It was noted that dopant atoms segregated to these interfaces. On the basis of ab initio calculations, the mechanisms by which P atoms were bonded and deactivated under the interface were identified. It was proposed that P segregation occurred via trapping at interfacial dangling bonds, trapping at vacancies and vacancy-O complexes bound under the interface and via the formation of pairs of 2-fold coordinated P atoms. The first mechanism was expected to be important at low dopant concentrations, or when no vacancies were available. The second one was expected to predominate at medium dopant concentrations after P implantation. The third one was expected to control segregation at dopant concentrations of 1019/cm3 or above.

A Unified Microscopic Mechanism for Donor Deactivation in Si R.Baierle, M.J.Caldas, J.Dabrowski, H.J.Mussig, V.Zavodinsky: Physica B, 1999, 273-274, 260-3