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 th...

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Bibliographic Details
Published in:Applied physics letters 2014-11, Vol.105 (18)
Main Authors: Boulfrad, Yacine, Lindroos, Jeanette, Wagner, Matthias, Wolny, Franziska, Yli-Koski, Marko, Savin, Hele
Format: Article
Language:English
Subjects:
Applied physics
BORON
Charge deposition
CHEMICAL ANALYSIS
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER
COPPER IONS
CRYSTAL DEFECTS
DEFECTS
ETCHING
Fysik
Light
Organic chemistry
OXYGEN
Photodegradation
Physics
SILICON
Silicon wafers
Surface layers
SURFACES
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Summary: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.
ISSN:0003-6951
1077-3118
1077-3118
DOI:10.1063/1.4901533