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569. Theoretical consideration of inhomogeneities in long thermionic systems
Classified abstracts 560--569 30 560. Photon emission from sputtered particles during ion bombardment. (Germany) The emission of photons, when the surfaces of metals, semiconductors, ionic crystals, and glasses are bombarded by 5 to 8 keV argon ions, has been studied by spectroscopic analysis. The ion bombardment unit consisted of a single hollow anode type dc ion source. mounted on top of a metallic chamber fitted with a quartz window The ion current density at the target surface was about 200/~A cm -6 for normal incidence. The bombardment chamber was evacuated to below 10-6 torr before the commencement of each experiment. The conditions for the resonance transfer of an electron between a metal and an ionized or excited atom at small distances from the surface are examined and applied to the sputtered particles of the various materials. It is established that these conditions govern the light emission from the low-energy sputtered particles of metals and are also to some extent applicable to semiconductors. For insulators, however, the radiation appears to come only from excited sputtered atoms. It is noted that the sputtering process can be used as an analytical tool. The discrete atomic lines of the various constituent elements in the target materials, especially insulators, observed during ion bombardment provide a new way of analyzing surfaces of materials. I S T Tsong, Phys Stat Sol(a), 7 (2), Oct 1971,451-458. 30 561. The effect of reactor irradiation on the electrical properties of amorphous germanium. (Germany) The effect of reactor irradiation on the electrical properties of thin films of amorphous germanium has been studied. The thin films were evaporated in a vacuum of about 10 -e torr on glass substrates. Irradiation was found to decrease the resistivity of heat treated germanium thin films at the same time increasing the dielectric losses of thin film capacitors made of the same material. O I A Tiainen, Phys Stat Sol (a), 7 (2), Oct 1971, 583-591. 30 562. On the mechanism of electrical breakdown of thin polymer films. (USSR) Characteristics of electrical breakdown of thin-film structures, metal-polymer-metal, are investigated. The polymer thin films were prepared by polymerization of octamethyltrisiioxane in glow discharge. It is found that tunnel emission of electrons from the cathode with subsequent impact ionization in the dielectric forms the basic breakdown mechanism. V Ya Ayvazov and V G Kobka, Zh Tekh Fiz, 41 (10), Oct 1971, 22442246 (in Russian). 30 563. Influence of the protective medium on the thermal stability of evaporated metallic films. (USSR) The thermal stability of gold and copper vacuum evaporated films in the temperature range 200 to 800°C is investigated. A relationship between adhesion and weldability of the films is found. Influence of the protective medium on the thermal stability of metallic films is discussed. I A Granberg and R A Svetlichnaya, Electronic Technology, SclentTechn Collect, Microelectronics, No 6, 1971, 161-163 (in Russian). 30 564. Calculation of the surface temperature of a film during deposition. (USSR) In vacuum deposition it is important to know the true temperature of the depositing film, because the surface temperature determines the rate of surface migration, the coefficients of accommodation and diffusion in the films and also the probability of many processes taking place in the films during condensation. After the beginning of evaporation, energy is transported to the substrate and the temperature of film is determined by evaporator radiation and condensation of material. Thermodynamic equilibrium is disturbed on commencement of evaporation. If the energy transported to the substrate is constant, then after some time thermodynamic equilibrium is restored. The surface layer is formed on all boundaries. The highest value of the coefficient of thermal resistance should be expected at the boundary metal-dielectric, where, except for high losses for disordering of structure, the change of heat transfer mechanism takes place. M M Nekrasov and A G Zaporozhets, Problems o f Microelectronics, Collect, Kiev Naukovaya Dumka 1971, 172-179 (in Russian).
30 565. Electrical resistance peak in superconducting lead films in a perpendicular magnetic field. (Germany) Current-voltage measurements in approximately 3 /~m thick lead films were made in a perpendicular magnetic field. Lead of high purity was evaporated at a pressure below 2 x 10-6 tort onto a glass substrate which was at or above room temperature. The evaporation rate was varied from 100 to 1000/~/sec. All measurements were made with the specimen in liquid helium at about 4.2°K. An electrical resistance peak was found in superconducting lead films in a perpendicular magnetic field. It is shown that the sloping sample edges formed on condensation of lead beyond the mask edge can be very important in transport measurements, and that they strongly influence the appearance of the resistance peak. K E Grey et al, Phys Star Sol (a), 7 (2), Oct 1971, K73-K76. 30 566. Electrical conductivity of thin films of lead oxide synthesized by reactive cathodic sputtering. (Germany) Thin films of PbO on glass substrates synthesized by diode reactive sputtering of lead in an atmosphere of argon containing 4 per cent of oxygen were investigated. According to the sputtering conditions, tetragonal aPbO or orthorombic/~PbO was obtained. Structure of the films was determined with the aid of x-ray methods. Thickness of the films varied from 1.5 to 2.8 /~m. Electric conductivity of the PbO films was investigated in the interval 140 to 560°K. The activation energies of/~PbO were (1.04-0.1) eV for temperatures above 460°K and (0.734-0.08) eV below 460°K. The activation energies of aPbO were (0.684-0.08) eV for temperatures above 320°K and (0.564-0.08) eV for temperatures below 320°K. The electrical conductivity of PbO thin films is 2 x 10-1° ohm-lcm -1 at room temperature. The thin films of aPbO doped with Bi and Ag were prepared and their electrical properties investigated. A Czapla and M Jachimovski, Phys Stat So/ (a), 7 (2), Oct 1971,
K79-K81 (in French). 30 567. Voltage characteristics of planar galvanomagnetic effect in thin ferromagnetic films. (Germany) Voltage characteristics of planar gaivanomagnetic effect are studied both theoretically and experimentally in thin ferromagnetic films. Samples were prepared by evaporation of a 79 per cent Ni, 16 per cent Fe, 4 per cent Mo alloyin a vacuum of approximately 10-6 torr onto optically plane glass substrates at 250°C in a magnetic field of about 120 Oe. In the same process electrodes were deposited. The ferromagnetic films were 500 to 1000/~ thick. It is found that the planar galvanomagnetic effect is applicable to the construction of thin-film multiplying elements. The voltage characteristics can be to some extent modified with respect to requirements by applying appropriate premagnetizing fields. Z Sczaniecki et al, Phys Stat Sol (a), 7 (2), Oct 1971, 597-602. 31. EVACUATION AND SEALING 31 568. Time characteristics of high-voltage controlled dischargers operating at low pressures. (USSR) The results of measurement of the time lags of controlled dischargers operating at voltages of 5 to 50 kV and initial pressures in the range 6 × 10-s to 6 × 10-6 torr are presented. It is supposed that at pressures above 4 x 10-8 torr the discharge initiating mechanism is determined by impact ionization of residual gas by electrons from the starting spark. At lower pressures in the range 10 -3 to 10-5 torr the plasma stream from the ignition region plays the determining role. G S Kichaeva, Zh Tekh Fiz, 41 (9), Sept 1971, 1963-1968 (in Russian). 31 569. Theoretical consideration of inhomogeneities in long thermionic systems. (USSR) Due to the dependence of the emission current on the emitter temperature, with negative slope, the heat transport from the emitter can decrease with increasing temperature and an instability in the caesium thermionic energy converter may arise. Linear and nonlinear theories of the arc regime of long caesium diodes are considered. Stationary states and their stability of caesium diode operation are studied. Yu Yu Abramov et al, Zh Tekh Fiz, 41 (9), Sept 1971, 1936-1942 (in
Russian). 171
30 565. Electrical resistance peak in superconducting lead films in a perpendicular magnetic field. (Germany) Current-voltage measurements in approximately 3 /~m thick lead films were made in a perpendicular magnetic field. Lead of high purity was evaporated at a pressure below 2 x 10-6 tort onto a glass substrate which was at or above room temperature. The evaporation rate was varied from 100 to 1000/~/sec. All measurements were made with the specimen in liquid helium at about 4.2°K. An electrical resistance peak was found in superconducting lead films in a perpendicular magnetic field. It is shown that the sloping sample edges formed on condensation of lead beyond the mask edge can be very important in transport measurements, and that they strongly influence the appearance of the resistance peak. K E Grey et al, Phys Star Sol (a), 7 (2), Oct 1971, K73-K76. 30 566. Electrical conductivity of thin films of lead oxide synthesized by reactive cathodic sputtering. (Germany) Thin films of PbO on glass substrates synthesized by diode reactive sputtering of lead in an atmosphere of argon containing 4 per cent of oxygen were investigated. According to the sputtering conditions, tetragonal aPbO or orthorombic/~PbO was obtained. Structure of the films was determined with the aid of x-ray methods. Thickness of the films varied from 1.5 to 2.8 /~m. Electric conductivity of the PbO films was investigated in the interval 140 to 560°K. The activation energies of/~PbO were (1.04-0.1) eV for temperatures above 460°K and (0.734-0.08) eV below 460°K. The activation energies of aPbO were (0.684-0.08) eV for temperatures above 320°K and (0.564-0.08) eV for temperatures below 320°K. The electrical conductivity of PbO thin films is 2 x 10-1° ohm-lcm -1 at room temperature. The thin films of aPbO doped with Bi and Ag were prepared and their electrical properties investigated. A Czapla and M Jachimovski, Phys Stat So/ (a), 7 (2), Oct 1971,
K79-K81 (in French). 30 567. Voltage characteristics of planar galvanomagnetic effect in thin ferromagnetic films. (Germany) Voltage characteristics of planar gaivanomagnetic effect are studied both theoretically and experimentally in thin ferromagnetic films. Samples were prepared by evaporation of a 79 per cent Ni, 16 per cent Fe, 4 per cent Mo alloyin a vacuum of approximately 10-6 torr onto optically plane glass substrates at 250°C in a magnetic field of about 120 Oe. In the same process electrodes were deposited. The ferromagnetic films were 500 to 1000/~ thick. It is found that the planar galvanomagnetic effect is applicable to the construction of thin-film multiplying elements. The voltage characteristics can be to some extent modified with respect to requirements by applying appropriate premagnetizing fields. Z Sczaniecki et al, Phys Stat Sol (a), 7 (2), Oct 1971, 597-602. 31. EVACUATION AND SEALING 31 568. Time characteristics of high-voltage controlled dischargers operating at low pressures. (USSR) The results of measurement of the time lags of controlled dischargers operating at voltages of 5 to 50 kV and initial pressures in the range 6 × 10-s to 6 × 10-6 torr are presented. It is supposed that at pressures above 4 x 10-8 torr the discharge initiating mechanism is determined by impact ionization of residual gas by electrons from the starting spark. At lower pressures in the range 10 -3 to 10-5 torr the plasma stream from the ignition region plays the determining role. G S Kichaeva, Zh Tekh Fiz, 41 (9), Sept 1971, 1963-1968 (in Russian). 31 569. Theoretical consideration of inhomogeneities in long thermionic systems. (USSR) Due to the dependence of the emission current on the emitter temperature, with negative slope, the heat transport from the emitter can decrease with increasing temperature and an instability in the caesium thermionic energy converter may arise. Linear and nonlinear theories of the arc regime of long caesium diodes are considered. Stationary states and their stability of caesium diode operation are studied. Yu Yu Abramov et al, Zh Tekh Fiz, 41 (9), Sept 1971, 1936-1942 (in
Russian). 171