A detailed investigation on internal thermal phenomena of GaAs hetero bipolar transistor (HBT) structure is presented especially when sub-collector is considered. This allows for a realistic and physical electro-thermal analysis. With the help of Joule heating calculation, a drifting heat source across the collector region is observed under real operation of large current density. Temperature distribution also verifies this phenomenon with further simulation. To get a better insight into the mechanism of the drifting action, the associated distributed high electric field is then analyzed. A thermally optimized HBT is then proposed with Gaussian doping in the sub-collector region. Compared to the original structure, the new design shows a reduction of maximum temperature by 9.5% with base current density of 2e-5 A/μm. The findings in this paper can help with accurate thermal modeling and provide suggestions for thermal optimized HBT design as well.

详细介绍了GaAs异质双极晶体管（HBT）结构的内部热现象，特别是在考虑了子集电极的情况下。这允许进行现实的和物理的电热分析。在焦耳热计算的帮助下，在大电流密度的实际操作下，可以观察到横跨集电极区域的热源漂移。温度分布还可以通过进一步仿真来验证这种现象。为了更好地了解漂移作用的机理，然后分析了相关的分布高电场。然后提出在子集电极区域中进行高斯掺杂的热优化HBT。与原始结构相比，新设计显示最高温度降低了9.5％，基本电流密度为2e-5 A /μm。