Patent ID: 7227226

Claim:
A semiconductor device comprising: a semiconductor substrate; a BOX film disposed on top of the semiconductor substrate; an active layer, disposed on top of the BOX film, comprising first, second, and third regions forming pn junctions in between that are substantially parallel to the surface of the BOX film; a gate electrode formed vertically in relation to the surface of the active layer; a gate insulator film disposed on an interface between the active layer and the gate electrode; a base region disposed proximate to the surface of the first region and adjacent to the gate electrode; a first main electrode region disposed within the base region; a second main electrode region formed from the surface of the active layer to the surface of the BOX film or protruding through the BOX film, and the second main electrode region being spaced from the base region; a first main electrode connected to the first main electrode region; a second main electrode connected to the second main electrode region; and a ground electrode connected to the semiconductor substrate on an opposite side surface from a surface having the BOX film on the semiconductor substrate, wherein the gate electrode is formed from the surface of the active layer to within the BOX film, the first main electrode region spans from the surface of the active layer to within the third region and the second main electrode region is formed from the surface of the active layer to the second region.