Title:	Opportunities for Silicon Epitaxy in Bulk Crystalline Silicon Photovoltaics
Author(s):	M. Recamán Payo, I. Kuzma-Filipek, A. Hajjiah, A. Uruena, T. Borgers, E. Cornagliotti, L. Tous, R. Russell, S. Singh, M. Debucquoy, F. Duerinckx, J. Szlufcik, J. Poortmans
Keywords:	Back-Surface-Field, Emitter, Boron, Silicon Epitaxy, Selective Epitaxial Growth
Topic:	WAFER-BASED SILICON SOLAR CELLS AND MATERIALS TECHNOLOGY
Subtopic:	Silicon Solar Cell Improvements
Event:	29th European Photovoltaic Solar Energy Conference and Exhibition
Session:	2CO.1.3
Pages:	497 - 502
ISBN:	3-936338-34-5
Paper DOI:	10.4229/EUPVSEC20142014-2CO.1.3
Price:	0,00 EUR
Document(s):	paper, presentation

Abstract/Summary:

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This work presents an overview of the opportunities in bulk crystalline silicon photovoltaics that have been explored using silicon epitaxy as doping technology. Epitaxy demonstrates to be an elegant and versatile technology which brings a lot of new opportunities to further simplify and improve the design and performance of bulk solar cells. Advantages are the doping profile flexibility, the reduced thermal budget, the absence of additional steps to remove glassy layers or activate dopants, the simplified integration of local doping by means of selective epitaxy, and the possibility of single-side deposition. The results presented herein demonstrate the potential of epitaxy by applying the process in three cell structures to grow a boron-doped layer. First, epitaxy is used to grow blanket doped layers as emitters on the full rear side of n-type PERT cells. Second, selective epitaxy is applied to locally grow the interdigitated emitter in n-type IBC cells. Third, selective epitaxy is applied to form the local BSF in p-type PERL cells. For each of these cell concepts, silicon epitaxy helped to simplify the reference BBr3 diffusion-based process, while keeping high efficiencies: 20.5 % for n-type PERT (226 cm2 cell), 22.8 % for IBC (4 cm2 cell) and at least +0.5 mA/cm2 and +10 % escape reflectance for p-type PERL cells compared to the standard PERC.