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Local PECVD SiOxNy/n-Poly-Si Deposition through a Shadow Mask for POLO IBC Solar Cells
V. Mertens, S. Schäfer, M. Stöhr, A. Mercker, A. Köhler, L. Mettner, R. Brendel, N. Ambrosius, T. Pernau, H. Haverkamp, T. Dullweber
PECVD, IBC Solar Cell, Shadow Mask
Silicon Materials and Cells
Subtopic: High Temperature Route for Si Cells
Event: 38th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2BO.11.1
135 - 139
ISBN: 3-936338-78-7
Paper DOI: 10.4229/EUPVSEC20212021-2BO.11.1
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Document(s): paper


We present a lean POLO IBC solar cell process flow using p-type Cz silicon wafers, where a local SiOxNy/n-poly-Si emitter is formed by PECVD-deposition of SiOxNy/n-a-Si through a glass-based shadow mask followed by a subsequent thermal anneal. Light microscope measurements confirm that the PECVD SiOxNy/n-a-Si pattern deposited on the Cz wafer matches the IBC glass shadow mask layout. A parasitic deposition extending ~60 µm per edge below the mask can occur. However, by an appropriate post-treatment, the parasitic deposition can be reduced to below 5 µm across the whole wafer. On IBC solar cell precursors with two-sided polished surfaces fabricated using the local PECVDdeposition of SiOxNy/n-a-Si we obtain a median implied open circuit voltage (iVoc) of 709 mV which is comparable to parallel processed samples using a wet-chemical interfacial oxide grown in DI/O3 plus PECVD n-a-Si with a median iVoc value of 705 mV. After further process optimization including introduction of a post-anneal cleaning step for improved AlOx/SiNx passivation the IBC cell precursors with textured front exhibit an excellent median implied Voc of 738 mV. These results show the principal feasibility of the POLO IBC process flow presented.