Comparison of thermal oxidation and plasma oxidation of 4H-SiC (0001) for surface flattening

The thermal oxidation and water vapor plasma oxidation of 4H-SiC (0001) were investigated. The initial oxidation rate of helium-based atmospheric-pressure plasma oxidation was six times higher than that of thermal oxidation. The oxide-SiC interface generated by plasma oxidation became flatter with increasing thickness of the oxide, whereas the interface generated by thermal oxidation was atomically flat regardless of the oxide thickness. Many pits were generated on the thermally oxidized surface, whereas few pits were observed on the surface oxidized by plasma. After the oxide layer generated plasma oxidation was removed, an atomically flat and pit-free SiC surface was obtained.