Title:	Understanding the Lifetime Evolution in N-Type Multicrystalline Silicon During Phosphorus Gettering and Hydrogenation
Author(s):	C. Ulzhöfer, B. Wolpensinger, J. Schmidt
Keywords:	Defects, n-Type, Multicrystalline-Silicon
Topic:	Wafer-Based Silicon Solar Cells and Materials Technology
Subtopic:	Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of
Event:	23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session:	2AO.3.5
Pages:	1051 - 1056
ISBN:	3-936338-24-8
Paper DOI:	10.4229/23rdEUPVSEC2008-2AO.3.5
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Phosphorus-doped n-type multicrystalline silicon (mc-Si) is frequently considered to be an alternative material compared to boron-doped p-type mc-Si which holds the biggest fraction of base materials in today’s worldwide photovoltaic market. In this paper, we describe the lifetime evolution of n-type mc-Si during different processes, such as phosphorus diffusion and hydrogenation, by means of spatially resolved microwave-detected photoconductance decay lifetime measurements. In addition, the total metal concentrations in particular regions of the wafers are examined by an advanced vapour phase decomposition total reflection x-ray fluorescence (VPDTXRF) method. The measured lifetimes correlate well with the total metal concentrations. After an optimized gettering and hydrogenation step, area-averaged lifetimes up to 900 μs are measured on the n-type mc-Si wafers with a resistivity of 4 Ωcm.