Patent ID: 7084484
Filing Date: 2006-08-01
Classification: H01L

Abstract:
1. A semiconductor integrated circuit comprising a plurality of bipolar transistors that are obtained by forming, in each of a plurality of transistor-producing regions, a first conductive type emitter layer on the front surface side of a second conductive type base layer that is formed on the front surface side of a first conductive collector layer and wherein the second conductive type base layer contains germanium, the first conductive type emitter layer being formed from a semiconductor material having a band gap larger than the base layer; the concentrations of first conductive type impurities contained in the emitter layer varying among the plurality of transistor-producing regions, causing the germanium concentrations to be different in base-emitter junction interfaces of at least two of the transistor-producing regions, thus making ON-state voltages, which are necessary for turning the plurality of the bipolar transistors into an ON state different from each other.