Temperature dependence of vibrational spectra of H-point defect complexes and H2* in Si -: art. no. 085205

Temperature dependences of optical-absorption spectra due to H vibration included in H-point defect complexes and H-2* in Si were investigated. Specimens were doped with H by annealing in H-2 gas followed by quenching. They were then irradiated with 3-MeV electrons at room temperature. Optical-absorption spectra of H-point defect complexes and H-2* were measured between 7 K and room temperature. The peaks investigated were those at 1838 cm(-1) [H-2*(AB)], 1870 cm(-1) (I2H2), 1987 cm(-1) (IH2), 2062 cm(-1) [H2*(BC)], 2073 cm(-1) (V2H2), and 2122 and 2145 cm(-1) (VH2); the complexes in parentheses are responsible for optical-absorption peaks and I, V, AB, and BC denote a self-interstitial, a vacancy, an antibonding site and a bond-centered site, respectively. The temperature-dependent peak positions and linewidths of V-related complexes, H-2*(AB) and I2H2 are well explained by the dephasing relaxation due to an anharmonic coupling of H vibration to one low-frequency mode. On the other hand, the interaction with all phonons in the relaxation explains those of H-2*(AB), H-2*(BC), and V2H2. These two models were not applicable to IH2.