Abstract: According to one embodiment, a semiconductor device, includes a semiconductor layer, a first base region of a first conductivity type, a first source region of a second conductivity type, a second base region of the first conductivity type, a back gate region of the first conductivity type, a drift region of the second conductivity type, a drain region of the second conductivity type, a first insulating region, a second insulating region, a gate oxide film, a first gate electrode, a second gate electrode, a first main electrode and a second main electrode. These constituent elements are provided on the surface of the semiconductor layer. The distance between the first base region and the first insulating region is not more than 1.8 ?m. The distance between the first base region and the first insulating region is shorter than a distance between the second base region and the second insulating region.

Abstract: According to one embodiment, a semiconductor device includes a semiconductor substrate, and first and second transistors. The substrate has a first conductivity type. The first and second transistors are provided on the substrate. The first and second transistors each include a gate electrode provided on the substrate, a gate insulating film provided between the substrate and the gate electrode, a source and a drain region of a second conductivity type, and a high-concentration channel region of the first conductivity type. The source and drain regions are provided in regions of an upper portion of the substrate. A region directly under the gate electrode is interposed between the regions. The high-concentration channel region is formed on a side of the source region of the region of the upper portion directly under the gate electrode. The high-concentration channel region has an effective impurity concentration higher than that of the upper portion.

Abstract: According to one embodiment, a semiconductor device, includes a semiconductor layer, a first base region of a first conductivity type, a first source region of a second conductivity type, a second base region of the first conductivity type, a back gate region of the first conductivity type, a drift region of the second conductivity type, a drain region of the second conductivity type, a first insulating region, a second insulating region, a gate oxide film, a first gate electrode, a second gate electrode, a first main electrode and a second main electrode. These constituent elements are provided on the surface of the semiconductor layer. The distance between the first base region and the first insulating region is not more than 1.8 ?m. The distance between the first base region and the first insulating region is shorter than a distance between the second base region and the second insulating region.