SEMICONDUCTOR DEVICE WITH A BIPOLAR TRANSISTOR AND METHOD OF MANUFACTURING SUCH A DEVICE

摘要

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). According to the invention, the sub-region comprising the mixed crystal of silicon and germanium extend substantially through the whole emitter region (1) up to the interlace with the intermediate region (22) and the doping atoms of the emitter region (1) are arsenic atoms. Such a device has a very steep n-type doping profile (50) and a very steep p- type doping profile (20) at or within the intermediate region (22) and thus excellent high- frequency behavior with a high cut-off frequency (fr). Preferably the emitter region (1) is doped with an arsenic implantation (I) in its upper half, the final doping profile being formed after an RTA. The invention also comprises a method of manufacturing a device (10) according to the invention.