ECN publication
Dielectric passivation schemes for high efficiency n-type c-Si solar cells
Saynova,  D.S.; Romijn, I.G.; Cesar, I.; Lamers, M.W.P.E.; Gutjahr, A.; Dingemans, G.; Knoops, H.C.M.; Loo, B.H.W. van de; Kessels, W.M.M.; Siarheyeva, O.; Granneman, E.; Gautero, L.; Borsa, D.M.; Venema, P.; Vlooswijk, A.H.G.
Published by: Publication date:
ECN Solar Energy 30-9-2013
ECN report number: Document type:
ECN-M--13-027 Conference Paper
Number of pages: Full text:
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We investigate the impact of different dielectric layers and stacks on the passivation properties of boron doped p++-emitters and phosphorous doped n+-BSFs which are relevant for competitive n-type cell conversion efficiencies. The applied passivation schemes are associated with specific properties at c-Si/dielectric interface and functional mechanisms. In this way we aim to gain a deeper understanding of the passivation mechanism of the differently doped fields within the n-type cells and identify options to further improve the efficiency. The deposition technologies in our study comprise industrial PECVD systems and/or ALD both in industrial and lab scale configurations. In case of p++-emitters the best results were achieved by combining field effect and chemical passivation using stacks of low temperature wet chemical oxide and thin ALD-AlOx capped with PECVD-SiNx. The corresponding Implied Voc values were of about (673+2) mV and J0 of (68+2) fA/cm2. For the n+-BSF passivation the passivation scheme based on SiOx with or without additional AlOx film deposited by a lab scale temporal ALD processes and capped with PECVD-SiNx layer yielded a comparable Implied Voc of (673 + 2) mV, but then corresponding to J0 value of (80 + 15) fA/cm2. This passivation scheme is mainly based on the chemical passivation and was also suitable for p++ surface. This means that we have demonstrated that for n-Pasha cells both the emitter and BSF can be passivated with the same type of passivation that should lead to > 20% cell efficiency. This offers the possibility for transfer this passivation scheme to advanced cell architectures, such as IBC.

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