A fundamental investigation was made of metal impurity interaction with extended defects, namely a small-angle grain boundary and bulk microdefects. It was shown that the distribution of copper silicide precipitates closely follows the density of bulk microdefects indicating the underlying physics of so-called good and bad grains frequently observed in mc-Si. Co-precipitation of copper and nickel in the same samples leads to virtually the same distribution of multimetal silicide precipitates which according to light-beam induced current measurements showed the same recombination activity as single-metal silicide particles. Transmission electron microscopy was used to show that for copper-rich and nickel-rich conditions two types of silicides co-exist, i.e. Cu3Si precipitates containing a small amount of nickel and NiSi2 precipitates containing some copper. Finally, phosphorus-diffusion gettering was discussed as the main gettering process used in present-day silicon photovoltaics. Special emphasis was put on the effect of extended defects and their interaction with metal impurities on phosphorus-diffusion gettering kinetics. It was shown that different limiting processes will be simultaneously operative in mc-Si as a result of inhomogeneous bulk defect distributions

Structure, Chemistry and Electrical Properties of Extended Defects in Crystalline Silicon for Photovoltaics. M.Seibt, D.Abdelbarey, V.Kveder, C.Rudolf, P.Saring, L.Stolze, O.Voss: Physica Status Solidi C, 2009, 6[8], 1847-55