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Impact of Compensated Solar-Grade Silicon on Czochralski Silicon Wafers and Solar Cells
S. Rein, W. Kwapil, J. Broisch, G. Emanuel, M. Spitz, I. Reis, A. Weil, D. Biro, M. Glatthaar, A.-K. Soiland, E. Enebakk, R. Tronstad
Czochralski (Cz), Defects, Degradation, Electrical Properties, Compensated Silicon
Wafer-based Silicon Solar Cells and Materials Technology
Subtopic: Mono- and Multicrystalline Silicon Materials and Cells
Event: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany
Session: 2DO.2.3
1140 - 1147
ISBN: 3-936338-25-6
Paper DOI: 10.4229/24thEUPVSEC2009-2DO.2.3
0,00 EUR
Document(s): paper


Alternative feedstock production routes avoiding the gaseous phase during the purification of the silicon result in significantly increased boron and phosphorus concentrations, which leads to compensation effects in the material. We studied Cz crystals with different mix-in ratios of compensated SoG silicon feedstock from Elkem Solar (100%, 50%, 33% and 0%) regarding the impurity content, the specific resistivity, the effective carrier lifetime, the Cz defect formation and the resulting solar cell parameters of cells processed in an industrial standard screenprinting process. We find that the compensated material is dominantly influenced by the intrinsic metastable Cz defect which is proportional to the net-doping concentration. It is demonstrated that at least up to a mix-in ratio of 33% there are no feedstock-dependent performance losses. There is potential for higher mix-in ratio for this feedstock by lowering the net acceptor dopant concentration.