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Improvement of the Quality of Multicrystalline-Silicon Wafers for the Manufacture of Silicon Heterojunction Solar Cells
R. Barrio Martin, N. González Peñalba, I. Torres, J. Cárabe, J.J. Gandía
Heterojunction, Passivation, Silicon Nitride, Multicrystalline Silicon
Silicon Materials and Cells
Subtopic: Manufacturing & Production of Si Cells
Event: 37th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2CV.1.34
350 - 353
ISBN: 3-936338-73-6
Paper DOI: 10.4229/EUPVSEC20202020-2CV.1.34
0,00 EUR
Document(s): paper, poster


The aim of this investigation is to establish an affordable process to improve the quality of multicrystalline (mcSi) wafers to be able to manufacture efficient low-cost and more sustainable Silicon Heterojunction Solar Cells (HIT). In this work, we propose a previous method to the fabrication of the cells, which consists on the passivation of the defects of the bulk of mcSi wafers with hydrogen (H) through the growth of hydrogenated silicon nitride (SiNx:H) thin layers by PECVD, using nitrogen (N2) and pure silane (SiH4) as precursor gases and without ammonia (NH3). SiNx:H obtained, provide enough H content and adequate properties to passivate a posteriori mc-Si wafers efficiently and to increase their minority carrier lifetimes. A post-annealed treatment is necessary to release the atomic hydrogen (H) from the SiNx:H and diffuses it through the bulk of mc-Si wafers. Finally, SiNx:H layers are completely removed, leaving surfaces ready for the growth of the subsequent thin layers and without the need for additional cleaning steps previous the manufacture of HIT solar cells. This passivation process can be also applied to HIT industrial technology based of low-cost p-type CZ silicon wafers.