Understanding the light-induced degradation at elevated temperatures: Similarities between multicrystalline and floatzone p-type silicon

Tim Niewelt, Florian Schindler, Wolfram Kwapil, Rebekka Eberle, Jonas Schön, Martin C. Schubert

Index: 10.1002/pip.2954

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Abstract

This paper discusses degradation phenomena in crystalline silicon. We present new investigations of the light- and elevated temperature-induced degradation of multicrystalline silicon. The investigations provide insights into the defect parameters as well as the diffusivity and solubility of impurity species contributing to the defect. We discuss possible defect precursor species and can rule out several metallic impurities. We find that an involvement of hydrogen in the defect could explain the characteristic observations for light- and elevated temperature-induced degradation. Furthermore, we demonstrate analogies to the light-induced degradation mechanisms at elevated temperatures observed in floatzone silicon, where several experimental results also indicate an involvement of hydrogen in the defect. Based on the similarities between multicrystalline and floatzone silicon, we suggest that both degradation phenomena might be caused by the same or similar defects. As we do not expect large concentrations of metals in floatzone silicon, we suggest that complexes of hydrogen and a species introduced during crystal growth might cause both degradation phenomena. We discuss light-induced degradation effects occurring in multicrystalline and monocrystalline silicon at elevated temperature. A direct comparison reveals several similarities and a potential involvement of hydrogen in the defect