Patent ID: 8742501

Claim:
A semiconductor device comprising: a main semiconductor layer of a first conductivity type, the main semiconductor layer having a first major surface and a second major surface opposite the first major surface, the main semiconductor layer having an impurity concentration distribution that repeatedly increases and decreases in a direction parallel to the first major surface thereof; an anode layer of a second conductivity type disposed on the first major surface of the main semiconductor layer; an anode electrode disposed on the anode layer; a cathode layer of the first conductivity type disposed on the second major surface of the main semiconductor layer; a cathode electrode disposed on the cathode layer; and a heavily doped layer of the first conductivity type formed between the main semiconductor layer and the cathode layer, the heavily doped layer being doped more heavily than the main semiconductor layer, the heavily doped layer having an impurity concentration distribution that repeatedly increases and decreases in a direction parallel to the first major surface of the main semiconductor layer.