Semiconductor device

A semiconductor device, comprising:

• a semiconductor substrate of a first conductivity type, and having a front surface and a back surface opposite to each other, the semiconductor substrate containing boron, a concentration of the boron therein being in a range from 5×1015/cm3 to 5×1016/cm3;
• a first semiconductor layer of the first conductivity type, provided on the front surface of the semiconductor substrate and having an impurity concentration lower than an impurity concentration of the semiconductor substrate, the first semiconductor layer having a first surface and a second surface opposite to each other, the second surface facing the semiconductor substrate;
• a second semiconductor layer of a second conductivity type, selectively provided on the first surface of the first semiconductor layer, the second semiconductor layer having a first surface and a second surface opposite to each other, the second surface facing the semiconductor substrate;
• a plurality of first semiconductor regions of the first conductivity type, selectively provided in the second semiconductor layer at the first surface thereof;
• a plurality of gate insulating films in contact with the second semiconductor layer, each having a first surface and a second surface opposite to each other, the second surface being in contact with the second semiconductor layer;
• a plurality of gate electrodes provided on the first surfaces of the gate insulating films, respectively;
• a plurality of first electrodes provided on the first surface of the second semiconductor layer and surfaces of the first semiconductor regions;
• and
• a second electrode provided on the back surface of the semiconductor substrate.