Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate having upper and lower surfaces;
• a first semiconductor layer of a first conductivity type provided on the upper surface of the semiconductor substrate, and the first semiconductor layer having a lower impurity concentration than that of the semiconductor substrate;
• a second semiconductor layer of a second conductivity type provided on an upper surface side of the first semiconductor layer;
• a first semiconductor region of the first conductivity type selectively provided in a surface layer on an upper surface side of the second semiconductor layer, and the first semiconductor region having a higher impurity concentration than that of the first semiconductor layer;
• an active region including at least a first gate insulating film in contact with the second semiconductor layer, a first gate electrode provided on an upper surface of the first gate insulating film, an interlayer insulating film provided on the first gate electrode, a first electrode in contact with the second semiconductor layer and the first semiconductor region, and a second electrode in contact with the lower surface of the semiconductor substrate;
• and
• an active region perimeter including a perimeter trench and a source ring region, the perimeter trench configured to surround the active region, the perimeter trench provided on the upper surface side of the second semiconductor layer, the perimeter trench configured to penetrate through the second semiconductor layer, and the source ring region configured to surround the perimeter trench, wherein
• the perimeter trench is configured such that a second gate electrode is provided inside the perimeter trench with a second gate insulating film interposed therebetween and is formed immediately below the first electrode.