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Title: Exceptional gettering response of epitaxially grown kerfless silicon

The bulk minority-carrier lifetime in p- and n-type kerfless epitaxial (epi) crystalline silicon wafers is shown to increase >500 during phosphorus gettering. We employ kinetic defect simulations and microstructural characterization techniques to elucidate the root cause of this exceptional gettering response. Simulations and deep-level transient spectroscopy (DLTS) indicate that a high concentra- tion of point defects (likely Pt) is “locked in” during fast (60 C/min) cooling during epi wafer growth. The fine dispersion of moderately fast-diffusing recombination-active point defects limits as-grown lifetime but can also be removed during gettering, confirmed by DLTS measurements. Synchrotron-based X-ray fluorescence microscopy indicates metal agglomerates at structural defects, yet the structural defect density is sufficiently low to enable high lifetimes. Consequently, after phosphorus diffusion gettering, epi silicon exhibits a higher lifetime than materials with similar bulk impurity contents but higher densities of structural defects, including multicrystalline ingot and ribbon silicon materials. As a result, device simulations suggest a solar-cell efficiency potential of this material >23%.
Authors:
 [1] ; ORCiD logo [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [2] ;  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. The Univ. of Manchester, Manchester (United Kingdom)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
EE0005314; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 119; Journal Issue: 6; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Delaware, Newark, DE (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; epitaxial silicon; metal impurities; gettering; solar cells; DLTS; kerfless; silicon; deep level transient spectroscopy; epitaxy; iron; point defects
OSTI Identifier:
1237895
Alternate Identifier(s):
OSTI ID: 1237381

Powell, D. M., Markevich, V. P., Hofstetter, J., Jensen, M. A., Morishige, A. E., Castellanos, S., Lai, B., Peaker, A. R., and Buonassisi, T.. Exceptional gettering response of epitaxially grown kerfless silicon. United States: N. p., Web. doi:10.1063/1.4940947.
Powell, D. M., Markevich, V. P., Hofstetter, J., Jensen, M. A., Morishige, A. E., Castellanos, S., Lai, B., Peaker, A. R., & Buonassisi, T.. Exceptional gettering response of epitaxially grown kerfless silicon. United States. doi:10.1063/1.4940947.
Powell, D. M., Markevich, V. P., Hofstetter, J., Jensen, M. A., Morishige, A. E., Castellanos, S., Lai, B., Peaker, A. R., and Buonassisi, T.. 2016. "Exceptional gettering response of epitaxially grown kerfless silicon". United States. doi:10.1063/1.4940947. https://www.osti.gov/servlets/purl/1237895.
@article{osti_1237895,
title = {Exceptional gettering response of epitaxially grown kerfless silicon},
author = {Powell, D. M. and Markevich, V. P. and Hofstetter, J. and Jensen, M. A. and Morishige, A. E. and Castellanos, S. and Lai, B. and Peaker, A. R. and Buonassisi, T.},
abstractNote = {The bulk minority-carrier lifetime in p- and n-type kerfless epitaxial (epi) crystalline silicon wafers is shown to increase >500 during phosphorus gettering. We employ kinetic defect simulations and microstructural characterization techniques to elucidate the root cause of this exceptional gettering response. Simulations and deep-level transient spectroscopy (DLTS) indicate that a high concentra- tion of point defects (likely Pt) is “locked in” during fast (60 C/min) cooling during epi wafer growth. The fine dispersion of moderately fast-diffusing recombination-active point defects limits as-grown lifetime but can also be removed during gettering, confirmed by DLTS measurements. Synchrotron-based X-ray fluorescence microscopy indicates metal agglomerates at structural defects, yet the structural defect density is sufficiently low to enable high lifetimes. Consequently, after phosphorus diffusion gettering, epi silicon exhibits a higher lifetime than materials with similar bulk impurity contents but higher densities of structural defects, including multicrystalline ingot and ribbon silicon materials. As a result, device simulations suggest a solar-cell efficiency potential of this material >23%.},
doi = {10.1063/1.4940947},
journal = {Journal of Applied Physics},
number = 6,
volume = 119,
place = {United States},
year = {2016},
month = {2}
}