Degradation of InGaAs/InP single heterojunction bipolar transistors under high energy electron irradiation

Abstract

Abstract The d.c. characteristics of InGaAs/InP single heterojunction bipolar transistors (SHBTs) were studied for the first time under high energy (∼1 MeV) electron radiation of cumulative dose up to 5.4×1015 electrons/cm2. No degradation was observed for electron doses below 1015/cm2. For electron doses greater than 1015/cm2 the following degradation effects were observed: (1) decrease in collector current; (2) decrease in current gain up to 50%; (3) an increase in collector saturation voltage by 0.2–0.8 V depending on base current; and (4) increase in output conductance. The degradation of collector current and current gain are thought to be due to increased recombination caused by radiation-induced defects in the base–emitter junction. The increase in collector saturation voltage is attributed to an increase in emitter contact resistance after irradiation. The increase in the avalanche multiplication in the reverse biased base–collector junction caused by radiation induced defects is believed to be responsible for increased output conductance after irradiation.