Characterization of Oxide Films on SiC by Spectroscopic Ellipsometry

We have, for the first time, evaluated the optical constants of thermally oxidized films on SiC by spectroscopic ellipsometry, and discussed the characteristics of SiC/SiO2interfaces. It was found that the effective refractive indices are smaller than those of the oxide films on Si. They increase with oxidation time, or oxide thickness, reaching to the values of Si oxides. The refractive indices also depend on the oxidation methods, and the pyrogenic oxidation brings about larger refractive indices than dry oxidation. The origin of the small refractive indices of oxide films on SiC was discussed in terms of interface structures and composition in comparison with those of oxide films on Si.