Minimizing Intrinsic Base Spreading Sheet Resistance for Silicon-Germanium Heterojunction Bipolar Transistor

The base resistance in the Silicon-Germanium heterojunction bipolar transistor (SiGe HBT) has a significant impact on its frequency response for millimeter-wave application and noise performance. To enhance the performance, the base resistance should be small. This work focuses on an approach to minimize the intrinsic base sheet resistance, which is a crucial parameter in deciding the internal base spreading resistance. The controlling parameters of the HBT are more sensitive to temperature, doping concentration of intrinsic base region and bias conditions. The precise measurement of the internal base resistance of the HBT device is challenging from its quantification perspective. Another prospect of this work, focusing on modeling, is a novel dc technique being used in the determination of the intrinsic base sheet resistance on a single doubly poly-Si base device structure using finite element method calculations. For verification of the qualitative data, calibration of the mobility model and Gummel characteristics with the experimental data has been completely optimized.