Title:	Firing-Stable PECVD SiOxNy/n-Poly-Si Passivating Contacts for High-Efficiency Silicon Solar Cells
Author(s):	M. Stöhr, J. Aprojanz, R. Brendel, T. Dullweber
Keywords:	Passivation, Polycrystalline, Silicon
Topic:	Silicon Materials and Cells
Subtopic:	High Temperature Route for Si Cells
Event:	38th European Photovoltaic Solar Energy Conference and Exhibition
Session:	2DV.3.2
Pages:	306 - 310
ISBN:	3-936338-78-7
Paper DOI:	10.4229/EUPVSEC20212021-2DV.3.2
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Passivating contacts based on SiOx/poly-Si enable very high solar cell conversion efficiencies. In this paper, we investigate and optimize the plasma-enhanced chemical vapor deposition (PECVD) of SiOxNy/n-a-Si stacks, their subsequent annealing to SiOxNy/n-poly-Si stacks followed by PECVD SiNx deposition and firing. Whereas the J0 of thermal SiOx/n-poly-Si stacks degrade after firing, PECVD SiOxNy/n-poly-Si stacks exhibit an excellent firing stability with J0 values down to 1.3 fA/cm² after firing which corresponds to an outstanding implied VOC of 744 mV. The application of different hydrogenation processes to the thermal SiOx/n-poly-Si and PECVD SiOxNy/n-poly-Si layers reveals, that both stacks achieve excellent passivation properties with J0 = 1.5 fA/cm² after maximum hydrogenation. However, only the PECVD SiOxNy/n-poly-Si stack maintains this excellent surface passivation after firing possibly due to a superior capability to retain the hydrogen at the c-Si/SiOxNy interface during firing, and thus demonstrates the potential as a future manufacturing process sequence.