First-principles calculation of interaction between interstitial O and As dopant in heavily As-doped Si

摘要

We investigate the interaction between interstitial oxygen (O_(i)) and As dopant in heavily As-doped Si using first-principles total-energy calculations. The interaction between O_(i) and As (substitutional) is found to be short ranged. The most stable configuration is with As and O_(i) as second nearest neighbors, forming -Si-O-Si-As- type complexes, with a binding energy of 0.14-0.21 eV. These complexes can trap O_(i) in their vicinity and thus reduce the O_(i) mobility. But the magnitude of trapping energy by such complexes is about fives times smaller than the value estimated from the experimentally observed retardation of O_(i) diffusion in heavily As-doped Si. We suggest that structural complexes involving other defects may resolve this discrepancy.