Morales-Vilches, A.B.; Decker, D.; Mazzarella, L.; Korte, L.; Schlatmann, R.; Sontag, D.; Stannowski, B.: Nanocrystalline n-Type Silicon Front Surface Field Layers: From Research to Industry Applications in Silicon Heterojunction Solar Cells. In: Proceedings : EU PVSEC 2018, 35th European Photovoltaic Solar Energy Conference and Exhibition : 24-28 September 2018, SQUARE - Brussels Meeting Centre, Brussels, Belgium. EUPVSEC, 2018. - ISBN 3-936338-50-7, p. 422-425
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Nanocrystalline silicon and silicon oxide (nc-Si(Ox):H) layers grown by plasma-enhanced chemical vapor deposition (PECVD) have shown low parasitic absorption and excellent contact properties when implemented as n-type front surface field (FSF) contact in rear-junction silicon heterojunction (SHJ) solar cells [1-3]. In this contribution we present results from the successful process transfer from the lab at PVcomB at the Helmholtz-Zentrum Berlin (HZB), to the industrial pilot line at Meyer Burger Germany GmbH (MBG). Conversion efficiencies > 22.5 % were demonstrated on SHJ cell (4 cm2) [2, 3]. The excellent cell performance in the lab and the potential to reduce parasitic absorption in the front stack by using nc-SiOx:H motivated the process transfer from HZB to MBG. Initial cross processing experiments on 244 cm² wafers showed the benefit of using nc-Si:H as FSF layer. We here also emphasize the role of the Si texture on a fast nc-Si:H nucleation. After cross processing experiments a successful transfer of the nc-Si:H process and fine tuning resulted in a median cell efficiency of 23.4 %. This is in the same range as the MGB reference on 244 cm² cells, noteworthy, at the same throughput. Currently work is ongoing to further improve the optical performance of the cells by adding oxygen (CO2).