Dislocation density reduction during impurity gettering in multicrystalline silicon

H. J. Choi, Mariana Bertoni, J. Hofstetter, D. P. Fenning, D. M. Powell, S. Castellanos, T. Buonassisi

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Isothermal annealing above 1250 °C has been reported to reduce the dislocation density in multicrystalline silicon (mc-Si), presumably by pairwise dislocation annihilation. However, this high-temperature process may also cause significant impurity contamination, canceling out the positive effect of dislocation density reduction on cell performance. Here, efforts are made to annihilate dislocations in mc-Si in temperatures as low as 820 °C, with the assistance of an additional driving force to stimulate dislocation motion. A reduction of more than 60% in dislocation density is observed for mc-Si containing intermediate concentrations of certain metallic species after P gettering at 820 °C. While the precise mechanism remains in discussion, available evidence suggests that the net unidirectional flux of impurities in the presence of a gettering layer may cause dislocation motion, leading to dislocation density reduction. Analysis of minority carrier lifetime as a function of dislocation density suggests that lifetime improvements after P diffusion in these samples can be attributed to the combined effects of dislocation density reduction and impurity concentration reduction. These findings suggest there may be mechanisms to reduce dislocation densities at standard solar cell processing temperatures.

Original languageEnglish (US)
Article number6330974
Pages (from-to)189-198
Number of pages10
JournalIEEE Journal of Photovoltaics
Volume3
Issue number1
DOIs
StatePublished - 2013
Externally publishedYes

Fingerprint

Silicon
Impurities
impurities
silicon
Isothermal annealing
Carrier lifetime
Temperature
Solar cells
Contamination
Fluxes
causes
Processing
carrier lifetime
minority carriers
contamination
solar cells
life (durability)
annealing
temperature

Keywords

  • Al gettering
  • dislocation density
  • dislocation impurity interaction
  • multicrystalline silicon
  • P gettering

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Choi, H. J., Bertoni, M., Hofstetter, J., Fenning, D. P., Powell, D. M., Castellanos, S., & Buonassisi, T. (2013). Dislocation density reduction during impurity gettering in multicrystalline silicon. IEEE Journal of Photovoltaics, 3(1), 189-198. [6330974]. https://doi.org/10.1109/JPHOTOV.2012.2219851

Dislocation density reduction during impurity gettering in multicrystalline silicon. / Choi, H. J.; Bertoni, Mariana; Hofstetter, J.; Fenning, D. P.; Powell, D. M.; Castellanos, S.; Buonassisi, T.

In: IEEE Journal of Photovoltaics, Vol. 3, No. 1, 6330974, 2013, p. 189-198.

Research output: Contribution to journalArticle

Choi, HJ, Bertoni, M, Hofstetter, J, Fenning, DP, Powell, DM, Castellanos, S & Buonassisi, T 2013, 'Dislocation density reduction during impurity gettering in multicrystalline silicon', IEEE Journal of Photovoltaics, vol. 3, no. 1, 6330974, pp. 189-198. https://doi.org/10.1109/JPHOTOV.2012.2219851
Choi, H. J. ; Bertoni, Mariana ; Hofstetter, J. ; Fenning, D. P. ; Powell, D. M. ; Castellanos, S. ; Buonassisi, T. / Dislocation density reduction during impurity gettering in multicrystalline silicon. In: IEEE Journal of Photovoltaics. 2013 ; Vol. 3, No. 1. pp. 189-198.
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