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Evaporation of silicon in vacuo
388
Classified Abstracts 924--931
Vacuum Applications 30.
E v a p o r a t i o n and S p u t t e r i n g
30 : 33 : 41 924. Investigations of titanium sheets for sputtering-ion pumps. (Italy) The properties of titanium sheets of different makers were investigated in ~'iew of their suitability to serve as cathode material in sputtering-ion pumps. Considerable differences were found in the pumping speed for argon (factor 5) and in the relation of discharge current to gas pressure (factor 2.5). By means of an omegatron the gas desorption during charging of the test tubes with argon was studied; different results were obtained. When a short-time glow discharge at higher pressures was applied, the quantities mentioned above did alter considerably. In one case jumping of the discharge was observed which caused desorption of large amounts of methane and carbonmonoxyd. (Germany) (Author) G. Reich, 2nd lnternat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 30 : 41 925. Evaporation of silicon in vacuo. (France) The author has attempted to produce crystalline silicon layers by thermal or electronic vaporization under a vacuum of the order of 10-~ torr. Various kinds of substrate were u s e d : glass, mica, fused silica, quartz, crystalline silicon, fluorspar and tantalum ribbon. The deposits were amorphous in all cases at substrate temperatures below 600 °C. Polycrystalline deposits were obtained at higher temperatures (600-900°C). It appears that oriented monocrystalline deposits would require substrate temperature of 1000°C or more, which could not be reached with the author's apparatus. (France) w.J.s. M. Richard, Le Vide, 18 (104), March/April 1963, 100-102.
trollable negative TCR indicate long life stability. The present state of the art cannot however realise a high yield of 2-3 per cent planar resistors without subsequent tailoring. The author describes the effect of various process variables on the electrical properties of thin films of chromium. The effect of deposition rate, stabilization heat treatment, substrate composition, topography and cleanliness are among the parameters discussed. It is hoped that with closer attention to these parameters, the precision of fabrication will improve. (U.S.A.) w.J.s. R. M. Chapman, Vacuum, 13 (6), June 1963, 213-221. 30 : 56 929. Small microcircuits formed direct from vapour.
(Great
Britain) Anon., Elect. Engng., 81, August 1962, 632.
Gas evolution from sputter-ion pumps during baking. No. 880.
30:11 See Abstr.
30 : 47 : 40 Methods employed for measuring the gas evolution from getters during evaporation. See Abstr. No. 972. 30 : 16 : 41 Depletive adsorption of hydrogen and carbon monoxide on nickel oxide. See Abstr. No. 889. 30 : 16:41 Some reactions of cyclohexene with hydrogen and deuterium on evaporated gold films. See Abstr. No. 888. 30 : 16 : 41 Surface potential study of the chemisorption of hydrogen and carbon monoxide on evaporated copper and gold films. See Abstr. No. 887.
30 : 41 926. Spatter
mechanism
during
metal
evaporation.
(Great
Britain) In the course of deposition of thin lead films by evaporation to depletion of a fixed charge contained in a flat molybdenum boat, spattering was found to occur erratically. The author examined various possible mechanisms for this phenomenon and concluded that it was probably due to high velocity vapour escaping as the charge oscillates in the boat. (U.S.A.) w.J.s. R. E. Rippere, et al., Vacuum, 13 (7), July 1963, 277-278. 30 : 41 927. Experimental thin film computer memory unit. (U.S.A.) The Radio Corporation of America has developed a thin film memory unit for computers. It operates at cryogenic temperatures at which the film becomes superconducting, the computer information being stored in the form of electric currents which persist indefin;tely. The unit consists of a glass plate, 2 in. square bearing several thin layers of tin, lead and silicon oxide which are deposited successively by evaporation forming a sandwich. It is capable of storing 16,384 items of information. High speed, compactness and reliability are claimed for this type of unit. Economic fabrication and design of circuit printing masks are problems still to be solved. (U.S.A.) w.J.s. Anon., Chem. & Engng. News, 41 (27), 8 July 1963, 55. 30 : 41 928. The effect of fabrication variables on chromium thin film resistors. (Great Britain) With the advent of ever higher circuit speeds, the low frequency dependence of chromium film resistors makes them increasingly desirable. Their slight positive ageing characteristic and con-
31,
E v a c u a t i o n and S e a l i n g
31 : 33 930. The analysis of residual gases in M g O cold cathode tube. (Italy) A cold cathode coated with a thin layer of magnesium oxide may be used for electron source of vacuum tube. But this cathode has generally short life, especially at high current density. The phenomena of the emission-decay is considered to be caused by the fact that the surface is continuously bombarded by electrons, and it seems greatly dependent upon the kind of residual gases in the MgO cold cathode. In this paper, some preliminary results of the analysis of residual gases in this tube are described, obtained by radio-frequency mass spectrometer (the Bennett type). We found that the residual gases consist mainly of H~O CO and CO~ which are said to deteriorate the emission. Consequently, it appears possible that the life performance is influenced particularly by the presence of gases of these types. (Japan) (Authors) I. Matsuda and H. Yamashita, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 31:22 931. Failure mechanism in traveling-wave tubes. (Italy) The results of an investigation of the failure mechanisms in a travelling-wave tube are discussed. The system tested consisted of a gridded, pulsed travelling-tube which has an 8.5 kV potential difference between the cathode and anode. The tube incorporated a getter to absorb residual gases and an oxide coated cathode as an electron emitter. The tubes were enclosed in
Classified Abstracts 924--931
Vacuum Applications 30.
E v a p o r a t i o n and S p u t t e r i n g
30 : 33 : 41 924. Investigations of titanium sheets for sputtering-ion pumps. (Italy) The properties of titanium sheets of different makers were investigated in ~'iew of their suitability to serve as cathode material in sputtering-ion pumps. Considerable differences were found in the pumping speed for argon (factor 5) and in the relation of discharge current to gas pressure (factor 2.5). By means of an omegatron the gas desorption during charging of the test tubes with argon was studied; different results were obtained. When a short-time glow discharge at higher pressures was applied, the quantities mentioned above did alter considerably. In one case jumping of the discharge was observed which caused desorption of large amounts of methane and carbonmonoxyd. (Germany) (Author) G. Reich, 2nd lnternat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 30 : 41 925. Evaporation of silicon in vacuo. (France) The author has attempted to produce crystalline silicon layers by thermal or electronic vaporization under a vacuum of the order of 10-~ torr. Various kinds of substrate were u s e d : glass, mica, fused silica, quartz, crystalline silicon, fluorspar and tantalum ribbon. The deposits were amorphous in all cases at substrate temperatures below 600 °C. Polycrystalline deposits were obtained at higher temperatures (600-900°C). It appears that oriented monocrystalline deposits would require substrate temperature of 1000°C or more, which could not be reached with the author's apparatus. (France) w.J.s. M. Richard, Le Vide, 18 (104), March/April 1963, 100-102.
trollable negative TCR indicate long life stability. The present state of the art cannot however realise a high yield of 2-3 per cent planar resistors without subsequent tailoring. The author describes the effect of various process variables on the electrical properties of thin films of chromium. The effect of deposition rate, stabilization heat treatment, substrate composition, topography and cleanliness are among the parameters discussed. It is hoped that with closer attention to these parameters, the precision of fabrication will improve. (U.S.A.) w.J.s. R. M. Chapman, Vacuum, 13 (6), June 1963, 213-221. 30 : 56 929. Small microcircuits formed direct from vapour.
(Great
Britain) Anon., Elect. Engng., 81, August 1962, 632.
Gas evolution from sputter-ion pumps during baking. No. 880.
30:11 See Abstr.
30 : 47 : 40 Methods employed for measuring the gas evolution from getters during evaporation. See Abstr. No. 972. 30 : 16 : 41 Depletive adsorption of hydrogen and carbon monoxide on nickel oxide. See Abstr. No. 889. 30 : 16:41 Some reactions of cyclohexene with hydrogen and deuterium on evaporated gold films. See Abstr. No. 888. 30 : 16 : 41 Surface potential study of the chemisorption of hydrogen and carbon monoxide on evaporated copper and gold films. See Abstr. No. 887.
30 : 41 926. Spatter
mechanism
during
metal
evaporation.
(Great
Britain) In the course of deposition of thin lead films by evaporation to depletion of a fixed charge contained in a flat molybdenum boat, spattering was found to occur erratically. The author examined various possible mechanisms for this phenomenon and concluded that it was probably due to high velocity vapour escaping as the charge oscillates in the boat. (U.S.A.) w.J.s. R. E. Rippere, et al., Vacuum, 13 (7), July 1963, 277-278. 30 : 41 927. Experimental thin film computer memory unit. (U.S.A.) The Radio Corporation of America has developed a thin film memory unit for computers. It operates at cryogenic temperatures at which the film becomes superconducting, the computer information being stored in the form of electric currents which persist indefin;tely. The unit consists of a glass plate, 2 in. square bearing several thin layers of tin, lead and silicon oxide which are deposited successively by evaporation forming a sandwich. It is capable of storing 16,384 items of information. High speed, compactness and reliability are claimed for this type of unit. Economic fabrication and design of circuit printing masks are problems still to be solved. (U.S.A.) w.J.s. Anon., Chem. & Engng. News, 41 (27), 8 July 1963, 55. 30 : 41 928. The effect of fabrication variables on chromium thin film resistors. (Great Britain) With the advent of ever higher circuit speeds, the low frequency dependence of chromium film resistors makes them increasingly desirable. Their slight positive ageing characteristic and con-
31,
E v a c u a t i o n and S e a l i n g
31 : 33 930. The analysis of residual gases in M g O cold cathode tube. (Italy) A cold cathode coated with a thin layer of magnesium oxide may be used for electron source of vacuum tube. But this cathode has generally short life, especially at high current density. The phenomena of the emission-decay is considered to be caused by the fact that the surface is continuously bombarded by electrons, and it seems greatly dependent upon the kind of residual gases in the MgO cold cathode. In this paper, some preliminary results of the analysis of residual gases in this tube are described, obtained by radio-frequency mass spectrometer (the Bennett type). We found that the residual gases consist mainly of H~O CO and CO~ which are said to deteriorate the emission. Consequently, it appears possible that the life performance is influenced particularly by the presence of gases of these types. (Japan) (Authors) I. Matsuda and H. Yamashita, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 31:22 931. Failure mechanism in traveling-wave tubes. (Italy) The results of an investigation of the failure mechanisms in a travelling-wave tube are discussed. The system tested consisted of a gridded, pulsed travelling-tube which has an 8.5 kV potential difference between the cathode and anode. The tube incorporated a getter to absorb residual gases and an oxide coated cathode as an electron emitter. The tubes were enclosed in