Semiconductor device

A semiconductor device, comprising:

• a trench portion which is provided in an upper surface side of a semiconductor substrate;
• a cathode region of a first conductivity type or a collect region of a second conductivity type which is provided in a lower surface side of the semiconductor substrate;
• a buffer region of the first conductivity type which is provided between a lower end of the trench portion and the cathode region or the collect region, and has a first peak, a second peak, a third peak, a fourth peak and a fifth peak higher than a bulk donor concentration of the semiconductor substrate in a doping concentration distribution in a depth direction, wherein
• the fourth peak is a shallowest peak closest to a lower surface of the semiconductor substrate,
• the third peak is a high concentration peak arranged at an upper side than the lower surface of the semiconductor substrate than the shallowest peak,
• the second peak is lower than the high concentration peak, and is arranged at an upper side than the lower surface of the semiconductor substrate than the high concentration peak,
• the first peak is lower than the high concentration peak, and is arranged closest to the upper surface side of the semiconductor substrate,
• the fifth peak is arranged between the second peak and the third peak, and
• at least one of the first peak, the second peak and the fifth peak is a low concentration peak that is ⅕ or less of the high concentration peak.