Semiconductor device having semiconductor regions with an impurity concentration distribution which decreases from a respective peak toward different semiconductor layers

Abstract

In a surface layer of a rear surface of the semiconductor substrate, an n-type cathode region and a p-type cathode region are each selectively provided. The n-type cathode region and the p-type cathode region constitute a cathode layer and are adjacent to each other along a direction parallel to the rear surface of the semiconductor substrate. The n-type cathode region and the p-type cathode region are in contact with a cathode electrode. In an n-type drift layer, plural n-type FS layers are provided at differing depths deeper from the rear surface of the semiconductor substrate than is the cathode layer. With such configuration, in a diode, a tradeoff relationship of forward voltage reduction and reverse recovery loss reduction may be improved and soft recovery may be realized.