Reactions of O molecules with an initially perfect 4H-SiC/SiO2 interface were studied by means of first-principles model calculations. It was shown that the most likely route of reactions in the oxidation process produced C interstitials at the interface, which could easily be emitted into the oxide. As a result, a stationary concentration of C interstitials was present at the interface with a gradient decreasing toward the oxide. The electronic structure of these defects may explain many of the observed features in the distribution of interface states.

Defects of the SiC/SiO2 Interface -Energetics of the Elementary Steps of the Oxidation Reaction. P.Deák, A.Gali, J.Knaup, Z.Hajnal, T.Frauenheim, P.Ordejón, J.W.Choyke: Physica B, 2003, 340-342, 1069-73