3D thermal simulations and modeling of multi-finger InP DHBTs for millimeter-wave power amplifiers

This paper presents the comparison between the simulated and measured thermal resistance of InP Double Heterojunction Bipolar Transistors (DHBT). 3D thermal simulations were carried out in order to compute the temperature distribution across the full structure due to a constant power excitation of devices with up to 8 emitter fingers. The surface temperature profile was then used to compute the average thermal resistance of the multi-finger devices. The comparison with the corresponding results obtained by electrical measurements show a good agreement. The temperature profiles from several simulations are used to extract the thermal resistance matrix used in the electro-thermal coupling network of a compact large-signal model.