Thermal behavior using analytical and numerical model in multi-finger power heterojuction Bipolar transistors

Abstract

The Transmission Line Matrix (TLM) explicit method has been used to model the transient thermal proprieties of various microwave HBT’s power structure. Control of the self-heating is of a paramount importance and changes the electronic performance of the device. The thermal effect is important to the AlGaAs / GaAs multiple emitter heterojunction bipolar transistors (HBT’s) due to the high current handling capability of such devices. Aimed toward predicting the HBT behavior and physical trends, we developed an analytical model incorporating the high current as well as thermal effects. The temperature distribution along the depth direction of the substrate is obtained from a three dimensional analysis by solving the steady-state heat flow equation. In this paper, an investigation of the thermal behavior of single emitter and multiemitter finger HBT microwave power device is exposed.