Patent ID: 6885061

Claim:
A semiconductor device comprising: a semiconductor substrate having a main surface and a back surface, including a first region, a second region and a third region, and having a first semiconductor layer of a first conductivity type formed over the main surface; a second semiconductor layer of a second conductivity type opposite to the first conductivity type formed over the first semiconductor layer in the first region; a plurality of first groove portions penetrating, in the first region, through the second semiconductor layer from the main surface of the semiconductor substrate; a first insulating film formed in the first groove portions; a first conductor formed over the first insulating film; a third semiconductor layer formed, in the second semiconductor layer, adjacent to the first groove portions and having the first conductivity type; a second groove portion formed in the second region; a second insulating film formed in the second groove portion; a second conductor formed over the second insulating film and electrically connected to the first conductor; and a plurality of fourth semiconductor layers of second conductivity type formed over the first semiconductor layer in the third region, wherein the second groove portion is adjacent to the second semiconductor layer and the fourth semiconductor layer, and wherein the second semiconductor layer and the fourth semiconductor layer each has a first impurity concentration and a first depth.