Thermal Characterization of InP/GaAsSb DHBTs: Effect of Emitter and Collector Layers

Modern telecommunication systems require transistors that can deliver high power levels at high frequencies. This poses challenges for the reliability of transistors operating close to their peak performance. The thermal behavior of mm-wave InP/GaAsSb DHBTs is studied for several emitter contact widths and lengths, and various epitaxial design alternatives are considered. The effect of the emitter and collector layer stacks is reported. Straightforward modifications to the GaInAs sub-collector contact thickness and composition significantly reduce the thermal resistance R
TH
and junction temperature. We show that a thin emitter yields similar thermal improvements in characteristics as improvements made to the collector design.