First-principles investigation of a bistable boron-oxygen interstitial pair in Si

Local density functional calculations are used to predict and compare the properties of the two distinct interstitial boron-interstitial oxygen (Bi Oi) complexes recently reported in the literature. The electronic and free energies, as well as the small transformation barrier, suggest that both forms of the defect are present at the temperature at which the defect forms. The vibrational spectra of the defects are predicted. The electrical levels of the defect are calculated and compared to experimental data. The existence of two forms of the Bi Oi defect may have implications for the lifetime degradation of space-based Czochralski-silicon solar cells.