Cathodoluminescence evidence of stress-induced outdiffusion of beryllium in AlGaAs/GaAs heterojunction bipolar transistors

Cathodoluminescence (CL) spectroscopy has been used for the first time in order to detect the base-dopant outdiffusion induced by current stress in AlGaAs/GaAs Be-doped heterojunction bipolar transistors (HBTs). The results show that diffusion of base dopant along the growth direction of the HBT structure occurs during the stress and this conclusion is confirmed by SIMS analysis. Integrated CL intensity variations induced by the stress suggest that the mechanism of recombination-enhanced impurity diffusion is responsible for diffusion of Be.