Analyses of the evolution of iron-silicide precipitates in multicrystalline silicon during solar cell processing

Jonas Schön*, Antti Haarahiltunen, Hele Savin, David P. Fenning, Tonio Buonassisi, Wilhelm Warta, Martin C. Schubert

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

29 Citations (Scopus)

Abstract

We simulate the precipitation of iron during the multicrystalline ingot crystallization process and the redistribution of iron during subsequent phosphorus diffusion gettering with a 2-D model. We compare the simulated size distribution of the precipitates with the X-ray fluorescence microscopy measurements of iron precipitates along a grain boundary. We find that the simulated and measured densities of precipitates larger than the experimental detection limit are in good agreement after the crystallization process. Additionally, we demonstrate that the measured decrease of the line density and the increase of the mean size of the iron precipitates after phosphorus diffusion gettering can be reproduced with the simulations. The size and spatial distribution of iron precipitates affect the kinetics of iron redistribution during the solar cell process and, ultimately, the recombination activity of the precipitated iron. Variations of the cooling rate after solidification and short temperature peaks before phosphorus diffusion strongly influence the precipitate size distribution. The lowest overall density of iron precipitates after phosphorus diffusion is obtained in the simulations with a temperature peak before phosphorus diffusion, followed by moderate cooling rates.

Original languageEnglish
Article number6313878
Pages (from-to)131-137
Number of pages7
JournalIEEE Journal of Photovoltaics
Volume3
Issue number1
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

Keywords

  • Gettering
  • impurities
  • semiconductor process modeling

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