On the effects of hydrogen in p-n-p transistors under forward current stress in a C-BiCMOS technology

Abstract

Boron-doped polysilicon emitter p-n-p transistors show current gain ( beta ) increase after forward current stress and recovery by subsequent low-temperature annealing. The results of isothermal and isochronal annealing suggest that the dissociation of boron-hydrogen pairs is responsible for recovery from the beta increase. Current stress indicates that atomic hydrogen transported to the poly/monosilicon interface and polysilicon grain boundaries by electromigration pairs with boron dopants, thereby reducing surface recombination velocity and increasing beta . >