Abstract: The invention relates to a transistor having an emitter (1), a collector (2), and a base layer (3), wherein the emitter (1) extends into the base layer (3), wherein the base layer (3) has an intrinsic region (4) arranged between the emitter (1) and the collector (2), and an extrinsic region (6) that runs between the intrinsic region (4) and a base contact (5), wherein the base layer (3) contains a first doping layer (7) doped with a trivalent doping substance, which extends into the extrinsic region (6) and which is counter-doped by means of a pentavalent counter-doping substance (8) in the region of the emitter (1). The electrical resistance of the base layer (3) can be reduced, in advantageous manner, by means of the first doping layer (7).