Characterization of silicon photovoltaic wafers using infrared photoelasticity

T. W. Lin, G. P. Horn, H. T. Johnson

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Reliability of silicon photovoltaic (PV) wafers is strongly influenced by defects and residual stresses from the crystallization and wire-sawing processes. Information about defects and stress in each wafer is important for improving the solar cell efficiency. An approach is developed for characterization of defects and residual stresses on silicon PV wafers. Utilizing a lock-in photoelastic imaging technique, the infrared grey-field polariscope (IR-GFP), retardation images are generated for individual silicon PV wafers taken from industry-grown single crystal stock. Full-wafer scale retardation images are compared with band-to-band photoluminescence (PL) images from the same wafers. The lock-in photoelastic imaging allows for better identification of defects than standard band-to-band PL imaging. Analytical models of elasticity are used to generate retardation patterns for dislocations and the residual thermal stresses. The theoretical retardation profiles are compared with the photoelastic image for defect identification and residual stress analysis. The approach is capable of relatively rapid wafer imaging, automated defect detection and stress analysis, and thus may be suitable for integration as an in-line reliability control process.

Original languageEnglish (US)
Title of host publicationResidual Stress, Thermomechanics and Infrared Imaging, Hybrid Techniques and Inverse Problems, - Proceedings of the 2013 Annual Conference on Experimental and Applied Mechanics
Number of pages6
StatePublished - 2014
Event2013 Annual Conference on Experimental and Applied Mechanics - Lombard, IL, United States
Duration: Jun 3 2013Jun 5 2013

Publication series

NameConference Proceedings of the Society for Experimental Mechanics Series
ISSN (Print)2191-5644
ISSN (Electronic)2191-5652


Other2013 Annual Conference on Experimental and Applied Mechanics
Country/TerritoryUnited States
CityLombard, IL


  • Defect detection
  • Dislocation
  • Photoelasticity
  • Residual thermal stress
  • Silicon

ASJC Scopus subject areas

  • General Engineering
  • Computational Mechanics
  • Mechanical Engineering


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