Patent ID: 8735974

Claim:
A semiconductor device comprising: a first semiconductor region of a first conductive type; a second semiconductor region of a second conductive type, the second semiconductor region being in contact with the first semiconductor region; a third semiconductor region of the first conductive type, the third semiconductor region being in contact with the second semiconductor region and separated from the first semiconductor region by the second semiconductor region; a fourth semiconductor region of the second conductive type, the fourth semiconductor region being in contact with the third semiconductor region and separated from the first and second semiconductor regions by the third semiconductor region; a first main electrode electrically connected with the first semiconductor region; a second main electrode electrically connected with the third and fourth semiconductor regions; a gate electrode insulated from the second main electrode, the gate electrode being connected with the second, third and fourth semiconductor regions via a first insulating film, and opposing a part of the third semiconductor region via the first insulating film, the part of the third semiconductor region separating the fourth semiconductor region from the second semiconductor region; and a conductive region electrically connected with the second main electrode, the conductive region being connected with the second and third semiconductor regions via a second insulating film, wherein the conductive region comprises a first conductive region of the first conductive type, and a second conductive region of the second conductive type, the second conductive region being in contact with the first conductive region, a second conductive type impurity concentration of the second conductive region is lower than that of the second semiconductor region, and within the conductive region, the first conductive region separates the second main electrode from the second semiconductor region, the second main electrode is separated from the second conductive region by the first conductive region, and the second semiconductor region is separated from the first conductive region by the second conductive region.