Formation energy of self-interstitials in carbon-doped Si determined by optical absorption due to hydrogen bound to self-interstitials

We determined the formation energy of self-interstitials in carbon (C)-doped Si from measurements of optical absorption due to hydrogen (H) bound to isolated self-interstitials. Specimens of C-doped Si were sealed in quartz capsules together with hydrogen (H) gas, with pressure being 1 atm at high temperature, and were annealed at high temperature for 1 h followed by quenching in water. We measured their optical absorption spectra at about 7 K with an FT-IR spectrometer. Several peaks coincided with those observed in proton-implanted Si. Hence, we conclude that complexes of simple point defects such as vacancies and self-interstitials with hydrogen atoms existed in those specimens. From the quenching temperature dependence of the peaks identified to be H bound to self-interstitials, the formation energy of self-interstitials in C-doped Si was estimated to be about 3 eV. (C) 1999 American Institute of Physics. [S0021-8979(99)08116-5].