Crucible for growing polysilicon ingot

Abstract

The invention relates to a crucible for growing silicon ingot in the field of solar energy, in particular to a crucible for growing polysilicon ingot. The crucible for growing the polysilicon ingot is characterized in that: a bottom plate 2 of the crucible is provided with a plurality of holes 3; and the depth of the holes 3 is 1 to 25 mm, the aperture of the level part of the holes 3 and the bottom plate 2 of the crucible is 1 to 30 mm, and the distributed density of the holes 3 and the bottom plate 2 of the crucible is 1 to 100 per square decimeter. By adopting the crucible for growing the polysilicon ingot to grow polysilicon ingot, the directionality of crystal grains of the polysilicon ingot can be remarkably improved, crystal grains of the polysilicon ingot predominate in and crystal orientation, multiple parallel twins boundaries caused by crystal face are reduced, the number of crystal boundaries is reduced, and simultaneously the percentage of sigma 3 shallow energy level crystal boundary is improved so as to effectively prolong the minority carrier lifetime of a silicon chip, and the conversion efficiency of solar cells made of the silicon chip is improved.

Description

technical field [0001] The invention relates to a crucible for growing silicon ingots in the field of solar energy, in particular to a crucible for growing polycrystalline silicon ingots. Background technique [0002] The current casting of polysilicon is generally carried out by directional solidification. Generally, a square crucible with a flat bottom consisting of a bottom surface and a side wall that defines the internal volume is used. A certain temperature gradient is formed at the bottom of the crucible by using processes such as lowering the crucible, raising the heat insulation cage, and water-cooling the crucible. The bottom plate gradually nucleates and grows. Due to the flat bottom and uniform temperature, disordered spontaneous nucleation leads to the formation of many crystal grains, the crystal orientation is chaotic, the directional impurity removal effect is poor, the minority carrier lifetime is low, and the conversion efficiency of the final solar cell i...

AI Technical Summary

Problems solved by technology

Due to the flat bottom and uniform temperature, disordered spontaneous nucleation leads to the formation of many crystal grains, the crystal orientation ...

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