FORMATION OF EXTENDED HYDROGEN COMPLEXES IN SILICON

We have examined the nucleation and growth of hydrogen clusters using pseudopotential total-energy calculations. A double-layer {111} H platelet, resulting from clustering of diatomic H-2* complexes, is lower in energy by 0.15 eV per H pair than interstitial H-2 molecules. This result explains two experimental observations: (1) the predominance of Si-H bonding observed in Si containing high H concentrations and (2) the formation of H {111} platelets. The H vibrational frequencies, H-H separations, and other properties of the platelet are in general agreement with experiment.