Exchange of deeply trapped and interstitial hydrogen in silicon

Using ab initio density-functional calculations, we examine possible exchange mechanisms between an interstitial hydrogen atom and a deeply bound H at a silicon-hydrogen bond. We determine a low-energy pathway for exchange, which involves an intermediate, metastable (Formula presented) complex with both hydrogen atoms strongly bound to the silicon atom. The energy barrier for the exchange process is (Formula presented) consistent with observations of hydrogen-deuterium exchange in (Formula presented) films.