Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, comprising:

• forming a first mask material having a first opening on a surface of a silicon carbide layer;
• performing first ion implantation of forming a first carbon region by implanting carbon (C) into the silicon carbide layer using the first mask material as a mask;
• forming a second mask material having a second opening on the surface of the silicon carbide layer, both end portions of the second opening disposed inside of both end portions of the first carbon region in a first direction parallel to the surface;
• performing second ion implantation of forming a first impurity region by implanting a first impurity into the silicon carbide layer using the second mask material as a mask;
• performing heat treatment at 1600° C. or higher;
• and
• performing third ion implantation of implanting carbon into the silicon carbide layer using the second mask material as a mask before the performing the second ion implantation.

A method for manufacturing a semiconductor device, comprising:

• forming a first mask material having a first opening on a surface of a silicon carbide layer;
• performing first ion implantation of forming a first carbon region by implanting carbon (C) into the silicon carbide layer using the first mask material as a mask;
• forming a second mask material having a second opening on the surface of the silicon carbide layer, both end portions of the second opening disposed inside of both end portions of the first carbon region in a first direction parallel to the surface;
• performing second ion implantation of forming a first impurity region by implanting a first impurity into the silicon carbide layer using the second mask material as a mask;
• and
• performing heat treatment at 1600° C. or higher,
• wherein the first impurity is nitrogen (N), or phosphorus (P), and
• a concentration of the carbon implanted by the first ion implantation is higher than a concentration of the first impurity implanted by the second ion implantation at any depth in the silicon carbide layer.