Ameliorated Thermal Performance of n-p-n and p-n-p GaAs/InGaAs/InGaP Collector-Up HBTs

To alleviate mutual heating, both n-p-n and p-n-p GaAs/InGaAs/InGaP collector-up heterojunction bipolar transistors with an effective heat-dissipation configuration (HDC), which can be used in power-amplifier circuits for next-generation wireless communication, have been successfully fabricated for the first time. Significantly different from recently proposed thermal-property-improving collector-up structures and thermal-via-hole designs, the HDC-implemented multifinger devices, with a graded InGaAs base but without the InGaP tunneling collector, are demonstrated to achieve compelling high-speed and heat-removing thermal performance. Preliminary results show that the thermal coupling has been substantially decreased, and nearly 20% amelioration, compared to previous work, in the temperature-rise ratio is obtained. Unprecedentedly, the HDC has a stronger influence on the p-n-p device than on the n-p-n device based on the empirical observations.