Orientation Dependence of the Oxidation of SiC Surfaces

The orientation dependence of the thermal oxidation rates in 6H-SiC has been investigated. The wet oxidation was performed in steam and in the temperature range of 1000 to 1200 °C. The linear rate sharply changes at an off-angle around 30° from the {0001}-face. This large anisotropy in oxidation rate will cause a difficulty in controlling the bird's beak length in LOCOS. The activation energy of the linear rate gradually increases from C-face to Si-face. The situation is quite different from silicon in which the orientation dependence of the activation energy is explained by the steric hindrance.