Effects of ion irradiation in the thermal oxidation of SIC

Abstract

We investigated the thermal growth of SiO₂ films on 6H-SiC (0001) samples irradiated with 170 keV Ar⁺ ions. Electronic, compositional, and structural features arisen from the irradiation process were accessed. All results are compared to those of nonirradiated substrates, revealing major differences due to ion bombardment such as the enhanced rate of oxidation, the variation of roughness of both oxide surface and SiO₂ /SiC interface, and of the stress in the formed oxide layer. Modifications on the electronic structure and crystallographic characteristics of the substrate underneath the oxide were also observed in samples in which the ion irradiation damaged layer was only partially consumed by the oxidation step. The present work evidences that a careful choice of sample preparation conditions is necessary to avoid undesired characteristics in the final SiO₂ /SiC structure and points to a way of preventing irradiation related degradation of electrical characteristics while maintaining the high oxidation rate.