The invention relates to a semiconductor device (10) with a semiconductor body (12) comprising a bipolar transistor with an emitter region, a base region and a collector region (1, 2, 3) of, respectively, a first conductivity type, a second conductivity type opposite to the first conductivity type, and the first conductivity type. One of the emitter or collector regions (1, 3) comprises a nanowire (30). The base region (2) has been formed from a layer (20) at the surface of the semiconductor body (12); the other one (3, 1) of the emitter or collector regions (1, 3) has been formed in the semiconductor body (12) below the base region (2). The emitter or collector region (1, 3) comprising the nanowire (30) has been provided on the surface of the semiconductor body (12) such that its longitudinal axis extends perpendicularly to the surface.