Ab initio study of the effect of hydrogen passivation on boron-oxygen-carbon related defect complexes in silicon

Abstract

We present hybrid density functional theory (DFT) study of defect complexes formed by oxygen, boron and carbon, in ion-implanted and electron-irradiated Czrolaski (CZ) silicon containing boron. The effect of hydrogen passivation on the defect complexes is also studied. The defects considered are the interstitial boron-interstital oxygen (BiOi) complex as well as interstitial boron-substitutional carbon (BiCs) complex, which are found in ion-implanted Czochralski silicon. Other defect complexes which are found in electron-irradiated CZ silicon and have been studied are the interstitial boron (Bi), substitutional boron-interstitial oxygen (BsOi), substitutional boron-interstitial boron (BsBi), interstitial boron-interstitial oxygen dimer (BiO2i), and substitutional boron-interstitial oxygen dimer (BsO2i). We found the defects to be stable in neutral charge state with the stability of the Bi, BiOi, BsBi, BiO2i and BsO2i increasing after hydrogen passivation. However, the stability of BsOi and BiCs defect complexes decreases after the hydrogen passivation. For the BsBi defect complex in particular, a deep donor level appeared after hydrogen passivation. Furthermore, we found a shift in the charge state transition levels in to the valence band for the donor levels, and a shift in to the conduction band for the acceptor levels for all the defects after hydrogen passivation. We compare our results with available theoretical and experimental studies.