Simulation of oxygen- or carbon containing complexes at silicon-silicon interface in cluster approximation

Transformation of the "core" atomic structure and electronic states of the tilt Sigma 5 theta = 37 degrees [001]/(130) grain boundary (GB) in poly-Si due to incorporation of oxygen or carbon atoms is studied using a MO LCAO method. C-containing complexes consist of Si2C. Si3C and Si,C configurations, depending on number n of C-atoms inserted into 5 - or 7 - fold interstitial positions at GB "core". Incorporation of O-atoms can form "chain"-like or "ring"-like configurations for n = 1 - 2 and SiO3 or SiO4 configurations for n = 3 - 4. O- and C-containing complexes at GB "core" result in formation of donor-like levels that are shifted with increasing number of contaminating atoms to the middle of the energy gap (from E-C to E-C - 0.6 eV) for O-incorporation and to the bottom of conduction band (from E-C - 0.536 eV to E-C - 0.043 eV) for C-incorporation. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim