A simple technique for measuring the thermal impedance and the thermal resistance of HBTs

This paper presents a new and simple method for characterizing the thermal behavior of heterojunction bipolar transistors, based on DC, AC and low frequency small signal measures of H (hybrid) parameters. Static characterization of the thermal behavior is achieved through the calculation of a thermal resistance, while a thermal impedance is used to describe thermal dynamic behavior. Validation results for the method obtained from both simulations and experimental data are included in the paper for a 10/spl times/2/spl times/40 /spl mu/m InGaP/GaAs power HBT.