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Formation of iridium silicides from Ir thin films on Si substrates. (USA)
Classified abstracts 4384-4393 indicates a need for increased understanding of the details of grainboundary diffusion in alloys. J C Hwang et al, J uppl Phys, 50 (3), 1979, 1349-1359. 30 4384. Theoretical model of thin-film deposition profile with shadow effect. (USA) A theoretical model and a computational algorithm are presented for the shadow deposition of thin films through a generalized mask of finite dimensions in a vacuum environment. The computer model enables a theoretical study of the deposited film thickness profile from extended sources with shadow effect. Numerical evaluation of the masked deposition profile has been carried out to illustrate the film-profile dependences on several basic mask parameters. Using computer-aided design procedures, a deposition mask has been successfully constructed for the fabrication of precisely shaped thin film Luneburg lenses for guided optical wave applications. S K Yao, J appl Phys, 50 (5). 1979, 3390-3395. 30 4385. Optical and electrical properties of evaporated amorphous silicon with hydrogen. (USA) The optical and electrical properties of evaporated amorphous silicon with hydrogen have been studied under various deposition conditions. Infrared measurements indicate that the hydrogen content of the films are comparable to a-Si: H films produced by other techniques. The optical-absorption coefficient below the band gap of w 1.55 eV was measured to be u 100 cm-’ for samples made at deposition temperatures of -275-325°C. For these samples the photoresponse at room temperature and the temperature dependence of the conductivities were studied. Dark conductivities were found to be thermally activated for T > 300 K with activation energies of -0.75 eV. We found type-l photoconductivity and investigated its dependence on the light intensity. When samples were heated to -175°C in a vacuum and then exposed to air, they exhibited timedependent increases in the dark conductivity and photoconductivity. Thiseffect was reversible by a reanneal in a vacuum. High-temperature anneals to -450°C increased the optical absorption below 1.4 eV and decreased the photoresponse significantly. A K Ghosh et al, J appl Phys, 50 (5). 1979, 3407-3413. 30 4386. Infrared quenching of photocapacitance in evaporated ZnS: Ag thin films. (USA) The deep centres in evaporated ZnS:Ag thin films have been characterized by observation of the infrared quenching of photocapacitance using Schottky barriers. The photoionization energy of holes for transitions from Ag centres to the valence band edge is determined to be 0.56 eV at 300 K. The spectral distribution of the photoionization cross-section of holes is obtained theoretically. It has been found that the magnitude of the photocapacitance quenching depends linearly on the intensity of the infrared illumination in the low-intensity range. The concentration profile of Ag impurities has been measured and is almost uniform throughout the depletion layer in the films.
(Japan)
superposed upon an expansion velocity u. In the particular experimental condition with rapid short circuit, the interaction was realized by electrons of low energy. The maximal temperature obtained with a thin 25 pm tantalum anode was of the order of 20 eV and hydrodynamic speed 1.4 cm ps-‘. The characteristics of the electron beam generator used were 600 kV, 200 kA, and 60 ns. (France) C Peugnet et al, J appl Phys, 50 (4), 1979, 2936-2939. 30 4389. Properties of high sensitivity GaP/In,Ga, -.P/GaAs:(Cs-0) transmission photocathodes. (USA) Negative electron affinity (NEA) GaAs photocathodes were vapour grown on GaP/In,Ga,-,P substrates with 0.4 < x < 0.65. The dependence of cathode sensitivity, electron diffusion length, cathode back-interface recombination velocity, and surface-escape probability on buffer-layer composition was determined. The optimal In,Ga,-,P composition for these samples was in the range of 52-55% InP. Indium unintentionally introduced into the GaAs causes a shift in the In,Ga, -*P composition for good lattice match. SIMS and AES measurements were made to obtain the chemical and electronic structure of the epitaxial layers. The photosensitivity dependence on both Zn doping concentration and cathode thickness are presented. The highest transmission mode photosensitivity measured was 740 pA/lm. D G Fisher and G H Olsen, J uppl Phys, 50 (4), 1979, 2930-2935. 30 4390. Vacuum coating of reflectors of small radius of curvature aided by gas scattering. (Germany) In the production of cold mirrors as used in 8 mm film projectors a large number of approximately hemispherical substrates (r z 20 mm) has to be coated simultaneously with several optically active layers. The optical thickness of each layer must be uniform within a few per cent both radially and with respect to rotational symmetry. An approximate calculation shows that this aim can be attained when use is made of the scattering of the evaporant at the atoms or molecules of an inert gas. The reflectors are mounted on discs rotating in a planetary movement so that the axis of each reflector is always pointing to the evaporator source. The system of interference layers produced that way is at least as much resistant to climatic stresses as are dielectric layers produced by orthodox high vacuum evaporation. K Steinfelder et al, Vakrrrrm, 28 (2), 1979, 48-53 (in Germon). 30 4391. Properties of TilN layers produced by ion-plating. (Germany) Constant substrate temperatures up to about 450°C can be attained in an ion plating plant fitted with a Piercetype electron gun only by appropriate adjustment of the discharge parameters without the use of a separate heat source. By reactive evaporating of titanium in a residual gas atmosphere of 8 x lo-’ mbar argon and 2.5 x 10e2 mbar nitrogen at a substrate temperature of 400°C the maximum microhardness HVO.OIN of 20,000 N x mm-’ is attained at a condensation rate of 20 pm x min-I. SEM investigations have shown that the layer consists almost entirely (except for 1%) of Ti,N. I Badny and G Kienel, Vukuum, 28 (6), 1979, 168-172 (in German).
30 4387. Formation of iridium silicides from Ir thin films on Si substrates. (USA) The formation of iridium silicides from the interaction of iridium films with single-crystal silicon substrates has been studied from 350 to 1000°C. Three distinct ohases. IrSi. , IrSi, _.,*I?). . _. and IrSi,.“, were identified. Different modes of formation were observed and investigated. IrSi and IrSi,.,s form in layers parallel to the substrate at temperatures from 350 to 900°C. The growth of IrSi, from nuclei that spread laterally occurs at about lOOo”C, where possible the kinetics were systematically studied. S Peters-son et al, J uppl Phyx, 50 (5), 1979, 3357-3365. 30 4388. Simultaneous measurement of the temperature and the hydrodynamic speed of a thin foil submitted to an intense electronic energy deposition. (USA) We have determined the temperature and hydrodynamic speed of a thin tantalum anode heated by a pinched relativistic electron beam. These measurements were simultaneously realized by analysing the speed distribution of thermal ions emitted by the plasma. The plasma ions can be represented by a Maxwellian velocity distribution
30 4392. Antireiiection coatings on plastic substrates. (Germany) The most well known anti-reflection coating on mineral glasses is a MgF, layer. This coating cannot be applied to plastic substrates even when a barrier layer between substrate and MgF, is used. A double layer system, consisting of ZrO, and a borosilica glass, is described which meets most of todays requirements for application on spectacle and magnification lenses as well as on lenses for cameras. The described double layer allows a low substrate temperature and can even be applied to temperature sensitive plastics such as PMMA. The evaporation is accomplished by an electron beam source with a special crucible. G Kienel and B Heinz, Vakuum, 28 (4), 108-112 (in German). 30 4393. Thick metallic films obtained by ion-plating. (France) An ion-plating deposition system using an electron beam evaporation source was developed to obtain adherent, thick and uniform thickness coatings on substrates with various configuration. Al, Sm, Y and W coatings were obtained with thicknesses between 80 and 2.000 pm. A Brothier et al, Vide, 34 (196), 1979, 109-I 11 (in French).
T Suda et al, J uppl Phys, 50 (5), 1979, 3638-3643.
242
(Japan)
superposed upon an expansion velocity u. In the particular experimental condition with rapid short circuit, the interaction was realized by electrons of low energy. The maximal temperature obtained with a thin 25 pm tantalum anode was of the order of 20 eV and hydrodynamic speed 1.4 cm ps-‘. The characteristics of the electron beam generator used were 600 kV, 200 kA, and 60 ns. (France) C Peugnet et al, J appl Phys, 50 (4), 1979, 2936-2939. 30 4389. Properties of high sensitivity GaP/In,Ga, -.P/GaAs:(Cs-0) transmission photocathodes. (USA) Negative electron affinity (NEA) GaAs photocathodes were vapour grown on GaP/In,Ga,-,P substrates with 0.4 < x < 0.65. The dependence of cathode sensitivity, electron diffusion length, cathode back-interface recombination velocity, and surface-escape probability on buffer-layer composition was determined. The optimal In,Ga,-,P composition for these samples was in the range of 52-55% InP. Indium unintentionally introduced into the GaAs causes a shift in the In,Ga, -*P composition for good lattice match. SIMS and AES measurements were made to obtain the chemical and electronic structure of the epitaxial layers. The photosensitivity dependence on both Zn doping concentration and cathode thickness are presented. The highest transmission mode photosensitivity measured was 740 pA/lm. D G Fisher and G H Olsen, J uppl Phys, 50 (4), 1979, 2930-2935. 30 4390. Vacuum coating of reflectors of small radius of curvature aided by gas scattering. (Germany) In the production of cold mirrors as used in 8 mm film projectors a large number of approximately hemispherical substrates (r z 20 mm) has to be coated simultaneously with several optically active layers. The optical thickness of each layer must be uniform within a few per cent both radially and with respect to rotational symmetry. An approximate calculation shows that this aim can be attained when use is made of the scattering of the evaporant at the atoms or molecules of an inert gas. The reflectors are mounted on discs rotating in a planetary movement so that the axis of each reflector is always pointing to the evaporator source. The system of interference layers produced that way is at least as much resistant to climatic stresses as are dielectric layers produced by orthodox high vacuum evaporation. K Steinfelder et al, Vakrrrrm, 28 (2), 1979, 48-53 (in Germon). 30 4391. Properties of TilN layers produced by ion-plating. (Germany) Constant substrate temperatures up to about 450°C can be attained in an ion plating plant fitted with a Piercetype electron gun only by appropriate adjustment of the discharge parameters without the use of a separate heat source. By reactive evaporating of titanium in a residual gas atmosphere of 8 x lo-’ mbar argon and 2.5 x 10e2 mbar nitrogen at a substrate temperature of 400°C the maximum microhardness HVO.OIN of 20,000 N x mm-’ is attained at a condensation rate of 20 pm x min-I. SEM investigations have shown that the layer consists almost entirely (except for 1%) of Ti,N. I Badny and G Kienel, Vukuum, 28 (6), 1979, 168-172 (in German).
30 4387. Formation of iridium silicides from Ir thin films on Si substrates. (USA) The formation of iridium silicides from the interaction of iridium films with single-crystal silicon substrates has been studied from 350 to 1000°C. Three distinct ohases. IrSi. , IrSi, _.,*I?). . _. and IrSi,.“, were identified. Different modes of formation were observed and investigated. IrSi and IrSi,.,s form in layers parallel to the substrate at temperatures from 350 to 900°C. The growth of IrSi, from nuclei that spread laterally occurs at about lOOo”C, where possible the kinetics were systematically studied. S Peters-son et al, J uppl Phyx, 50 (5), 1979, 3357-3365. 30 4388. Simultaneous measurement of the temperature and the hydrodynamic speed of a thin foil submitted to an intense electronic energy deposition. (USA) We have determined the temperature and hydrodynamic speed of a thin tantalum anode heated by a pinched relativistic electron beam. These measurements were simultaneously realized by analysing the speed distribution of thermal ions emitted by the plasma. The plasma ions can be represented by a Maxwellian velocity distribution
30 4392. Antireiiection coatings on plastic substrates. (Germany) The most well known anti-reflection coating on mineral glasses is a MgF, layer. This coating cannot be applied to plastic substrates even when a barrier layer between substrate and MgF, is used. A double layer system, consisting of ZrO, and a borosilica glass, is described which meets most of todays requirements for application on spectacle and magnification lenses as well as on lenses for cameras. The described double layer allows a low substrate temperature and can even be applied to temperature sensitive plastics such as PMMA. The evaporation is accomplished by an electron beam source with a special crucible. G Kienel and B Heinz, Vakuum, 28 (4), 108-112 (in German). 30 4393. Thick metallic films obtained by ion-plating. (France) An ion-plating deposition system using an electron beam evaporation source was developed to obtain adherent, thick and uniform thickness coatings on substrates with various configuration. Al, Sm, Y and W coatings were obtained with thicknesses between 80 and 2.000 pm. A Brothier et al, Vide, 34 (196), 1979, 109-I 11 (in French).
T Suda et al, J uppl Phys, 50 (5), 1979, 3638-3643.
242