Retarded oxygen diffusion in heavily phosphorus-doped Czochralski silicon: experiments and first-principles...

The effect of heavy phosphorus (P) doping on oxygen diffusion in Czochralski (Cz) silicon has been experimentally and theoretically investigated. It is experimentally found that the oxygen diffusion in heavily P-doped Cz silicon is retarded, with a diffusion activation energy which is ∼0.12 eV larger than that of its lightly P-doped counterpart. First-principles calculations suggest that the P-O complexes in the -P-Si-O-Si- configuration can form in heavily P-doped Cz silicon, leading to the trapping of interstitial oxygen (O(i)) atoms at the twelve equivalent second-nearest neighbors of the P atoms. Furthermore, the calculated increase of the oxygen diffusion activation energy, taking account of the trapping effect of such P-O complexes, is in accordance with the experimental result. This indicates that the retarded oxygen diffusion in the heavily P-doped Cz silicon can be ascribed to the trapping of O(i) atoms associated with the formation of the aforementioned P-O complexes.