Study of reaction process on Ni/4H–SiC contact

Abstract

The present study deals with mechanisms of the reaction process of fabricated thin film Ni/SiC contacts by means of XRD, XPS and Raman spectroscopy. After annealing SiC samples sputter coated with Ni at 800 and 950°C in vacuum for 20 min, the dominant silicide is textured Ni2Si. Its formation consists of two stages: initial reaction rate and subsequent diffusion controlled stage. For ultra thin initial Ni layer (∼3–6 nm), islands formation of Ni2Si is observed after heat treatment. Increasing the Ni film thickness prevents this phenomenon. The C released owing to the Ni2Si formation reaction forms a thin graphite layer on the top of the surface and also tends to form cluster inside the reaction layer. The overall degree of graphitisation is higher at 950°C than that at 800°C.