Leakage and hFEdegradation in microwave bipolar transistors

The phenomenon of h
FE
degradation due to an excessive reverse collector bias voltage has been investigated. The correlation between this h
FE
degradation phenomenon and the anomalously high collector leakage currents has been established. A model based on channels arising from diffusion induced pipes and spikes is presented. The model successfully explains these phenomena as observed in shallow-diffused microwave transistors.