Minority carrier lifetime in silicon photovoltaics: The effect of oxygen precipitation

Article English OPEN
Murphy, JD ; McGuire, RE ; Bothe, K ; Voronkov, VV ; Falster, RJ (2014)
  • Publisher: Elsevier BV
  • Journal: Solar Energy Materials and Solar Cells, volume 120, issue PART A, pages 402-411 (issn: 0927-0248)
  • Related identifiers: doi: 10.1016/j.solmat.2013.06.018, doi: 10.1016/j.solmat.2013.06.018
  • Subject: Renewable Energy, Sustainability and the Environment | Surfaces, Coatings and Films | TP | Electronic, Optical and Magnetic Materials | TA

Single-crystal Czochralski silicon used for photovoltaics is typically supersaturated with interstitial oxygen at temperatures just below the melting point. Oxide precipitates therefore can form during ingot cooling and cell processing, and nucleation sites are typically vacancy-rich regions. Oxygen precipitation gives rise to recombination centres, which can reduce cell efficiencies by as much as 4% (absolute). We have studied the recombination behaviour in p-type and n-type monocrystalline silicon with a range of doping levels intentionally processed to contain oxide precipitates with a range of densities, sizes and morphologies. We analyse injection-dependent minority carrier lifetime measurements to give a full parameterisation of the recombination activity in terms of Shockley-Read-Hall statistics. We intentionally contaminate specimens with iron, and show recombination activity arises from iron segregated to oxide precipitates and surrounding defects. We find that phosphorus diffusion gettering reduces the recombination activity of the precipitates to some extent. We also find that bulk iron is preferentially gettered to the phosphorus diffused layer rather than to oxide precipitates. © 2013 The Authors.
  • References (58)
    58 references, page 1 of 6

    [1] A. Borghesi, B. Pivac, A. Sassella, A. Stella, Oxygen precipitation in silicon, Journal of Applied Physics 77 (1995) 4169.

    [2] W. Bergholz, M.J. Binns, G.R. Booker, J.C. Hutchison, S.H. Kinder, S. Messoloras, R.C. Newman, R.J. Stewart, J.G. Wilkes, A study of oxygen precipitation in silicon using high-resolution transmission electron microscopy, small-angle neutron scattering and infrared absorption, Philosophical Magazine B 59 (1989) 499.

    [3] R. Falster, V.V. Voronkov, V.Y. Resnik, M.G. Milvidskii, Thresholds for effective internal gettering in silicon wafers, Proceedings of the Electrochemical Society, High Purity Silicon, VIII, 2004, pp. 188-201.

    [4] R.C. Newman, Oxygen diffusion and precipitation in Czochralski silicon, Journal of Physics: Condensed Matter 12 (2000) R335.

    [5] S.M. Myers, M. Seibt, W. Schröter, Mechanisms of transition-metal gettering in silicon, Journal of Applied Physics 88 (2000) 3795.

    [6] R.J. Falster, W. Bergholz, The gettering of transition metals by oxygen-related defects in silicon, Journal of the Electrochemical Society 137 (1990) 1548.

    [7] J. Haunschild, I.E. Reis, J. Geilker, S. Rein, Detecting efficiency-limiting defects in Czochralski-grown silicon wafers in solar cell production using photoluminescence imaging, Physica Status Solidi Rapid Research Letters 5 (2011) 199.

    [8] P.K. Kulshreshtha, Y. Yoon, K.M. Youssef, E.A. Good, G. Rozgonyi, Oxygen precipitation related stress-modified crack propagation in high growth rate Czochralski silicon wafers, Journal of the Electrochemical Society 159 (2012) H125.

    [9] R. Søndena, Y. Hu, M. Juel, M.S. Wiig, H. Angelskår, Characterization of the OSFband structure in n-type Cz-Si using photoluminescence-imaging and visual inspection, Journal of Crystal Growth 367 (2013) 68.

    [10] K. Youssef, M. Shi, C. Radue, E. Good, G. Rozgonyi, Effect of oxygen and associated residual stresses on the mechanical properties of high growth rate Czochralski silicon, Journal of Applied Physics 113 (2013) 133502.

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