Title:	Interplay of IBC Cell's Front Surface Doping, Passivation Quality, and Stability under Ultraviolet Light Exposure
Author(s):	H. Chu, V. Kuruganti, R. Roescu, C. Peter, V.D. Mihailetchi
Keywords:	Surface Passivation, IBC, Si Solar Cell, UV Degradation
Topic:	Silicon Materials and Cells
Subtopic:	High Temperature Route for Si Cells
Event:	38th European Photovoltaic Solar Energy Conference and Exhibition
Session:	2DV.3.9
Pages:	311 - 316
ISBN:	3-936338-78-7
Paper DOI:	10.4229/EUPVSEC20212021-2DV.3.9
Price:	0,00 EUR
Document(s):	paper, poster

Abstract/Summary:

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We study the UV stability of lightly doped n- type Si surfaces with a sheet resistance of 154 Ohm/sq, 935 Ohm/sq and 1480 Ohm/sq. These surfaces are passivated by a layer stack consisting of thermal SiO2 and PECVD SiNx and the resulting J0 is in the range of 10 to 40 fA/cm2. We applied these lightly diffused surfaces for the FSFs of IBC cells, and for symmetric n+/n/n+ lifetime samples. We found out that although the 6-inch IBC cells with lighter doped FSFslead to better Voc, they showed more degradation after the UV exposure test (dose of 45 kWh/m2, equivalent to three times of IEC test). The degradation is likely caused by the increase of front surface recombination. Lastly, we summarize several UV degradation test results for both p- and n-type surfaces, based on which it seems that it is advisable to check the UV stability for not only the IBC cells but also other cell concepts which have a lightly doped or even undoped front surface.