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Textured silicon surface passivation by high‐rate expanding thermal plasma deposited SiN and thermal SiO 2 /SiN stacks for crystalline silicon solar cells
Author(s) -
van Erven A. J. M.,
Bosch R. C. M.,
Bijker M. D.
Publication year - 2008
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.841
Subject(s) - passivation , materials science , wafer , silicon , silicon nitride , crystalline silicon , optoelectronics , monocrystalline silicon , thermal , layer (electronics) , saturation current , thermal oxidation , solar cell , nanotechnology , electrical engineering , physics , engineering , voltage , meteorology
Expanding thermal plasma (ETP) deposited silicon nitride (SiN) with optical properties suited for the use as antireflection coating (ARC) on silicon solar cells has been used as passivation layer on textured monocrystalline silicon wafers. The surface passivation behavior of these high‐rate (>5 nm/s) deposited SiN films has been investigated for single layer passivation schemes and for thermal SiO 2 /SiN stack systems before and after a thermal treatment that is normally used for contact‐firing. It is shown that as‐deposited ETP SiN used as a single passivation layer almost matches the performance of a thermal oxide. Furthermore, the SiN passivation behavior improves after a contact‐firing step, while the thermal oxide passivation degrades which makes ETP SiN a better alternative for single passivation layer schemes in combination with a contact‐firing step. Moreover, using the ETP SiN as a part of a thermal SiO 2 /SiN stack proves to be the best alternative by realizing very low dark saturation current densities of <20 fA/cm 2 on textured solar‐grade FZ silicon wafers and this is further improved to <10 fA/cm 2 after the anneal step. Optical and electrical film characterizations have also been carried out on these SiN layers in order to study the behavior of the SiN before and after the thermal treatment. Copyright © 2008 John Wiley & Sons, Ltd.