Characterization and measurement of non-linear temperature rise and thermal resistance in InP heterojunction bipolar transistors

We present a method of measurement and characterization of the differential thermal resistance and non-linear temperature rise for small GaAs and InP heterojunction bipolar transistors. It is shown that nonlinear thermal behavior of the transistor can be completely described by the zero power thermal resistance and linear temperature coefficient, and that for small devices the zero power thermal resistance approximately scales with emitter area and that this scaling is more favorable for InP HBTs when compared to GaAs HBTs.