Semiconductor device, and method of manufacturing semiconductor device

A semiconductor device comprising:

• an n-type semiconductor substrate;
• a p-type anode region formed in the semiconductor substrate on its front surface side;
• an n-type field stop region formed in the semiconductor substrate on its rear surface side with protons as a donor;
• and
• an n-type cathode region formed in the semiconductor substrate to be closer to its rear surface than the field stop region is, wherein
• a concentration distribution of the donor in the field stop region in its depth direction has a first peak, and a second peak that is closer to the rear surface of the semiconductor substrate than the first peak is, and has a concentration lower than that of the first peak,
• a carrier lifetime in at least a partial region including the first peak is longer than a carrier lifetime in the anode region,
• a carrier lifetime at a depth position at which the concentration distribution of the donor exhibits the first peak is longer than the carrier lifetime in the anode region,
• the concentration distribution of the donor in the field stop region in its depth direction has a plurality of peaks,
• the first peak is a peak closest to the front surface of the semiconductor substrate among the plurality of peaks, and
• the region that has a carrier lifetime longer than that in the anode region extends toward the front surface side of the semiconductor substrate past a position at which the concentration distribution of the donor exhibits the first peak.