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Steep versus exponential absorption edge in amorphous germanium: evidence for the effect of oxygen. (zechoslovakia)
Classified abstracts
344-357
30 344. Thermal effects occurring during the process of 6hn growth in vacuum. (USSR) The change in film temperature due to thermal flux from the evaporator is evaluated during growth of epitaxial Ge films at a deposition rate of 20-30 A/s with substrate temperature 800°C. The calculations show that at small deposition rates and high initial substrate temperature, the change in surface temperature of the growing film does not exceed 2-3°C. A B Markaryan and G A Kurov, Microelectronics Moscow Znst Electron Technoi, No 7, 1971, 19-25 (in Russian). 30
345. Influence of the orientation plane on level of doping and distribution of impurities in gallium arsenide epitaxial films. (USSR) It is shown that the degree of doping in pure epitaxial films of GaAs grown in a gas-transport system, Ga-AsC&-H,, is strongly dependent on the orientation of the substrate plane. The experimental results are explained on the basis of the molecular kinetic theory. B S Lisenker et al, li’eorg Mater, 8 (4), April 1972,670-675 (in Russian). 30 346. Dependence of the structure of tellurium tilms on the nature of the
substrate. (USSR) Tellurium films on amorphous, polycrystalline and single crystal substrates, 3000 8, thick, were investigated by x-ray methods. It is found that on amorphous and polycrystalline substrates, polycrystalline tellurium films are formed. On single crystal substrates, a single crystal phase in the tellurium films is also formed. S A Zorkina and A V Bulgadaev, Euryat Znst fiatural Sci, Siberian Dept Acad Sci USSR,
No 3, 1971, 61-64 (in Russian).
30 347. Influence of electrostatic potential of substrate on properties of
AlsO3 films prepared by the electron-beam method. (USSR) It is found that the magnitude and polarity of electric current flowing through a substrate, during the deposition of aluminium oxide film on it, depends on the value of negative potential applied to it. The best electro-physical properties have the aluminium oxide films deposited at those potential values which give an electric current through substrate close to zero. K A Osipov and I I Orlov, Dokl AN SSSR, 202 (3), 1972,570-571 (in Russian). 348. Switching effect in films of electrolytic copper oxides. (USSR)
30
Switching effects have been observed in diode structures based on films of copper oxides prepared by electrolytic oxidation of copper plates or thin copper films evaporated in vacuum. E M Kosarevich and V M Parkun, Strength Plasticity Metals, CON, Minsk Nauk Tekhn 1971, 176-177 (in Russian). 30 349. Steep versus exponential absorption edge in amorphous germanium:
evidence for the effect of oxygen. (Czechoslovakia) Absorption edge and temperature dependence of electrical conductivity in thin films of amorphous germanium are investigated. A first set of samples was prepared by sputtering in especially purified argon with oxygen content under 1 ppm, while another set was prepared in argon containing 10 ppm of oxygen. It is found that absorption edge of amorphous germanium thin film prepared in purified argon has the exponential shape in contrast to a steep decrease at absorption lower than 10s cm-l observed in films containing a higher amount of oxygen. Electrical conductivity of the higher oxygen content films is about two orders of magnitude lower than that of the films prepared in argon with small content of oxygen. It is supposed that trapping of oxygen gives rise to a redistribution of the density of states. M Zavetova et al, Czech J Phys, B 22 (5), 1972, 429-431. 30 350. Radiation of electrons passing through thin Blms of metals. (USSR) Radiation emitted in the visible and ultraviolet regions, on passing 100 keV electrons through thin films of Al, Ag, Au and Cu 100 to 1000 A thick, are investigated. The films were prepared by vacuum evaporation of metals on collodium substrates. The target was placed inside the vacuum chamber, in which pressure of 5 x 10m6 torr was maintained. The spectral and angular distributions of the radiation and also the dependence of its intensity on electron energy, film thickness, angle of electron entrance into the film and optical con-
stants of the substances are investigated. An analysis of the experimental data shows that the distributions completely agree with the _ Ginzburg-Franck theory of transition radiation. F R Arutvunyan et al. Zh Eksuer Teor Fiz. I 62 (4). ~I,_Aoril 1972. 1263_ 1271 (in &s&an). ’ 30 351. Thin films of metals prepared by an ion-thermal method. (USSR)
Thin films of various metals were prepared by ionized atomic beams on various substrates potential. The films have good adhesion and S V Zinenko et al, Electron Technol, Scient-tech zation Production,
deposition of partially with applied negative continuity.
Coll, Technol OrganiNo 6, 1971, 63-66 (in Russian).
30 352. Investigation of thin films of stilhene derivatives subjected to
bombardment in electron microscope. (Rumania) Thin films of stilbene derivatives were condensed in vacuum at lo-@ torr on glass substrates and then bombarded and observed in an electron microscope. It is found that transformations from amorphous into polycrystalline and then into a single crystal state are stimulated by bombardment at a current of 3 x 10eB A. Prolonged bombardment results in disturbance of the single crystal state and transformation to polycrystalline and finally into amorphous state occurs. I Georgescu Iulia and G Theodorescu, Rev Rum Phys, 16 (9), 1971, 1065-1066
(in French). 30
353. Strength of thin-film metal-oxide compositions. (USSR)
Microhardness and mechanical strength of multi-layer condensates of the system Ni-SiO are investigated. Experimental results are discussed. L S Palatnik et al, Fiz Met Metalloved, 32 (6), 1971, 1312-1313 (in Russian). 30 354. Microstructure of CdTe epitaxial films on Ge prepared by the
sandwich method. (Bulgaria) CdTe epitaxial and polycrystalline films, with thickness 1 to 20 pm, were grown on the (11 l), (100) and (112) planes of Ge by sublimation of single crystal or pressed material in inert ambient using a closed process. Temperatures of the source and the substrate were 580 and 41O”C, respectively. P R Kamadjiev et al, Dokl Bolg Akad Nauk, 24 (9), 1971, 1155-l 158. 30 355. Inclined textures in CdS films. (USSR) Inclined textures are observed in CdS films prepared by sputtering of the components on amorphous substrates. It is shown that the determining role in the growth rate of films is played by the intensity of Cd sputtering and in formation of inclined textures--the position of the substrate with respect to the direction of the atomic beam of the metallic component. _ K V Shalimova and V A Dmitriev, Kristallografiya, 17 (l), 1972,227 (in Russian).
30 356. Thickness dependence of the electrical transport properties of
germanium films. (Germany) The conductivity and the Hall effect in germanium films deposited by electron beam evaporation in vacuum on glass and alumina substrates kept at 600 and 700°C have been investigated at room temperature in vacuum as function of film thickness. The conductivity decreases with increasing thickness, and the highest deposition temperature yields the lowest conductivity. A model based on an inhomogeneous distribution of dislocations within polycrystalline films is proposed. The results of this model are in good agreement with the experimental observations. The decrease in density of dislocations with distance from the film-substrate interface is due to termination of dislocations at crystallite boundaries. The spatial dependence is of exponential character with decay constant of the order of the crystallite size. (Norway). J S Jobannessen, Phys Stat Sol (a), 11 (2), June 1972,469-478.
30 357. Preparation and electrical properties of AI-AIN-Si structures.
(Germany) AlN films were deposited on polished n-type Si substrates by means of reactive rf sputtering. A triode sputtering system with nitrogen pressure in the range of 1.5 x 10e4 to 6 x 10es torr, frequency of 2.5 MHz, effective radio-frequency voltage of 0.2 to 1.4 kV and substrate temperature of 70 to 470°C was used. At nitrogen pressure of 10m3 147
344-357
30 344. Thermal effects occurring during the process of 6hn growth in vacuum. (USSR) The change in film temperature due to thermal flux from the evaporator is evaluated during growth of epitaxial Ge films at a deposition rate of 20-30 A/s with substrate temperature 800°C. The calculations show that at small deposition rates and high initial substrate temperature, the change in surface temperature of the growing film does not exceed 2-3°C. A B Markaryan and G A Kurov, Microelectronics Moscow Znst Electron Technoi, No 7, 1971, 19-25 (in Russian). 30
345. Influence of the orientation plane on level of doping and distribution of impurities in gallium arsenide epitaxial films. (USSR) It is shown that the degree of doping in pure epitaxial films of GaAs grown in a gas-transport system, Ga-AsC&-H,, is strongly dependent on the orientation of the substrate plane. The experimental results are explained on the basis of the molecular kinetic theory. B S Lisenker et al, li’eorg Mater, 8 (4), April 1972,670-675 (in Russian). 30 346. Dependence of the structure of tellurium tilms on the nature of the
substrate. (USSR) Tellurium films on amorphous, polycrystalline and single crystal substrates, 3000 8, thick, were investigated by x-ray methods. It is found that on amorphous and polycrystalline substrates, polycrystalline tellurium films are formed. On single crystal substrates, a single crystal phase in the tellurium films is also formed. S A Zorkina and A V Bulgadaev, Euryat Znst fiatural Sci, Siberian Dept Acad Sci USSR,
No 3, 1971, 61-64 (in Russian).
30 347. Influence of electrostatic potential of substrate on properties of
AlsO3 films prepared by the electron-beam method. (USSR) It is found that the magnitude and polarity of electric current flowing through a substrate, during the deposition of aluminium oxide film on it, depends on the value of negative potential applied to it. The best electro-physical properties have the aluminium oxide films deposited at those potential values which give an electric current through substrate close to zero. K A Osipov and I I Orlov, Dokl AN SSSR, 202 (3), 1972,570-571 (in Russian). 348. Switching effect in films of electrolytic copper oxides. (USSR)
30
Switching effects have been observed in diode structures based on films of copper oxides prepared by electrolytic oxidation of copper plates or thin copper films evaporated in vacuum. E M Kosarevich and V M Parkun, Strength Plasticity Metals, CON, Minsk Nauk Tekhn 1971, 176-177 (in Russian). 30 349. Steep versus exponential absorption edge in amorphous germanium:
evidence for the effect of oxygen. (Czechoslovakia) Absorption edge and temperature dependence of electrical conductivity in thin films of amorphous germanium are investigated. A first set of samples was prepared by sputtering in especially purified argon with oxygen content under 1 ppm, while another set was prepared in argon containing 10 ppm of oxygen. It is found that absorption edge of amorphous germanium thin film prepared in purified argon has the exponential shape in contrast to a steep decrease at absorption lower than 10s cm-l observed in films containing a higher amount of oxygen. Electrical conductivity of the higher oxygen content films is about two orders of magnitude lower than that of the films prepared in argon with small content of oxygen. It is supposed that trapping of oxygen gives rise to a redistribution of the density of states. M Zavetova et al, Czech J Phys, B 22 (5), 1972, 429-431. 30 350. Radiation of electrons passing through thin Blms of metals. (USSR) Radiation emitted in the visible and ultraviolet regions, on passing 100 keV electrons through thin films of Al, Ag, Au and Cu 100 to 1000 A thick, are investigated. The films were prepared by vacuum evaporation of metals on collodium substrates. The target was placed inside the vacuum chamber, in which pressure of 5 x 10m6 torr was maintained. The spectral and angular distributions of the radiation and also the dependence of its intensity on electron energy, film thickness, angle of electron entrance into the film and optical con-
stants of the substances are investigated. An analysis of the experimental data shows that the distributions completely agree with the _ Ginzburg-Franck theory of transition radiation. F R Arutvunyan et al. Zh Eksuer Teor Fiz. I 62 (4). ~I,_Aoril 1972. 1263_ 1271 (in &s&an). ’ 30 351. Thin films of metals prepared by an ion-thermal method. (USSR)
Thin films of various metals were prepared by ionized atomic beams on various substrates potential. The films have good adhesion and S V Zinenko et al, Electron Technol, Scient-tech zation Production,
deposition of partially with applied negative continuity.
Coll, Technol OrganiNo 6, 1971, 63-66 (in Russian).
30 352. Investigation of thin films of stilhene derivatives subjected to
bombardment in electron microscope. (Rumania) Thin films of stilbene derivatives were condensed in vacuum at lo-@ torr on glass substrates and then bombarded and observed in an electron microscope. It is found that transformations from amorphous into polycrystalline and then into a single crystal state are stimulated by bombardment at a current of 3 x 10eB A. Prolonged bombardment results in disturbance of the single crystal state and transformation to polycrystalline and finally into amorphous state occurs. I Georgescu Iulia and G Theodorescu, Rev Rum Phys, 16 (9), 1971, 1065-1066
(in French). 30
353. Strength of thin-film metal-oxide compositions. (USSR)
Microhardness and mechanical strength of multi-layer condensates of the system Ni-SiO are investigated. Experimental results are discussed. L S Palatnik et al, Fiz Met Metalloved, 32 (6), 1971, 1312-1313 (in Russian). 30 354. Microstructure of CdTe epitaxial films on Ge prepared by the
sandwich method. (Bulgaria) CdTe epitaxial and polycrystalline films, with thickness 1 to 20 pm, were grown on the (11 l), (100) and (112) planes of Ge by sublimation of single crystal or pressed material in inert ambient using a closed process. Temperatures of the source and the substrate were 580 and 41O”C, respectively. P R Kamadjiev et al, Dokl Bolg Akad Nauk, 24 (9), 1971, 1155-l 158. 30 355. Inclined textures in CdS films. (USSR) Inclined textures are observed in CdS films prepared by sputtering of the components on amorphous substrates. It is shown that the determining role in the growth rate of films is played by the intensity of Cd sputtering and in formation of inclined textures--the position of the substrate with respect to the direction of the atomic beam of the metallic component. _ K V Shalimova and V A Dmitriev, Kristallografiya, 17 (l), 1972,227 (in Russian).
30 356. Thickness dependence of the electrical transport properties of
germanium films. (Germany) The conductivity and the Hall effect in germanium films deposited by electron beam evaporation in vacuum on glass and alumina substrates kept at 600 and 700°C have been investigated at room temperature in vacuum as function of film thickness. The conductivity decreases with increasing thickness, and the highest deposition temperature yields the lowest conductivity. A model based on an inhomogeneous distribution of dislocations within polycrystalline films is proposed. The results of this model are in good agreement with the experimental observations. The decrease in density of dislocations with distance from the film-substrate interface is due to termination of dislocations at crystallite boundaries. The spatial dependence is of exponential character with decay constant of the order of the crystallite size. (Norway). J S Jobannessen, Phys Stat Sol (a), 11 (2), June 1972,469-478.
30 357. Preparation and electrical properties of AI-AIN-Si structures.
(Germany) AlN films were deposited on polished n-type Si substrates by means of reactive rf sputtering. A triode sputtering system with nitrogen pressure in the range of 1.5 x 10e4 to 6 x 10es torr, frequency of 2.5 MHz, effective radio-frequency voltage of 0.2 to 1.4 kV and substrate temperature of 70 to 470°C was used. At nitrogen pressure of 10m3 147