ACTIVE THIN FILM TECHNIQUES MICROMIN PROGRAM.
Interim development rept. no. 7
SYLVANIA ELECTRIC PRODUCTS INC WALTHAM MASS
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The purpose of the investigation is to develop a process for depositing device-quality silicon andor germanium films on glazed polycrystalline insulating substrates by vacuum evaporation of silicon andor germanium and to form thin film diodes and transistors in these films. Major changes in the high vacuum evaporation equipment included removal of the chemical baffle and replacement of both the former electron gun and source holder by a compact electron beam evaporation source. The rate of silicon deposition was increased from 2 to 12 microns per hour. Vacuum-deposited silicon insulated gate field effect transistors were fabricated with transconductances in the range 100 to 300. The electrical characteristics of these devices were studied for use in a preamplifier circuit. A number of annealed silicon films have been analyzed by X-ray diffraction which show that during annealing of rheotaxial silicon films, the orientation changes from preferred 110 with a minor of 331 to 111 orientation and which firmly establish the improved crystallographic nature of rheotaxially grown silicon films. Modifications were made in the Hall equipment for low temperature work and improvements were made in metal contacts to the silicon films. Derivation of the equations for PME and photoconductive voltages are presented for calculation of the lifetime of minority carriers by an expression independent of light intensity and of surface recombination velocities. Author