Abstract: The invention relates to a semiconductor device with a substrate and a semiconductor body of silicon comprising a bipolar transistor with an emitter region, a base region and a collector region which are respectively of the N-type conductivity, the P-type conductivity and the N-type conductivity by the provision of suitable doping atoms, wherein the base region comprises a mixed crystal of silicon and germanium, the base region is separated from the emitter region by an intermediate region of silicon having a doping concentration which is lower than the doping concentration of the emitter region and with a thickness smaller than the thickness of the emitter region, and the emitter region comprises a sub-region comprising a mixed crystal of silicon and germanium which is positioned at the side of emitter region remote from the intermediate region.

Abstract: A metal-base transistor is suggested. The transistor comprises a first and a second electrode (2, 6) and base electrode (6) to control current flow between the first and second electrode. The first electrode (2) is made from a semiconduction material. The base electrode (3) is a metal layer deposited on top of the semiconducting material forming the first electrode. According the invention the second electrode is formed by a semiconducting nanowire (6) being in electrical contact with the base electrode (3).

Abstract: The invention relates to a semiconductor device (10) with a substrate and a semiconductor body of silicon comprising a bipolar transistor with an emitter region (1), a base region (2) and a collector region (3) which are respectively of the N-type conductivity, the P-type conductivity and the N-type conductivity by the provision of suitable doping atoms, wherein the base region (2) comprises a mixed crystal of silicon and germanium, the base region (2) is separated from the emitter region by an intermediate region (22) of silicon having a doping concentration which is lower than the doping concentration of the emitter region (1) and with a thickness smaller than the thickness of the emitter region (1) and the emitter region (1) comprises a sub-region comprising a mixed crystal of silicon and germanium which is positioned at the side of emitter region (1) remote from the intermediate region (22).