Patent ID: 9620499
Date: 2017-04-11
CPC Classifications: H01L

Claim:
1. A semiconductor device comprising: a semiconductor substrate comprising an IGBT region and a diode region, an emitter electrode provided on a front surface of the semiconductor substrate in the IGBT region; an anode electrode provided on the front surface of the semiconductor substrate in the diode region; and a rear electrode provided on a rear surface of the semiconductor substrate, wherein the IGBT region comprises: an emitter region of an n-type and in contact with the emitter electrode; a body region of a p-type and in contact with the emitter electrode; an IGBT drift region of the n-type and separated from the emitter region by the body region; a collector region of the p-type, separated from the body region by the IGBT drift region, and in contact with the rear electrode; a gate insulating film in contact with the body region; and a gate electrode facing the body region via the gate insulating film, the diode region comprises: an anode region of the p-type and in contact with the anode electrode; a diode drift region of the n-type, bordering the anode region on a rear surface side, and connected to the IGBT drift region; a buffer region of the n-type and bordering the diode drift region on the rear surface side; and a cathode region of the n-type, bordering the buffer region on the rear surface side, and in contact with the rear electrode, in a view of n-type impurity concentration distribution along a direction from the front surface to the rear surface, a local minimum value of an n-type impurity concentration is located at a border between the cathode region and the buffer region, and a local maximum value of the n-type impurity concentration is located in the buffer region, a peak value of the n-type impurity concentration in the cathode region and the local maximum value are higher than the n-type impurity concentration in the diode drift region, at least one of the buffer region and the cathode region comprises a crystal defect region in which crystal defects are distributed in a higher concentration than a region around the crystal defect region, and a peak value of a crystal defect concentration in the view of crystal defect concentration distribution along the direction from the front surface to the rear surface is located in a region on the rear surface side with respect to a specific position having the n-type impurity concentration which is a half of the local maximum value, the specific position being located on a front surface side with respect to a position of the local maximum value.