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 (β) increase after forward current stress and recovery by subsequent low-temperature annealing. The results of isothermal and isochronal annealing suggest that the dissociation of hydrogen-boron pairs is responsible for recovery from the β increase. It is implicated from current stress 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 β. © 1993 IEEE