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1086. A molecular vacuum pump
Classified abstracts 1077--1087 18 1077. Low-pressure high-frequency discharge in combined highfrequency and static magnetic field close to electron cyclotron resonance. (USSR) Ultrahigh-frequency discharge in mercury vapour at pressure of 1 × 10-3 torr in combined high frequency and static magnetic field near the electron cyclotron resonance is investigated experimentally. The experimental arrangement is described. K S Golovanivskiy and V D Dugar-Zhabon, Zh Tekh Fiz, 41 (1), Jan 1971, 104--113 (in Russian). 18 1078. Dependence of cathode properties on neon doping and discharge current. (Hungary) The influence of neon gas doping on the cathode properties of mercury vapour-argon discharges is investigated. The dependence on the partial pressure of neon of the cathode fall, cathode spot temperature, length of cathode side spaces, the field strength of the positive column, the voltage drop, and power consumption of the discharge tube was determined. The dependence of cathode properties on the discharge current was also determined. J F Bito, .4eta Tech Acad Sci Hung, 68 (1-2), 1970, 29-49. 18 1079. A laser beam method for the examination of cathode spaces. (Hungary) An interferometric method using a laser beam is presented which enables determination of the value of the electron concentration, its time dependence and axial distribution in the cathode space of gas discbarge. J F Bito, Acta Tech AcadSci Hung, 68 (1-2), 1970, 161-178.
II. V a c u u m apparatus and auxiliaries 20. P U M P I N G SYSTEMS 2O 1083. Ultrahigh vacuum apparatus for evaporation of semiconductors and metals by electron beam. (USSR) A n ultrahigh vacuum apparatus for electron beam evaporation of metals and semiconductors has been built. It can also be used for obtaining epitaxial layers of semiconductors. The apparatus consists of a working chamber, an inlet chamber, two electron guns for evaporation of pure silicon and the alloying process, and a lock separating the inlet and working chamber. G N Gridneva et al, Elektron Tekh Materialy, 5, 1970, 131-134 (in
Russian). 20 1084. Design problems of vacuum systems in equipment for ion sputtering of materials. (USSR) In contrast to equipments for thermal evaporation which usually operate at 10-5 to 10-7 torr, ion sputtering systems have to be initially evacuated to high vacuum and then operate for a long time in conditions of medium vacuum with considerable flow of inert gas or mixture of inert and reactive gases. These requirements are difficult to fulfil by conventional pumps. In most cases efficient protection against penetration of vapour of the pump fluids is necessary. The choice of the proper vacuum system can be made only after experimental verification and mass spectrometric analysis of the residual ambient. V P Belevskiy et al, Elektron Tekh Mikroelektron, 3, 1970, 5-12 (in
Russian).
18
20
1080. The cathode-plasma interaction of low-pressure arc discharges with oxide cathodes. (Hungary) Analysis of the static and functional parameters of the oxide cathode and their influence on the discharge spaces is presented. Coupling between cathode and cathode space is ensured through the emission current and the ion current impinging on the cathode. J F Bito, Acta Teeh Acad Sci Hung, 68 (1-2), 1070, 255-258.
1085. Automated pumping system and control of apparatus for vacuum deposition of thin films. (USSR) Application of pneumatic switching arrangement (with electromagnetic control) in combination with a system of vacuum measurement at different locations, the signals of which control the successive actions of mechanisms, enabled the development of an automated pumping system with a high degree of reliability and flexible programming of control. Utilization of a liquid nitrogen trap with automatic maintenance of liquid nitrogen level during operation of the high vacuum pump enabled the ultimate pressure of 1 × 10 7 tort to be reliably attained in the working chamber. A A Alekseev et al, Elektron Tekh Mikroelektron, 3, 1970, 136-142
18:47 1081. Mass-spectrometric investigation of the degnssing of polycrystalline tantalum carbide cathodes. (USSR) Using a mass spectrometer, the process of degassing of a polycrystalline tantalum carbide cathode, prepared by annealing of tantalum ribbon in benzol vapour at high temperature, is investigated. Simultaneously with degassing, the thermionic current from cathode surface is measured. It is found that the work function increases with enhancement of carbon-containing component concentration. The tantalum carbide surface is made free from carbon at low temperature by interaction with oxygen and water vapour contained in residual gases. With a cathode temperature increase, the quantity of evaporating carbon from the tantalum carbide surface is augmented. At high temperatures of the order of 2000°K, carbon is removed from tantalum carbide not only by interaction with residual gases of the vacuum system but also by evaporation. E F Chaykovskiy and V A Vlasenko, Monokryst Tekh, 2, 1970, 147151 (in Russian). 18 1082. Cathodic sputtering of M g O and AgMg alloy by residual gas ions. (USSR) The method and results of measurement of some parameters of cathodic sputtering of MgO and AgMg alloy under the action of residual gas ion bombardment, consisting mainly of No + and O2+, are presented. The coefficients of cathode sputtering and their dependence on the ion current density are determined. The dependence of the sputtering rate on the ion energy and the thickness of the removed layer of the activated alloy is measured. The changes of secondary electron emission properties of the alloy due to sputtering are investigated. The analysis of the results provides a qualitative determination of the distribution of MgO in the sample depth. V N Leposhinskaya and E M Zarutskiy, Elektron Tekh Elektronluch Fotoelektr Prib, 2, 1970, 60-64 (in Russian).
494
(in Russian). 21. P U M P S AND P U M P FLUIDS 21 1086. A molecular vacuum pump. (USSR) An improved version of a molecular vacuum pump is described; the pump differs from existing versions in that helical grooves are made in the stator in a direction opposite to the corresponding grooves in the rotor. The slope of the grooves increases in the direction of evacuation, and the number of grooves in the stator and rotor is greater near the inlet than near the outlet pipes. Apart from this the general form of the pump is quite conventional, except that special additional arrangements are made in order to ensure the good vacuum properties of the rotor shaft and the pulley attached to the latter, as well as compensating for any slight vibrations which may occur in motion. I R Zatsman, USSR Patent, No 270,166, appl 6th Dec 1965, publd 14th Aug 1970. 21 1087. Orbitron getter-ion pump. (USSR) Two types of orbitron getter-ion pump have been developed, the OGIN--0.3 and OGIN--0.1, intended for application in thin film deposition systems. The OGIN--0.3 is mounted directly in the working volume to decrease the pressure and improve the residual gas composition. The O G I N ~ 0 . 1 is used as supplementary pump in high vacuum systems with cryogenic pumping to remove noncondensible components from the residual ambient. The cylindrical body of the OGIN--O.I is equipped with a water cooling jacket. The body of the O G 1 N ~ ) . 3 is made of separate plates which protect the pumped volume against penetration of sublimated titanium and provide free
II. V a c u u m apparatus and auxiliaries 20. P U M P I N G SYSTEMS 2O 1083. Ultrahigh vacuum apparatus for evaporation of semiconductors and metals by electron beam. (USSR) A n ultrahigh vacuum apparatus for electron beam evaporation of metals and semiconductors has been built. It can also be used for obtaining epitaxial layers of semiconductors. The apparatus consists of a working chamber, an inlet chamber, two electron guns for evaporation of pure silicon and the alloying process, and a lock separating the inlet and working chamber. G N Gridneva et al, Elektron Tekh Materialy, 5, 1970, 131-134 (in
Russian). 20 1084. Design problems of vacuum systems in equipment for ion sputtering of materials. (USSR) In contrast to equipments for thermal evaporation which usually operate at 10-5 to 10-7 torr, ion sputtering systems have to be initially evacuated to high vacuum and then operate for a long time in conditions of medium vacuum with considerable flow of inert gas or mixture of inert and reactive gases. These requirements are difficult to fulfil by conventional pumps. In most cases efficient protection against penetration of vapour of the pump fluids is necessary. The choice of the proper vacuum system can be made only after experimental verification and mass spectrometric analysis of the residual ambient. V P Belevskiy et al, Elektron Tekh Mikroelektron, 3, 1970, 5-12 (in
Russian).
18
20
1080. The cathode-plasma interaction of low-pressure arc discharges with oxide cathodes. (Hungary) Analysis of the static and functional parameters of the oxide cathode and their influence on the discharge spaces is presented. Coupling between cathode and cathode space is ensured through the emission current and the ion current impinging on the cathode. J F Bito, Acta Teeh Acad Sci Hung, 68 (1-2), 1070, 255-258.
1085. Automated pumping system and control of apparatus for vacuum deposition of thin films. (USSR) Application of pneumatic switching arrangement (with electromagnetic control) in combination with a system of vacuum measurement at different locations, the signals of which control the successive actions of mechanisms, enabled the development of an automated pumping system with a high degree of reliability and flexible programming of control. Utilization of a liquid nitrogen trap with automatic maintenance of liquid nitrogen level during operation of the high vacuum pump enabled the ultimate pressure of 1 × 10 7 tort to be reliably attained in the working chamber. A A Alekseev et al, Elektron Tekh Mikroelektron, 3, 1970, 136-142
18:47 1081. Mass-spectrometric investigation of the degnssing of polycrystalline tantalum carbide cathodes. (USSR) Using a mass spectrometer, the process of degassing of a polycrystalline tantalum carbide cathode, prepared by annealing of tantalum ribbon in benzol vapour at high temperature, is investigated. Simultaneously with degassing, the thermionic current from cathode surface is measured. It is found that the work function increases with enhancement of carbon-containing component concentration. The tantalum carbide surface is made free from carbon at low temperature by interaction with oxygen and water vapour contained in residual gases. With a cathode temperature increase, the quantity of evaporating carbon from the tantalum carbide surface is augmented. At high temperatures of the order of 2000°K, carbon is removed from tantalum carbide not only by interaction with residual gases of the vacuum system but also by evaporation. E F Chaykovskiy and V A Vlasenko, Monokryst Tekh, 2, 1970, 147151 (in Russian). 18 1082. Cathodic sputtering of M g O and AgMg alloy by residual gas ions. (USSR) The method and results of measurement of some parameters of cathodic sputtering of MgO and AgMg alloy under the action of residual gas ion bombardment, consisting mainly of No + and O2+, are presented. The coefficients of cathode sputtering and their dependence on the ion current density are determined. The dependence of the sputtering rate on the ion energy and the thickness of the removed layer of the activated alloy is measured. The changes of secondary electron emission properties of the alloy due to sputtering are investigated. The analysis of the results provides a qualitative determination of the distribution of MgO in the sample depth. V N Leposhinskaya and E M Zarutskiy, Elektron Tekh Elektronluch Fotoelektr Prib, 2, 1970, 60-64 (in Russian).
494
(in Russian). 21. P U M P S AND P U M P FLUIDS 21 1086. A molecular vacuum pump. (USSR) An improved version of a molecular vacuum pump is described; the pump differs from existing versions in that helical grooves are made in the stator in a direction opposite to the corresponding grooves in the rotor. The slope of the grooves increases in the direction of evacuation, and the number of grooves in the stator and rotor is greater near the inlet than near the outlet pipes. Apart from this the general form of the pump is quite conventional, except that special additional arrangements are made in order to ensure the good vacuum properties of the rotor shaft and the pulley attached to the latter, as well as compensating for any slight vibrations which may occur in motion. I R Zatsman, USSR Patent, No 270,166, appl 6th Dec 1965, publd 14th Aug 1970. 21 1087. Orbitron getter-ion pump. (USSR) Two types of orbitron getter-ion pump have been developed, the OGIN--0.3 and OGIN--0.1, intended for application in thin film deposition systems. The OGIN--0.3 is mounted directly in the working volume to decrease the pressure and improve the residual gas composition. The O G I N ~ 0 . 1 is used as supplementary pump in high vacuum systems with cryogenic pumping to remove noncondensible components from the residual ambient. The cylindrical body of the OGIN--O.I is equipped with a water cooling jacket. The body of the O G 1 N ~ ) . 3 is made of separate plates which protect the pumped volume against penetration of sublimated titanium and provide free