ECN publication
Title:
Reduced Effect of B-O Degradation on Multicrystalline Silicon Wafers Compared to Czochralski Silicon Wafers
 
Author(s):
 
Published by: Publication date:
ECN Solar Energy 11-9-2006
 
ECN report number: Document type:
ECN-RX--06-030 Conference Paper
 
Number of pages: Full text:
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Presented at: 21st European Photovoltaic Solar Energy Conference and Exhibition, Dresden, Germany, 4-8 september 2006.

Abstract:
The quality of multicrystalline wafers is improving nowadays due to ingot and solar cell process optimisation. In the near future the effect of boron-oxygen (BO)-related light induced degradation could become perhaps as important for multicrystalline wafers as it currently is for monocrystalline Czochralski (CZ ) wafers. In this paper boron-oxygen light induced degradation is investigated for multicrystalline silicon wafers. A special measurement procedure is required due to the presence of interstitial iron in mc-Si wafers. The degraded lifetime of the mc wafers in most cases is at the upper limit of the degraded lifetime experimentally determined by Bothe et al on CZ wafers. It is found that in mc-Si, in the presence of high carbon concentration (>8 ppma), this proposed lifetime limit is even exceeded. This implies a reduced effect of the BO defect and a new higher limit for the degraded lifetime, in the presence of carbon.


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