Semiconductor device and method manufacturing the same

A method for manufacturing a semiconductor device comprising:

• forming an n− type layer at a first surface of an n+ type silicon carbide substrate;
• etching the n− type layer to form a first trench and a second trench thereon;
• forming a p type region adjacent to a side surface of the second trench and extending to a lower surface of the second trench;
• forming an auxiliary n+ type region on the p type region and the n− type layer;
• forming an n+ type region separated from the auxiliary n+ type region and disposed in the p type region;
• forming an auxiliary electrode on the auxiliary n+ type region;
• forming a gate insulating layer in the first trench;
• forming a gate electrode on the gate insulating layer;
• forming an insulating layer on the gate electrode and the auxiliary electrode;
• forming a source electrode on the insulating layer and the n+ type region;
• and
• forming a drain electrode at a second surface of the n+ type silicon carbide substrate,
• wherein the auxiliary electrode is separated from the gate electrode and the source electrode, and
• wherein the source electrode is in contact with the n+ type region,
• wherein the semiconductor device includes:
• the n− type layer disposed at the first surface of the n+ type silicon carbide substrate;
• the p type region disposed in the n− type layer;
• the auxiliary n+ type region disposed on the p type region or in the p type region;
• the n+ type region disposed in the p type region;
• the auxiliary electrode disposed on the auxiliary n+ type region and the p type region;
• the gate electrode separated from the auxiliary electrode and disposed on the n− type layer;
• the source electrode separated from the auxiliary electrode and the gate electrode;
• and
• the drain electrode disposed at the second surface of the n+ type silicon carbide substrate,
• wherein the auxiliary n+ type region and the n+ type region are separated from each other, and
• the source electrode is in contact with the n+ type region.