330
Classified Abstracts 679--690
Vacuum Applications 30.
E v a p o r a t i o n and S p u t t e r i n g
30 : 33 679. Metal oxide film resistors. Manufacturer's announcement (Electrosil, Ltd.). Anon., Brit. Commun. & Electronics, 9 (5), May 1962, 395.
1050°C. The films were generally subjected to heat-treatment after the deposition. The films as deposited were generally of p-type, but the films made with heat-treatment were converted to n-type. This tendency was ascribed to the boundary effects of crystallized particles or aggregations in the layer. (Author) Y. Kataoka, J. Phys. Soc. Japan, 17 (6), June 1962, 967-969.
30 680. Missiles spur growth of multi films. United States. Multi films consist of two or more films applied in a vacuum to a base material, usually glass or quartz. The coatings consist of dielectric materials such as magnesium fluoride, zinc sulphide, or silicon and germanium compounds. The deposition is carried out by evaporation and subsequent condensation of the coating material on the cooled base. Special vacuum tanks are used for this process, enabling the coating of surfaces of several square feet. Coating thickness is carefully controlled and even in the most complicated cases, comprising possibly up to 40 film layers, the total thickness of the deposits will not exceed 40tz. By varying the materials, numbers of layers and thickness of the individual films, light filters of remarkable efficiency can be constructed which will selectively transmit or reflect wavelengths ranging from the shortest visible to the near infrared. Such filters have received extensive application in the missile industries as covers for solar cells and infrared homing or sensing devices. Other applications cover high altitude photography and laser systems. The outstanding performance and reliability of multi film filters has also led to their use in industry for heat control and colour separation or as beam dividers and first surface mirrors, w.J.s. Anon., Chem. & Engng News, 40 (33), 13 Aug. 1962, 40-41. 30 : 56 681. Thin metal films in millimetre wave measurements. Great Britain. In a millimetre wave measurement project it was necessary to design some coupling and reflecting discs for use in circular waveguide. The use of evaporated metal films on thin glass discs was investigated and the results obtained are detailed for metal films with and without slots. (Author) M. H. Cumin, Electronic Engng, 33 (406), Dec. 1961, 808-810. 3O 682. Die Aufdampflechnik und ihre Anwendungsgebiete. (The technique of vapour depositing). West Germany. The present study deals with the application of very thin films by means of condensation of the gaseous phase in vacuum (in German). D.A.P. M. Auw~irter, Feinwerktechnik, 66 (4), April 1962, 145-151.
683. Cyclotron resonance in thin metallic films. H. Suzuki and K. Ariyama, J. Phys. Soc. Japan, 17 (4), April 1962, 704-705. 30
30 686. Cathode sputtering in hollow cathode discharges. Japan. In order to investigate the processes responsible for a negative resistance of the hollow cathode discharge, several discharge parameters are measured with a Langmuir probe. The vapour density distribution of the sputtered cathode metal are measured by the absorption method of the resonance radiation of the metal atom. Almost all the metal atoms in the central part of the cathode space are found to be ionized or excited. (Author) J. Musha, J. Phys. Soc. Japan, 17 (9), Sept. 1962, 1440-1446. 30:51 687. Colloquium on optical materials--Paris, 1961. France. Brief report, including reference to a whole day devoted to the realm of thin films. The proceedings are not to be published in book form, but authors are to be encouraged to submit their papers for publication in Optiea Acta. (Author, modified) K. M. Greenland, J. Sci. Instrum., 38 (l 1), Nov. 1961, 418-419. 3O 688. Production of superconducting niobium films by vacuum-are deposition. United States. Previous work has shown that tantalum films with bulk metal transition properties can be prepared in vacua of the order of 10-l° t o r t by sublimation from a heated tantalum spiral at a deposition rate of 250A,/min. The authors estimate that in order to produce pure niobium films by the same method, a vacuum of at least 10-zl torr may be required. By using a vacuum arc technique, the authors succeeded in producing niobium films on glass substrates placed at a distance of 3 mm from the point of contact of the two arc electrodes, the system being at the relatively high pressure of 5 × 10-6 torr. w . J . s . M. S. P. Lucas and D. T. Meyer, Nature, Lond., 193 (4817), 24 Feb. 1962, 766-767. 30 689. Epitaxial growth of silicon by vacuum evaporation. Great Britain. The silicon was evaporated in a specially designed electron bombardment furnace, the evaporation being performed in a vacuum of 10-5-10 -6 tort. The maximum rate of deposition was 3/z/min, the substrate being a single silicon crystal kept at 1100-1250°C, the exact value depending on the rate of deposition the high temperature corresponding to the faster rate. The vacuum deposition described by the author seems to offer certain advantages over the chemical method at present in use (hydrogen reduction of silicon halides), the main one being the possibility of manufacturing complete devices in vacuum. W . J . S.
684. Absorption bands in evaporated BaO films. T. Tomotika, J. Phys. Soc. Japan, 17 (5), May 1962, 872-873.
B. A. Unvala, Nature, Lond., 194 (4832), 9 June 1962, 966-967.
30 685. Some properties of evaporated silicon films. Japan. Silicon films have been formed by the vacuum evaporation method. The nature of the films has been observed by studies of the effect of heat-treatment on resistivity, Hall mobility and X-ray diffraction. Silicon was deposited on fused quartz substrates held at a certain temperature between 950°C and
30 690. Sputtered intermetallic films. United States. The antimonides of indium and gallium can be readily deposited by means of cathodic sputtering on fused silica. Pressure during sputtering was approximately 10-2 torr, the substrate having been previously thoroughly degassed at 10-5 torr. From optical examination of the films, the author