Patent ID: 8502345

Claim:
A reverse-conducting insulated gate bipolar transistor comprising: a MOS gate structure on a first major surface of a first conductivity type semiconductor substrate, the MOS gate structure including, a second conductivity type base region, a first conductivity type emitter region selectively formed in the surface region of the second conductivity type base region, and a gate electrode disposed, via an insulation film, on a surface of the second conductivity type base region at a place between a surface of the emitter region and the first major surface of the first conductivity type semiconductor substrate; and a rear surface side structure in a second major surface side of the semiconductor substrate, the rear surface side structure including, a plurality of recessed parts in a vertical direction, the recessed parts being repeated periodically along the second major surface, a depth D of each of the recessed parts being greater than 5 μm, a plurality of protruding parts interposed between the recessed parts, a second conductivity type collector region on a bottom surface of each of the recessed parts, a first field stop region of a first conductivity type positioned above and in line with each collector region and being at a position deeper than the collector region, each first field stop region being separated from the collector region and from other first field stop regions, a first conductivity type cathode region on a top surface of the protruding part, and a first conductivity type second field stop region in the protruding part at a position deeper than the cathode region and shallower than the collector region.