Investigation of Carbon Interstitials in the Vicinity of the Si0₂/4H-SiC(0001) Interface

Native defects, including carbon vacancies and interstitials, are understood to be important defects that degrade device performance. In particular, during oxidation to form SiO₂-dielectric layers, carbon interstitials are thought to be injected into the SiC channels. Using density functional theory, the kinetics of diffusion of interstitial from the SiO₂/4H-SiC(0001) interface has been investigated. The results show that the injection of a carbon interstitial from a site at the 4H-SiC-SiO₂ interface is hindered by an additional 1 eV relative to the migration barrier of the native defect in bulk 4H-SiC.