Semiconductor device

Abstract

A semiconductor device, including a substrate of a first conductivity type, an active region and a termination structure portion formed on a front surface of the substrate, and a plurality of regions of a second conductivity type formed concentrically surrounding the periphery of the active region in the termination structure portion. Each region has a higher impurity concentration than one of the regions adjacent thereto on an outside thereof. The plurality regions include first and second semiconductor regions, and an intermediate region sandwiched between, and in contact with, the first and second semiconductor regions, and a third semiconductor region. The intermediate region includes a plurality of first subregions and a plurality of second subregions that are alternately arranged along a path in parallel to a boundary between the active region and the termination structure portion, the second subregions having a lower impurity concentration than the first subregions.