AlGaAs/GaAs heterojunction bipolar transistors for power applications: issues of thermal effect and reliability
AlGaAs/GaAs heterojunction bipolar transistor (HBT) has the advantages of superior switching speed, wide linearity, and high current handling capability. As a result, the device has gained popularity in designing power amplifiers for RF and microwave applications. However, the high power in the HBT, together with the poor thermal conductivity of GaAs, gives rise to significant thermal effect and reduced reliability in such a device. This paper presents an overview on the simulation, modeling, and reliability of AlGaAs/GaAs HBTs. Emphasis will be placed on the effects of thermalelectrical interacting behavior on the dc and ac performance of the HBT. The thermal-induced degradation process in the HBT will also be addressed and analyzed.
heterojunction bipolar transistor thermal effect semiconductor