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1177. Preparation and some electrophysical parameters of MIS structures
Classified abstracts 1170--1179 30 1170. Electronic properties of thin films of ZnO. (Hungary) Electrical properties of thin ZnO films prepared by radiofrequency sputtering are investigated. The films have been prepared either with a pure zinc target or with a ZnO sintered target in atmosphere of argon or oxygen. Typical work pressure was 5 × 10-3 torr and the deposition rate was between 50 and 100 A/min. The thickness of the studied films was of 0.5 to 5 #m and the substrate temperature varied from 25 to 450°C. Resistivity of the films was measured in dependence on the oxygen pressure in the sputtering module. At a critical pressure of the order of 7 × 10-5 torr a metal-semi-insulator transition was observed in films prepared from the pure zinc target. The frequency dependence of the films was also studied. (France) J Vuillod and B K Chakraverty, International ConfPhys Chem Semt-
conductors Heterojunctions Layer Structure, Vol 4, Akademiai Kiado Budapest 1971, 243-250. 3O 1171. Optical and electrical properties of sputtered amorphous silicon. (Hungary) Optical absorption and electrical properties of diode-sputtered amorphous silicon films on glass, silica, sapphire and copper substrates are investigated. Sputtering was performed in a flow of purified argon at 5 × 10-3 torr with a deposition rate of 120 A/mm. (Czechoslovakia) M Zavetova and J Zemek, International Conf Phys Chem SemLcon-
ductors Heterojunctions Layer Structure, 1Iol 4, Akademiat Kiado Budapest 1971, 251-258. 3O 1172. The influence of annealing on electrical properties of thin vaponr-deposited films of Cd3As~. (Hungary) Thin films of Cd3As= were prepared by direct evaporation of a bulk Cd3As= in vacuum of 10-4 to 10-5 torr on mica or glass substrates with deposition rates of 2000 to 4000/~/min. Cd3As= films of low resistivity, well defined crystalline structure, and electron mobilities of 2000 to 3000 cm=/V sec were obtained, when the substrate temperature was 160 to 180°C. After coverage with thin layer of vapour deposited SIOx the films were annealed in air. During annealing some irreversible changes took place related to recrystalhzation, growth of larger crystallites and ordering of structure, resulting in higher conductivity and carrier mobility. Thin-film Hall elements and batteries of Cd3As2 evaporated and protected recrystallized films have good stability and reproducibihty of basic electrical parameters. (Poland) L Zdnowicz et al, International Conf Phys Chem Semiconductors
Heterojunctions Layer Structure, Vol 4, Akademiai Kiado Budapest 1971, 259-268. 3O 1173. Preparation and properties of silicon nitride films and their applications. (Hungary) The growth of silicon nitride film from chemical vapour reactions of silane and silane tetrachloride with ammoniain hydrogen atmosphere is considered. Growth rates were calculated thermodynamically as functions of temperature and initial concentration of gases and the conditions for growing film of stoichiometric composition were studied. An experimental system with SiCI,-NH3-H= is described, in which SiCI4 and NHa gases are mixed at high temperature. The films obtained were examined by an infrared spectrophotometer and an optical microscope. Capacitance-voltage characteristics were measured for these films. As an application of Si3N4 film, the masking properties for the selective epitaxial growth of silicon are described. The experimental results show that the Si3N, film has the best quality as a mask, it is quite stable in H~ and SiCI4 atmosphere at high temperature. (Japan) T Arizumi et al, International Conf Phys Chem Semiconductors
Heterojuncttons Layer Structure, Vol 5, Akademiat Kiado Budapest
30 1175. Production and properties of MIS structures on the basis of germanium nitride. (Hungary) A low-temperature technique for production of germanium nitride films is developed. The Ge3N4 films are prepared in a closed, preevacuated two-region reactor by nitrlde sublimation on semiconductor substrate, with nitride produced as a result of hydrazine and germanium interaction. The initial pressure of hydrazine is 12 torr and corresponds to the pressure of N=H4 saturated vapour above the liquid at the temperature of 20°C. The thickness of Ge3N, films varies linearly with the time of the process and the precipitation rate is 0.2 #m/hour. Thickness of the films is determined by interference methods. Chemical, physical and electrical properties of germanium nltrlde films are studied. Electrongraphical studies of sublimated Ge3N4 films show that they are amorphous. The surface of nltride films is homogeneous and does not contain any appreciable cracks and pores. The films are used for semiconductor passivation and MIS structure production. (USSR) G D Bagratishvili et al, International ConfPhys Chem Semiconductors
Heterojunctions Layer Structure, Iiol 5, Akademiai Kiado Budapest 1971, 65-70. 30 1176. Influence of the metallization on the charges in various M O S structures. (Hungary) Influence of the metalhzatlon on the charges after heat treatment in various MOS structures is investigated. MOS structures were made of n-type chemically-mechanically polished silicon wafers covered by a 1000 A thick oxide layer. The metallmation was made by methods of vacuum evaporation at 10-5 torr, diode sputtering in argon at pressure of 1.5 x 10-1 torr and electron-beam evaporation of AI, Sb, Mo, Au, Cr and NICr alloy. A R Herman and B V Jancsecz, International ConfPhys Chem Semi-
conductors Heterojunctions Layer Structure, Vol 5, Akademiai Kiado Budapest 1971, 109-115. 30 1177. Preparation and some electrophysical parameters of MIS structures. (Hungary) The results of investigation of dielectric films of sdicon oxymtride are presented. Some electrophyslcal properties of MIS structures with multllayer silicon oxynltnde films are described. Dielectric coatings of various compositions from pure oxide to silicon nitride were prepared by vapour-gas deposition by interaction of silicon tetrachloride with NH3 and CO= mixture at 1000°C in hydrogen in a contmuous process with epitaxial deposition of silicon. Infrared spectroscopy showed that the films represent a molecular mixture of natural silicon oxynitride with silicon oxide or sihcon nitride. It is found that it is possible to obtain samples without mobile ions and with a wide fast surface state density range. (USSR) A U Malinin et al, International Conf Phys Chem Semiconductors
Heterofunctions Layer Structure, Vol 5, Akademiai Kiado Budapest 1971, 129-141. 30 1178. Current and breakdown characteristics of amorphous SiO= in metal-oxide-semiconductor structure. (Hungary) A field controlled transition from a high to a low impedance state is observed in MOS structures after a forming of the material. MOS structures containing thermally oxidized silicon film and metallic grids of AI or Au deposited in a vacuum of 10-5 torr were used m the experiments. (France) A Plenier and B K Chakraverty, International ConfPhys Chem Semi-
1971, 7-25.
conductors Heterojunctions Layer Structure, Vol 5, Akademiai Kiado Budapest 1971, 161-170.
30 1174. Electronic processes on the interface semiconductor-dielectric. (Hungary) The semiconductor-dielectric interface in thin-film metal-insulatorsemiconductor structures is considered. Cathodic sputtering with reaction and deposition from gas plasma are recommended as optimal methods for obtalnmg an external dielectric protective film on semiconductor films. (USSR) A V Rzhanov, International ConfPhys Chem Semwonductors Heterojunctions Layer Structure, Vol 5, Akademtat Kiado Budapest 1971, 4152.
30 1179. Charge carrier exchange between semiconductor and insulator (Hungary) Charge carrier exchange in the interface semiconductor-insulator is investigated by measuring capacitance-voltage curves of MIS capacitors. The samples were p- or n-type silicon or germanium wafers with deposited SiO~ or Si3N4 films. Alumlmum top electrodes were evaporated in vacuum. SiOz was grown on St by thermal or anodic oxidation and on Ge was deposited by pyrolytic decomposition of tetraethoxysilane in hydrogen gas or by radio-frequency
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conductors Heterojunctions Layer Structure, Vol 4, Akademiai Kiado Budapest 1971, 243-250. 3O 1171. Optical and electrical properties of sputtered amorphous silicon. (Hungary) Optical absorption and electrical properties of diode-sputtered amorphous silicon films on glass, silica, sapphire and copper substrates are investigated. Sputtering was performed in a flow of purified argon at 5 × 10-3 torr with a deposition rate of 120 A/mm. (Czechoslovakia) M Zavetova and J Zemek, International Conf Phys Chem SemLcon-
ductors Heterojunctions Layer Structure, 1Iol 4, Akademiat Kiado Budapest 1971, 251-258. 3O 1172. The influence of annealing on electrical properties of thin vaponr-deposited films of Cd3As~. (Hungary) Thin films of Cd3As= were prepared by direct evaporation of a bulk Cd3As= in vacuum of 10-4 to 10-5 torr on mica or glass substrates with deposition rates of 2000 to 4000/~/min. Cd3As= films of low resistivity, well defined crystalline structure, and electron mobilities of 2000 to 3000 cm=/V sec were obtained, when the substrate temperature was 160 to 180°C. After coverage with thin layer of vapour deposited SIOx the films were annealed in air. During annealing some irreversible changes took place related to recrystalhzation, growth of larger crystallites and ordering of structure, resulting in higher conductivity and carrier mobility. Thin-film Hall elements and batteries of Cd3As2 evaporated and protected recrystallized films have good stability and reproducibihty of basic electrical parameters. (Poland) L Zdnowicz et al, International Conf Phys Chem Semiconductors
Heterojunctions Layer Structure, Vol 4, Akademiai Kiado Budapest 1971, 259-268. 3O 1173. Preparation and properties of silicon nitride films and their applications. (Hungary) The growth of silicon nitride film from chemical vapour reactions of silane and silane tetrachloride with ammoniain hydrogen atmosphere is considered. Growth rates were calculated thermodynamically as functions of temperature and initial concentration of gases and the conditions for growing film of stoichiometric composition were studied. An experimental system with SiCI,-NH3-H= is described, in which SiCI4 and NHa gases are mixed at high temperature. The films obtained were examined by an infrared spectrophotometer and an optical microscope. Capacitance-voltage characteristics were measured for these films. As an application of Si3N4 film, the masking properties for the selective epitaxial growth of silicon are described. The experimental results show that the Si3N, film has the best quality as a mask, it is quite stable in H~ and SiCI4 atmosphere at high temperature. (Japan) T Arizumi et al, International Conf Phys Chem Semiconductors
Heterojuncttons Layer Structure, Vol 5, Akademiat Kiado Budapest
30 1175. Production and properties of MIS structures on the basis of germanium nitride. (Hungary) A low-temperature technique for production of germanium nitride films is developed. The Ge3N4 films are prepared in a closed, preevacuated two-region reactor by nitrlde sublimation on semiconductor substrate, with nitride produced as a result of hydrazine and germanium interaction. The initial pressure of hydrazine is 12 torr and corresponds to the pressure of N=H4 saturated vapour above the liquid at the temperature of 20°C. The thickness of Ge3N, films varies linearly with the time of the process and the precipitation rate is 0.2 #m/hour. Thickness of the films is determined by interference methods. Chemical, physical and electrical properties of germanium nltrlde films are studied. Electrongraphical studies of sublimated Ge3N4 films show that they are amorphous. The surface of nltride films is homogeneous and does not contain any appreciable cracks and pores. The films are used for semiconductor passivation and MIS structure production. (USSR) G D Bagratishvili et al, International ConfPhys Chem Semiconductors
Heterojunctions Layer Structure, Iiol 5, Akademiai Kiado Budapest 1971, 65-70. 30 1176. Influence of the metallization on the charges in various M O S structures. (Hungary) Influence of the metalhzatlon on the charges after heat treatment in various MOS structures is investigated. MOS structures were made of n-type chemically-mechanically polished silicon wafers covered by a 1000 A thick oxide layer. The metallmation was made by methods of vacuum evaporation at 10-5 torr, diode sputtering in argon at pressure of 1.5 x 10-1 torr and electron-beam evaporation of AI, Sb, Mo, Au, Cr and NICr alloy. A R Herman and B V Jancsecz, International ConfPhys Chem Semi-
conductors Heterojunctions Layer Structure, Vol 5, Akademiai Kiado Budapest 1971, 109-115. 30 1177. Preparation and some electrophysical parameters of MIS structures. (Hungary) The results of investigation of dielectric films of sdicon oxymtride are presented. Some electrophyslcal properties of MIS structures with multllayer silicon oxynltnde films are described. Dielectric coatings of various compositions from pure oxide to silicon nitride were prepared by vapour-gas deposition by interaction of silicon tetrachloride with NH3 and CO= mixture at 1000°C in hydrogen in a contmuous process with epitaxial deposition of silicon. Infrared spectroscopy showed that the films represent a molecular mixture of natural silicon oxynitride with silicon oxide or sihcon nitride. It is found that it is possible to obtain samples without mobile ions and with a wide fast surface state density range. (USSR) A U Malinin et al, International Conf Phys Chem Semiconductors
Heterofunctions Layer Structure, Vol 5, Akademiai Kiado Budapest 1971, 129-141. 30 1178. Current and breakdown characteristics of amorphous SiO= in metal-oxide-semiconductor structure. (Hungary) A field controlled transition from a high to a low impedance state is observed in MOS structures after a forming of the material. MOS structures containing thermally oxidized silicon film and metallic grids of AI or Au deposited in a vacuum of 10-5 torr were used m the experiments. (France) A Plenier and B K Chakraverty, International ConfPhys Chem Semi-
1971, 7-25.
conductors Heterojunctions Layer Structure, Vol 5, Akademiai Kiado Budapest 1971, 161-170.
30 1174. Electronic processes on the interface semiconductor-dielectric. (Hungary) The semiconductor-dielectric interface in thin-film metal-insulatorsemiconductor structures is considered. Cathodic sputtering with reaction and deposition from gas plasma are recommended as optimal methods for obtalnmg an external dielectric protective film on semiconductor films. (USSR) A V Rzhanov, International ConfPhys Chem Semwonductors Heterojunctions Layer Structure, Vol 5, Akademtat Kiado Budapest 1971, 4152.
30 1179. Charge carrier exchange between semiconductor and insulator (Hungary) Charge carrier exchange in the interface semiconductor-insulator is investigated by measuring capacitance-voltage curves of MIS capacitors. The samples were p- or n-type silicon or germanium wafers with deposited SiO~ or Si3N4 films. Alumlmum top electrodes were evaporated in vacuum. SiOz was grown on St by thermal or anodic oxidation and on Ge was deposited by pyrolytic decomposition of tetraethoxysilane in hydrogen gas or by radio-frequency
662