Formation Energy of Interstitial Si in Au-Doped Si Determined by Optical Absorption Measurements of H Bound to Interstitial Si

We determined the formation energy of interstitial Si in Au-doped Si from the measurements of optical absorption due to hydrogen (H) bound to interstitial Si. Si crystals were doped with Au by a vapor method; namely, specimens were sealed in quartz capsules together with a piece of Au wire and then annealed at high temperature followed by quenching in water. Then the specimens were doped with H by annealing them in hydrogen atmosphere of 1 atm. followed by quenching. We measured optical absorption of those specimens after quenching from various temperatures. From the temperature dependence of the 2223 cm-1 line identified as being due to H bound to interstitial Si, the formation energy of interstitial Si in Au-doped Si was determined to be about 2.1 eV.