Degradation of DC Characteristics of InGaAs/InP Single Heterojunction Bipolar Transistors under Electron Irradiation

The effects of high energy (~1 MeV) electron irradiation on the DC characteristics of InGaAs/InP single heterojunction bipolar transistors (SHBTs) are investigated. The device characteristics do not show any significant change for electron doses 10 sup (15)/cm sup 2. For higher doses, devices show a decrease in collector current, a degradation of common-emitter current gain, an increase in collector saturation voltage and an increase in the collector output conductance. A simple SPICE-like device model is developed to describe the DC characteristics of SHBTs. The model parameters extracted from the measured DC characteristics of the devices before and after irradiation are used to get an insight into the physical mechanisms responsible for the degradation of the devices.