A semiconductor device includes a body zone in a semiconductor mesa, which is formed between neighboring control structures that extend from a first surface into a semiconductor body. A drift zone forms a first pn junction with the body zone. In the semiconductor mesa, the drift zone includes a first drift zone section that includes a constricted section of the semiconductor mesa. A minimum horizontal width of the constricted section parallel to the first surface is smaller than a maximum horizontal width of the body zone. An emitter layer between the drift zone and the second surface parallel to the first surface includes at least one first zone of a conductivity type of the drift zone.