Thin silicon oxide films on N-type 4H-SiC prepared by scanning frequency anodization method

The effect of selective anodization on SiC in direct voltage superimposed with alternative voltage of scanning frequencies has been investigated. Compared with the gate oxides grown with direct voltage or alternative voltage of a constant frequency, the oxide charge and the interface state density of the sample with scanning frequencies are significantly reduced. It is suggested that the bulk traps and interface traps in the oxides can be compensated during the scanning frequency anodization process since the scanning frequencies are in close proximity to the response times of interface states.