Silicon carbide semiconductor device with trench gate and dummy gate source structures

A SiC semiconductor device comprising:

• a SiC chip having a main surface that includes a first surface, a second surface hollowed in a thickness direction at a first depth outside the first surface, and a connecting surface connecting the first surface and the second surface, and in which a mesa is defined by the first surface, the second surface and the connecting surface;
• a transistor structure formed at an inward portion of the first surface, the transistor structure including a trench gate structure that has a second depth less than the first depth and a trench source structure that has a third depth exceeding the second depth and that adjoins the trench gate structure in one direction;
• a dummy structure formed at a peripheral edge portion of the first surface, the dummy structure including a plurality of dummy trench source structures each of which has the third depth and that adjoin each other in the one direction;
• and
• a second dummy structure formed in a region between the transistor structure and the dummy structure in the peripheral edge portion of the first surface, the second dummy structure including a dummy trench gate structure having the second depth and a second dummy trench source structure that has the third depth and that adjoins the dummy trench gate structure in the one direction.