Classified abstracts 1114-1126

density, ratio of (SiO+Si) to SiOx and dielectric constant. The results show that the electron-gun evaporated films are approxi- mately 1.25 +0.05 greater in density and 1.2 times higher in dielectric value than the resistance-heated films, although both films have the same composition of (SiO+Si) per volume. This indicates that the higher dielectric constant of the electron-gun evaporated films is related to the higher density of the electron-gun process. R Y Shlmoda et al, Vacuum, 18 (5), May 1968, 269-272.

30 1114. The epitaxinl growth of zinc sulphide on silicon by vacuum evaporation. (Great Britain). Epitaxial layers, up to 5 microns thick, of zinc sulphide have been grown on thermally cleaned (111) surfaces of single-crystal silicon discs. The vacuum system was equipped with aluminium gaskets, which permit the baking of the entire system to 400°C. The silicon furnace, zinc sulphide source, cleaning technique of the silicon surface, and the method of growing the zinc sulphide layers are described. The importance of producing a clean silicon surface and of maintaining constant temperatures during the deposition has been demonstrated. P L Jones et al, Brit J Appl Phys, Set 2, 1 (3), 1968, 283-290.

30 1115. A mask to make tartan carbon films for electron microscopy. (Great Britain). A mask is described for producing a carbon film giving four different thicknesses by superimposing two evaporations at right angles without breaking the vacuum. The masks used are microharps consisting of a frame with beryllium copper wire 0.15 mm in diameter spaced to give 0.15 mm gaps between strands. The evaporation technique used is conventional. A Fursey, J Sci Instrum, Set 2, 1 (3), 1968, 357-358.

30 1116. Equipment for reproducible and thorough cleaning of substrates. (Great Britain) A technique of cleaning, based on spinning the substrate at 2000 rpm in a cleaning medium, and on removing the residual solvents by spinning in air. A complete cleaning technique is described. M Yea, Lab Practice, 17 (4), 1968, 466, 473.

30 1117. Samarium isotope thin films for nuclear investigations. (USSR) Samples of Srn20a, enriched by La, were baked at 1000°C in air and subsequently 25 hours at 600°C under vacuum of 5 × 10 -s tort. The thin films were prepared by decomposition at 1100°C, under 10 -~ tort, on a water cooled stainless steel substrate coated by ceresine. In this way, self-supporting films, 1 to 6 microns thick, containing 0.4 per cent of 02, 0.03 per cent of Ha and 0.016 per cent of N2, were obtained. L G Lishenko et al, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 19-20 (in Russian).

3O 1118. Preparation of polycrystalline scintillation layers. (USSR) A beta-radiation detector was prepared by evaporation of stilbene at 100 to 150°C under a vacuum of 0.1 tort. Lucite was employed as the substrate. B ' I Slmlaev, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 59-60 (in Russian).

30 1119. Stabilization of the evaporation rate of aluminium in vacuum. (USSR) Aluminium was evaporated in a tungsten heater made in the form of a cylindrical spring, 10 mm in diameter with a pitch of 8 mm, and the evaporation rate was measured by the oscillating quartz method. It was found that the rate of evaporation, V, in g/sec can be described by the formulaeV=0.033 (P =0.1) where P is input power of the heater in kW. The formula is valid within 10 per cent for quantities of evaporated aluminium in the range 0.05 to 0.5 g. I L Roykh and S N Fedosov, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 160-161 (in Russian).

3O 1120. Preparation of thin films, free of macrodefects, by evaporation under vacuum. (USSR) To prevent spraying of drops of evaporated material from the boat onto the substrate, graphite dust was poured on the surface of the melted material. In this way, only vapours may emerge from the boat. Thin films of Sb2S8 were prepared by this method.

D V Belyshkin et al, Pribory Tekh Eksper, 13 (2), March-April 1968, 229-230 (in Russian).

3O 1121. Levelling properties of amorphous silicon monoxide films. (USSR) The levelling properties of SiO thin films evaporated on aluminium films at 20°C, under 8 × 10 -5 torr, were investigated. It was found that surface inhomogeneities on the substrate of 0 to 600 A are levelled by SiO and only defects larger than 600 A are carried over into the replica. A N Rodnev and G A Efimenko, lzv VUZ Fiz, 11 (3), 1968, 144-147 (in Russian).

30 1122. New vacuum apparatus for depositing thin films. (USSR) A new form of vacuum apparatus for depositing thin films on dielectric and other substrates is described. The apparatus may be used for manufacturing thin-film bolometric elements as used in measuring the power of centimetre and millimetre radio waves, for producing high-quality, stable coatings on the sensitive elements of laser radiation receivers, and for other similar operations. The apparatus enables the operator to seal off the space containing the thin-film element without breaking the general vacuum; this is particularly important in manufacturing such elements from materials liable to be attacked by atmospheric air. E V Churkin and V A Yugov, Trans Metrological lnst USSR, No 90, 1967, 150, 112-120 (in Russian).

3O 1123. Apparatus for producing and studying thin films. (USSR) An improved form of apparatus for vacuum-depositing thin films of various materials on a large number of targets without intermediate breaking of the vacuum is described. After deposition the samples may be subjected to heat treatment and electron bombardment, their secondary-emission coefficients may be measured and their structures may be examined by electron diffraction in the same apparatus. The new apparatus has a number of advantages over its predecessors in that heating is effected directly in the samples under consideration without the intervention of special heating elements, and also in that the heating may be severely localized so as to obtain high temperature gradients where required. S K Kulov and L G Shesternev, Trans Sci Tech ConfRes Achievements During 1966-1967, Moscow Power lnst, Electronics Section, Moscow, 1967, 37-40 (in Russian).

30 1124. Anticorrosion cadmium plating by cathodic sputtering in vacuo. (USSR) A method of depositing corrosion-resistant surface layers of cadmium on car engine parts to a thickness of 15/~ by cathodic sputtering in vacuo is described. This is the only method of cadmium plating completely eliminating the danger of hydrogen absorption and the embrittlement frequently arising therefrom. The same method may be applied to other metal coatings such as chromium and copper. Coatings deposited by this method adhere firmly to the underlying metal and are in no way inferior to electrodeposited coatings as regards corrosion resistance. Z Ya Mazo and I L Blaer, Collection "Introduction of Vacuum Metallization into Industry", Riga, 1967, 55-57 (in Russian).

3O 1125. Methods of thin film thickness measurement. (USSR) Methods of thin film thickness measurement are reviewed including determinations based on changes in film resistivity, temperature coefficient of resistivity, work function and capacitance; optical methods based on changes in light intensity, interferometric methods and some special optical methods. X-ray techniques and the Pulker- Ritter method are also considered. L S Palatnik et al, Zavodsk Lab, 34 (3), 1968, 288-297 (in Russian).

30 : 64 1126. Thin film preparation by vacuum deposition. (USSR) The general practice of thin film preparation by evaporation and sputtering techniques is described in this handbook. B S Danilin, book pubM by Energiya, Moscow 1967, 312 pages, price 1.10 Rb (in Russian--original title: Vakuumnoe nanesenie tonkikh plenok ).

493