Patent ID: 8878294

Claim:
A semiconductor device comprising: a semiconductor layer; a first conductive region provided in a surface of the semiconductor layer; a second conductive region provided in a surface layer portion of the semiconductor layer in spaced relation from the first conductive region, the second conductive region including a well disposed in the surface layer portion, an upper most portion of the well being spaced apart from said surface of the semiconductor layer; a gate insulation film provided in contact with a portion of said surface of the semiconductor layer present between the first conductive region and the second conductive region; a gate electrode provided on the gate insulation film; and an isolation portion, in a form of a trench isolation structure, provided between the second conductive region and the gate insulation film for isolating the second conductive region and the gate insulation film from each other so that the second conductive region and the gate insulation film do not touch each other, wherein no such isolation portion is provided between the first conductive region and the gate insulation film, wherein the gate insulation film touches the isolation portion and is spaced apart from the second conductive region so that the gate insulation film does not touch the second conductive region, the well extends toward the first conductive region beyond the isolation portion, and the semiconductor layer has a semiconductor region disposed between the first conductive region and the well, the semiconductor region extending between the gate insulation film and the upper most portion of the well so as to touch the isolation portion.