Effect of the Silicon Nitride Coating of Quartz Crucible on Impurity Distribution in Ingot-Cast Multicrystalline Silicon

Authors

  • Jiayan Li,

    1. School of Materials Science and Engineering, Dalian University of Technology, Dalian, People's Republic of China
    2. Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian, People's Republic of China
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  • Mei Liu,

    1. School of Materials Science and Engineering, Dalian University of Technology, Dalian, People's Republic of China
    2. Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian, People's Republic of China
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  • Yi Tan,

    Corresponding author
    1. Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian, People's Republic of China
    • School of Materials Science and Engineering, Dalian University of Technology, Dalian, People's Republic of China
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  • Lishi Wen

    1. School of Materials Science and Engineering, Dalian University of Technology, Dalian, People's Republic of China
    2. Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian, People's Republic of China
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tanyi@dlut.edu.cn

Abstract

Multicrystalline silicon ingots were fabricated via the directional solidification method in a vacuum induction furnace using silicon nitride (Si3N4) as quartz crucible coating. The effect of Si3N4 coating on the impurity content, transference, and distribution in Si ingots was investigated. The results can be summarized as follows: The impurities contained in Si ingots, including Fe, Ca, Mn, Cu, P, and B, were found to decrease at varying degrees when the inner surface of the quartz crucible was coated with Si3N4. A mixed layer composted by Si3N4 and Si was observed on the surface of the Si ingot. This mixed layer provided microdefects for the nucleation of metallic impurities. The Fe and N contents in the Si/Si3N4 mixed layer changed with the same tendency, and FeSi2 particles formed on the Si/Si3N4 crystalline boundary. Both Fe and Ca precipitated in the SiC particles near the Si ingot/Si3N4-coating interface.

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