<title>Current gain degradation of boron-doped polysilicon emitter transistors under forward current stress in a C-BiCMOS technology</title>

Abstract

The conventional hydrogen-contained plasma etching for emitter via hole opening can introduce atomic hydrogen into poly emitter. After short time forward current stress, p-n-p transistors fabricated by this process show increase of both current gain ((beta) ) and base current 1/f noise in the median bias region. The subsequent low temperature annealing characteristics of p-n-p indicate that hydrogen boron pairs are dissociated. The (beta) increase during current stress can be explained by the reduction of effective surface recombination velocity of emitter due to hydrogen boron pair formation.