Thermal-Stability Enhancement of InGaP/GaAs Collector-Up HBTs

A number of intricate configurations have been proposed to enhance the thermal stability of state-of-the-art power heterojunction bipolar transistors (HBTs). Existing structures for alleviating temperature-interference effects within HBTs are nevertheless not efficient enough to realize miniaturized power amplifiers in next-generation cellular phones. Key thermal parameters, including the temperature-distribution profile, the thermal resistance, the out power, and the power-added efficiency (PAE), of a cost-effective heat-spreading structure have been optimized by the device-physics-based genetic algorithm, and a demonstration on multifinger InGaP/GaAs collector-up HBTs, which exhibit noticeable RF performance, is presented. Comparatively, the significant results, which guarantee the reliability, indicate that the thermal resistance can be substantially decreased by 50%, and a PAE of more than 55% is attained from this novel design.