The first stage in the anneal of interstitial B below room temperature in Czochralski-grown Si was the formation of the interstitial B–O (BiOi) defect. First principles modelling showed that this defect had a structure similar to the interstitial C–O complex. However, whereas the latter defect was characterized by local vibrational mode infra-red spectroscopy, there was no information on the local vibrational modes of BiOi even though the defect was known to be a dominant interstitial B defect in irradiated Czochralski-Si. Here, density functional calculations were carried out in order to determine its vibrational modes and respective isotope shifts. It was concluded that it possessed 6 local vibrational modes. As in the case of CiOi, an O-related vibrational mode was found with a frequency far below the 1136/cm of the O interstitial, characteristic of the 3-fold coordinated O.

Ab initio Calculation of the Local Vibrational Modes of the Interstitial Boron–Interstitial Oxygen Defect in Si. A.Carvalho, R.Jones, J.Coutinho, P.R.Briddon: Journal of Physics - Condensed Matter, 2005, 17[17], L155-9