Method for loading primary polycrystalline silicon material and reclaimed material in production of casting monocrystals

Abstract

The invention provides a method for loading a primary polycrystalline silicon material and a reclaimed material in production of casting monocrystals. The method comprises the following step: layers of monocrystal seeds, broken silicon slices, flaw-pieces, primary dense bar stocks or a large cauliflower-like material, small primary silicon material, the reclaimed material and a small reclaimed material are laid from the bottom of a crucible in sequence. The method has characteristics as follows: by means of the broken silicon slices, stress concentration above a seed crystal layer is avoided,thermal shock of a silicon liquid to the seed crystal layer at a melting stage is reduced, and dislocation caused by the stress concentration and thermal stress is reduced; the primary silicon material is laid at the lower part of the crucible, the reclaimed material is laid at the upper part of the crucible, and dislocation and polycrystals produced by impurity gathering at the initial seeding stage are reduced; a flaw-piece layer is tightly attached to the wall of the crucible, so that falling of a coating can be reduced, the adjacent flaw-pieces are spaced with certain distance, the flaw-pieces are prevented from expanding and extruding the crucible at high temperature, and the risk of crucible breakage can be reduced.

Description

technical field [0001] The invention relates to a method for charging primary polysilicon material and recycled material when producing cast single crystal. Background technique [0002] Crystalline silicon occupies an absolute advantage in the current solar energy material market. In terms of its crystal form, it can be divided into three categories: amorphous silicon, monocrystalline silicon, and polycrystalline silicon. The cost of amorphous silicon cells is low, but the conversion efficiency is also low, and due to the light-induced attenuation effect of amorphous silicon, its performance stability is poor; the content of impurities and defects in monocrystalline silicon cells is low, and the conversion efficiency is high, but The preparation process is complicated, and the purity of raw materials is high, so the production cost is also high; the production cost of polycrystalline silicon cells is low, but there are a large number of grain boundaries, high-density disloc...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for charging primary polysilicon material and reclaimed material when producing cast single crystal, which solves the problem that the existing primary polycrystalline silicon material and reclaimed material charging method has a great influence on the quality of cast single crystal, and There are many studies on the laying method of single crystal seed layer, but less research on the charging method of primary polysilicon material and recycled material

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