)

    Dixon, E.

    1997-06-01

    The success of silicon IC technology in producing a wide variety of microstructures relies heavily on the orientation dependant etching observed for silicon in alkaline media. Despite the rapid growth of this industry, the chemical and electrochemical mechanisms by which anisotropic etching occurs remain poorly understood. The most common etchant systems in use are ethylenediamine-pyrocatechol-water (EPW) and potassium hydroxide-isopropanol-water (KOH-IPA), and whilst these systems are highly plane selective they each have distinct disadvantages. The occurrence of inhomogeneities such as micropyramids and pits on the surface of etched substrates is a particularly disadvantageous characteristic of many alkaline etching systems. A complete understanding of the chemical and electrochemical anisotropic etching mechanisms is essential in order to obtain more reproducible etching, improved etch rate ratios and the development of more reliable etching baths. Wet chemical etching experiments to evaluate the etching rates for the different alkali metal cations have shown that similar etch rates are observed for LiOH, NaOH and KOH but those of RbOH and CsOH are significantly lower. The presence of impurities was shown to worsen the etched wafer's surface finish obtained in these etching baths. Additives have been shown to dramatically improve the surface finish with the presence of IPA in conjunction with etchant oxygenation virtually eliminating all surface defects. Electrochemical experiments were used to assess the electrochemical behaviour of Si p-(100) in of a wide variety of etchants and variations were seen according to the etchant used. A.C impedance spectroscopy showed a variation in the flat-band potential (V FB ) according to alkali metal hydroxide etchant used. These trends were similarly observed in the presence of isopropanol. Oxygenation was observed to reproducibly alter the flat-band potentials. A.c impedance spectroscopic studies additionally confirmed the

  18. Influence of copper foil polycrystalline structure on graphene anisotropic etching

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Kamal P. [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Mahyavanshi, Rakesh D. [Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Kalita, Golap, E-mail: kalita.golap@nitech.ac.jp [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Tanemura, Masaki [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2017-01-30

    Graphical abstract: Hexagonal hole formation with anisotropic etching independent of the stripes and wrinkles in the synthesized graphene. We also observed variation in etched pattern of the graphene depending on the base Cu grain orientations, attributing to difference in nucleation and growth process. - Highlights: • Reveal the influence of copper polycrystalline structure on anisotropic etching of graphene. • Hexagonal hole formation with etching is observed to be independent of stripes and wrinkles in graphene. • Variation in etched pattern of graphene depending on the base Cu grain is confirmed. • This finding will help to understand the nature of microscopic etched pattern in graphene. - Abstract: Anisotropic etching of graphene and other two dimensional materials is an important tool to understand the growth process as well as enabling fabrication of various well-defined structures. Here, we reveal the influence of copper foil polycrystalline structure on anisotropic etching process of as-synthesized graphene. Graphene crystals were synthesized on the polycrystalline Cu foil by a low-pressure chemical vapor deposition (LPCVD) system. Microscopic analysis shows difference in shape, size and stripes alignment of graphene crystals with dissimilar nucleation within closure vicinity of neighboring Cu grains. Post-growth etching of such graphene crystals also significantly affected by the crystallographic nature of Cu grains as observed by the field emission scanning electron microscope (FE-SEM) and electron back scattered diffraction (EBSD) analysis. Hexagonal hole formation with anisotropic etching is observed to be independent of the stripes and wrinkles in the synthesized graphene. We also observed variation in etched pattern of the graphene depending on the base Cu grain orientations, attributing to difference in nucleation and growth process. The findings can facilitate to understand the nature of microscopic etched pattern depending on metal

  19. Influence of copper foil polycrystalline structure on graphene anisotropic etching

    International Nuclear Information System (INIS)

    Sharma, Kamal P.; Mahyavanshi, Rakesh D.; Kalita, Golap; Tanemura, Masaki

    2017-01-01

    Graphical abstract: Hexagonal hole formation with anisotropic etching independent of the stripes and wrinkles in the synthesized graphene. We also observed variation in etched pattern of the graphene depending on the base Cu grain orientations, attributing to difference in nucleation and growth process. - Highlights: • Reveal the influence of copper polycrystalline structure on anisotropic etching of graphene. • Hexagonal hole formation with etching is observed to be independent of stripes and wrinkles in graphene. • Variation in etched pattern of graphene depending on the base Cu grain is confirmed. • This finding will help to understand the nature of microscopic etched pattern in graphene. - Abstract: Anisotropic etching of graphene and other two dimensional materials is an important tool to understand the growth process as well as enabling fabrication of various well-defined structures. Here, we reveal the influence of copper foil polycrystalline structure on anisotropic etching process of as-synthesized graphene. Graphene crystals were synthesized on the polycrystalline Cu foil by a low-pressure chemical vapor deposition (LPCVD) system. Microscopic analysis shows difference in shape, size and stripes alignment of graphene crystals with dissimilar nucleation within closure vicinity of neighboring Cu grains. Post-growth etching of such graphene crystals also significantly affected by the crystallographic nature of Cu grains as observed by the field emission scanning electron microscope (FE-SEM) and electron back scattered diffraction (EBSD) analysis. Hexagonal hole formation with anisotropic etching is observed to be independent of the stripes and wrinkles in the synthesized graphene. We also observed variation in etched pattern of the graphene depending on the base Cu grain orientations, attributing to difference in nucleation and growth process. The findings can facilitate to understand the nature of microscopic etched pattern depending on metal

  20. Liquid droplet sensing using twisted optical fiber couplers fabricated by hydrofluoric acid flow etching

    Science.gov (United States)

    Son, Gyeongho; Jung, Youngho; Yu, Kyoungsik

    2017-04-01

    We report a directional-coupler-based refractive index sensor and its cost-effective fabrication method using hydrofluoric acid droplet wet-etching and surface-tension-driven liquid flows. The proposed fiber sensor consists of a pair of twisted tapered optical fibers with low excess losses. The fiber cores in the etched microfiber region are exposed to the surrounding medium for efficient interaction with the guided light. We observe that the etching-based low-loss fiber-optic sensors can measure the water droplet volume by detecting the refractive index changes of the surrounding medium around the etched fiber core region.

  1. Treatment of Row Leachate Using Catalytic Wet Oxidation Processes in Combination Hydrogen Peroxide, A Case Study of Isfahan Composting Factory Leachate

    Directory of Open Access Journals (Sweden)

    Behrouz Karimi

    2013-08-01

    Full Text Available Treatment of toxic organic compounds is one of the major applications of the Wet Air Oxidation (WAO processes. The process can be defined  as the oxidation of substances, either in the form of solutions or suspensions, with the use of an oxidant (oxygen or air at elevated pressure and temperature. The aim of this paper was to study of Catalytic Wet Oxidation (CWAO with hydrogen peroxide to improve removal efficiency of organic matter and ammonia mainly produced in Isfahan composting factory leachate. The experiment was carried out by adding 1.5 Lit pretreated leachate sample to 3 Lit autoclave reactor. Four parameters are considered: pressure (8–12 bar; temperature (100–300 °C; retention time (30–90 min; H2O2 (1–5 mL/L.The highest removal efficiencies of COD and BOD were achieved at 300°C; approximately 44% and 48% were destroyed, respectively. On the other hand, highest ammonium removal efficiency was achieved at 100 °C in which approximately 63.8% was removed. The efficiency of aqueous phase oxidation can be largely improved by the use of H2O2 as catalyst. Therefore, catalytic wet oxidation would provide an environmentally attractive option for control of organic and toxic wastes problems. Temperature was found to be the most important control variable of the wet oxidation process of leachate.

  2. Recovery of phosphorus and aluminium from sewage sludge ash by a new wet chemical elution process (SESAL-Phos-recovery process).

    Science.gov (United States)

    Petzet, S; Peplinski, B; Bodkhe, S Y; Cornel, P

    2011-01-01

    The potential of a new wet chemical process for phosphorus and aluminium recovery from sewage sludge ash by sequential elution with acidic and alkaline solutions has been investigated: SESAL-Phos (sequential elution of sewage sludge ash for aluminium and phosphorus recovery). Its most innovative aspect is an acidic pre-treatment step in which calcium is leached from the sewage sludge ash. Thus the percentage of alkaline soluble aluminium phosphates is increased from 20 to 67%. This aluminium phosphate is then dissolved in alkali. Subsequently, the dissolved phosphorus is precipitated as calcium phosphate with low heavy metal content and recovered from the alkaline solution. Dissolved aluminium is recovered and may be reused as a precipitant in wastewater treatment plants.

  3. Determination of etching parameters for pulsed XeF2 etching of silicon using chamber pressure data

    Science.gov (United States)

    Sarkar, Dipta; Baboly, M. G.; Elahi, M. M.; Abbas, K.; Butner, J.; Piñon, D.; Ward, T. L.; Hieber, Tyler; Schuberth, Austin; Leseman, Z. C.

    2018-04-01

    A technique is presented for determination of the depletion of the etchant, etched depth, and instantaneous etch rate for Si etching with XeF2 in a pulsed etching system in real time. The only experimental data required is the pressure data collected temporally. Coupling the pressure data with the knowledge of the chemical reactions allows for the determination of the etching parameters of interest. Using this technique, it is revealed that pulsed etching processes are nonlinear, with the initial etch rate being the highest and monotonically decreasing as the etchant is depleted. With the pulsed etching system introduced in this paper, the highest instantaneous etch rate of silicon was recorded to be 19.5 µm min-1 for an initial pressure of 1.2 Torr for XeF2. Additionally, the same data is used to determine the rate constant for the reaction of XeF2 with Si; the reaction is determined to be second order in nature. The effect of varying the exposed surface area of Si as well as the effect that pressure has on the instantaneous etch rate as a function of time is shown applying the same technique. As a proof of concept, an AlN resonator is released using XeF2 pulses to remove a sacrificial poly-Si layer.

  4. Quasi-stationary heterogeneous states of electrolyte at electrodeposition and etching process in a gradient magnetic field of a magnetized ferromagnetic ball

    International Nuclear Information System (INIS)

    Gorobets, O.Yu.; Gorobets, Yu.I.; Bondar, I.A.; Legenkiy, Yu.A.

    2013-01-01

    We report the results of the experimental study of the shape of the interface separating areas with different magnetic susceptibilities of paramagnetic etching products formed in an inhomogeneous magnetic field in the vicinity of a magnetized steel ball during its corrosion. The theoretical model describing the shape and size of this interface as well as the distribution of the paramagnetic etching product concentration inside this area is proposed. The shape of the interface was calculated taking into account the pressure balance. - Highlights: ► Phase separation of an electrolyte is reported in an inhomogeneous magnetic field. ► The shape of the interface was calculated taking into account the pressure balance. ► The etching products represent the nano-sized clusters inside the paramagnetic phases.

  5. Quasi-stationary heterogeneous states of electrolyte at electrodeposition and etching process in a gradient magnetic field of a magnetized ferromagnetic ball

    Energy Technology Data Exchange (ETDEWEB)

    Gorobets, O.Yu. [National Technical University of Ukraine ' KPI' , Prospect Peremogy, 37, 03056 Kiev (Ukraine); Gorobets, Yu.I., E-mail: Gorobets@imag.kiev.ua [Institute for Magnetism, Prospect Vernadskogo, 36-b, 03142 Kiev (Ukraine); Bondar, I.A., E-mail: ivanna_bondar@ukr.net [National Technical University of Ukraine ' KPI' , Prospect Peremogy, 37, 03056 Kiev (Ukraine); Legenkiy, Yu.A., E-mail: legen_yu@ukr.net [Donetsk National University of Ukraine, Universitetskaya Street 24, 340055 Donetsk (Ukraine)

    2013-03-15

    We report the results of the experimental study of the shape of the interface separating areas with different magnetic susceptibilities of paramagnetic etching products formed in an inhomogeneous magnetic field in the vicinity of a magnetized steel ball during its corrosion. The theoretical model describing the shape and size of this interface as well as the distribution of the paramagnetic etching product concentration inside this area is proposed. The shape of the interface was calculated taking into account the pressure balance. - Highlights: Black-Right-Pointing-Pointer Phase separation of an electrolyte is reported in an inhomogeneous magnetic field. Black-Right-Pointing-Pointer The shape of the interface was calculated taking into account the pressure balance. Black-Right-Pointing-Pointer The etching products represent the nano-sized clusters inside the paramagnetic phases.

  6. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  7. Wet cutting

    Energy Technology Data Exchange (ETDEWEB)

    Hole, B. [IMC Technical Services (United Kingdom)

    1999-08-01

    Continuous miners create dust and methane problems in underground coal mining. Control has usually been achieved using ventilation techniques as experiments with water based suppression have led to flooding and electrical problems. Recent experience in the US has led to renewed interest in wet head systems. This paper describes tests of the Hydraphase system by IMC Technologies. Ventilation around the cutting zone, quenching of hot ignition sources, dust suppression, the surface trial gallery tests, the performance of the cutting bed, and flow of air and methane around the cutting head are reviewed. 1 ref., 2 figs., 2 photos.

  8. Future developments in etched track detectors for neutron dosimetry

    International Nuclear Information System (INIS)

    Tommasino, L.

    1987-01-01

    Many laboratories engaged in the field of personal neutron dosimetry are interested in developing better etching processes and improving the CR-39 detecting materials. To know how much effort must still be devoted to the development of etch track dosimetry, it is necessary to understand the advantages. limitations and degree of exploitation of the currently available techniques. So much has been learned about the chemical and electrochemical etching processes that an optimised combination of etching processes could make possible the elimination of many of the existing shortcomings. Limitations of etched track detectors for neutron dosimetry arise mainly because the registration occurs only on the detector surface. These damage type detectors are based on radiation induced chain scission processes in polymers, which result in hole-type tracks in solids. The converse approach, yet to be discovered, would be the development of cure-track detectors, where radiation induced cross linking between organic polymer chains could result in solid tracks in liquids. (author)

  9. Ethanol Wet-bonding Technique Sensitivity Assessed by AFM

    OpenAIRE

    Osorio, E.; Toledano, M.; Aguilera, F.S.; Tay, F.R.; Osorio, R.

    2010-01-01

    In ethanol wet bonding, water is replaced by ethanol to maintain dehydrated collagen matrices in an extended state to facilitate resin infiltration. Since short ethanol dehydration protocols may be ineffective, this study tested the null hypothesis that there are no differences in ethanol dehydration protocols for maintaining the surface roughness, fibril diameter, and interfibrillar spaces of acid-etched dentin. Polished human dentin surfaces were etched with phosphoric acid and water-rinsed...

  10. Development and Optimization of a Wet Granulation Process at Elevated Temperature for a Poorly Compactible Drug Using Twin Screw Extruder for Continuous Manufacturing.

    Science.gov (United States)

    Meena, Anuprabha K; Desai, Divyakant; Serajuddin, Abu T M

    2017-02-01

    The objective of this study was to enhance tabletability of a poorly compactible drug, acetaminophen, by wet granulation using twin screw extruder at high temperature. It was desired that there would be minimum amounts of excipients used and the granules obtained after extrusion would be dry and fall within a size range suitable for tableting without any further processing. Mixtures of acetaminophen (95%) with binders (5% povidone or partially pregelatinized starch) were wet granulated through twin screw extruder at 70°C by adding 7% w/w water. The process had a short granulation time (processing temperature used, no drying after extrusion was needed. By optimizing formulation and processing parameters, >90% granules in the size range of 125 to 1000 μm (1.7 MPa, which was superior to that of tablets prepared by conventional high shear wet granulation. As the granules could be extruded continuously and did not require drying and milling, the method was amenable to continuous processing. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  11. Fast Etching of Molding Compound by an Ar/O2/CF4 Plasma and Process Improvements for Semiconductor Package Decapsulation

    NARCIS (Netherlands)

    Tang, J.; Gruber, D.; Schelen, J.B.J.; Funke, H.J.; Beenakker, C.I.M.

    2012-01-01

    Decapsulation of a SOT23 semiconductor package with 23 um copper wire bonds is conducted with an especially designed microwave induced plasma system. It is found that a 30%-60% CF4 addition in the O2/CF4 etchant gas results in high molding compound etching rate. Si3N4 overetching which is

  12. Etching characteristics of Si{110} in 20 wt% KOH with addition of hydroxylamine for the fabrication of bulk micromachined MEMS

    Science.gov (United States)

    Rao, A. V. Narasimha; Swarnalatha, V.; Pal, P.

    2017-12-01

    Anisotropic wet etching is a most widely employed for the fabrication of MEMS/NEMS structures using silicon bulk micromachining. The use of Si{110} in MEMS is inevitable when a microstructure with vertical sidewall is to be fabricated using wet anisotropic etching. In most commonly employed etchants (i.e. TMAH and KOH), potassium hydroxide (KOH) exhibits higher etch rate and provides improved anisotropy between Si{111} and Si{110} planes. In the manufacturing company, high etch rate is demanded to increase the productivity that eventually reduces the cost of end product. In order to modify the etching characteristics of KOH for the micromachining of Si{110}, we have investigated the effect of hydroxylamine (NH2OH) in 20 wt% KOH solution. The concentration of NH2OH is varied from 0 to 20% and the etching is carried out at 75 °C. The etching characteristics which are studied in this work includes the etch rates of Si{110} and silicon dioxide, etched surface morphology, and undercutting at convex corners. The etch rate of Si{110} in 20 wt% KOH + 15% NH2OH solution is measured to be four times more than that of pure 20 wt% KOH. Moreover, the addition of NH2OH increases the undercutting at convex corners and enhances the etch selectivity between Si and SiO2.

  13. More vertical etch profile using a Faraday cage in plasma etching

    Science.gov (United States)

    Cho, Byeong-Ok; Hwang, Sung-Wook; Ryu, Jung-Hyun; Moon, Sang Heup

    1999-05-01

    Scanning electron microscope images of sidewalls obtained by plasma etching of an SiO2 film with and without a Faraday cage have been compared. When the substrate film is etched in the Faraday cage, faceting is effectively suppressed and the etch profile becomes more vertical regardless of the process conditions. This is because the electric potential in the cage is nearly uniform and therefore distortion of the electric field at the convex corner of a microfeature is prevented. The most vertical etch profile is obtained when the cage is used in fluorocarbon plasmas, where faceting is further suppressed due to the decrease in the chemical sputtering yield and the increase in the radical/ion flux on the substrate.

  14. Ion-beam etching of ramps in thin film heterostructures

    International Nuclear Information System (INIS)

    Mozhaev, P. B.; Mozhaeva, Ju. E.; Komissinskii, P. V.

    2002-01-01

    Ion-beam patterning of thin films and heterostructures is one of the most common processes of fabrication of thin film devices and structures. 'Directed' nature of ion-beam etching provides a possibility to form certain profiles on the films surface, like shallow ramps, when etching is performed at some inclination angle. A simple geometrical model is presented, describing the formation of a ramp as a shadow of the mask on the film surface. Good agreement with the experiment can be obtained if the mask etching is taken into account. The etching at the opposite direction ('high-angle etching') also can be satisfactory described by the model. The profile of the slope - positive or negative curvature, pits near the end of the ramp - is discussed as a function of the etch rate dependence on the incidence angle. Such etch rate dependences for some often used materials were measured. An area of instability of the resulting ramp shape is found for the 'high-angle etching'. The model is compared with the experimental data reported by other groups. Finally ion-beam etching of a rotating sample at non-normal incidence is discussed, the results are compared with experimental data. (Authors)

  15. Modeling of the angular dependence of plasma etching

    International Nuclear Information System (INIS)

    Guo Wei; Sawin, Herbert H.

    2009-01-01

    An understanding of the angular dependence of etching yield is essential to investigate the origins of sidewall roughness during plasma etching. In this article the angular dependence of polysilicon etching in Cl 2 plasma was modeled as a combination of individual angular-dependent etching yields for ion-initiated processes including physical sputtering, ion-induced etching, vacancy generation, and removal. The modeled etching yield exhibited a maximum at ∼60 degree sign off-normal ion angle at low flux ratio, indicative of physical sputtering. It transformed to the angular dependence of ion-induced etching with the increase in the neutral-to-ion flux ratio. Good agreement between the modeling and the experiments was achieved for various flux ratios and ion energies. The variation of etching yield in response to the ion angle was incorporated in the three-dimensional profile simulation and qualitative agreement was obtained. The surface composition was calculated and compared to x-ray photoelectron spectroscopy (XPS) analysis. The modeling indicated a Cl areal density of 3x10 15 atoms/cm 2 on the surface that is close to the value determined by the XPS analysis. The response of Cl fraction to ion energy and flux ratio was modeled and correlated with the etching yields. The complete mixing-layer kinetics model with the angular dependence effect will be used for quantitative surface roughening analysis using a profile simulator in future work.

  16. Micropatterning on cylindrical surfaces via electrochemical etching using laser masking

    International Nuclear Information System (INIS)

    Cho, Chull Hee; Shin, Hong Shik; Chu, Chong Nam

    2014-01-01

    Highlights: • Various micropatterns were fabricated on the cylindrical surface of a stainless steel shaft. • Selective electrochemical dissolution was achieved via a series process of laser masking and electrochemical etching. • Laser masking characteristics on the non-planar surface were investigated. • A uniform mask layer was formed on the cylindrical surface via synchronized laser line scanning with a rotary system. • The characteristics of electrochemical etching on the non-planar surface were investigated. - Abstract: This paper proposes a method of selective electrochemical dissolution on the cylindrical surfaces of stainless steel shafts. Selective electrochemical dissolution was achieved via electrochemical etching using laser masking. A micropatterned recast layer was formed on the surface via ytterbium-doped pulsed fiber laser irradiation. The micropatterned recast layer could be used as a mask layer during the electrochemical etching process. Laser masking condition to form adequate mask layer on the planar surface for etching cannot be used directly on the non-planar surface. Laser masking condition changes depending on the morphological surface. The laser masking characteristics were investigated in order to form a uniform mask layer on the cylindrical surface. To minimize factors causing non-uniformity in the mask layer on the cylindrical surface, synchronized laser line scanning with a rotary system was applied during the laser masking process. Electrochemical etching characteristics were also investigated to achieve deeper etched depth, without collapsing the recast layer. Consequently, through a series process of laser masking and electrochemical etching, various micropatternings were successfully performed on the cylindrical surfaces

  17. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    International Nuclear Information System (INIS)

    Angermann, Heike

    2014-01-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D it (E), and density D it,min of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly based on

  18. A novel technique for die-level post-processing of released optical MEMS

    International Nuclear Information System (INIS)

    Elsayed, Mohannad Y; Beaulieu, Philippe-Olivier; Briere, Jonathan; Ménard, Michaël; Nabki, Frederic

    2016-01-01

    This work presents a novel die-level post-processing technique for dies including released movable structures. The procedure was applied to microelectromechanical systems (MEMS) chips that were fabricated in a commercial process, SOIMUMPs from MEMSCAP. It allows the performance of a clean DRIE etch of sidewalls on the diced chips enabling the optical testing of the pre-released MEMS mirrors through the chip edges. The etched patterns are defined by photolithography using photoresist spray coating. The photoresist thickness is tuned to create photoresist bridges over the pre-released gaps, protecting the released structures during subsequent wet processing steps. Then, the chips are subject to a sequence of wet and dry etching steps prior to dry photoresist removal in O 2 plasma. Processed micromirrors were tested and found to rotate similarly to devices without processing, demonstrating that the post-processing procedure does not affect the mechanical performance of the devices significantly. (technical note)

  19. Removal of organic pollutants in tannery wastewater from wet-blue fur processing by integrated Anoxic/Oxic (A/O) and Fenton: Process optimization

    DEFF Research Database (Denmark)

    Wang, Yong; Li, Weiguang; Angelidaki, Irini

    2014-01-01

    Treatment of tannery wastewater has been a challenge in remediation of aquatic environment in developing countries. Removal of organic pollutants in tannery wastewater from wet-blue fur processing was studied using integrated processes of Anoxic/Oxic and Fenton. Analysis of COD composition based...... 80%. In the subsequent Fenton oxidation, effects of initial pH and H2O2 dose on COD removal were investigated, and response surface methodology was adopted to obtain the optimal conditions as initial pH of 4.0, H2O2 dose of 14.0mM, H2O2:Fe2+ molar ratio of 10.6, and reaction time of 3h to achieve...... the highest COD removal of 55.87%. GC-MS analysis was carried out to observe the change of organic composition during Fenton oxidation, and most of the residual organic pollutants resistant to Fenton treatment belonged to organosilanes and saturated alkanes. This study will provide useful information...

  20. Physical and chemical processes for the generation of 1-μm-structures

    International Nuclear Information System (INIS)

    Mader, L.

    1979-01-01

    The following processes for the realization of fine structures in isolator and metal layers on silicon wafers have been studied: Wet chemical etching of silicon dioxide and aluminum layers; plasma etching of polysilicon layers; ion beam etching of silicon dioxide and polysilicon layers, lift-off technique for metal pattern generation. Test structures and functioning integrated circuits (memory cells, CCDs) with minimum dimensions of 1.5 μm were realized using these methods of pattern generation. (orig.) 891 ORU/orig. 892 MB [de

  1. Anisotropic etching of silicon for application in micro machine using plasma of SF6/CH4/O2/Ar and SF6/CF4/O2/Ar

    International Nuclear Information System (INIS)

    Reyes B, C.; Moshkalyov, S.A.; Swart, J.W.

    2004-01-01

    We investigated the reactive ion etching of silicon using SF 6 /CH 4 (CF 4 )/O 2 /Ar gas mixtures containing fluorine for MEMS applications. Etch rates and anisotropy of etch profiles were examined as a function of gas composition, material of electrode, and RF power. Etch depths were measured using a profilometers, and etch profiles were analyzed by scanning electron microscope. As a mask material, an aluminium film deposited by evaporation, was used. High anisotropy of etching of 0.95 was achieved at etch depths up to 20-30 micrometers and etch rates of approximately 0.3-0.6 μm/min. Highly anisotropic etching is based on a mechanism that enhance the ion bombarding and protects the sidewalls due to polymerization and/or oxidation mechanisms in order to avoid the lateral etch. However, under the anisotropic etching conditions, considerable damages of the etched surfaces (roughness formation), were observed. After etching experiments, wet / dry cleaning procedures were applied to remove surface residues resulting from the reactive ion etching and to improve the etched surface morphology. (Author)

  2. Commercial development of a new process of uraniferous ore sintering by pelletizing before dump leaching (wet process) application to a very clayey ore of Nord-Aquitaine

    International Nuclear Information System (INIS)

    Videau, G.; Roche, M.

    1990-01-01

    Much of the French uranium ore contains clay of sedimentary origin or derived from the alteration of rocks of the granite type. During a dump leaching operation by a wet process, these clays reduce the percolation rates and sometimes the percolation rates are so low that the very essence of the dump leaching operation can be called in question. This problem arises particularly for the treatment of the ore of Nord-Aquitaine. The results of tests, carried out at the SEPA in Bessines, have shown that after pelletizing clayey ores with sodium silicate in the presence of sulphuric acid for the polymerization of the silicate, the percolation rates were much increased. This new method was successfully applied, from a laboratory column to a pilot dump of 500 tonnes for the very clayey ore of Nord-Aquitaine. This ore of low grade (approx. 1000 ppm of U) seems to be difficult to upgrade by any other method of treatment in the present economic context [fr

  3. Etching process optimization using NH{sub 4}Cl aqueous solution to texture ZnO:Al films for efficient light trapping in flexible thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, S., E-mail: susanamaria.fernandez@ciemat.es [CIEMAT, Departamento de Energias Renovables, Madrid (Spain); Abril, O. de [ISOM and Departamento de Fisica Aplicada, Escuela Tecnica Superior de Ingenieros de Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Naranjo, F.B. [Grupo de Ingenieria Fotonica, Universidad de Alcala, Departamento de Electronica, Alcala de Henares, Madrid (Spain); Gandia, J.J. [CIEMAT, Departamento de Energias Renovables, Madrid (Spain)

    2012-04-02

    0.5 {mu}m-thick aluminum-doped zinc oxide (ZnO:Al) films were deposited at 100 Degree-Sign C on polyethylene terephthalate substrates by Radio Frequency magnetron sputtering. The as-deposited films were compact and dense, showing grain sizes of 32.0 {+-} 6.4 nm and resistivities of (8.5 {+-} 0.7) Multiplication-Sign 10{sup -4} {Omega} cm. The average transmittance in the visible wavelength range of the structure ZnO:Al/PET was around 77%. The capability of a novel two-step chemical etching using diluted NH{sub 4}Cl aqueous solution to achieve efficient textured surfaces for light trapping was analyzed. The results indicated that both the aqueous solution and the etching method resulted appropriated to obtain etched surfaces with a surface roughness of 32 {+-} 5 nm, haze factors at 500 nm of 9% and light scattering at angles up to 50 Degree-Sign . To validate all these results, a commercially ITO coated PET substrate was used for comparison.

  4. Pulse plating of Pt on n-GaAs (1 0 0) wafer surfaces: Synchrotron induced photoelectron spectroscopy and XPS of wet fabrication processes

    International Nuclear Information System (INIS)

    Ensling, D.; Hunger, R.; Kraft, D.; Mayer, Th.; Jaegermann, W.; Rodriguez-Girones, M.; Ichizli, V.; Hartnagel, H.L.

    2003-01-01

    Preparation steps of Pt/n-GaAs Schottky contacts as applied in the fabrication process of varactor diode arrays for THz applications are analysed by photoelectron spectroscopy. Pulsed cathodic deposition of Pt onto GaAs (1 0 0) wafer surfaces from acidic solution has been studied by core level photoelectron spectroscopy using different excitation energies. A laboratory AlKα source as well as synchrotron radiation of hν=130 and 645 eV at BESSY was used. Chemical analyses and semiquantitative estimates of layer thickness are given for the natural oxide of an untreated wafer surface, a surface conditioning NH 3 etching step, and stepwise pulse plating of Pt. The structural arrangement of the detected species and interface potentials are considered

  5. Technique for etching monolayer and multilayer materials

    Science.gov (United States)

    Bouet, Nathalie C. D.; Conley, Raymond P.; Divan, Ralu; Macrander, Albert

    2015-10-06

    A process is disclosed for sectioning by etching of monolayers and multilayers using an RIE technique with fluorine-based chemistry. In one embodiment, the process uses Reactive Ion Etching (RIE) alone or in combination with Inductively Coupled Plasma (ICP) using fluorine-based chemistry alone and using sufficient power to provide high ion energy to increase the etching rate and to obtain deeper anisotropic etching. In a second embodiment, a process is provided for sectioning of WSi.sub.2/Si multilayers using RIE in combination with ICP using a combination of fluorine-based and chlorine-based chemistries and using RF power and ICP power. According to the second embodiment, a high level of vertical anisotropy is achieved by a ratio of three gases; namely, CHF.sub.3, Cl.sub.2, and O.sub.2 with RF and ICP. Additionally, in conjunction with the second embodiment, a passivation layer can be formed on the surface of the multilayer which aids in anisotropic profile generation.

  6. Preparation of zinc ferrite nano powders by high energy wet-milling method and investigation of Crystallites size variation during this process

    International Nuclear Information System (INIS)

    Masoudi, H.; Aftabi, A.; Mozafari, M.; Amighian, J.

    2007-01-01

    In this research work ZnFe 2 O 4 nano powders were prepared by high-energy wet-milling process, using metallic Fe and Zn powders. The process was investigated by XRD technique. 10% of the zinc ferrite was formed after 10 h milling. The as-milled sample was annealed at 500, 550 and 600 d egree C . Ultimately a single sample was obtained at 600 d egree C . Using sherrer's formula, the mean crystallite size of the as-milled and annealed powders were calculated. These were in the range of 17.9 to 20.4 nm.

  7. Study on Oil Pressure Characteristics and Trajectory Tracking Control in Shift Process of Wet-Clutch for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Junqiu Li

    2016-01-01

    Full Text Available Accurate control of oil pressure of wet-clutch is of great importance for improving shift quality. Based on dynamic models of two-gear planetary transmission and hydraulic control system, a trajectory tracking model of oil pressure was built by sliding mode control method. An experiment was designed to verify the validity of hydraulic control system, through which the relationship between duty cycle of on-off valve and oil pressure of clutch was determined. The tracking effect was analyzed by simulation. Results showed that oil pressure could follow well the optimal trajectory and the shift quality was effectively improved.

  8. Optimization of permanganic etching of polyethylenes for scanning electron microscopy

    International Nuclear Information System (INIS)

    Naylor, K.L.; Phillips, P.J.

    1983-01-01

    The permanganic etching technique has been studied as a function of time, temperature, and concentration for a series of polyethylenes. Kinetic studies show that a film of reaction products builds up on the surface, impeding further etching, an effect which is greatest for the lowest-crystallinity polymers. SEM studies combined with EDS show that the film contains sulfur, potassium and some manganese. An artifact is produced by the etching process which is impossible to remove by washing procedures if certain limits of time, temperature, and concentration are exceeded. For lower-crystallinity polyethylenes multiple etching and washing steps were required for optimal resolution. Plastic deformation during specimen preparation, whether from scratches or freeze fracturing, enhances artifact formation. When appropriate procedures are used, virtually artifact-free surfaces can be produced allowing a combination of permanganic etching and scanning electron microscopy to give a rapid method for detailed morphological characterization of bulk specimens

  9. Effects of mask imperfections on InP etching profiles

    International Nuclear Information System (INIS)

    Huo, D.T.C.; Yan, M.F.; Wynn, J.D.; Wilt, D.P.

    1990-01-01

    The authors have demonstrated that the quality of etch masks has a significant effect on the InP etching profiles. In particular, the authors have shown that mask imperfections can cause defective etching profiles, such as vertical sidewalls and extra mask undercutting in InP. The authors also discovered that the geometry of these defective profiles is determined by the orientation of the substrate relative to the direction of the mask imperfections. Along a left-angle 110 right-angle line mask defect, the downward etching process changes the left-angle 110 right-angle v-grooves to vertical sidewalls without extra undercutting. For v-grooves aligned along the left-angle 110 right-angle direction, defects on the mask give a significant extra undercutting without changing the etching profile

  10. Particle precipitation in connection with KOH etching of silicon

    DEFF Research Database (Denmark)

    Nielsen, Christian Bergenstof; Christensen, Carsten; Pedersen, Casper

    2004-01-01

    This paper considers the precipitation of iron oxide particles in connection with the KOH etching of cavities in silicon wafers. The findings presented in this paper suggest that the source to the particles is the KOH pellets used for making the etching solution. Experiments show that the precipi......This paper considers the precipitation of iron oxide particles in connection with the KOH etching of cavities in silicon wafers. The findings presented in this paper suggest that the source to the particles is the KOH pellets used for making the etching solution. Experiments show...... that the precipitation is independent of KOH etching time, but that the amount of deposited material varies with dopant type and dopant concentration. The experiments also suggest that the precipitation occurs when the silicon wafers are removed from the KOH etching solution and not during the etching procedure. When...... not removed, the iron oxide particles cause etch pits on the Si surface when later processed and exposed to phosphoric acid. It has been found that the particles can be removed in an HCl solution, but not completely in an H2SO4- H2O2 solution. The paper discusses the involved precipitation mechanism in terms...

  11. High temperature reactive ion etching of iridium thin films with aluminum mask in CF4/O2/Ar plasma

    Directory of Open Access Journals (Sweden)

    Chia-Pin Yeh

    2016-08-01

    Full Text Available Reactive ion etching (RIE technology for iridium with CF4/O2/Ar gas mixtures and aluminum mask at high temperatures up to 350 °C was developed. The influence of various process parameters such as gas mixing ratio and substrate temperature on the etch rate was studied in order to find optimal process conditions. The surface of the samples after etching was found to be clean under SEM inspection. It was also shown that the etch rate of iridium could be enhanced at higher process temperature and, at the same time, very high etching selectivity between aluminum etching mask and iridium could be achieved.

  12. Dry etching technologies for the advanced binary film

    Science.gov (United States)

    Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Yoshimori, Tomoaki; Azumano, Hidehito; Muto, Makoto; Nonaka, Mikio

    2011-11-01

    ABF (Advanced Binary Film) developed by Hoya as a photomask for 32 (nm) and larger specifications provides excellent resistance to both mask cleaning and 193 (nm) excimer laser and thereby helps extend the lifetime of the mask itself compared to conventional photomasks and consequently reduces the semiconductor manufacturing cost [1,2,3]. Because ABF uses Ta-based films, which are different from Cr film or MoSi films commonly used for photomask, a new process is required for its etching technology. A patterning technology for ABF was established to perform the dry etching process for Ta-based films by using the knowledge gained from absorption layer etching for EUV mask that required the same Ta-film etching process [4]. Using the mask etching system ARES, which is manufactured by Shibaura Mechatronics, and its optimized etching process, a favorable CD (Critical Dimension) uniformity, a CD linearity and other etching characteristics were obtained in ABF patterning. Those results are reported here.

  13. A novel surface micromachining process to fabricate AlN unimorph suspensions and its application for RF resonators

    NARCIS (Netherlands)

    Saravanan, S.; Saravanan, S.; Berenschot, Johan W.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

    2006-01-01

    A novel surface micromachining process is reported for aluminum nitride (AlN) thin films to fabricate piezoelectric unimorph suspension devices for micro actuator applications. Wet anisotropic etching of AlN thin film is used with a Cr metal mask layer in the microfabrication process. Tetra methyl

  14. Nanostructured silicon via metal assisted catalyzed etch (MACE): chemistry fundamentals and pattern engineering

    Science.gov (United States)

    Toor, Fatima; Miller, Jeffrey B.; Davidson, Lauren M.; Nichols, Logan; Duan, Wenqi; Jura, Michael P.; Yim, Joanne; Forziati, Joanne; Black, Marcie R.

    2016-10-01

    There are a range of different methods to generate a nanostructured surface on silicon (Si) but the most cost effective and optically interesting is the metal assisted wet chemical etching (MACE) (Koynov et al 2006 Appl. Phys. Lett. 88 203107). MACE of Si is a controllable, room-temperature wet-chemical technique that uses a thin layer of metal to etch the surface of Si, leaving behind various nano- and micro-scale surface features or ‘black silicon’. MACE-fabricated nanowires (NWs) provide improved antireflection and light trapping functionality (Toor et al 2016 Nanoscale 8 15448-66) compared with the traditional ‘iso-texturing’ (Campbell and Green 1987 J. Appl. Phys. 62 243-9). The resulting lower reflection and improved light trapping can lead to higher short circuit currents in NW solar cells (Toor et al 2011 Appl. Phys. Lett. 99 103501). In addition, NW cells can have higher fill factors and voltages than traditionally processed cells, thus leading to increased solar cell efficiencies (Cabrera et al 2013 IEEE J. Photovolt. 3 102-7). MACE NW processing also has synergy with next generation Si solar cell designs, such as thin epitaxial-Si and passivated emitter rear contact (Toor et al 2016 Nanoscale 8 15448-66). While several companies have begun manufacturing black Si, and many more are researching these techniques, much of the work has not been published in traditional journals and is publicly available only through conference proceedings and patent publications, which makes learning the field challenging. There have been three specialized review articles published recently on certain aspects of MACE or black Si, but do not present a full review that would benefit the industry (Liu et al 2014 Energy Environ. Sci. 7 3223-63 Yusufoglu et al 2015 IEEE J. Photovolt. 5 320-8 Huang et al 2011 Adv. Mater. 23 285-308). In this feature article, we review the chemistry of MACE and explore how changing parameters in the wet etch process effects the resulting

  15. Dry Etching Characteristics of Amorphous Indium-Gallium-Zinc-Oxide Thin Films

    International Nuclear Information System (INIS)

    Zheng Yanbin; Li Guang; Wang Wenlong; Li Xiuchang; Jiang Zhigang

    2012-01-01

    Amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) backplane technology is the best candidate for flat panel displays (FPDs). In this paper, a-IGZO TFT structures are described. The effects of etch parameters (rf power, dc-bias voltage and gas pressure) on the etch rate and etch profile are discussed. Three kinds of gas mixtures are compared in the dry etching process of a-IGZO thin films. Lastly, three problems are pointed out that need to be addressed in the dry etching process of a-IGZO TFTs. (plasma technology)

  16. Study of the pore-opening process of latent tracks of light low-energetic ions in CR-39 by means of electrolytic etching

    International Nuclear Information System (INIS)

    Oganesyan, V.R.

    2005-01-01

    In this thesis the irradiation of 10-μm thick CR-39 foils with 5.5-7 MeV protons and of 22-400 μm thick CR-39 foils with 4.85-28 MeV α-particles with subsequent determination of the etching velocities is described. By means of scanning electron microscopy (SEM) the pore shape after irradiation was determined. From the analysis of the track profiles by means of SEM the track-nucleus diameter for 28 MeV α particles was determined to 1.4 nm. (HSI)

  17. Development of deep silicon plasma etching for 3D integration technology

    Directory of Open Access Journals (Sweden)

    Golishnikov А. А.

    2014-02-01

    Full Text Available Plasma etch process for thought-silicon via (TSV formation is one of the most important technological operations in the field of metal connections creation between stacked circuits in 3D assemble technology. TSV formation strongly depends on parameters such as Si-wafer thickness, aspect ratio, type of metallization material, etc. The authors investigate deep silicon plasma etch process for formation of TSV with controllable profile. The influence of process parameters on plasma etch rate, silicon etch selectivity to photoresist and the structure profile are researched in this paper. Technology with etch and passivation steps alternation was used as a method of deep silicon plasma etching. Experimental tool «Platrane-100» with high-density plasma reactor based on high-frequency ion source with transformer coupled plasma was used for deep silicon plasma etching. As actuation gases for deep silicon etching were chosen the following gases: SF6 was used for the etch stage and CHF3 was applied on the polymerization stage. As a result of research, the deep plasma etch process has been developed with the following parameters: silicon etch rate 6 µm/min, selectivity to photoresist 60 and structure profile 90±2°. This process provides formation of TSV 370 µm deep and about 120 µm in diameter.

  18. Dry etching of ITO by magnetic pole enhanced inductively coupled plasma for display and biosensing devices

    Energy Technology Data Exchange (ETDEWEB)

    Meziani, T. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Vatican City State, Holy See,) (Italy)]. E-mail: tarik.meziani@jrc.it; Colpo, P. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy)]. E-mail: pascal.colpo@jrc.it; Lambertini, V. [Centro Ricerche Fiat, Strada Torino 50, 10043 Orbassano (TO) (Italy); Ceccone, G. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy); Rossi, F. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy)

    2006-03-15

    The dry etching of indium tin oxide (ITO) layers deposited on glass substrates was investigated in a high density inductively coupled plasma (ICP) source. This innovative low pressure plasma source uses a magnetic core in order to concentrate the electromagnetic energy on the plasma and thus provides for higher plasma density and better uniformity. Different gas mixtures were tested containing mainly hydrogen, argon and methane. In Ar/H{sub 2} mixtures and at constant bias voltage (-100 V), the etch rate shows a linear dependence with input power varying the same way as the ion density, which confirms the hypothesis that the etching process is mainly physical. In CH{sub 4}/H{sub 2} mixtures, the etch rate goes through a maximum for 10% CH{sub 4} indicating a participation of the radicals to the etching process. However, the etch rate remains quite low with this type of gas mixture (around 10 nm/min) because the etching mechanism appears to be competing with a deposition process. With CH{sub 4}/Ar mixtures, a similar feature appeared but the etch rate was much higher, reaching 130 nm/min at 10% of CH{sub 4} in Ar. The increase in etch rate with the addition of a small quantity of methane indicates that the physical etching process is enhanced by a chemical mechanism. The etching process was monitored by optical emission spectroscopy that appeared to be a valuable tool for endpoint detection.

  19. Evaluation of Pentafluoroethane and 1,1-Difluoroethane for a Dielectric Etch Application in an Inductively Coupled Plasma Etch Tool

    Science.gov (United States)

    Karecki, Simon; Chatterjee, Ritwik; Pruette, Laura; Reif, Rafael; Sparks, Terry; Beu, Laurie; Vartanian, Victor

    2000-07-01

    In this work, a combination of two hydrofluorocarbon compounds, pentafluoroethane (FC-125, C2HF5) and 1,1-difluoroethane (FC-152a, CF2H-CH3), was evaluated as a potential replacement for perfluorocompounds in dielectric etch applications. A high aspect ratio oxide via etch was used as the test vehicle for this study, which was conducted in a commercial inductively coupled high density plasma etch tool. Both process and emissions data were collected and compared to those provided by a process utilizing a standard perfluorinated etch chemistry (C2F6). Global warming (CF4, C2F6, CHF3) and hygroscopic gas (HF, SiF4) emissions were characterized using Fourier transform infrared (FTIR) spectroscopy. FC-125/FC-152a was found to produce significant reductions in global warming emissions, on the order of 68 to 76% relative to the reference process. Although etch stopping, caused by a high degree of polymer deposition inside the etched features, was observed, process data otherwise appeared promising for an initial study, with good resist selectivity and etch rates being achieved.

  20. Designer-Wet Micromodels for Studying Potential Changes in Wettability during Microbial Enhanced Oil Recovery

    Science.gov (United States)

    Armstrong, R. T.; Wildenschild, D.

    2010-12-01

    Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary recovery of oil. Some bacteria can facilitate the mobilization of oil through the production of amphiphilic compounds called biosurfactants that reduce the interfacial tension (IFT) between immiscible phases. Additionally, most bacteria have an inclination to colonize surfaces and form biofilm, which can change a reservoir's wetting properties or clog preferential flow paths. Herein, we aim to understand changes in wettability during MEOR under mixed wettability conditions within silicon etched micromodels and to identify the type of oil field (i.e. based on wettability) in which MEOR is likely to be most profitable. To quantify porous media wettability, macro-scale indexes (obtained with techniques such as the Carter or Amott methods) are used regularly. However, these measurements lack the capability for characterization of changes in wettability during MEOR treatment, and only provide macro-scale information. In an effort to understand micro-scale temporal and spatial changes in wettability we measure interfacial curvature from stereo microscope images using level set methods. Curvature, from the perspective of the oil phase, is positive for a concave interface (i.e. water-wet surface) and negative for a convex interface (i.e. oil-wet surface). Thus, shifts in the radius of curvature distribution (i.e. from positive to negative or conversely) are indicative of wettability changes. Both curvature distributions using level-set methods and the Carter method are used to characterize wettability before and after microbial treatment. In preliminary studies aimed at understanding wettability changes due to microbial surface interactions by Bacillus mojavensis JF-2, oil droplets were placed on glass slides suspended in growth media and the resulting contact angle was measured over time. Results showed that a water-wet surface will become more water wet as JF-2 accumulated in

  1. Periodically pulsed wet annealing approach for low-temperature processable amorphous InGaZnO thin film transistors with high electrical performance and ultrathin thickness

    OpenAIRE

    Kim, Ye Kyun; Ahn, Cheol Hyoun; Yun, Myeong Gu; Cho, Sung Woon; Kang, Won Jun; Cho, Hyung Koun

    2016-01-01

    In this paper, a simple and controllable ?wet pulse annealing? technique for the fabrication of flexible amorphous InGaZnO thin film transistors (a-IGZO TFTs) processed at low temperature (150??C) by using scalable vacuum deposition is proposed. This method entailed the quick injection of water vapor for 0.1?s and purge treatment in dry ambient in one cycle; the supply content of water vapor was simply controlled by the number of pulse repetitions. The electrical transport characteristics rev...

  2. High-density carbon nanotube wet-laid buckypapers with enhanced strength and conductivity using a high-pressure homogenization process

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jun; Jang, Si Hoon; Park, No Hyung; Jeong, Won Young; Lim, Dae Young [Human and Culture Convergence Technology Group, Korea Institute of Industrial Technology (KITECH), Ansan (Korea, Republic of); Oh, Jun Young; Yang, Seung Jae [Dept. of Applied Organic Materials Engineering, Inha University, Incheon (Korea, Republic of)

    2017-04-15

    In this work, we prepared homogeneously dispersed carbon nanotubes in water using a high-pressure homogenizer, while high-density carbon nanotube buckypapers were prepared by wet-laid process. The strength and conductivity of the buckypaper were increased dramatically after the high-pressure homogenization because of the increased density and uniformity of the paper. In addition, the buckypapers containing various additives and treated with SOCl{sub 2} exhibited further increase of strength and conductivity resulting from the binding and the p-type doping effect. The buckypapers with high electrical conductivity exhibited superior electromagnetic interference shielding effectiveness that could be applied for structural shielding materials.

  3. Optical diagnostics for plasma etching

    NARCIS (Netherlands)

    Bisschops, T.H.J.; Kroesen, G.M.W.; Veldhuizen, van E.M.; de Zeeuw, C.J.H.; Timmermans, C.J.

    1985-01-01

    Several optical diagnostics were used to det. plasma properties and etch rates in an single wafer etch reactor. Results of UV-visible spectroscopy and IR absorption spectroscopy, indicating different mol. species and their densities are presented. The construction of an interferometer to det. the

  4. Cradle-to-gate life cycle assessment of the dry etching step in the manufacturing of photovoltaic cells

    Directory of Open Access Journals (Sweden)

    Otto Andersen

    2014-11-01

    Full Text Available A new photovoltaic silicon crystalline solar cell dry chemical etching process (DCEP is developed. It is an alternative to the current State-of-the-Art (SoA wet chemical etching process (WCEP, associated with relatively large environmental loadings in the form of high water consumption and emissions of greenhouse gases with high Global Warming Potential (GWP. In order to compare the environmental impacts of DCEP to the corresponding impacts from WCEP, a comparative attributional life cycle assessment (LCA is conducted. From the LCA it can be concluded that the DCEP will lead to 86% reduction in water consumption compared to WCEP (acidic, and 89% reduction compared to WCEP (alkaline. The emissions of greenhouse gases, as expressed by the GWP100 indicator of the etching step, are also reduced with 63% and 20% respectively, when compared with current SoA acidic and alkaline WCEP. The toxicity impacts are also assessed to be lower for the DCEP compared to WCEP technologies, although the uncertainty is relatively high for the applied toxicity indicators. All in all, DCEP can reduce the CO2eq emissions of solar photovoltaic systems production by 5-10%.

  5. Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

    Energy Technology Data Exchange (ETDEWEB)

    Grégoire, Geneviève, E-mail: genevieve.gregoire@univ-tlse3.fr [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062 Toulouse (France); Sharrock, Patrick, E-mail: patrick.sharrock@gmail.com [CNRS UMR 5302, University Toulouse III, Mines-Albi, 81013 Albi (France); Prigent, Yann, E-mail: prigent@chimie.ups-tlse.fr [Institut de Chimie de Toulouse (ICT) – FR 2599, Faculté des Sciences et de l' Ingénierie, University Toulouse III, 31062 Toulouse (France)

    2016-09-01

    A universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 °C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat.

  6. Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

    International Nuclear Information System (INIS)

    Grégoire, Geneviève; Sharrock, Patrick; Prigent, Yann

    2016-01-01

    A universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 °C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat.

  7. Nanorods on surface of GaN-based thin-film LEDs deposited by post-annealing after photo-assisted chemical etching

    OpenAIRE

    Chen, Lung-Chien; Lin, Wun-Wei; Liu, Te-Yu

    2017-01-01

    This study investigates the optoelectronic characteristics of gallium nitride (GaN)-based thin-film light-emitting diodes (TF-LEDs) that are formed by a two-step transfer process that involves wet etching and post-annealing. In the two-step transfer process, GaN LEDs were stripped from sapphire substrates by the laser lift-off (LLO) method using a KrF laser and then transferred onto ceramic substrates. Ga-K nanorods were formed on the surface of the GaN-based TF-LEDs following photo-assisted ...

  8. Periodically pulsed wet annealing approach for low-temperature processable amorphous InGaZnO thin film transistors with high electrical performance and ultrathin thickness.

    Science.gov (United States)

    Kim, Ye Kyun; Ahn, Cheol Hyoun; Yun, Myeong Gu; Cho, Sung Woon; Kang, Won Jun; Cho, Hyung Koun

    2016-05-20

    In this paper, a simple and controllable "wet pulse annealing" technique for the fabrication of flexible amorphous InGaZnO thin film transistors (a-IGZO TFTs) processed at low temperature (150 °C) by using scalable vacuum deposition is proposed. This method entailed the quick injection of water vapor for 0.1 s and purge treatment in dry ambient in one cycle; the supply content of water vapor was simply controlled by the number of pulse repetitions. The electrical transport characteristics revealed a remarkable performance of the a-IGZO TFTs prepared at the maximum process temperature of 150 °C (field-effect mobility of 13.3 cm(2) V(-1) s(-1); Ion/Ioff ratio ≈ 10(8); reduced I-V hysteresis), comparable to that of a-IGZO TFTs annealed at 350 °C in dry ambient. Upon analysis of the angle-resolved x-ray photoelectron spectroscopy, the good performance was attributed to the effective suppression of the formation of hydroxide and oxygen-related defects. Finally, by using the wet pulse annealing process, we fabricated, on a plastic substrate, an ultrathin flexible a-IGZO TFT with good electrical and bending performances.

  9. Periodically pulsed wet annealing approach for low-temperature processable amorphous InGaZnO thin film transistors with high electrical performance and ultrathin thickness

    Science.gov (United States)

    Kim, Ye Kyun; Ahn, Cheol Hyoun; Yun, Myeong Gu; Cho, Sung Woon; Kang, Won Jun; Cho, Hyung Koun

    2016-01-01

    In this paper, a simple and controllable “wet pulse annealing” technique for the fabrication of flexible amorphous InGaZnO thin film transistors (a-IGZO TFTs) processed at low temperature (150 °C) by using scalable vacuum deposition is proposed. This method entailed the quick injection of water vapor for 0.1 s and purge treatment in dry ambient in one cycle; the supply content of water vapor was simply controlled by the number of pulse repetitions. The electrical transport characteristics revealed a remarkable performance of the a-IGZO TFTs prepared at the maximum process temperature of 150 °C (field-effect mobility of 13.3 cm2 V−1 s−1; Ion/Ioff ratio ≈ 108; reduced I-V hysteresis), comparable to that of a-IGZO TFTs annealed at 350 °C in dry ambient. Upon analysis of the angle-resolved x-ray photoelectron spectroscopy, the good performance was attributed to the effective suppression of the formation of hydroxide and oxygen-related defects. Finally, by using the wet pulse annealing process, we fabricated, on a plastic substrate, an ultrathin flexible a-IGZO TFT with good electrical and bending performances. PMID:27198067

  10. The effect of a zinc–tin-oxide layer used as an etch-stopper layer on the bias stress stability of solution-processed indium–gallium–zinc-oxide thin-film transistors

    International Nuclear Information System (INIS)

    Kim, Chul Ho; Rim, You Seung; Kim, Hyun Jae

    2014-01-01

    We investigated the bias stress stability of solution-processed indium–gallium–zinc-oxide thin-film transistors (IGZO TFTs) using zinc–tin-oxide (ZTO) as the etch-stopper layer, the so-called dual-active-layered ZTO/IGZO TFT (DALZI TFT). The DALZI TFT can use a low-cost back-channel-etch structure because of the high chemical stability of the upper ZTO layer. The DALZI TFT exhibited only a threshold voltage shift of −1.86 V under negative bias illumination stress (NBIS) conditions (stress time = 1000 s), while the unpassivated IGZO TFT suffered from a threshold voltage shift of −19.59 V under NBIS conditions (stress time = 1000 s). The superior bias stress stability of the DALZI TFT is attributed not only to the densification effect by the multi-stacking process but also to the lower sensitivity to ambient gases (e.g., oxygen and water vapour) due to the low oxygen vacancy in the upper ZTO layer. (paper)

  11. Single-crystal silicon trench etching for fabrication of highly integrated circuits

    Science.gov (United States)

    Engelhardt, Manfred

    1991-03-01

    The development of single crystal silicon trench etching for fabrication of memory cells in 4 16 and 64Mbit DRAMs is reviewed in this paper. A variety of both etch tools and process gases used for the process development is discussed since both equipment and etch chemistry had to be improved and changed respectively to meet the increasing requirements for high fidelity pattern transfer with increasing degree of integration. In additon to DRAM cell structures etch results for deep trench isolation in advanced bipolar ICs and ASICs are presented for these applications grooves were etched into silicon through a highly doped buried layer and at the borderline of adjacent p- and n-well areas respectively. Shallow trench etching of large and small exposed areas with identical etch rates is presented as an approach to replace standard LOCOS isolation by an advanced isolation technique. The etch profiles were investigated with SEM TEM and AES to get information on contathination and damage levels and on the mechanism leading to anisotropy in the dry etch process. Thermal wave measurements were performed on processed single crystal silicon substrates for a fast evaluation of the process with respect to plasma-induced substrate degradation. This useful technique allows an optimization ofthe etch process regarding high electrical performance of the fully processed memory chip. The benefits of the use of magnetic fields for the development of innovative single crystal silicon dry

  12. Laser etching of polymer masked leadframes

    Science.gov (United States)

    Ho, C. K.; Man, H. C.; Yue, T. M.; Yuen, C. W.

    1997-02-01

    A typical electroplating production line for the deposition of silver pattern on copper leadframes in the semiconductor industry involves twenty to twenty five steps of cleaning, pickling, plating, stripping etc. This complex production process occupies large floor space and has also a number of problems such as difficulty in the production of rubber masks and alignment, generation of toxic fumes, high cost of water consumption and sometimes uncertainty on the cleanliness of the surfaces to be plated. A novel laser patterning process is proposed in this paper which can replace many steps in the existing electroplating line. The proposed process involves the application of high speed laser etching techniques on leadframes which were protected with polymer coating. The desired pattern for silver electroplating is produced by laser ablation of the polymer coating. Excimer laser was found to be most effective for this process as it can expose a pattern of clean copper substrate which can be silver plated successfully. Previous working of Nd:YAG laser ablation showed that 1.06 μm radiation was not suitable for this etching process because a thin organic and transparent film remained on the laser etched region. The effect of excimer pulse frequency and energy density upon the removal rate of the polymer coating was studied.

  13. High-throughput anisotropic plasma etching of polyimide for MEMS

    International Nuclear Information System (INIS)

    Bliznetsov, Vladimir; Manickam, Anbumalar; Ranganathan, Nagarajan; Chen, Junwei

    2011-01-01

    This note describes a new high-throughput process of polyimide etching for the fabrication of MEMS devices with an organic sacrificial layer approach. Using dual frequency superimposed capacitively coupled plasma we achieved a vertical profile of polyimide with an etching rate as high as 3.5 µm min −1 . After the fabrication of vertical structures in a polyimide material, additional steps were performed to fabricate structural elements of MEMS by deposition of a SiO 2 layer and performing release etching of polyimide. (technical note)

  14. Anisotropic etching of tungsten-nitride with ICP system

    CERN Document Server

    Lee, H G; Moon, H S; Kim, S H; Ahn, J; Sohn, S

    1998-01-01

    Inductively Coupled Plasma ion streaming etching of WN sub x film is investigated for preparing x-ray mask absorber patterns. SF sub 6 gas plasma provides for effective etching of WN sub x , and the addition of Ar and N sub 2 results in higher dissociation of SF sub 6 and sidewall passivation effect, respectively. Microloading effect observed for high aspect ratio patterns is minimized by multi-step etching and O sub 2 plasma treatment process. As a result, 0.18 mu m WN sub x line and space patterns with vertical sidewall profile are successfully fabricated.

  15. Method of plastic track detector electrochemical etching

    International Nuclear Information System (INIS)

    D'yakov, A.A.

    1984-01-01

    The review of studies dealing with the development of the method for the electro-chemical etching (ECE) of the plastic track detectors on the base of polyethy-leneterephthalate (PET) and polycarbonate (PC) is given. Physical essence of the method, basic parameters of the processes, applied equipment and methods of measurement automation are considered. The advantages of the method over the traditional chemical etching are pointed out. Recommendations on the detector operation modes when detecting fission fragments, α-particles and fast neutrons are given. The ECE method is based on the condition that during chemical etching the high-voltage sound frequency alternating electric field is applied to the detector. In this case the detector serves as an isolating layer betWeen two vessels with etching solution in which high-voltage electrode are submerged. At a fixed electric field potential higher (over than the threshold value) at the end of the etching track cone atree-like discharge spot arises. It is shown that when PET is used for fast neutron detection it is advisable to apply for ECE the PEW solution (15g KOH+40 g C 2 H 2 OH + 45g H 2 O) the field potential should constitute 30 kVxcm -1 at the freqUency of 9 kHz. In the case of fission fragment detection Using ECE and PC the following ECE conditions are recommended: 30% KOH etcher, field potential of 10 kVxcm -1 , 2-4 kHz frequency. It is concluded that the ECE method permits considerably eXtend the sphere of plastic track detector application for detecting ionizing particles,

  16. A novel nano-nonwoven fabric with three-dimensionally dispersed nanofibers: entrapment of carbon nanofibers within nonwovens using the wet-lay process

    International Nuclear Information System (INIS)

    Karwa, Amogh N; Davis, Virginia A; Tatarchuk, Bruce J; Barron, Troy J

    2012-01-01

    This study demonstrates, for the first time, the manufacturing of novel nano-nonwovens that are comprised of three-dimensionally distributed carbon nanofibers within the matrices of traditional wet-laid nonwovens. The preparation of these nano-nonwovens involves dispersing and flocking carbon nanofibers, and optimizing colloidal chemistry during wet-lay formation. The distribution of nanofibers within the nano-nonwoven was verified using polydispersed aerosol filtration testing, air permeability, low surface tension liquid capillary porometry, SEM and cyclic voltammetry. All these characterization techniques indicated that nanofiber flocks did not behave as large solid clumps, but retained the ‘nanoporous’ structure expected from nanofibers. These nano-nonwovens showed significant enhancements in aerosol filtration performance. The reduction–oxidation reactions of the functional groups on nanofibers and the linear variation of electric double-layer capacitance with nanofiber loading were measured using cyclic voltammetry. More than 65 m 2 (700 ft 2 ) of the composite were made during the demonstration of process scalability using a Fourdrinier-type continuous pilot papermaking machine. The scalability of the process with the control over pore size distribution makes these composites very promising for filtration and other nonwoven applications. (paper)

  17. Wet-process Fabrication of Low-cost All-solid Wire-shaped Solar Cells on Manganese-plated Electrodes

    International Nuclear Information System (INIS)

    Fan, Xing; Zhang, Xiaoying; Zhang, Nannan; Cheng, Li; Du, Jun; Tao, Changyuan

    2015-01-01

    Highlights: • All-solid wire-shaped flexible solar cells are firstly assembled on low-cost Mn-plated fibers. • Energy efficiency improved by >27% after coating a layer of Mn on various substrates. • The cell is fabricated via wet process under low temperature and mild pH conditions. • Stable flexible solar cells are realized on lightweight and low-cost polymer fiber. - Abstract: All-solid wire-shaped flexible solar cells are assembled for the first time on low-cost Mn-plated wires through wet-process fabrication under low temperature and mild pH conditions. With a price cheap as the steel, metal Mn can be easily plated on almost any substrates, and evidently promote the photovoltaic efficiency of wire-shaped solar cells on various traditional metal wire substrates, such as Fe and Ti, by 27% and 65%, respectively. Flexible solar cell with much lower cost and weight is assembled on Mn-plated polymer substrate, and is still capable of giving better performance than that on Fe or Ti substrate. Both its mechanical and chemical stability are good for future weaving applications. Owing to the wire-type structure, such low-cost metals as Mn, which are traditionally regarded as unsuitable for solar cells, may provide new opportunities for highly efficient solar cells

  18. Magnetic behavior of iron-modified MCM-41 correlated with clustering processes from the wet impregnation method

    Energy Technology Data Exchange (ETDEWEB)

    Cuello, Natalia I.; Elías, Verónica R. [Centro de Investigación y Tecnología Química (CITeQ) (UTN-CONICET), Facultad Regional Córdoba. Maestro López y Cruz Roja Argentina, Ciudad Universitaria, Córdoba 5016 (Argentina); Winkler, Elin [Centro Atómico Bariloche, Comisión Nacional de Energía Atómica – CONICET, Avenue Bustillo 9500, San Carlos de Bariloche 8400 (Argentina); Pozo-López, Gabriela; Oliva, Marcos I. [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba – IFEG, CONICET, Ciudad Universitaria, Córdoba 5000 (Argentina); Eimer, Griselda A., E-mail: geimer@frc.utn.edu.ar [Centro de Investigación y Tecnología Química (CITeQ) (UTN-CONICET), Facultad Regional Córdoba. Maestro López y Cruz Roja Argentina, Ciudad Universitaria, Córdoba 5016 (Argentina)

    2016-06-01

    Magnetic MCM-41 type mesoporous silica materials were synthetized and modified with different iron loadings by the wet impregnation method. The evolution of iron speciation, depending on the metal loading and associated with a particular magnetic behavior was investigated by M vs. H curves, FC–ZFC curves, EPR spectroscopy and other complementary techniques such as SEM, TEM, and chemisorption of pyridine followed by FT-IR studies. A superparamagnetic contribution was larger for the lower loadings suggesting the high dispersion of very small sized iron nanospecies. However, this contribution decreased with increasing metal loading due to the growth of magnetically blocked nanoparticles (hematite) on the outer surface. Finally, a bimodal size distribution for the superparamagnetic nanospecies could be inferred; then the anisotropy constant for this phase and the corresponding nanospecies sizes were estimated. - Highlights: • All samples showed a main superparamagnetic contribution. • The oxide particles grow at expense of superparamagnetic nanospecies. • Bimodal distribution of nanospecies in superparamagnetic regime was determined. • The anisotropy constant for superparamagnetic nanospecies was calculated.

  19. Structural, morphological, wettability and thermal resistance properties of hydro-oleophobic thin films prepared by a wet chemical process

    International Nuclear Information System (INIS)

    Phani, A.R.

    2006-01-01

    The structural properties of fluorine containing polymer compounds make them highly attractive materials for hydro-oleophobic applications. However, most of these exhibit low surface energy and poor adhesion on the substrates. In the present investigation, crack free, smooth and uniform thin films of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole] -co-tetrafluoroethylene (TFD-co-TFE) with good adhesion have been deposited by wet chemical spin-coating technique on polished AISI 440C steel substrates. The as-deposited films (xerogel films) have been subjected to annealing for 1 h at different temperatures ranging from 100 to 500 deg. C in an argon atmosphere. The size growth of the nano-hemispheres increased from 8 nm for xerogel film to 28 nm for film annealed at 400 deg. C. It was found that as the annealing temperature increased from 100 to 400 deg. C, nano-hemisphere-like structures were formed, which in turn have shown increase in the water contact angle from 122 deg. to 147 deg. and oil (peanut) contact angle from 85 deg. to 96 deg. No change in the water contact angle (122 deg.) has been observed when the films deposited at room temperature were heated in air from 30 to 80 deg. C as well as exposed to steam for 8 days for 8 h/day indicating thermal stability of the film

  20. Fabrication of SiC nanopillars by inductively coupled SF6/O2 plasma etching

    International Nuclear Information System (INIS)

    Choi, J H; Bano, E; Latu-Romain, L; Dhalluin, F; Chevolleau, T; Baron, T

    2012-01-01

    In this paper, we demonstrate a top-down fabrication technique for nanometre scale silicon carbide (SiC) pillars using inductively coupled plasma etching. A set of experiments in SF 6 -based plasma was carried out in order to realize high aspect ratio SiC nanopillars. The etched SiC nanopillars using a small circular mask pattern (115 nm diameter) show high aspect ratio (7.4) with a height of 2.2 µm at an optimum bias voltage (300 V) and pressure (6 mTorr). Under the optimal etching conditions using a large circular mask pattern with 370 nm diameter, the obtained SiC nanopillars exhibit high anisotropy features (6.4) with a large etch depth (>7 µm). The etch characteristic of the SiC nanopillars under these conditions shows a high etch rate (550 nm min -1 ) and a high selectivity (over 60 for Ni). We also studied the etch profile of the SiC nanopillars and mask evolution over the etching time. As the mask pattern size shrinks in nanoscale, vertical and lateral mask erosion plays a crucial role in the etch profile of the SiC nanopillars. Long etching process makes the pillars appear with a hexagonal shape, coming from the crystallographic structure of α-SiC. It is found that the feature of pillars depends not only on the etching process parameters, but also on the crystallographic structure of the SiC phase. (paper)