- Email: [email protected]
1265. Electron diffraction study of the crystallization kinetics of amorphous antimony films
Classified abstracts 1256-1265 path is added to the sealogram of the corresponding concentrically machined surface. The possibility of using these conclusions in optimizing the design of vacuum seals is discussed. (Israel) A Roth and A Inbar, Vacuum, 18 (6), June 1968, 309-317. 23 1256. Improved tee connections for vacuum systems. (USA) Improved welded tee connections are made by drawing a die of circular cross section through an elliptical cut-out in the wall of the main tube to form a smooth tee transition. The shape of the cut-out is such that the end of the tee is a fiat surface requiring only minor weld preparations. The end of the tee is then butt-welded by a full penetration fusion weld. to the extension tube H M Ruess, Rep LA-DC 8978, 1967, 13 pages (Sci Tech Aerospace Reps, 8 (4), 517, N68-13875). 26. AUTOMATIC PROTECTIVE AND CONTROL EQUIPMENT 26 1257. Cryostat for thermal measurements between 2-300°K. (USA) A modification of the Giauque-Johnston cryostat for thermal measurements in the temperature range 2-300°K has been designed and constructed. A variable temperature regulated radiation shield between the cold wall and the inner sections of the cryostat leads to a working section which can be maintained to a millidegree at any temperature in the working range of the cryostat. J Bigeleisen et al, Rev Sci lnstrum, 39 (3), 1968, 353-356. 27. LEAK DETECTORS AND LEAK DETECTION 27:18 Quadrapoles, monopoles and ion traps. See abstract number 1225. 27 : 22 Combined leak detector and high sensitivity vacuum gauge. See abstract number 1251. 28. HEATING EQUIPMENT AND THERMOMETERS 28 1258. Thermoelectric potentials for a tungsten-tantalum thermocouple from 0 to 420°C. (Great Britain) The thermoelectric potentials produced by a W-Ta thermocouple were measured at several international secondary fixed-temperature points. The thermocouple may be used in direct contact with boiling mercury for extended periods. (USA) L V Feigenbutz, J Sci lnstrum, Ser 2, 1 (4), 1968, 489-490.
III. Vacuum applications 30. EVAPORATION AND SPUTTERING Calculation of ion bombarding energy and its distribution in rf sputtering. See abstract number 1217. 30:18 Efficient sputtering in a cold-cathode discharge in magnetron geometry. See abstract number 1218. 3O 1259. Effect of oxygen on the rf sputtering rate of SiO2. (USA) The rf sputtering rate of SiO= decreases rapidly when comparatively small partial pressures (about 10-~ tort) of oxygen are added to the argon sputtering gas. The magnitude of the increase is also dependent on the rf input power. Both of these phenomena are explained by a model which assumes that the sputtering rate is lowered by the replacement (from the gas) of oxygen atoms which have previously been sputtered out of the SiO2 target. R E Jones et al, J Vac Sci Technol, 5 (3), May-June 1968, 84-87. 3O 1260. Fractionation of Ni-Cr-Cu-AI alloys during vacuum evaporation.
(USA) Several apparent anomalies were found between experimental and theoretical compositions of thin films, when deposited from Ni-Cr-CuAI alloys. Films were obtained by condensation during successive intervals of evaporation, and analysis was performed by emission spectrographic techniques. Theoretical compositions were calculated
by successive approximations using Langmuir's equation and Raoult's Law. These predicted that the initial major components should be A1 and Cr with the copper concentration remaining fairly constant throughout the evaporation. Experimentally, more Ni and Cu and less Cr appeared in the initial films than the theory predicted. The rate of evaporation of AI was strongly dependent upon the source temperature and initial composition. These anomalies are explained by the formation of intermetallic compounds in the source. A model for the evaporation mechanism is proposed. R A Swift et al, J Vac Sci Technol, 5 (3), May-June 1968, 79-83. 30:33 1261. Rapid method for preparing single stage carbon replicas for electron microscopy of some mineral crystals. (USA) A method is described, in which on the surface of CaF2 to be examined a film of sodium chloride is deposited by thermal evaporation in vacuum. Carbon film of the required thickness was then deposited on the thin layer (50A) of NaC1 without breaking the vacuum. These carbon replicas were easily detached from the surfaces by oblique dipping in distilled water. A R Patel and S M Patel, Rev Sci Instrum, 39 (3), 1968, 409-410. 30 : 32 1262. A low-energy ion source for the deposition of chromium. (Great Britain) The feasibility of depositing metal films from a well-defined, beam of positively charged chromium ions is discussed. The design and development of an ion source suitable for this work are described and problems related to the extraction, focusing and deflection of such an ion beam are considered. It is found that the desired focusing and deflection conditions cannot be achieved in practice because of certain fundamental limitations. A low-energy beam of less than 500 eV is necessary to obtain a deposit and prevent damage to the substrate by sputtering. Thus space charge effects become predominant, causing spreading of the beam. A lens system having a very short focal length is necessary to give a high beam convergence angle. This limits the deflection obtainable without loss of definition. Energy spread within the beam may also contribute to poor focusing. A minimum beam diameter of 0.5 mm has been obtained from an ion beam of energy 230 eV having a current density of 8 microA mm -=. Under these conditions the condensation coefficient was found to be approximately 25 per cent giving a deposition rate of 100 A min -~. B A Probyn, Brit J Appl Phys, Ser 2, 1 (4), 1968, 457-465. 30 : 33 1263. Stripping thin oxide films from metals. (Great Britain) A technique is described for stripping thin (25 A or less) oxide films from metals for electron microscopy. Plastic is used as a temporary support and a tartan carbon film is retained as a permanent support. The prepared surface is first coated with thin evaporated carbon film as a permanent support. A rigid support is added by depositing Alloprene D (ICI) from chloroform solution. The coated specimen is treated with a solution of iodine in methanol until the metal is completely dissolved. T G Dye et al, J Sci lnstrum, Set 2, 1 (4), 1968, 463-464. 30 1264. Study on the structure of evaporated gold particles by means of a high resolution electron microscope. (Japan) The structure of evaporated gold particles was examined through the (111) lattice image observation. Rock salt substrates cleaved in the atmosphere were placed on a copper plate heated up to 300°C. Gold was deposited onto these rocksalt faces in a vacuum of 1 × 10-s torr at a rate of a few ~/min. After the deposition (5-50 A~) was finished the copper plate was cooled below 100°C and the gold deposit was coated with carbon. The carbon film with gold particles on it was separated from the substrate onto a water surface, and mounted on a micro-grid. The nucleation process is explained. T Komoda, Japan J Appl Phys, 7 (1), 1968, 27-30. 3O 1265. Electron diffraction study of the crystallization kinetics of amorphous antimony films. (USSR) Amorphous antimony films with the thickness of 150 A, were condensed under vacuum of 10-5 torr at 135 to 200°C and the kinetics of crystalline structure formation were observed. The energy of activation of the films (19 kcal/mol) and the activation energy of the crystal growth (9.5 kcal/mol) were determined. G A Efendiev and F I Aliev, Dokl Akad Nauk SSSR, 179 (2), 21st Fe5 1968, 314-315 (in Russian).
535
III. Vacuum applications 30. EVAPORATION AND SPUTTERING Calculation of ion bombarding energy and its distribution in rf sputtering. See abstract number 1217. 30:18 Efficient sputtering in a cold-cathode discharge in magnetron geometry. See abstract number 1218. 3O 1259. Effect of oxygen on the rf sputtering rate of SiO2. (USA) The rf sputtering rate of SiO= decreases rapidly when comparatively small partial pressures (about 10-~ tort) of oxygen are added to the argon sputtering gas. The magnitude of the increase is also dependent on the rf input power. Both of these phenomena are explained by a model which assumes that the sputtering rate is lowered by the replacement (from the gas) of oxygen atoms which have previously been sputtered out of the SiO2 target. R E Jones et al, J Vac Sci Technol, 5 (3), May-June 1968, 84-87. 3O 1260. Fractionation of Ni-Cr-Cu-AI alloys during vacuum evaporation.
(USA) Several apparent anomalies were found between experimental and theoretical compositions of thin films, when deposited from Ni-Cr-CuAI alloys. Films were obtained by condensation during successive intervals of evaporation, and analysis was performed by emission spectrographic techniques. Theoretical compositions were calculated
by successive approximations using Langmuir's equation and Raoult's Law. These predicted that the initial major components should be A1 and Cr with the copper concentration remaining fairly constant throughout the evaporation. Experimentally, more Ni and Cu and less Cr appeared in the initial films than the theory predicted. The rate of evaporation of AI was strongly dependent upon the source temperature and initial composition. These anomalies are explained by the formation of intermetallic compounds in the source. A model for the evaporation mechanism is proposed. R A Swift et al, J Vac Sci Technol, 5 (3), May-June 1968, 79-83. 30:33 1261. Rapid method for preparing single stage carbon replicas for electron microscopy of some mineral crystals. (USA) A method is described, in which on the surface of CaF2 to be examined a film of sodium chloride is deposited by thermal evaporation in vacuum. Carbon film of the required thickness was then deposited on the thin layer (50A) of NaC1 without breaking the vacuum. These carbon replicas were easily detached from the surfaces by oblique dipping in distilled water. A R Patel and S M Patel, Rev Sci Instrum, 39 (3), 1968, 409-410. 30 : 32 1262. A low-energy ion source for the deposition of chromium. (Great Britain) The feasibility of depositing metal films from a well-defined, beam of positively charged chromium ions is discussed. The design and development of an ion source suitable for this work are described and problems related to the extraction, focusing and deflection of such an ion beam are considered. It is found that the desired focusing and deflection conditions cannot be achieved in practice because of certain fundamental limitations. A low-energy beam of less than 500 eV is necessary to obtain a deposit and prevent damage to the substrate by sputtering. Thus space charge effects become predominant, causing spreading of the beam. A lens system having a very short focal length is necessary to give a high beam convergence angle. This limits the deflection obtainable without loss of definition. Energy spread within the beam may also contribute to poor focusing. A minimum beam diameter of 0.5 mm has been obtained from an ion beam of energy 230 eV having a current density of 8 microA mm -=. Under these conditions the condensation coefficient was found to be approximately 25 per cent giving a deposition rate of 100 A min -~. B A Probyn, Brit J Appl Phys, Ser 2, 1 (4), 1968, 457-465. 30 : 33 1263. Stripping thin oxide films from metals. (Great Britain) A technique is described for stripping thin (25 A or less) oxide films from metals for electron microscopy. Plastic is used as a temporary support and a tartan carbon film is retained as a permanent support. The prepared surface is first coated with thin evaporated carbon film as a permanent support. A rigid support is added by depositing Alloprene D (ICI) from chloroform solution. The coated specimen is treated with a solution of iodine in methanol until the metal is completely dissolved. T G Dye et al, J Sci lnstrum, Set 2, 1 (4), 1968, 463-464. 30 1264. Study on the structure of evaporated gold particles by means of a high resolution electron microscope. (Japan) The structure of evaporated gold particles was examined through the (111) lattice image observation. Rock salt substrates cleaved in the atmosphere were placed on a copper plate heated up to 300°C. Gold was deposited onto these rocksalt faces in a vacuum of 1 × 10-s torr at a rate of a few ~/min. After the deposition (5-50 A~) was finished the copper plate was cooled below 100°C and the gold deposit was coated with carbon. The carbon film with gold particles on it was separated from the substrate onto a water surface, and mounted on a micro-grid. The nucleation process is explained. T Komoda, Japan J Appl Phys, 7 (1), 1968, 27-30. 3O 1265. Electron diffraction study of the crystallization kinetics of amorphous antimony films. (USSR) Amorphous antimony films with the thickness of 150 A, were condensed under vacuum of 10-5 torr at 135 to 200°C and the kinetics of crystalline structure formation were observed. The energy of activation of the films (19 kcal/mol) and the activation energy of the crystal growth (9.5 kcal/mol) were determined. G A Efendiev and F I Aliev, Dokl Akad Nauk SSSR, 179 (2), 21st Fe5 1968, 314-315 (in Russian).
535