Hot carrier induced bipolar transistor degradation due to base dopant compensation by hydrogen: theory and experiment

New experimental and analytical results are presented which show that extrinsic and intrinsic base dopant compensation by hydrogen is responsible for large changes in the bipolar transistor parameters of emitter-base breakdown voltage (V_ebo), forward collector current (I_c) and series base resistance (R_bx) when such transistors are operated under avalanche and inverted mode stress conditions. A new physical model has been developed to explain the observed changes in V_ebo and I_c as a function of stress time, and the analytical results are shown to be well correlated with the experimental data. Lastly, the effects of degradation on transistor voltage gain bandwidth (f_max) and emitter coupled bipolar comparator delay (τ_delay) are assessed and discussed in terms of circuit performance degradation