Thermal And Reverse Base Current Effects On Heterojunction Bipolar Transistors And Circuits

An empirical model of a heterojunction bipolar transistor is presented. The model expands the Gummel-Poon equations to account for device self-heating, base current reversal, and the collector-emitter offset voltage. It is shown that self-heating has implications for the cutoff frequency of the HBT for the frequency response of a small-signal amplifier, and also for the thermal stability of a current mirror circuit. © 1995 IEE