Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate of a first conductivity type and including a wide bandgap semiconductor material having a bandgap wider than that of silicon;
• a first semiconductor layer of the first conductivity type provided on a front surface of the semiconductor substrate, the first semiconductor layer including the wide bandgap semiconductor material and having an impurity concentration lower than that of the semiconductor substrate, the first semiconductor layer having a first side and a second side;
• a second semiconductor layer of a second conductivity type provided on the first side of the first semiconductor layer opposite the second side facing the semiconductor substrate, the second semiconductor layer including the wide bandgap semiconductor material and having a first side and a second side;
• a third semiconductor layer of the first conductivity type provided on the first side of the second semiconductor layer opposite the second side facing the semiconductor substrate, the third semiconductor layer including the wide bandgap semiconductor material;
• a second-conductivity-type semiconductor region provided selectively in the third semiconductor layer, penetrating the third semiconductor layer in a depth direction and reaching the second semiconductor layer, the second-conductivity-type semiconductor region having an impurity concentration higher than that of the second semiconductor layer;
• a trench penetrating the third semiconductor layer and the second semiconductor layer and reaching the first semiconductor layer;
• a gate insulating film provided on walls of the trench;
• a gate electrode provided in the trench and sandwiched, in the trench, by the gate insulating film;
• a first electrode provided in contact with the third semiconductor layer and the second-conductivity-type semiconductor region;
• and
• a second electrode provided in contact with a rear surface of the semiconductor substrate, wherein
• a width between the trench and an adjacent trench is 1 μm or less, and a depth of the trench is 1 μm or less, and
• the semiconductor device has a breakdown voltage class of 1200V or higher.