First-principles study of Cl diffusion in cubic SiC

Abstract

Chlorine-based precursors allow the fast growth of thick SiC epilayers for fabricating high-voltage devices. Since it was demonstrated that epitaxial growth with a Cl-based chemistry can affect p-type doping, the issue of Cl diffusion SiC is technologically relevant therefore we present a first principles study of the migration mechanisms of Cl in cubic SiC. We first discuss the equilibrium structure of different Cl-related defect configurations (isolated interstitials and complex defects) which have either been reported in the literature or calculated in the present study. Following this analysis, we focus on two migration mechanisms: The interstitialcy and the vacancy-mediated mechanism. We found that Cl diffuses in SiC via a vacancy-mediated mechanism and the value of the diffusivity is estimated.