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Electrical conduction in thin aggregated metal films
ABSTRACTS ON M I C R O E L E C T R O N I C S AND R E L I A B I L I T Y
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possible to relate electrical characteristics to physical parameters, describe operating characteristics to physical parameters, describe operating characteristics and indicate circuits x~here the T F T may be particularly useful. Active R-C filters for tantalum thin film circuitry. D. vo~ DER PFORDTEN, Frequen.: 18, 150 (1964). (In German.) The methods for the synthesis of linear active R.C. filters as devised by Linvill and Yanagisawa are studied for their usability in tantalum thin-film circuitry. It turns out that some of the methods under consideration lead to circuits with non-crossing R-C r.e:works and non-crossing incoming leads and accordingly to basic applicability only, if the chassis-ground pole is taken out repeatedly of the filter circuits. Studies of transparent electrically conductive tin dioxide layers. H. LADWlC, Silikat Technik June, 182 (1964). The electrical properties of tin dioxide layers have been investigated as a function of manufacturing conditions and admixtures. The results obtained show that the conductivity of SnOo layers is decisively determined by its structure and degree of oxidation. The chloric content of layers prepared from SnCI 4 is thought not to be the main cause of their particularly good conductivity. An incorporation of foreign ions primarily depends on the hydrolytic properties of compounds used. A' resistance variation is caused by hydrolysing chlorides at minimum values of concentration from o.1 to 5 atomic per cent. The conductivity was influenced by all the acetates investigated from 0"1 atomic per cent or less. Etching polished depressions in glass plates. P. W. KENDALL,Journal of Scientific Instruments 41, 485 (1964). In the course of investigations into various ways of producing glass cells for Hall coefficient determinations on liquid metals, it was found that the hydrofluoric acid etching technique can be used to produce in polished plates, of plate glass standard, depressions several cm" in area and as much as 25 E~mdeep, which still retain the polished appearance and general uniformity of the original surface. An examination of the Newton fringe pattern at the edge of a trough 41 ,~m deep in soda-glass showed that step down occupied a width of 0.4 ram. Electrical conduction in thin aggregated metal films. R. M. HILL, Nature, Lond. 204, 35 (1964). An electrical field effect has been observed between discontinuous aggregated thin evaporated films of gold and the substrate on which they were deposited. The gold films were prepared in a vacuum of about 10 +6 torr; soda and borosilicate glasses were used as the substrates. The substrates were cleaned with detergent solutions and baked in vacuum at a temperature of 320°C for 4 hr; they were then cooled to 300°C and the films deposited. The field effect observed is similar to that observed by Cox, and Bonfiglioli and Malvano for continuous films, but the magnitude of the change of resistance involved is much larger. It suggests that conduction in the aggregated films occurs by electron tunnelling through the substrate, and is aided by the presence of trapping centres in the glass. An analysis of the CdSe thin-film triode as a current limiter. W. A. GUTIERREZand H. L. WILSON. IEEE Trans. on Electron Devices, ED-11, 466 (1964). An analysis of the insulated-gate thin-film fieldeffect triode as a current limiter is presented, and a comparison between theory and experiment is made for samples with cadmium selenide as the semiconductor layer. The theoretical treatment involves the extension of the analysis ofp-n junction type current limiters to the thin-film, insulated-gate, field-effect device. Although the insulated-gate devices are operable in either enhancement or depletion modes, the analysis applies only to depletion mode operation. Good correlation between predicted and experimental values is found. This provides strong evidence that depletion mode operation of the device involves the modulation of semiconductor conductivity through a field induced variation of the depth of the space charge region. The characteristics of vacuum deposited cadmium selenide current limiters are also described. Application of low energy sputtering for thin film deposition. J. W. NICKERSONand R. Mos~soN, SCP and Solid State Technology 7, 33 (1964). Low energy sputtering, to date, has been used primarily for research and only a few papers have dealt with the deposition of thin films from a limited number o
311
possible to relate electrical characteristics to physical parameters, describe operating characteristics to physical parameters, describe operating characteristics and indicate circuits x~here the T F T may be particularly useful. Active R-C filters for tantalum thin film circuitry. D. vo~ DER PFORDTEN, Frequen.: 18, 150 (1964). (In German.) The methods for the synthesis of linear active R.C. filters as devised by Linvill and Yanagisawa are studied for their usability in tantalum thin-film circuitry. It turns out that some of the methods under consideration lead to circuits with non-crossing R-C r.e:works and non-crossing incoming leads and accordingly to basic applicability only, if the chassis-ground pole is taken out repeatedly of the filter circuits. Studies of transparent electrically conductive tin dioxide layers. H. LADWlC, Silikat Technik June, 182 (1964). The electrical properties of tin dioxide layers have been investigated as a function of manufacturing conditions and admixtures. The results obtained show that the conductivity of SnOo layers is decisively determined by its structure and degree of oxidation. The chloric content of layers prepared from SnCI 4 is thought not to be the main cause of their particularly good conductivity. An incorporation of foreign ions primarily depends on the hydrolytic properties of compounds used. A' resistance variation is caused by hydrolysing chlorides at minimum values of concentration from o.1 to 5 atomic per cent. The conductivity was influenced by all the acetates investigated from 0"1 atomic per cent or less. Etching polished depressions in glass plates. P. W. KENDALL,Journal of Scientific Instruments 41, 485 (1964). In the course of investigations into various ways of producing glass cells for Hall coefficient determinations on liquid metals, it was found that the hydrofluoric acid etching technique can be used to produce in polished plates, of plate glass standard, depressions several cm" in area and as much as 25 E~mdeep, which still retain the polished appearance and general uniformity of the original surface. An examination of the Newton fringe pattern at the edge of a trough 41 ,~m deep in soda-glass showed that step down occupied a width of 0.4 ram. Electrical conduction in thin aggregated metal films. R. M. HILL, Nature, Lond. 204, 35 (1964). An electrical field effect has been observed between discontinuous aggregated thin evaporated films of gold and the substrate on which they were deposited. The gold films were prepared in a vacuum of about 10 +6 torr; soda and borosilicate glasses were used as the substrates. The substrates were cleaned with detergent solutions and baked in vacuum at a temperature of 320°C for 4 hr; they were then cooled to 300°C and the films deposited. The field effect observed is similar to that observed by Cox, and Bonfiglioli and Malvano for continuous films, but the magnitude of the change of resistance involved is much larger. It suggests that conduction in the aggregated films occurs by electron tunnelling through the substrate, and is aided by the presence of trapping centres in the glass. An analysis of the CdSe thin-film triode as a current limiter. W. A. GUTIERREZand H. L. WILSON. IEEE Trans. on Electron Devices, ED-11, 466 (1964). An analysis of the insulated-gate thin-film fieldeffect triode as a current limiter is presented, and a comparison between theory and experiment is made for samples with cadmium selenide as the semiconductor layer. The theoretical treatment involves the extension of the analysis ofp-n junction type current limiters to the thin-film, insulated-gate, field-effect device. Although the insulated-gate devices are operable in either enhancement or depletion modes, the analysis applies only to depletion mode operation. Good correlation between predicted and experimental values is found. This provides strong evidence that depletion mode operation of the device involves the modulation of semiconductor conductivity through a field induced variation of the depth of the space charge region. The characteristics of vacuum deposited cadmium selenide current limiters are also described. Application of low energy sputtering for thin film deposition. J. W. NICKERSONand R. Mos~soN, SCP and Solid State Technology 7, 33 (1964). Low energy sputtering, to date, has been used primarily for research and only a few papers have dealt with the deposition of thin films from a limited number o