Atomic-scale mechanisms of oxygen precipitation and thin-film oxidation of SiC

We report first-principles calculations in terms of which we describe the atomic-scale mechanisms of the nucleation and growth of SiO2 precipitates in cubic SiC. A three-oxygen cluster is found to be analogous to the well-known "thermal donor" in Si. Emission of a CO molecule converts it into an SiO2-like precipitate that can grow further. We propose that similar processes can account for the observed CO emission during SiC oxidation and the trapping of C atoms at the SiC-SiO2 interface.