Patent ID: 7560782

Claim:
An integrated transistor device comprising: a chip of semiconductor material; an electrical-insulation region delimiting an active area in said chip; a bipolar transistor formed in said active area and including: a collector region; a bipolar base region contiguous to said collector region; and an emitter region accommodated in said bipolar base region; and a MOSFET contiguous with the bipolar transistor and including: a source region, arranged at a distance from said bipolar base region; a drain region; a channel region arranged between said source and drain regions; and an insulated-gate region that extends on top of said active area and on top of said channel region; wherein said bipolar base region is contiguous with a first side of the drain region and forms, with the drain region, a common base structure shared by said bipolar transistor and said MOSFET, wherein said common base structure comprises a LDD drain region surrounding said drain region at a bottom and on a second side thereof facing said channel region, said LDD drain region being formed as a continuation of said bipolar base region, thereby said drain region is surrounded at the first and second sides and at the bottom by said LDD drain region and said bipolar base region.