Preparation and Properties of Vacuum-deposited Germanium Thin Films

Abstract

Germanium thin films have been prepared on hot Pyrex glass, mica, and single-crystal germanium substrates by thermal evaporation in high vacuum. The electrical characteristics of the prepared films are most sensitive to the substrate temperature. Excellent germanium film can be obtained at substrate temperatures between 450°C and 550°C. Their crystalline structures were examined by electron diffraction and the electrical characteristics were measured. It was found that N-type germanium film can be prepared if germanium and phosphorus or arsenic are evaporated at the same time. The properties of such N-type films are described, and the doping process with donor impurity is discussed briefly. The properties of a P-N junction photocell, a tunnel diode, and a piezoresistive element thus prepared are described.