Characterization and Compact Modeling of the Thermal Resistance of SiGe HBTs From Cryogenic to Room Temperature

The thermal resistance ${R}_{\text {th}}$ of SiGe heterojunction bipolar transistors (HBTs) is characterized and modeled at cryogenic temperatures up to room temperature (RT). A physics-based analytical solution for the thermal resistance has been derived for this wide temperature range. Two formulations including both chuck temperature and power dependence of ${R}_{\text {th}}$ have been developed and show good agreement with data from both 3-D thermal simulation and measurements.