Semiconductor device and method of manufacturing the same

A wide band gap semiconductor device comprising:

• a semiconductor layer having a first surface and a second surface;
• a trench formed on the first surface of the semiconductor layer;
• a first region of a first conductivity type formed at a first surface of the semiconductor layer, the first region forming part of a side surface of the trench;
• a second region of a second conductivity type formed on a side of the first region facing the second surface of the semiconductor layer, the second region forming part of the side surface of the trench;
• a third region of the first conductivity type formed on a side of the second region facing the second surface of the semiconductor layer, the third region forming a bottom surface of the trench;
• an insulating film formed on an inner surface of the trench;
• and
• a first electrode embedded inside the insulating film in the trench, wherein
• the second region integrally includes a first portion arranged closer to the first surface of the first surface of the semiconductor layer than to the bottom surface of the trench, and a second portion projecting from the first portion toward the second surface of the semiconductor layer to a depth below the bottom surface of the trench, and
• the second portion of the second region defines a boundary surface with the third region, the boundary region being at an incline with respect to the first surface of the semiconductor layer.