A new type of hydrogen molecules in silicon

The Raman line of a new hydrogen molecule at approximately 3820 cm(-1) has been observed for the first time in silicon after Si+ ion implantation with proper doses, followed by hydrogen atom treatment. The assignment was confirmed by isotope shifts to 2770 cm(-1) for D-2, molecule and to 3353 cm(-1) for HD molecule. Both the ion-dose dependence and hydrogenation-temperature dependence of the Raman intensity of the Hz molecules correlate with those of the intensity of peaks of Si-H stretching observed at 1957 +/- 1.8 cm(-1) and at approximately 2185 and 2210 cm(-1). We propose a model where the hydrogen molecule corresponding to the 3820 cm(-1) vibrational line is trapped in or adjacent to small II-terminated multivacancies. (C) 1999 Elsevier Science B.V. All rights reserved.