Anomalous Diffusion at the Interface of Thin Bimetallic Film of Bi and Sb

Abstract

The intermetallic diffusion was studied by electron and X-ray diffraction and electrical resistance measurement on vacuum deposited thin bimetallic films of Bi and Sb. The formation of triple-layer, which consisted of two outer layers of Bi and Sb and the intermediate layer of solid solution of the definite composition, was observed in the course of heating in vacuum. Such an anomalous diffusion could not be expected from a usual diffusion couple of bulk specimens. It was found that the degree of such a triple-layer formation depended on the kind and deposition rates of secondary deposits, and the maximum thickness of the intermediate layer attaind by diffusion was confined to a certain limiting value. The defectiveness of films was deduced from electrical resistance measurements, the results of which were related to the triple-layer formation. Tentative explanation and discussions for were proposed, assuming the existence of some strained intermediate layer of certain thickness where the diffusion rapidly took place.