Amorphous metal-semiconductor contacts for high temperature electronics—I Materials and characterisation

In this and a companion paper, we summarise the achievement of a metal-semiconductor contact whose electrical characteristics degrade only over tens of hours at 500°C. Although initially conceived as a barrier to Au diffusion, the thin amorphous metal film now fails because of out-diffusion of elements of the semiconductor. In this paper we summarise the rationale for using amorphous metal films, the choice of alloys, the fabrication of test structures, and the characterisation of these structures before and after exposure to temperatures as high as 700°C for 24 hr. The companion paper describes the thermal degradation of Schottky barrier characteristics of metal films on both Si and GaAs.