Low Roughness SiC Trench Formed by ICP Etching with Sacrificial Oxidation and Ar Annealing Treatment

A simple post-trench treatment of SiC trench was developed to improve the trench morphology. The post-trench treatment was comprised of sacrificial oxidation at 1150°C and high temperature annealing in Ar ambient at 1500°C where the sacrificial oxidation was carried out before the high temperature Ar annealing. The sacrificial oxidation can eliminate most of the step bunching in the trench sidewall which resulted in a relatively smooth surface. The high temperature Ar annealing can further reduce the roughness of the trench sidewall as well as round the trench corner. An ideal morphology of the SiC trench without obvious degradation in the SiC top surface has been realized by the proposed post-trench treatment.