Research on thermal-electrical characteristics of SiGe HBTs with different Ge profiles

The thermal-electrical characteristics of SiGe HBTs with three kinds of Ge profiles (box, trapezoidal and triangular) in the base are investigated in this paper. The results show that SiGe HBTs with trapezoidal and triangular Ge-profile could improve the peak temperature, non-uniformity of surface temperature distribution, and the sensibility of the gain and cutoff frequency to temperature compared with SiGe HBT with box Ge profile. However, these properties of SiGe HBT with triangular Ge profile are superior to that of trapezoidal Ge profile.