Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate;
• a first region of a first conductivity type formed on a front surface side of the semiconductor substrate;
• a drift region of a second conductivity type formed closer to a rear surface of the semiconductor substrate than the first region is;
• a buffer region of a second conductivity type that:
• is formed closer to the rear surface of the semiconductor substrate than the drift region is;
• and has a plurality of peaks of an impurity concentration distribution that are higher than an impurity concentration of the drift region;
• a lifetime killer that:
• is arranged on a rear surface side of the semiconductor substrate;
• and shortens a carrier lifetime;
• and
• a second region of a first conductivity type formed between:
• a peak that is closest to the rear surface of the semiconductor substrate among the plurality of peaks of the impurity concentration distribution in the buffer region;
• and the rear surface of the semiconductor substrate, wherein
• a peak of a concentration distribution of the lifetime killer is arranged between a peak that is closest to a front surface of the semiconductor substrate among the plurality of peaks of the impurity concentration distribution in the buffer region, and a rear surface side of the buffer region,
• the peak of the concentration distribution of the lifetime killer is within the buffer region,
• the peak of the concentration distribution of the lifetime killer is arranged at a position that does not overlap any one or more of the plurality of peaks of the impurity concentration distribution in the buffer region,
• the peak of the concentration distribution of the lifetime killer is arranged at a position that does not overlap a peak of an impurity concentration distribution in the second region,
• the semiconductor substrate has a transistor portion in which a transistor is formed and a diode portion in which a diode is formed,
• the second regions are discretely provided in the diode portion, and
• on a plane parallel with the rear surface of the semiconductor substrate, a distance D between a boundary between the transistor portion and the diode portion and the second region is greater than an interval between the second regions.

A semiconductor device comprising:

• a semiconductor substrate;
• a first region of a first conductivity type formed on a front surface side of the semiconductor substrate;
• a drift region of a second conductivity type formed closer to a rear surface of the semiconductor substrate than the first region is;
• a buffer region of a second conductivity type that:
• is formed closer to the rear surface of the semiconductor substrate than the drift region is;
• and has one or more peaks of an impurity concentration that are higher than an impurity concentration of the drift region;
• and
• a second region of a first conductivity type formed between:
• a peak that is closest to the rear surface of the semiconductor substrate among the peaks of the impurity concentration in the buffer region;
• and the rear surface of the semiconductor substrate, wherein
• the semiconductor substrate has a transistor portion in which a transistor is formed and a diode portion in which a diode is formed,
• the second regions are discretely provided in the diode portion, and
• on a plane parallel with the rear surface of the semiconductor substrate, a distance D between a boundary between the transistor portion and the diode portion and the second region is greater than an interval between the second regions.