Patent ID: 7872282

Claim:
A semiconductor device comprising: a semiconductor substrate of a first conductivity type; an active region that includes a well of a second conductivity type selectively formed in a surface region of a first principal surface side of the semiconductor substrate; a base region of the second conductivity type selectively formed in the surface region at a different position from that of the well; an emitter region of the first conductivity type selectively formed in a surface region of the base region of the second conductivity type; a gate insulation film covering a portion of a surface of the base region of the second conductivity type locating between a surface of the emitter region and a portion of the surface of the semiconductor substrate; a gate electrode formed on the gate insulation film; an isolation diffusion region of the second conductivity type formed surrounding the active region and extending from the first principal surface to a second principal surface of the semiconductor substrate; a collector region of the second conductivity type formed in a surface region of the second principal surface; a voltage blocking structure region formed between the isolation diffusion region of the second conductivity type and the active region; and an emitter electrode in contact commonly with both a surface of the emitter region and a portion of the surface of the base region; wherein the voltage blocking structure region includes a plurality of deep first field limiting rings in an inner circumferential side of the surface region of the first principal surface side, a plurality of shallow second field limiting rings in an outer circumferential side of the surface region of the first principal surface side, a plurality of insulation films each covering a portion of the first principal surface between the first field limiting rings and a portion of the principal surface between the second field limiting rings, and a plurality of conductive field plates in contact with the field limiting ring, the field limiting ring projecting over surfaces of the adjacent insulation films.