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532. Investigation of possibility of heating of large-size glass parts by high-temperature heating elements
Classified abstracts 532--540 devices is not lower than the sensitivity reached with the aid of an attached helium leak detector. L G Molchanova et al, Electronic Technology, Scient-Techn Collect, UHF Electronics, No 7, 1971, 63-67 (in Russian). 28. HEATING E Q U I P M E N T AND THERMOMETERS 28 532. Investigation of possibility of heating of large-size glass parts by high-temperature heating elements. (USSR) The possibility of heating the glass parts of vacuum systems by iodine lamps with parabolic reflectors, is investigated. It is shown that using this method, a glass temperature of 500°C can be attained in 12 minutes. Construction of the heating elements with iodine lamps and parabolic reflectors is discussed. O G Smirnov et al, Electronic Technology, Scient-Techn Collect, Technology and Organization of Production, No 3, 1971, 68-74 in
Russian).
III. Vacuum applications 30. EVAPORATION AND SPUTTERING
Russian). 30
533. Physical properties of CdGa2Se4 compound. (USSR) The physical properties of the semi-conducting compound CdGa~Se4 are investigated using single crystal, polycrystalline and thin-film samples. Thin films of CdGa~Se4 were prepared both by slow evaporation of the bulk material in vacuum and by the discrete evaporation method. Both methods give similar results. The electrical conductivity of the thin films is measured. The thin films possess photoconductivity. M P Tyrzin and V G Tyrzin, Neorg Mater, 7 (10), 1971, 1855-1856
(in Russian). 30 534. Dissolution of evaporated silver films in tin-lead solders. (Hungary) The dissolution rate of 1000 to 10000 .~ silver films evaporated on glass plates in vacuum was investigated in tin-lead solders. The dissolving effect of silver films in tin-lead solder containing 3 per cent of silver was found to be considerably lower than that of types containing no silver. A Horvath, Finommechanika, 10 (3), 1971, 93-95 (in Hungarian). 3O 535. Influence of structural disorder on electric strength of thin films of fused silica. (USSR) The dependence of electric strength on the average dimensions of short-range order in amorphous structures, and the size of crystallization regions in a fused silica matrix, is investigated for thin 0.1 to 0.9 /~m films of pyrolytic fused silica. The fused silica films were prepared by pyrolytic decomposition from the vapour phase. Varying decomposition conditions, films with different degree of short-range order were obtained. Grain sizes in the range 30 to 150 ~ were prepared. After annealing in vacuum at 10-5 torr and 800°C, the grain size increases to 400 A. The electric strength of the thin fused silica films depends on dielectric thickness; decreases at small dimensions of crystallization regions; and reaches a maximum at an average grain size of 110 A.. For thick films, and also large grain sizes, an increase in the electric strength is observed. A phenomenological model is presented which describes the conditions for disturbance of stationary states of conductance electrons due to the action of an external field in the presence of short-range order, with different types of density fluctuations in the structure of amorphous dielectrics. V F Korzo, Fiz Tverd Tela, 13 (6), 1971, 1564-1572 (in Russian). 30 536. Negative resistance of heterojunctions p-ZnTe - n-CdSe, p-ZnTe n-CdS and p-ZnTe - CdSxSel.x. (USSR) Results of experimental investigations of volt-ampere and voltcapacity characteristics of heterojunctions p-ZnTe - n-CdSe, n-CdS, n-CdSxSe~,x are presented. The heterojunctions were manufactured by epitaxial growth of cadmium chalcogenides on zinc telluride substrates using the method of chemical transport reaction. Nonrectifying contacts to cadmium chalcogenide films were obtained by vacuum evaporation of indium with subsequent vacuum annealing. At liquid nitrogen temperature, a negative resistance region is obtained in the volt-ampere characteristics of the heterojunctions. Ya A Fedotov et al, Fiz Tekh Polup, 5 (9), 1971, 1754-1759 (in Russian).
168
30 537. Contact of a shock wave with a silicon surface during thin film deposition. (USSR) A gas-phase deposition process for silicon and silicon dioxide in a shock tube, is investigated. On volume compression of single crystal silicon by a shock wave, plastic defects are produced in silicon, over a certain range of pressure and temperature, and a redistribution of energy levels occurs in silicon. The kinetics of silicon or silicon dioxide thin film growth is investigated on variously oriented single crystal silicon surfaces in a shock tube and the defect structure of the films is determined. The processes of film condensation were explored during the time from 0 to 10 /~sec using an interferometer and electron-optical high-speed camera. The substrate was attached to the end face of the shock tube. After reaching the pressure of 5 × 10-5 torr in the low-pressure canal of the tube, the silicon surface was cleaned by helium ions. In the preparation of the films, the original mixture (SiCI~: H~=0.04) was admitted into the low-pressure canal by means of a pulsed valve. Then a metallic diaphragm separating the low-pressure and high-pressure canals was ruptured. In the preparation of SiO2 films, oxygen was added to the original mixture The obtained results give information on the time course of reaction in the gas and on the substrate surface influence on film formation. N A Mescheryakov, Fiz Tekh Polup, 5 (7), 1971, 1428-1433 (in 30 538. Electrolytic photography on evaporated films of lead sulphide. (USSR) The process of long-wave photography on lead sulphide films is described, in which the application of an electric field to the system semiconductor-electrolyte is used as a factor controlling sensitivity. The image is formed immediately on the semi-conductor surface. The lead sulphide films were prepared by vacuum evaporation with subsequent annealing. Glass plates with transparent electrodes of tin dioxide were used as substrates. The films were contacted with electrolyte during exposures. Exposures were performed through a germanium filter and the flux of light incident on the glass substrate was not higher than 10-4 W/cm 2. Accounting for absorption in the glass and tin dioxide layer, the true power incident on the lead sulphide film was of the order of 10-5 W/cm 2. The exposure time, corresponding to the time of application of the voltage of 3 to 15 V, was in the range of 1 to I0 see. The photographic image on the lead sulphide film surface was formed due to deposition of a metallic layer in the illuminated spots as a result of electron-hole pair formation. L V Belyakov et al, Fiz Tekh Polup, 5 (7), 1971, 1466-1468 (in Russian). 30 539. Electrical and photoelectric properties of some thln-film amorphous heterostruetures. (USSR) The electrical and photoelectric properties of thin-film amorphous heterostructures prepared by successive deposition on glass substrates of basic semitransparent electrodes, are investigated. Two semiconducting films form the heterostructure and surface semitransparent electrodes. The semiconducting films were deposited by thermal evaporation in vacuum at 10-5 torr using a shock evaporation method, depositing decomposing materials. The heterostructures: n-Se - p-Sb2S3, p-T1 ~Se. mAs2Se 3- n-Sb~S 3and n-CdS - p-SbzSe.~were examined in detail. The heterostructures possess high photosensitivity. Lux-ampere and spectral characteristics and kinetics of photoresponse are studied experimentally. It is found that inertia of photoresponse is reduced on reverse bias and increases with forward bias voltage. A strong dependence of the parameters and characteristics of the heterostructures on the thickness of the amorphous films is found, which is explained by the low values of the drift length of charge carriers in the electric field characteristic for amorphous semiconductors. It is proposed that the investigated hetero-junctions may be applied in television pick-up tubes and in electro-photographic devices. B T Kolomiets et al, Fiz Tekh Polup, 5 (8), 1971, 1533-1540 (in
Ruysian). 30 540. Epitaxial p-n hetero-junction in the system Pbl.xSnxSe-PbS. (USSR) To prepare hetero-junctions, the substrates of p-type Pbq~.9.~.Sn0,~Se were used. Epitaxial growth of the film was performed in vacuum at 5 × l0 -~ torr with evaporation of n-type PbS. Temperature of the substrates during epitaxial growth was 350 to 400°C. Volt-ampere
Russian).
III. Vacuum applications 30. EVAPORATION AND SPUTTERING
Russian). 30
533. Physical properties of CdGa2Se4 compound. (USSR) The physical properties of the semi-conducting compound CdGa~Se4 are investigated using single crystal, polycrystalline and thin-film samples. Thin films of CdGa~Se4 were prepared both by slow evaporation of the bulk material in vacuum and by the discrete evaporation method. Both methods give similar results. The electrical conductivity of the thin films is measured. The thin films possess photoconductivity. M P Tyrzin and V G Tyrzin, Neorg Mater, 7 (10), 1971, 1855-1856
(in Russian). 30 534. Dissolution of evaporated silver films in tin-lead solders. (Hungary) The dissolution rate of 1000 to 10000 .~ silver films evaporated on glass plates in vacuum was investigated in tin-lead solders. The dissolving effect of silver films in tin-lead solder containing 3 per cent of silver was found to be considerably lower than that of types containing no silver. A Horvath, Finommechanika, 10 (3), 1971, 93-95 (in Hungarian). 3O 535. Influence of structural disorder on electric strength of thin films of fused silica. (USSR) The dependence of electric strength on the average dimensions of short-range order in amorphous structures, and the size of crystallization regions in a fused silica matrix, is investigated for thin 0.1 to 0.9 /~m films of pyrolytic fused silica. The fused silica films were prepared by pyrolytic decomposition from the vapour phase. Varying decomposition conditions, films with different degree of short-range order were obtained. Grain sizes in the range 30 to 150 ~ were prepared. After annealing in vacuum at 10-5 torr and 800°C, the grain size increases to 400 A. The electric strength of the thin fused silica films depends on dielectric thickness; decreases at small dimensions of crystallization regions; and reaches a maximum at an average grain size of 110 A.. For thick films, and also large grain sizes, an increase in the electric strength is observed. A phenomenological model is presented which describes the conditions for disturbance of stationary states of conductance electrons due to the action of an external field in the presence of short-range order, with different types of density fluctuations in the structure of amorphous dielectrics. V F Korzo, Fiz Tverd Tela, 13 (6), 1971, 1564-1572 (in Russian). 30 536. Negative resistance of heterojunctions p-ZnTe - n-CdSe, p-ZnTe n-CdS and p-ZnTe - CdSxSel.x. (USSR) Results of experimental investigations of volt-ampere and voltcapacity characteristics of heterojunctions p-ZnTe - n-CdSe, n-CdS, n-CdSxSe~,x are presented. The heterojunctions were manufactured by epitaxial growth of cadmium chalcogenides on zinc telluride substrates using the method of chemical transport reaction. Nonrectifying contacts to cadmium chalcogenide films were obtained by vacuum evaporation of indium with subsequent vacuum annealing. At liquid nitrogen temperature, a negative resistance region is obtained in the volt-ampere characteristics of the heterojunctions. Ya A Fedotov et al, Fiz Tekh Polup, 5 (9), 1971, 1754-1759 (in Russian).
168
30 537. Contact of a shock wave with a silicon surface during thin film deposition. (USSR) A gas-phase deposition process for silicon and silicon dioxide in a shock tube, is investigated. On volume compression of single crystal silicon by a shock wave, plastic defects are produced in silicon, over a certain range of pressure and temperature, and a redistribution of energy levels occurs in silicon. The kinetics of silicon or silicon dioxide thin film growth is investigated on variously oriented single crystal silicon surfaces in a shock tube and the defect structure of the films is determined. The processes of film condensation were explored during the time from 0 to 10 /~sec using an interferometer and electron-optical high-speed camera. The substrate was attached to the end face of the shock tube. After reaching the pressure of 5 × 10-5 torr in the low-pressure canal of the tube, the silicon surface was cleaned by helium ions. In the preparation of the films, the original mixture (SiCI~: H~=0.04) was admitted into the low-pressure canal by means of a pulsed valve. Then a metallic diaphragm separating the low-pressure and high-pressure canals was ruptured. In the preparation of SiO2 films, oxygen was added to the original mixture The obtained results give information on the time course of reaction in the gas and on the substrate surface influence on film formation. N A Mescheryakov, Fiz Tekh Polup, 5 (7), 1971, 1428-1433 (in 30 538. Electrolytic photography on evaporated films of lead sulphide. (USSR) The process of long-wave photography on lead sulphide films is described, in which the application of an electric field to the system semiconductor-electrolyte is used as a factor controlling sensitivity. The image is formed immediately on the semi-conductor surface. The lead sulphide films were prepared by vacuum evaporation with subsequent annealing. Glass plates with transparent electrodes of tin dioxide were used as substrates. The films were contacted with electrolyte during exposures. Exposures were performed through a germanium filter and the flux of light incident on the glass substrate was not higher than 10-4 W/cm 2. Accounting for absorption in the glass and tin dioxide layer, the true power incident on the lead sulphide film was of the order of 10-5 W/cm 2. The exposure time, corresponding to the time of application of the voltage of 3 to 15 V, was in the range of 1 to I0 see. The photographic image on the lead sulphide film surface was formed due to deposition of a metallic layer in the illuminated spots as a result of electron-hole pair formation. L V Belyakov et al, Fiz Tekh Polup, 5 (7), 1971, 1466-1468 (in Russian). 30 539. Electrical and photoelectric properties of some thln-film amorphous heterostruetures. (USSR) The electrical and photoelectric properties of thin-film amorphous heterostructures prepared by successive deposition on glass substrates of basic semitransparent electrodes, are investigated. Two semiconducting films form the heterostructure and surface semitransparent electrodes. The semiconducting films were deposited by thermal evaporation in vacuum at 10-5 torr using a shock evaporation method, depositing decomposing materials. The heterostructures: n-Se - p-Sb2S3, p-T1 ~Se. mAs2Se 3- n-Sb~S 3and n-CdS - p-SbzSe.~were examined in detail. The heterostructures possess high photosensitivity. Lux-ampere and spectral characteristics and kinetics of photoresponse are studied experimentally. It is found that inertia of photoresponse is reduced on reverse bias and increases with forward bias voltage. A strong dependence of the parameters and characteristics of the heterostructures on the thickness of the amorphous films is found, which is explained by the low values of the drift length of charge carriers in the electric field characteristic for amorphous semiconductors. It is proposed that the investigated hetero-junctions may be applied in television pick-up tubes and in electro-photographic devices. B T Kolomiets et al, Fiz Tekh Polup, 5 (8), 1971, 1533-1540 (in
Ruysian). 30 540. Epitaxial p-n hetero-junction in the system Pbl.xSnxSe-PbS. (USSR) To prepare hetero-junctions, the substrates of p-type Pbq~.9.~.Sn0,~Se were used. Epitaxial growth of the film was performed in vacuum at 5 × l0 -~ torr with evaporation of n-type PbS. Temperature of the substrates during epitaxial growth was 350 to 400°C. Volt-ampere