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707. Evaporation coefficient of graphite
Classified Abstracts
Vacuum 30.
705-720
285
Applications
Evaporation and Sputtering
31.
30 705. High vacuum problems in thin film studies. (Great Britain) Brit. Communications and Electronics, 10, Aug. 1963, 634.
Evacuation and Sealing 31
713. New (U.S.A.)
developments
in manufacture
Walter H. Kohl, Metal Progress,
of electron
tubes.
85 (5), May 1964, 83-88.
30 706. Epitaxy of compound semiconductors by Rash evaporation.
32.
(U.S.A.)
J. L. Richards et al., J. Appl. Phys., 34 (1 l), Nov. 1963,3418-3420. 30 707. Evaporation coefficient of graphite. (USA .) R. P. Burns&al., J. Chem. Phys.,40(4), Feb. 15 1964,1161-1162. 30 708. Preparation of uniaxial permalloy films by cathodic sputtering on glass and metal substrates. (U.S. A.) B. L. Flur and J. Riseman, J. Appl. Phys., 35 (2), Feb. 1964, 344-
347. 30 709. Thin layers of silver evaporated under vacuum at low rates of deposition forming a metastable structure. (France) C. Boulesteix, C.R. Acad. Sci., 257 (lo), 2 Sept. 1963, 1695-1698. (In French).
710. Photoetching of thin lead films with nitromethane.
30 (U.S.A.)
Thin evaporated lead films have been photoetched with gaseous nitromethane activated by ultraviolet radiation. The rate of etching (of the order of 10 Ajmin) varies inversely with the volume of the system, is proportional to the square root of the radiation intensity, and is proportional to the partial pressure of nitromethane and then saturates at a limiting pressure. The presence of nitrogen in the system strongly retards the etching reaction. The rate of reaction has been calculated as a function of the radiation wave length by use of a set of transmission filters. For lead, the wavelength band of 2680 i 5OA gives the largest positive contribution to the rate, while a band at 2530 4 5OA inhibits the reaction by about 370 per cent of the observed rate. (U.S.A.) (Author) L. H. Kaplan, J. Phys. Chem., 68, Jan, 1964,94-100. 30 711. High resistance sputtered films. (U.S.A.) A note describing work at the Bell Telephone laboratories, where thin films having surface resistance of up to 10 kilohms per square have been made by sputtering tantalum in a partial oxygen atmosphere. By comparison, with a nitrogen atmosphere, the resistance obtained is less than 200 ohms per square. After sputtering, the surface of the sputtered film is electrolytically oxydized to “ trim ” the resistance value and to protect the film. The temperature coefficient of resistance was found to be between + 100 and - 500 parts per million per “C.
Note from Bell Laboratories, 10, July 1963, 553.
Brit.
Communications
and Elec-
tronics,
30 712. Ultra-thin films. (U.S.A.) This note describes work at the Westinghouse laboratories, on thin film deposition at 10-l* torr, of films only 1OA units thick. The chamber used is of double-walled construction in stainless steel, with the interspace filled with liquid nitrogen. Brit. Communications and EIectronics., 11, Jan. 1964, 23.
Nucleonics
32 714. Zero gradient synchrotron particle accelerator in Illinois. (Great Britain) Engineer, 217 (5632),
116-118 ; and(5634)
33.
3 Jan. 1964, 61-63 ; (5633) 10 Jan. 1964, 17 Jan. 1964,157-158.
General Physics and Electroncs
33 715. Nonlinear rf behavior of electron beams with velocity distribution. (II) Application to rectangular velocity distribution (U.S.A.)
T. G. Mihran and S. P. Yu, J. Appt. Phys., 34 (IO), Oct. 1963, 2976-2984. 33 716. Nonlinear rf behavior of electron beams with velocity distribution. (I) General Analysis. (U.S. A.) S. P. Yu and T. G. Mihran, J. Appl. Phys., 34 (lo), Oct. 1963, 2972-2976. 33 717. Miniature gas laser. (Great Britain) H. Koppe, Electra. Equip. News, 6, May, 1964, 42. 33 718. Electron beam unit. (Great Britain) Nuclear Engng., 9 (94) March, 1964, 110. 33 719. Excess-kinetic-energy ions in organic mass spectra. (U.S.A.) J. Olmstead III et al., J. Chem Phys., 40 (8), 15 April, 1964, 21142122. 33 720. Electron emission microscopy. ( W. Germany) A lengthy review article dealing mainly with work published during the past 10 years in various countries. The author points out the limitation of conventional electron microscopy in that only very thin specimens are sufficiently transparent to electrons. In emission microscopy, the surface to be studied is made to emit electrons and these are directed by lenses to form an image on a fluorescent screen or photographic plate. This image contains detail of the microstructure of the surface examined because of the dependence of work function on this microstructure, and because of the variation of the angle of electron emission with crystal gain orientation. Furthermore, when the emission is produced by bombardment or irradiation (see below), surface structure will cause local micro-variations in angle of incidence of the bombardment irradiation, to which the electron emission is sensitive. The use of field emission is not discussed in this article, but photoemission, secondary emission and thermionic emission are all considered. The article reviews the electron optics of the cathode lens and derives an expression for the limit of resolution of the system. In the section on the use of photoemission, there are details of suitable light (u.v.) sources for irradiating the specimen (cathode),
Vacuum 30.
705-720
285
Applications
Evaporation and Sputtering
31.
30 705. High vacuum problems in thin film studies. (Great Britain) Brit. Communications and Electronics, 10, Aug. 1963, 634.
Evacuation and Sealing 31
713. New (U.S.A.)
developments
in manufacture
Walter H. Kohl, Metal Progress,
of electron
tubes.
85 (5), May 1964, 83-88.
30 706. Epitaxy of compound semiconductors by Rash evaporation.
32.
(U.S.A.)
J. L. Richards et al., J. Appl. Phys., 34 (1 l), Nov. 1963,3418-3420. 30 707. Evaporation coefficient of graphite. (USA .) R. P. Burns&al., J. Chem. Phys.,40(4), Feb. 15 1964,1161-1162. 30 708. Preparation of uniaxial permalloy films by cathodic sputtering on glass and metal substrates. (U.S. A.) B. L. Flur and J. Riseman, J. Appl. Phys., 35 (2), Feb. 1964, 344-
347. 30 709. Thin layers of silver evaporated under vacuum at low rates of deposition forming a metastable structure. (France) C. Boulesteix, C.R. Acad. Sci., 257 (lo), 2 Sept. 1963, 1695-1698. (In French).
710. Photoetching of thin lead films with nitromethane.
30 (U.S.A.)
Thin evaporated lead films have been photoetched with gaseous nitromethane activated by ultraviolet radiation. The rate of etching (of the order of 10 Ajmin) varies inversely with the volume of the system, is proportional to the square root of the radiation intensity, and is proportional to the partial pressure of nitromethane and then saturates at a limiting pressure. The presence of nitrogen in the system strongly retards the etching reaction. The rate of reaction has been calculated as a function of the radiation wave length by use of a set of transmission filters. For lead, the wavelength band of 2680 i 5OA gives the largest positive contribution to the rate, while a band at 2530 4 5OA inhibits the reaction by about 370 per cent of the observed rate. (U.S.A.) (Author) L. H. Kaplan, J. Phys. Chem., 68, Jan, 1964,94-100. 30 711. High resistance sputtered films. (U.S.A.) A note describing work at the Bell Telephone laboratories, where thin films having surface resistance of up to 10 kilohms per square have been made by sputtering tantalum in a partial oxygen atmosphere. By comparison, with a nitrogen atmosphere, the resistance obtained is less than 200 ohms per square. After sputtering, the surface of the sputtered film is electrolytically oxydized to “ trim ” the resistance value and to protect the film. The temperature coefficient of resistance was found to be between + 100 and - 500 parts per million per “C.
Note from Bell Laboratories, 10, July 1963, 553.
Brit.
Communications
and Elec-
tronics,
30 712. Ultra-thin films. (U.S.A.) This note describes work at the Westinghouse laboratories, on thin film deposition at 10-l* torr, of films only 1OA units thick. The chamber used is of double-walled construction in stainless steel, with the interspace filled with liquid nitrogen. Brit. Communications and EIectronics., 11, Jan. 1964, 23.
Nucleonics
32 714. Zero gradient synchrotron particle accelerator in Illinois. (Great Britain) Engineer, 217 (5632),
116-118 ; and(5634)
33.
3 Jan. 1964, 61-63 ; (5633) 10 Jan. 1964, 17 Jan. 1964,157-158.
General Physics and Electroncs
33 715. Nonlinear rf behavior of electron beams with velocity distribution. (II) Application to rectangular velocity distribution (U.S.A.)
T. G. Mihran and S. P. Yu, J. Appt. Phys., 34 (IO), Oct. 1963, 2976-2984. 33 716. Nonlinear rf behavior of electron beams with velocity distribution. (I) General Analysis. (U.S. A.) S. P. Yu and T. G. Mihran, J. Appl. Phys., 34 (lo), Oct. 1963, 2972-2976. 33 717. Miniature gas laser. (Great Britain) H. Koppe, Electra. Equip. News, 6, May, 1964, 42. 33 718. Electron beam unit. (Great Britain) Nuclear Engng., 9 (94) March, 1964, 110. 33 719. Excess-kinetic-energy ions in organic mass spectra. (U.S.A.) J. Olmstead III et al., J. Chem Phys., 40 (8), 15 April, 1964, 21142122. 33 720. Electron emission microscopy. ( W. Germany) A lengthy review article dealing mainly with work published during the past 10 years in various countries. The author points out the limitation of conventional electron microscopy in that only very thin specimens are sufficiently transparent to electrons. In emission microscopy, the surface to be studied is made to emit electrons and these are directed by lenses to form an image on a fluorescent screen or photographic plate. This image contains detail of the microstructure of the surface examined because of the dependence of work function on this microstructure, and because of the variation of the angle of electron emission with crystal gain orientation. Furthermore, when the emission is produced by bombardment or irradiation (see below), surface structure will cause local micro-variations in angle of incidence of the bombardment irradiation, to which the electron emission is sensitive. The use of field emission is not discussed in this article, but photoemission, secondary emission and thermionic emission are all considered. The article reviews the electron optics of the cathode lens and derives an expression for the limit of resolution of the system. In the section on the use of photoemission, there are details of suitable light (u.v.) sources for irradiating the specimen (cathode),