Hydrogen passivation of boron acceptors in silicon: Raman studies

Raman scattering is used for an investigation of the passivation of substitutional boron acceptors in crystalline silicon by atomic hydrogen. The disappearance of free holes in the passivated samples can be observed via the changes of the zone-center optical-phonon line shape (Fano broadening). Parallel to the disappearance of the free holes, the localized vibrational modes of substitutional boron vanish, providing direct evidence for pair formation between B and H. A new boron mode at 650 ${\mathrm{cm}}^{\mathrm{-}1}$ is observed in the spectra of passivated samples.