Effect of emitter-base bias during pre-irradiation infrared illumination on the radiation response of bipolar transistors

Enhancement and suppression of radiation-induced current-gain degradation in bipolar transistors has been observed after pre-irradiation infrared (IR) illumination under reverse and forward emitter-base bias, respectively. The effect of the IR illumination decreases during isochronal anneal and almost completely disappears at 100/spl deg/C. A qualitative physical model has been proposed to explain the experimental results. The effect can be caused by an IR-light-induced transition between the neutral and dipole configurations of the precursor defects without changing the net electric charge. Possible applications of the effects are discussed.