Two-step debonding of hydrogen from boron acceptors in silicon

Previous work has demonstrated that B⋅H pairs in silicon thermally dissociate obeying simple first-order kinetics if they are located in a region depleted of majority carriers. B⋅H debonding in equilibrium, however, is a slower, more complex process. We have investigated the dissociation of B⋅H pairs under a variety of equilibrium and nonequilibrium conditions and have demonstrated that the dissociation process is strongly influenced by the local concentration of majority and minority carriers. In particular, we show that injection of minority carriers can markedly accelerate the dissociation process. A model is proposed which suggests that hydrogen released from an acceptor, while initially positive, must always be neutralized before escape is possible. This picture correctly describes the time dependence of debonding in both equilibrium and forward-biased diodes.