The spectral features of localized vibration of H bound to group-III acceptors in Si were reported. In order to avoid the Fano effect on line-broadening, homogeneously doped specimens with group-III acceptors and H with low concentrations were used. Consequently, the line shapes were closely fitted by Lorentzian functions; thus indicating that the shapes were affected by 2 dynamic effects: energy relaxation and de-phasing. While the spectra of B-H, Al-H and Ga-H pairs were found to show only one sideband in the lower-frequency region of the main peak, sidebands appeared in both the lower-and higher-frequency regions in the case of In-H. This appearance of the sidebands in the case of In-H pairs was unexpected on the basis of a previous model. By analyzing the linewidth of the main peak at around 6K, the energy relaxation times T1, were estimated to be much shorter than those previously observed for the complexes of the point defect and H in Si. Moreover, a chemical trend was also found: As the covalent radius of the group-III acceptor increased, the T1 became shorter. Temperature dependences of the linewidth and peak shift of the main peak were analyzed based on de-phasing models. The analysis showed that the experimental results cannot be explained by the Persson-Ryberg model in the weak-coupling limit of the anharmonic coupling between the local vibrational mode and bath ones, suggesting that the anharmonic coupling was intermediate or strong.

Infrared Spectra of Hydrogen Bound to Group-III Acceptors in Si - Homogeneous Line Broadening and Sidebands. M.Suezawa, N.Fukata, M.Saito, H.Yamada-Kaneta: Physical Review B, 2002, 65[7], 075214 (8pp)