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

Multicrystalline silicon ingots were fabricated via the directional solidification method in a vacuum induction furnace using silicon nitride ( Si 3 N 4 ) as quartz crucible coating. The effect of Si 3 N 4 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 Si 3 N 4 . A mixed layer composted by Si 3 N 4 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 / Si 3 N 4 mixed layer changed with the same tendency, and Fe Si 2 particles formed on the Si / Si 3 N 4 crystalline boundary. Both Fe and Ca precipitated in the SiC particles near the Si ingot/ Si 3 N 4 ‐coating interface.