Surface Topographical Analysis of Face Terminated Wet Thermal Oxidation of 4H-SiC Substrate

Author(s): Sanjeev Kumar Gupta, Ameer Azam and Jamil Akhtar

The surface topographical analysis of SiO2 on si-rich and c-rich faces of 4H-SiC has been experimentally analyzed by conductive atomic force microscopy (C-AFM) and surface profiler. Wet thermal oxidation process has been performed in horizontal quartz furnace at 1110ºC with the flow of molecular oxygen from 30 minutes to 180 minutes. Rate of oxidation on c-face has been found nearly 10 times faster than on si-face of 4H-SiC wafer. Stylus based surface profiler and Ellipsometer have been employed for oxidized surface roughness and oxide thickness measurements, respectively. We report that oxidized, c-face contained higher roughness and more atomic density than si-face. The bare surfaces of 4H-SiC faces contribute for the roughness in the respective thermally grown oxides. Si-face surface of 4H-SiC is smoother than c-face surface owing to its epitaxy nature. Atomic scale surface morphology of the oxide on si-face and c-face was captured by employing AFM in constant height mode. A number of samples have been oxidized for each experiment in order to generate statistical data.

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