Theoretical calculations of temperature and current profiles in multi-finger heterojunction bipolar transistors

Abstract A theoretical analysis is presented to determine both the temperature profile and current distribution among the fingers for a multi-finger heterojunction bipolar transistor designed for microwave power applications. This analysis allows for arbitrary transistor geometries and non-uniform emitter ballast resistors in the fingers. The effects of varying ballast resistances, emitter width, emitter length, and spacing between the fingers will be discussed.