Non-ideal current - voltage characteristics in MBE-grown heterojunction bipolar transistors

Abstract

The current - voltage characteristics of heterojunction bipolar transistors and Si homojunction bipolar transistors grown by MBE have been measured with the aim of elucidating the causes of degraded common-emitter gain and low . It is shown that high reverse diode leakage currents arising from Zener tunnelling contribute to low in all structures considered. In forward bias, recombination currents in the space charge layers are the dominant cause of excess base current at temperatures above . Below this temperature a defect-assisted tunnelling mechanism gives rise to diode non-ideality.