Patent ID: 10573730

Abstract:
A bipolar transistor is described. In accordance with one aspect of the present invention the bipolar transistor comprises a semiconductor body including a collector region and a base region arranged on top of the collector region. The base region has a first crystalline structure and is at least partly doped with dopants of a first doping type. The collector region is laterally enclosed by a trench isolation and is doped with dopants of a second doping type. The transistor further comprises a conductive base contact layer laterally enclosing the base region which is doped with dopants of the first doping type. The base contact layer comprises a part with the first crystalline structure and a part with a second crystalline structure, wherein the part with the second crystalline structure laterally encloses the part with the first crystalline structure. The transistor further comprises an emitter region arranged on the base region, wherein the emitter region is doped with dopants of the second doping type and forming a pn-junction with the base region.