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Title: Experimental evidence on removing copper and light-induced degradation from silicon by negative charge

In addition to boron and oxygen, copper is also known to cause light-induced degradation (LID) in silicon. We have demonstrated previously that LID can be prevented by depositing negative corona charge onto the wafer surfaces. Positively charged interstitial copper ions are proposed to diffuse to the negatively charged surface and consequently empty the bulk of copper. In this study, copper out-diffusion was confirmed by chemical analysis of the near surface region of negatively/positively charged silicon wafer. Furthermore, LID was permanently removed by etching the copper-rich surface layer after negative charge deposition. These results demonstrate that (i) copper can be effectively removed from the bulk by negative charge, (ii) under illumination copper forms a recombination active defect in the bulk of the wafer causing severe light induced degradation.
Authors:
; ; ;  [1] ; ;  [2]
  1. Department of Micro and Nanosciences, Aalto University, Tietotie 3, 02150 Espoo (Finland)
  2. SolarWorld Innovations GmbH, Berthelsdorfer Str. 111A, 09599 Freiberg (Germany)
Publication Date:
OSTI Identifier:
22391905
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BORON; CHEMICAL ANALYSIS; COPPER; COPPER IONS; CRYSTAL DEFECTS; DEFECTS; ETCHING; OXYGEN; SILICON; SURFACES