Extraction of Compact Static Thermal Model Parameters for SiGe HBTs

In this article, we present and evaluate compact static thermal model parameter extraction techniques for modern silicon germanium heterojunction bipolar transistors (SiGe HBTs). We found that the model implementation of thermal resistance ( ${R}_{\text {th}}$ ) based on only junction temperature is implicit requiring time-consuming iterative procedure which may lead to potential instabilities. Dedicated extraction techniques are proposed for obtaining compact model-specific ${R}_{\text {th}}$ and its temperature coefficient. The proposed method is primarily validated on SPICE generated synthetic data. Next in order to showcase a compact model-independent verification, we also test the method using detailed thermal simulation from TCAD. Finally, we apply our extraction technique on measured data from fabricated transistors. The results are benchmarked to already obtained nominal ${R}_{\text {th}}$ values from the same device family.