Silicon-Germanium (SiGe) heterojunction bipolar transistors (HBTs) with a low emitter doping concentration (LEC) are investigated with respect to their electrical characteristics in dependence of the Germanium profile shape. The study is based on one-dimensional (1D) device simulation using a realistic doping and Ge profile as baseline. While keeping the doping profile unchanged the Ge profile is modified to evaluate its impact on major electrical figure of merits such as transit frequency, ideality factor, early voltage, noise figure, as well as on process control monitors (PCMs) such as internal base sheet resistance and area specific depletion capacitances. The variations in electrical characteristics and PCMs are briefly explained on a theoretical basis with regard to the impact on compact and statistical modeling. (C) 2003 Elsevier Ltd. All rights reserved.