Leakage and hFEdegradation in microwave bipolar transistors

The phenomenon of hFEdegradation due to an excessive reverse collector bias voltage has been investigated. The correlation between this hFEdegradation 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.