To form an oxide film (chemical oxide film) on the orientation Si plane and the orientation C plane of an SiC crystal by applying a low temperature chemical oxidation technology to the SiC crystal plane.
In an oxidation process where an oxide film is formed directly on the orientation Si plane and orientation C plane of an SiC crystal by exposing an SiC crystal substrate heated to several hundreds degrees Celsius to vapor phase nitric acid atmosphere, the vapor phase nitric acid atmosphere is generated from high concentration nitric acid by heating and boiling. When the oxidation is performed about 4 hours while maintaining the concentration of nitric acid stably, an SiO2/SiC structure of extremely good quality not containing carbon compound is created on the surface of orientation C plane (000-1) of an n-type 4H-SiC crystal.
