Semiconductor device

A semiconductor device comprising:

• a semiconductor layer of a first-conductivity-type that has a main surface and that includes an active region set at the main surface, a current detection region set at the main surface away from the active region, and a boundary region set in a region between the active region and the current detection region at the main surface;
• a first body region of a second-conductivity-type formed in a surface layer portion of the main surface at the active region;
• a first trench gate structure formed in the main surface at the active region;
• a second body region of the second-conductivity-type formed in the surface layer portion of the main surface at the current detection region;
• a second trench gate structure formed in the main surface at the current detection region;
• a well region of the second-conductivity-type formed in the surface layer portion of the main surface at the boundary region;
• a dummy trench gate structure formed in an electrically floating state in the main surface at the boundary region and electrically isolated from at least the first trench gate structure;
• and
• an interlayer insulation layer formed on the well region for covering the well region at the boundary region;
• wherein the interlayer insulation layer includes a thin film portion and a thick film portion which has a thickness that exceeds a thickness of the thin film portion, and
• wherein the thick film portion is formed at a portion that covers the current detection region in the interlayer insulation layer.