Passivation and reactivation of {H,P} pairs in Si

It is known that H passivated P doped Si is easily reactivated at room temperature by injection of holes. Recent experimental studies have shown thatthis reaction is reversible, i.e., that passivation can again be achieved in the presence of free electrons without further exposure to atomic H. This suggests that reactivation does not involve the debonding of H but merely the transition of the defect to a positive charge state. We calculated the kinetics of the reactions {H,P}⁰+h⁺→{H,P}⁺ and {H,P}⁺+e^-→{H,P}⁰. The former reaction occurs spontaneously while the latter one is very slow. We also calculated the vibrational frequencies of H in the {H,P}⁺ state and find it to be close to the unidentified, donor-dependent IR mode of H first reported in 1988.