Patent ID: 7420228

Claim:
A bipolar transistor comprising: a collector region of a first conduction type; a subcollector region of the first conduction type, which is electrically connected to the collector region at a first side of the collector region; a base region of the second conduction type which is provided at a second side of the collector region, the base region having a smaller cross section than the collector region; an emitter region of the first conduction type, which is provided above the base region on the side remote from the collector region; and a carbon-doped semiconductor region, which is provided on the first side alongside the collector region, the carbon-doped semiconductor region having a carbon concentration of 10 19 -10 21 cm −3 ; wherein the collector region has, in the overlap region with the base region, a zone having an increased doping of the first conduction type compared with the remaining region; and the carbon-doped semiconductor region laterally extends alongside the zone and the remaining region of the collector region, and prevents a lateral outdiffusion from the zone into the remaining region of the collector region.