ELECTRICAL PROPERTIES OF SPUTTERED GERMANIUM FILMS

Measurements of Hall coefficient and conductivity were made on thick sputtered germanium films as grown, and also after they were thinned down repeatedly by step etching. By means of a differential procedure, the carrier concentration and mobility within each film was then determined as a function of distance from the film's interface with the substrate. Invariably, the carrier concentration was found to be largest, and the mobility lowest, in a film layer adjacent to the substrate. the carrier concentration rapidly decreased with distance from the interface and became approximately constant beyond a film thickness of about 3 μ. The reduction in concentration correlated with an increase in mobility. As in most work with vacuum-deposited germanium, the films were p-type. Higher deposition temperatures tended to produce lower hole concentrations and higher mobilities at the interface as well as in the bulk of a film. © 1969.