PROBLEM TO BE SOLVED: To solve a problem that contact resistance is high when a metal layer is directly formed on a surface of an SiC substrate and it is necessary to form silicide on the SiC surface in order to reduce the contact resistance thereby to increase the required number of processes.SOLUTION: In a manufacturing method of a semiconductor device using an SiC substrate, contact resistance is decreased by generating graphene on a surface of the SiC substrate. When the surface of the SiC substrate is etched by coating a part of the surface of the SiC substrate with a protection layer, irregularity is formed on the surface of the SiC substrate and a boundary between the SiC substrate and the protection layer is exposed on a lateral face of a recess. When the boundary is exposed, etching progresses along an interface between the SiC substrate and the protection layer and gaps are formed. A distances of the gap decreases with the increasing distance from the lateral face. As a result, an inclined surface i
