Patent ID: 8648447

Claim:
A semiconductor rectifier device comprising: an anode electrode; an anode area that adjoins the anode electrode and is made of a second conductivity type semiconductor; a drift layer that adjoins the anode area and is made of a low-concentration first conductivity type semiconductor; a minority carrier absorption layer that adjoins the drift layer and is made of a first conductivity type semiconductor having a concentration higher than that of the drift layer; a high-resistance semiconductor layer that adjoins the minority carrier absorption layer, has less thickness than the drift layer and is made of a first conductivity type semiconductor having a concentration lower than that of the minority carrier absorption layer; a cathode contact layer that adjoins the high-resistance semiconductor layer and is made of a first conductivity type semiconductor having a concentration higher than the high-resistance semiconductor layer; and a cathode electrode adjoining the cathode contact layer, wherein a relation between a concentration of an impurity and a thickness of the minority carrier absorption layer is set to a range satisfying the following Equation 1 D r >=4 E +20 E −d r [Equation 1] where, Dr denotes the concentration (cm −3 ) of an impurity, and dr denotes the thickness (μm) of the minority carrier layer.