Title:	Ultrafast Lifetime Regeneration in an Industrial Belt-Line Furnace Applying Intense Illumination at Elevated Temperature
Author(s):	D.C. Walter, T. Pernau, J. Schmidt
Keywords:	Lifetime, Regeneration, Permanent Deactivation, BO Defect Center
Topic:	Wafer-Based Silicon Solar Cells and Materials Technology
Subtopic:	Manufacturing and Processing
Event:	32nd European Photovoltaic Solar Energy Conference and Exhibition
Session:	2DO.1.1
Pages:	469 - 473
ISBN:	3-936338-41-8
Paper DOI:	10.4229/EUPVSEC20162016-2DO.1.1
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Solar cells made of boron-doped, oxygen-rich Czochralski-grown silicon (Cz-Si) wafers suffer from a degradation in conversion efficiency upon illumination. This effect, sometimes labeled “light-induced degradation” (LID), is caused by a defect center within the silicon bulk, often referred to as BO defect, which activates its recombination properties under illumination leading to a degradation of the carrier lifetime. However, the BO defect center can be permanently deactivated, i.e. the lifetime can be permanently recovered, under illumination at elevated temperature. Within this contribution, we focus on transferring our lab-type BO deactivation process, using a hotplate and a halogen lamp, into an ultrafast high-throughput process, applying an industrial-type belt-furnace especially designed for this very purpose by centrotherm photovoltaics AG. Using this industrial furnace, inline processing in a solar cell production line is feasible. Our investigation clearly shows that a permanent recovery of the lifetime with an industrial belt-furnace can be achieved. In addition, we prove this result also for a shorter lab-type version of the longer industrial belt-furnace. The lifetimes reached after processing can be comparable to the lifetimes obtained on the same Cz-Si materials after applying our lab-type approach. Excellent stability of the lifetime is verified for up to 1000 hours of illumination at room temperature.