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503. Structure and properties of transition layers formed in the epitaxy process. (Germany)
Classified abstracts
503-513
30 503. Structure and properties of transition layers formed in the epitaxy process. (Germany) Structure and properties of transition layers formed in the vacuum epitaxy process are considered. The initial stages of the film formation under the conditions of hetero- and homoepitaxy are studied. Factors which promote the formation of the transition layer are discussed. (USSR) L N Aieksandrov, WhysStat Sol (a), 11 (l), May 1972,9-37. 30 504. Formation and motion of dislocations in the crystallization process of selenium from the amorphous phase. (Germany) The crystallization of Se from the amorphous phase has been studied by an in situ technique. Amorphous films of red Se were prepared by condensation in vacuum of 10m5 torr on unheated NaCl substrates. The layers separated from the substrate were the starting material for the investigation of the crystallization process in vacuum of lo- 5 torr in the electron microscope with photographic image recording. The nucleation and further growth of the crystalline grains occurred owing to the heating by the electron beam used for getting the transmission image. The front of a growing crystal is established to serve as the main source of the defects. The density of the originating dislocations depends on the temperature of crystallization, on the rate of temperature with time, and the geometrical peculiarities of the front. Inside the growing crystal an intense motion of dislocations, their interaction with each other, and with other defects is observed. (USSR) A L Aseev et al, WhysStat Sol (a), 10 (l), March 1972, 297-306. 30 505. Trap diitributions in dlphenylpolyene films. (Germany) Injection currents in diphenylbutadiene, diphenylhexatriene and diphenyloctatetraene films obtained by thermal deposition in vacuum have been studied. From temperature measurements of the spacecherge-limited currents the trap parameters are determined and the current carrier mobility is calculated. The results allow one to assume that the real quasicontinuous trap distribution in the polycrystalline films of the studied substances is close to an exponential one. The change of film structure due to changes of substrate temperature, deposition rate, deposition pressure and other factors gives rise to a change of the trap spectrum. (USSR) N I Ganuahak et al, Whys Stat Sol (a), 10 (2), April 1972, 667-672. 30 506. Photoconductivity as a tool for the study of deep electronic traps of metal-oxid~ilicon sandwiches. (Germany) Photownductivity measurements associated with capacitance-voltage curves have been used as a tool to study electronic traps in thermally grown SiOt. The oxides are grown and metallized under very clean conditions. All treatments (ultrahigh vacuum cleaning, oxidation, annealing, and electrode deposition) a;e made in the same ultra-high vacuum equipment and without any exposure to room air. The oxide films are grown on (111) oriented IO ohm cm p-type wafers by heating at 1250°C under 100 torr of dry oxygen for 6 h. The resulting oxide layer is approximately 2500 A thick and the annealing oxygen pressures used were/lOmg, 10W4, 1, 5, lo,40 and 100 torr. It is shown that the presence and amount of deep traps is directly related to the oxygen pressure during the last high-temperature anneal after oxidation. (France) F Barruel and J C PMer, WhysStat Sol (a), 10 (2), April 1972, 555562. 30 [email protected] of single crystal tellurium lllms by epitaxial growth on selenium. (Germany) Thin single crystal tellurium slices with large (lOi0) faces were freshly cleaved f;om bulk material. High purity selenium was evaporated in a vacuum of low5 torr and deposited on the (lOTO) faces of the tellurium slices heated to 115°C: The tellurium &ys&s, covered with a single crystal selenium layer, were brought onto a surface of 20 per cent nitric acid and the tellurium was dissolved. Thin single crystal films of trigonal tellurium grow epitaxially from the vapour phase on the (1010) faces of trigonal selenium 6lms prepared according to the described method. After vapourizing the selenium from the double layers, the selfsupporting tellurium films of a thickness below 1000 A are obtained. The electron diffraction patterns of the films are discussed. P Bammes et al, WhysStat Sol (a), 10 (2), April 1972, 365-369.
30 508. Recrystallization of evaporated cadmium suiphide films doped with silver. (Germany) It is shown that recrystallization of cadmium sulphide films evaporated in vacuum of 10e6 is influenced by the presence of minute amounts of impurities of the same order of magnitude as the doping levels of monocrystalline CdS (4 x low3 at %). The role of the impurities as activators or inhibitors of recrystallization is related to the type of ionized centres created (acceptor of donor centres). Experimental results are discussed. (Belgium) C Herinckx et al, Whys Stat Sol (a), 10 (2), April 1972, 387-399 (in French). 31. EVACUATION
AND SEALING
31 509. Influence of buffer gas on operation of quantum generator using Rb*’ vapours with optical pumping. (USSR) A theoretical and experimental study of the operation of a rubidium quantum generator with its evacuated resonator filled by nitrogen or mixture of nitrogen and argon, is presented. The resonator of the quantum generator was connected to a vacuum system enabling evacuation to 10m5 torr. Buffer gas was admitted in the resonator __-tn __ pressure of 2 to 50 torr. Press& was measured by an oil manometer with accuracy of kO.3 torr. Metallic caesium was used to getter the residual oxygen. It is shown that a quantum generator with a small temperature coefficient of frequency can be made using buffer gas. E N Bazarov et al, Radiotekh Elektron, 17 (3), March 1972, 556564 (in Russian). 31 510. Device for cutting the electrodes of electrical vacuum systems. (USSR) A device for cutting off (trimming) the electrodes of electrical vacuum apparatus (valves, cathode-ray tubes) in a mass-production line is described. In the proposed arrangement special grooves and springs are provided to set the cutting edges in the optimum position and to allow for the spread in the dimensions of different items belonging to the same batch. After the cutting operation has been performed, springs return the cutters to their original position ready for the next item. V D Abdula et al, USSR Patent No 322801, uppl 29th June 1970, publd 14th Feb 1972. 31 511. Method of measuring the occupation (space) factor of the grids of electrical vacuum devices. (USSR) A convenient method of measuring the space or occupation factor of the grids of electrical vacuum devices (valves, cathode-ray tubes, etc.) is described. The grid in question is earthed and made the central element of a three-electrode system. The first electrode generates an electromagnetic field and the third records the change in this field due to the screening action of the grid, itself djrectly related to the space factor. In this way the space factors of grids of any geometrical shape may easily be measured. V I Petrov, USSR Patent No 322802, appl 6th Ott 1969, publd 14th Feb 1972. 31 512. An anti-emission alloy. (USSR) A new alloy for use in making the grids of valves and other parts of electrical vacuum apparatus required to have low emission properties is proposed. The alloy comprises Cu 10-20, Al l-4 per cent, balance Ti; it thus contains more titanium and less copper than alloys at present used for this purpose. The aluminium is added in order to make the alloy more workable when used as a coating on molybdenum and tungsten wires. The melting point of the alloy is 115015OO”C, depending on the exact composition, and it has far better gettering capabilities than its predecessors. A S Kuz’menko et al, USSR Patent No 316130, ~~~129th April 1968, publd 27th Dee 1971. 31 513. Method of processing electrical vacuum apparatus. (USSR) A new method of processing electrical vacuum apparatus is proposed; this method differs from conventional techniques in that the system is evacuated only after heating the shell to its maximum temperature, thus reducing both time of treatment and percentage of breakages. The breakage rate falls by a factor of 50 without detriment to the
503-513
30 503. Structure and properties of transition layers formed in the epitaxy process. (Germany) Structure and properties of transition layers formed in the vacuum epitaxy process are considered. The initial stages of the film formation under the conditions of hetero- and homoepitaxy are studied. Factors which promote the formation of the transition layer are discussed. (USSR) L N Aieksandrov, WhysStat Sol (a), 11 (l), May 1972,9-37. 30 504. Formation and motion of dislocations in the crystallization process of selenium from the amorphous phase. (Germany) The crystallization of Se from the amorphous phase has been studied by an in situ technique. Amorphous films of red Se were prepared by condensation in vacuum of 10m5 torr on unheated NaCl substrates. The layers separated from the substrate were the starting material for the investigation of the crystallization process in vacuum of lo- 5 torr in the electron microscope with photographic image recording. The nucleation and further growth of the crystalline grains occurred owing to the heating by the electron beam used for getting the transmission image. The front of a growing crystal is established to serve as the main source of the defects. The density of the originating dislocations depends on the temperature of crystallization, on the rate of temperature with time, and the geometrical peculiarities of the front. Inside the growing crystal an intense motion of dislocations, their interaction with each other, and with other defects is observed. (USSR) A L Aseev et al, WhysStat Sol (a), 10 (l), March 1972, 297-306. 30 505. Trap diitributions in dlphenylpolyene films. (Germany) Injection currents in diphenylbutadiene, diphenylhexatriene and diphenyloctatetraene films obtained by thermal deposition in vacuum have been studied. From temperature measurements of the spacecherge-limited currents the trap parameters are determined and the current carrier mobility is calculated. The results allow one to assume that the real quasicontinuous trap distribution in the polycrystalline films of the studied substances is close to an exponential one. The change of film structure due to changes of substrate temperature, deposition rate, deposition pressure and other factors gives rise to a change of the trap spectrum. (USSR) N I Ganuahak et al, Whys Stat Sol (a), 10 (2), April 1972, 667-672. 30 506. Photoconductivity as a tool for the study of deep electronic traps of metal-oxid~ilicon sandwiches. (Germany) Photownductivity measurements associated with capacitance-voltage curves have been used as a tool to study electronic traps in thermally grown SiOt. The oxides are grown and metallized under very clean conditions. All treatments (ultrahigh vacuum cleaning, oxidation, annealing, and electrode deposition) a;e made in the same ultra-high vacuum equipment and without any exposure to room air. The oxide films are grown on (111) oriented IO ohm cm p-type wafers by heating at 1250°C under 100 torr of dry oxygen for 6 h. The resulting oxide layer is approximately 2500 A thick and the annealing oxygen pressures used were/lOmg, 10W4, 1, 5, lo,40 and 100 torr. It is shown that the presence and amount of deep traps is directly related to the oxygen pressure during the last high-temperature anneal after oxidation. (France) F Barruel and J C PMer, WhysStat Sol (a), 10 (2), April 1972, 555562. 30 [email protected] of single crystal tellurium lllms by epitaxial growth on selenium. (Germany) Thin single crystal tellurium slices with large (lOi0) faces were freshly cleaved f;om bulk material. High purity selenium was evaporated in a vacuum of low5 torr and deposited on the (lOTO) faces of the tellurium slices heated to 115°C: The tellurium &ys&s, covered with a single crystal selenium layer, were brought onto a surface of 20 per cent nitric acid and the tellurium was dissolved. Thin single crystal films of trigonal tellurium grow epitaxially from the vapour phase on the (1010) faces of trigonal selenium 6lms prepared according to the described method. After vapourizing the selenium from the double layers, the selfsupporting tellurium films of a thickness below 1000 A are obtained. The electron diffraction patterns of the films are discussed. P Bammes et al, WhysStat Sol (a), 10 (2), April 1972, 365-369.
30 508. Recrystallization of evaporated cadmium suiphide films doped with silver. (Germany) It is shown that recrystallization of cadmium sulphide films evaporated in vacuum of 10e6 is influenced by the presence of minute amounts of impurities of the same order of magnitude as the doping levels of monocrystalline CdS (4 x low3 at %). The role of the impurities as activators or inhibitors of recrystallization is related to the type of ionized centres created (acceptor of donor centres). Experimental results are discussed. (Belgium) C Herinckx et al, Whys Stat Sol (a), 10 (2), April 1972, 387-399 (in French). 31. EVACUATION
AND SEALING
31 509. Influence of buffer gas on operation of quantum generator using Rb*’ vapours with optical pumping. (USSR) A theoretical and experimental study of the operation of a rubidium quantum generator with its evacuated resonator filled by nitrogen or mixture of nitrogen and argon, is presented. The resonator of the quantum generator was connected to a vacuum system enabling evacuation to 10m5 torr. Buffer gas was admitted in the resonator __-tn __ pressure of 2 to 50 torr. Press& was measured by an oil manometer with accuracy of kO.3 torr. Metallic caesium was used to getter the residual oxygen. It is shown that a quantum generator with a small temperature coefficient of frequency can be made using buffer gas. E N Bazarov et al, Radiotekh Elektron, 17 (3), March 1972, 556564 (in Russian). 31 510. Device for cutting the electrodes of electrical vacuum systems. (USSR) A device for cutting off (trimming) the electrodes of electrical vacuum apparatus (valves, cathode-ray tubes) in a mass-production line is described. In the proposed arrangement special grooves and springs are provided to set the cutting edges in the optimum position and to allow for the spread in the dimensions of different items belonging to the same batch. After the cutting operation has been performed, springs return the cutters to their original position ready for the next item. V D Abdula et al, USSR Patent No 322801, uppl 29th June 1970, publd 14th Feb 1972. 31 511. Method of measuring the occupation (space) factor of the grids of electrical vacuum devices. (USSR) A convenient method of measuring the space or occupation factor of the grids of electrical vacuum devices (valves, cathode-ray tubes, etc.) is described. The grid in question is earthed and made the central element of a three-electrode system. The first electrode generates an electromagnetic field and the third records the change in this field due to the screening action of the grid, itself djrectly related to the space factor. In this way the space factors of grids of any geometrical shape may easily be measured. V I Petrov, USSR Patent No 322802, appl 6th Ott 1969, publd 14th Feb 1972. 31 512. An anti-emission alloy. (USSR) A new alloy for use in making the grids of valves and other parts of electrical vacuum apparatus required to have low emission properties is proposed. The alloy comprises Cu 10-20, Al l-4 per cent, balance Ti; it thus contains more titanium and less copper than alloys at present used for this purpose. The aluminium is added in order to make the alloy more workable when used as a coating on molybdenum and tungsten wires. The melting point of the alloy is 115015OO”C, depending on the exact composition, and it has far better gettering capabilities than its predecessors. A S Kuz’menko et al, USSR Patent No 316130, ~~~129th April 1968, publd 27th Dee 1971. 31 513. Method of processing electrical vacuum apparatus. (USSR) A new method of processing electrical vacuum apparatus is proposed; this method differs from conventional techniques in that the system is evacuated only after heating the shell to its maximum temperature, thus reducing both time of treatment and percentage of breakages. The breakage rate falls by a factor of 50 without detriment to the