Effect of substrate orientation and crystal anisotropy on the thermally oxidized SiO2/SiC interface

We use the high–low capacitance–voltage technique and the conductance–frequency techniques to characterize the SiO2/SiC interface formed by thermal oxidation of the silicon-face (0001) c-axis, the (112̄0) a-axis, and the (11̄00) a-axis orientations of 6H–SiC. The oxidation rate of the a-axis orientations is 3–5 times higher than that of the silicon face. Interface state densities on the a-axis orientations are a factor of 4–10 times higher than the Si-face c-axis orientation for both n-type and p-type dopings. Maximum oxide electric breakdown fields are about 10–11 MV/cm for both a-axis and c-axis orientations for an oxide thickness of about 60 nm.