Manufacturing method of silicon carbide semiconductor device

A manufacturing method of a silicon carbide semiconductor device, comprising:

• providing a semiconductor substrate of silicon carbide, a surface of the semiconductor substrate being tilted within a range of 0 degrees or greater and 8 degrees or less from any one among a (000-1) surface and a (11-20) surface;
• forming a gate insulating film on the surface of a semiconductor substrate by subjecting the semiconductor substrate to a first heat treatment and a second heat treatment after the first heat treatment, the first heat treatment being performed in an oxidation atmosphere comprised of nitrogen oxide, the second heat treatment being performed in an atmosphere including hydrogen;
• forming a gate electrode on the gate insulating film;
• forming an interlayer insulating film that electrically insulates a metal film from the gate electrode;
• forming the metal film on the surface of the semiconductor substrate;
• subjecting the semiconductor substrate to a third heat treatment performed in an inert gas atmosphere, one of lowering a resistivity of the gate electrode and baking the interlayer insulating film being effected by the third heat treatment;
• and
• subjecting the semiconductor substrate to a fourth heat treatment performed in an inert gas atmosphere so as to form an electrical contact between the semiconductor substrate and the metal film.