Improving thermal management of multi-finger InGaP collector-up HBTs with a highly compact heat-spreading structure by GA

A variety of complex configurations have been attempted to enhance the thermal stability of modern heterojunction bipolar transistors (HBTs). Existing structures for improving thermal management of power HBTs, nevertheless, are not small enough to realize miniaturized power amplifiers in high-efficiency cellular phones. A highly compact heat-spreading structure (HSS) simulated by the genetic algorithm (GA) is proposed, and the demonstration on multi-finger InGaP/GaAs collector-up HBTs, which show noticeable power performance, is presented. Comparatively, the improved results indicate that the thermal resistance can be substantially decreased by 50%, and a power-added efficiency (PAE) more than 55% is achieved from this novel design.