Semiconductor device

A semiconductor device, comprising:

• a first semiconductor region of a first conductivity type, provided in a semiconductor substrate that has a first main surface and a second main surface opposite to each other in a depth direction thereof;
• a second semiconductor region of a second conductivity type, provided between the first main surface of the semiconductor substrate and the first semiconductor region;
• a trench penetrating through the second semiconductor region, from the first main surface of the semiconductor substrate in the depth direction, and terminating in the first semiconductor region;
• a gate electrode provided in the trench, via a gate insulating film;
• a plurality of third semiconductor regions of the first conductivity type, selectively provided between the first main surface of the semiconductor substrate and the second semiconductor region, the plurality of third semiconductor regions each being in contact with the gate insulating film at a corresponding one of sidewalls of the trench;
• a plurality of fourth semiconductor regions, selectively provided between the first main surface of the semiconductor substrate and the second semiconductor region, the plurality of fourth semiconductor regions each being in contact with the gate insulating film at a corresponding one of the sidewalls of the trench;
• a plurality of fifth semiconductor regions of the second conductivity type, selectively provided between the first main surface of the semiconductor substrate and the second semiconductor region, apart from the trench, the plurality of fifth semiconductor regions having an impurity concentration higher than an impurity concentration of the second semiconductor region;
• a first electrode in contact with the plurality of third semiconductor regions, the plurality of fourth semiconductor regions, and the plurality of fifth semiconductor regions;
• and
• a second electrode in contact with a second main surface of the semiconductor substrate, wherein
• the plurality of fourth semiconductor regions is a plurality of first-conductivity-type regions having an impurity concentration of the first conductivity type lower than an impurity concentration of the plurality of third semiconductor regions or is a plurality of second-conductivity-type regions having an impurity concentration of the second conductivity type lower than the impurity concentration of the second semiconductor region at a portion thereof that is in a vicinity of and along the sidewalls of the trench.