Electron paramagnetic resonance is used to study a near surface defect in oxidized 4H/6H SiC substrates and 3C SiC epitaxial layers. The defect is observed after wet oxidation and a 900 °C dry thermal treatment, but the defect is not located in the oxide. The heat treatment activates the EPR center by removing a hydrogen-related species from a C bond. Oxidation studies suggest that reaction of H2O with SiC creates the defect. However, an alternative theory in which the defect is intrinsic to SiC cannot be disregarded.
