Thermal resistance in trench-isolated Si/SiGe heterojunction bipolar transistors

We present a study of thermal resistance in trench-isolated Si/SiGe heterojunction bipolar transistors (HBTs), using a technique based on isothermal collector current measurement. Measured thermal resistance is in good agreement with a realistic three-dimensional (3-D) numerical model; emitter metallization, shallow trenches, and heat flow through the deep trench walls are all shown to have a significant effect on the thermal resistance.