MANUFACTURE OF SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To obtain a gate oxide film with a low defect density and a high dielectric strength. SOLUTION: A silicon carbide layer 13 is formed on the surface of a silicon substrate 11, at least the silicon carbide layer 13 is thermally oxidized and a silicon oxide film 14 is formed on the surface of the silicon substrate 11, and the silicon oxide film 14 is used as the gate oxide film of a MOS transistor. Namely, since all of the silicon oxide film 14 are not formed by the thermal oxidation of the silicon substrate 11 itself, the crystal defect in the silicon substrate 11 cannot be easily taken into the silicon oxide film 14 even if the crystal defect exists in the silicon substrate 11.