Semiconductor device having superjunction structure formed of p-type and n-type pillar regions

Abstract

A semiconductor device includes: a semiconductor layer of a first conductivity type; a first semiconductor pillar region of the first conductivity type provided on a major surface of the semiconductor layer; a second semiconductor pillar region of a second conductivity type provided adjacent to the first semiconductor pillar region on the major surface of the semiconductor layer, the second semiconductor pillar region forming a periodic arrangement structure substantially parallel to the major surface of the semiconductor layer together with the first semiconductor pillar region; a first main electrode; a first semiconductor region of the second conductivity type; a second semiconductor region of the first conductivity type; a second main electrode; a control electrode; and a high-resistance semiconductor layer provided on the semiconductor layer in an edge termination section surrounding the first semiconductor pillar region and the second semiconductor pillar region. The high-resistance semiconductor layer has a lower dopant concentration than the first semiconductor pillar region. A boundary region is provided between a device central region and the edge termination section. The first semiconductor pillar region and the second semiconductor pillar region adjacent to the high-resistance semiconductor layer in the boundary region have a depth decreasing stepwise toward the edge termination section.