Plasma Etch Void Formed at the SiC Film/Si Substrate Interface

Abstract

Cubic silicon carbide films are grown on the Si (111) substrate by means of hydrogen plasma sputtering. Formation mechanisms of the hollow voids at the SiC film/Si substrate interface are studied by varying both the film growth temperature from 650°C to 850°C, and the film growth time from 2 s to 55 h. A two-step etching model is proposed to explain the formation mechanisms, based on our experimental results. The etching first starts from the point defects, and etch pits first appear near the Si substrate surface. When this first etching stops due to growth of a SiC film on the first etch pits, subseguent etching starts around the first etch pits and results in the hollow voids at the film/substrate interface at substrate temperatures above 650°C. The depth of the hollow voids becomes constant with growth time after a continuous SiC film is formed over the Si substrate.