Interfacial Transitional Layer in SiO2 Film Thermally Grown on SiC(000-1)

Abstract

The uniformity of SiO2 film thermally grown on 4H-SiC was characterized by atomic force microscopic observation of the emerged SiO2 surface after each step-etching using diluted HF solution. It was found that roughness of the emerged SiO2 surface drastically increases near the SiO2/SiC interface. This means that the film quality near the interface is not two-dimensionally uniform. We described the two-dimensionally non-uniform. On the other hand, the amount of roughness increase at the middle region was small, indicating the middle region is uniform film. These results indicate that the region is two-dimensionally uniform. These results indicate that the oxide film contains non-uniformly when just after being formed, and then the two-dimensional film uniformity is gradually improved during subsequent oxidation. Density profiles of SiO2 films were also characterized. The uniformity improvement was discussed in terms of impurity desorption and film density.