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4.12 Low-frequency properties of dielectric film
Second
Colloquium
on Thin Films (COTHIF)
4.6 Effect of vacuum on the high-frequency properties of thin metal film resistors. Gold and chromium films of similar geometric form were deposited on various glass and special plastic substrates by evaporation at lo-& to lo-* torr with evaporation rates in the range 10 to 100 A/set. The resistor films were given an additional heat treatment. The frequency range of resistors prepared under different growth conditions and the effect of vacuum on the uniformity of the film growth were investigated. The results show a correlation between film uniformity and frequency range of the resistor. M Lomniczy (Budapest, Hungary), (in German). 4.7 Dependence of some properties of Ni-Cr thin films on the parameters of the production processes. Three aspects of the production of nickel/chromium thin film resistors are discussed: the dependence of the temperature coefficient of resistance on deposition rate; the spread of resistance values obtained in a given cycle for evaporation both from the liquid and from the solid state; and the relation between resistivity and deposition rate, taking account of surface roughness in the substrate. J Boros-Gyevi and G Moth1 (Budapest, Hungary). 4.8 Vacuum deposited resistive thin films with high specific resistivity. The results of structural investigations of thin films with extremely high specific resistivity are presented, including: relations between the basic materials and their oxides; changes of structure due to heat treatment and their influence on the conduction mechanism; and the structural conditions for stability. A PaIll& E Farkas and G Bede (Budapest, Hungary). 4.9 Dependence of thermal coefficients on preparation conditions for evaporated gold and chromium films on amorphous substrates. The temperature was varied during the evaporation process between -50 and 400°C under pressures from 1O-6 to 10-O torr. Films were subjected to various additional heat treatments in vacuum and in atmosphere. Relations between evaporation rate, degree of vacuum, effect of heat treatment and the overall thermal coefficients are considered. These experiments were supplemented with film structure investigations. From the results conclusions are drawn regarding the preparation of films with given thermal coefficients. M Lomniczy (Budapest, Hungary), (in German). 4.10 Processes during the heat treatment of vacuum deposited NiCr Bhns. Nickel/chromium films (0 to 90 per cent Ni) prepared by flash evaporation already showed some degree of oxidation which could be increased by increasing the chromium content. Films of various composition were exposed to heat treatments for different times and temperatures and resistivity changes recorded. These changes could be attributed partly to thermal arranging and partly to oxidation. Temperature coefficient increased with increasing temperature of heat treatment while electrical stability reached an optimum value. The results may be accounted for by segregation of the metallic and oxide parts of the film, a process which might be observed by electron diffraction techniques. S Brass, E Jets and A Mihalyi (Budapest, Hungary). 4.11 Production techniques for integrated thin film circuits. The physical and electrical properties of integrated thin film circuits and their dependence on the method of preparation are considered as well as some associated technological problems. Production methods for individual circuit elements such as resistors and capacitors are described. Reliability testing and economic aspects of thin film circuits are also discussed. J Katona (Budapest, Hungary), (in German). 4.12 Low-frequency properties of dielectric films. Measurements on vacuum deposited dielectric tilms at very low frequencies have shown the existence of two loss mechanisms: blocking of charge carriers at the electrodes leading to space-charge polarization with effective dielectric constants of the order of 10’ to 106; and partial blocking of charge carriers at intercrystallite boundaries producing a second dispersion region at higher frequencies. The first mechanism does not appreciably alfect the normal audio or radio frequency range at room temperature. In the second, the individual crystallites function as separate polarizable units
producing a distribution of relaxation times and causing losses extending into the radio frequency spectrum. Activation energies are of the order of 1 eV. C Weaver (Glasgow, Scotland). 4.13 Production method for capacitors, suitable for thin lllm microcircuits. The development of production techniques for capacitors in the range lOO-60,000 pF is described. Single or multiple capacitors are produced on a single support by evaporation under high vacuum. These devices find extensive applications in electronic apparatus. A Wolkenberg and D Szymanski (Warsaw, Poland), (in German). 4.14 Evaluation of thin film capacitors. Capacitors of the type Al/Al,O,/metal, with 5 to 250 nF capacitance were prepared by vacuum deposition of the electrodes with the dielectrics produced by anodic oxidation. The influence of the following factors on the reproducibility and dispersion of capacitance values was investigated: accuracy of mask sheets and their method of application; grain size of the aluminium surface; and the thickness of the dielectric film. G Wollitzer and T Strausz (Budapest, Hungary), (in German). 4.15 Vacuum deposited cerium fluoride capacitors for microcircuits. Vapour sources and substrates based on alumina ceramics were developed for the production of cerium fluoride capacitors. The sources permit high evaporation rates and prevent small particles being shot off from the source to the substrate. It has been shown that such particles give rise to short circuiting and poor electrical properties as well as strain in the dielectric layer. Cerium fluoride films gave capacitors with comparitively higher permitivity, higher figure of merit and lower loss factors. They also exhibit very good stability to moisture and storage in unconditioned atmosphere. V Hermansky (Hradec Kralove, CSSR). 4.16 Effect of non-uniform thickness of thin dielectric tllms on capacitance and tunnel currents. Sandwich thin film elements of the metal-insulator-metal type are considered with the assumption that the thickness (s) of the insulating layer is non-uniform and, at any given point is equal to nq, when q is a positive constant, closely related to the mean interatomic distance, and n is an integer with Poisson distribution. Relation between thickness, capacitance and tunnel currents are derived which show good agreement with experimental results of other authors. The effect of density of surface states at the metal-insulator interface is also taken into account. Z Hurych (Prague, CSSR). 4.17 The temperature dependence of the loss factor in SiO capacitors. The composition of silicon monoxide films greatly affects their electrical properties. It was experimentally verified that increasing the temperature of the supporting layer lowered the chemisorption of oxygen and at the same time increased the loss factor. The temperature/loss factor curve was obtained. A Wolkenberg (Warsaw, Poland), (in German). 4.18 Insulator films on germanium and their electrical properties. Thin films of silicon dioxide on germanium substrates were prepared by pyrolytic decomposition of tetraethoxysilane. Germanium dioxide films were also prepared, the hexagonal structure by treatment of the germanium substrate with concentrated nitric acid and the tetragonal type by prolonged heating at 700°C in water vapour. For both insulators the dielectric constant and breakdown and electrical surface properties were determined by field effect measurements. Surface structure was investigated by X-ray and electron microscopic analyses. G Oertel (Berlin-Adlershof, DDR), (in German). 4.19 Investigation of some mechanical and electrical properties of metal lllms formed on Si and Si02 surfaces. Metal films and film systems which are compatible with both the semiconductor and protective properties of silicon dioxide films are of increasing importance to modem semiconductor techniques. The mechanical and electrical properties of various metal films on silicon and on silicon dioxide were investigated. G Motal and J Bores-Gyevi (Budapest, Hungary). 337
Colloquium
on Thin Films (COTHIF)
4.6 Effect of vacuum on the high-frequency properties of thin metal film resistors. Gold and chromium films of similar geometric form were deposited on various glass and special plastic substrates by evaporation at lo-& to lo-* torr with evaporation rates in the range 10 to 100 A/set. The resistor films were given an additional heat treatment. The frequency range of resistors prepared under different growth conditions and the effect of vacuum on the uniformity of the film growth were investigated. The results show a correlation between film uniformity and frequency range of the resistor. M Lomniczy (Budapest, Hungary), (in German). 4.7 Dependence of some properties of Ni-Cr thin films on the parameters of the production processes. Three aspects of the production of nickel/chromium thin film resistors are discussed: the dependence of the temperature coefficient of resistance on deposition rate; the spread of resistance values obtained in a given cycle for evaporation both from the liquid and from the solid state; and the relation between resistivity and deposition rate, taking account of surface roughness in the substrate. J Boros-Gyevi and G Moth1 (Budapest, Hungary). 4.8 Vacuum deposited resistive thin films with high specific resistivity. The results of structural investigations of thin films with extremely high specific resistivity are presented, including: relations between the basic materials and their oxides; changes of structure due to heat treatment and their influence on the conduction mechanism; and the structural conditions for stability. A PaIll& E Farkas and G Bede (Budapest, Hungary). 4.9 Dependence of thermal coefficients on preparation conditions for evaporated gold and chromium films on amorphous substrates. The temperature was varied during the evaporation process between -50 and 400°C under pressures from 1O-6 to 10-O torr. Films were subjected to various additional heat treatments in vacuum and in atmosphere. Relations between evaporation rate, degree of vacuum, effect of heat treatment and the overall thermal coefficients are considered. These experiments were supplemented with film structure investigations. From the results conclusions are drawn regarding the preparation of films with given thermal coefficients. M Lomniczy (Budapest, Hungary), (in German). 4.10 Processes during the heat treatment of vacuum deposited NiCr Bhns. Nickel/chromium films (0 to 90 per cent Ni) prepared by flash evaporation already showed some degree of oxidation which could be increased by increasing the chromium content. Films of various composition were exposed to heat treatments for different times and temperatures and resistivity changes recorded. These changes could be attributed partly to thermal arranging and partly to oxidation. Temperature coefficient increased with increasing temperature of heat treatment while electrical stability reached an optimum value. The results may be accounted for by segregation of the metallic and oxide parts of the film, a process which might be observed by electron diffraction techniques. S Brass, E Jets and A Mihalyi (Budapest, Hungary). 4.11 Production techniques for integrated thin film circuits. The physical and electrical properties of integrated thin film circuits and their dependence on the method of preparation are considered as well as some associated technological problems. Production methods for individual circuit elements such as resistors and capacitors are described. Reliability testing and economic aspects of thin film circuits are also discussed. J Katona (Budapest, Hungary), (in German). 4.12 Low-frequency properties of dielectric films. Measurements on vacuum deposited dielectric tilms at very low frequencies have shown the existence of two loss mechanisms: blocking of charge carriers at the electrodes leading to space-charge polarization with effective dielectric constants of the order of 10’ to 106; and partial blocking of charge carriers at intercrystallite boundaries producing a second dispersion region at higher frequencies. The first mechanism does not appreciably alfect the normal audio or radio frequency range at room temperature. In the second, the individual crystallites function as separate polarizable units
producing a distribution of relaxation times and causing losses extending into the radio frequency spectrum. Activation energies are of the order of 1 eV. C Weaver (Glasgow, Scotland). 4.13 Production method for capacitors, suitable for thin lllm microcircuits. The development of production techniques for capacitors in the range lOO-60,000 pF is described. Single or multiple capacitors are produced on a single support by evaporation under high vacuum. These devices find extensive applications in electronic apparatus. A Wolkenberg and D Szymanski (Warsaw, Poland), (in German). 4.14 Evaluation of thin film capacitors. Capacitors of the type Al/Al,O,/metal, with 5 to 250 nF capacitance were prepared by vacuum deposition of the electrodes with the dielectrics produced by anodic oxidation. The influence of the following factors on the reproducibility and dispersion of capacitance values was investigated: accuracy of mask sheets and their method of application; grain size of the aluminium surface; and the thickness of the dielectric film. G Wollitzer and T Strausz (Budapest, Hungary), (in German). 4.15 Vacuum deposited cerium fluoride capacitors for microcircuits. Vapour sources and substrates based on alumina ceramics were developed for the production of cerium fluoride capacitors. The sources permit high evaporation rates and prevent small particles being shot off from the source to the substrate. It has been shown that such particles give rise to short circuiting and poor electrical properties as well as strain in the dielectric layer. Cerium fluoride films gave capacitors with comparitively higher permitivity, higher figure of merit and lower loss factors. They also exhibit very good stability to moisture and storage in unconditioned atmosphere. V Hermansky (Hradec Kralove, CSSR). 4.16 Effect of non-uniform thickness of thin dielectric tllms on capacitance and tunnel currents. Sandwich thin film elements of the metal-insulator-metal type are considered with the assumption that the thickness (s) of the insulating layer is non-uniform and, at any given point is equal to nq, when q is a positive constant, closely related to the mean interatomic distance, and n is an integer with Poisson distribution. Relation between thickness, capacitance and tunnel currents are derived which show good agreement with experimental results of other authors. The effect of density of surface states at the metal-insulator interface is also taken into account. Z Hurych (Prague, CSSR). 4.17 The temperature dependence of the loss factor in SiO capacitors. The composition of silicon monoxide films greatly affects their electrical properties. It was experimentally verified that increasing the temperature of the supporting layer lowered the chemisorption of oxygen and at the same time increased the loss factor. The temperature/loss factor curve was obtained. A Wolkenberg (Warsaw, Poland), (in German). 4.18 Insulator films on germanium and their electrical properties. Thin films of silicon dioxide on germanium substrates were prepared by pyrolytic decomposition of tetraethoxysilane. Germanium dioxide films were also prepared, the hexagonal structure by treatment of the germanium substrate with concentrated nitric acid and the tetragonal type by prolonged heating at 700°C in water vapour. For both insulators the dielectric constant and breakdown and electrical surface properties were determined by field effect measurements. Surface structure was investigated by X-ray and electron microscopic analyses. G Oertel (Berlin-Adlershof, DDR), (in German). 4.19 Investigation of some mechanical and electrical properties of metal lllms formed on Si and Si02 surfaces. Metal films and film systems which are compatible with both the semiconductor and protective properties of silicon dioxide films are of increasing importance to modem semiconductor techniques. The mechanical and electrical properties of various metal films on silicon and on silicon dioxide were investigated. G Motal and J Bores-Gyevi (Budapest, Hungary). 337