Production method of solar energy level polysilicon ingot with crystalline grains arranged regularly

Abstract

The invention discloses a production method of solar energy level polysilicon ingot with crystalline grains arranged regularly, which comprises the following steps: a seed crystal layer is arranged on a plane at the bottom of a flat-bottom crucible in advance, then silicon melt is arranged in the flat-bottom crucible, or silicon raw material arranged in the flat-bottom crucible is heated and melted to form the silicon melt, and the polysilicon ingot is prepared by the inducing of the seed crystal layer, wherein the seed crystal layer is formed by tightly arranging nine or more than nine rectangular seed crystals, the seed crystals are arranged along the crystal direction (100) of the normal direction of the plane at the bottom of the flat-bottom crucible, and the included angle of the two adjacent seed crystals along the crystal direction of the normal direction of the spicing surface is 30-60 degrees. In the production method, the special seed crystal layer is adopted, so that the productivity of the silicon ingot is increased, the possibility of breakage of the silicon ingot is reduced, the minority carrier lifetime of the silicon ingot also can be prolonged, and the quality of the silicon crystal can be improved.

Description

technical field [0001] The invention belongs to the field of crystalline silicon manufacture, and in particular relates to a method for producing solar-grade polycrystalline silicon ingots with regular arrangement of crystal grains. Background technique [0002] Silicon single crystal and silicon polycrystalline ingot are the most commonly used materials for crystalline silicon solar cells. In addition to the pulling method (Czochralski method) and zone melting method (Floating Zone method), the manufacturing method of silicon single crystal can also be realized by directional solidification method (ie, casting method). When using the directional solidification method, the bottom of the crucible is covered with a seed crystal or a seed layer composed of multiple seed crystals, and the silicon raw material is melted into a silicon melt in the crucible (refer to the Chinese invention patent application with application number 201010198142.5 and the patent number is ZL200910152...

AI Technical Summary

Problems solved by technology

When the number of grain boundaries is large, these traps and recombination centers will severely reduce the minority carrier diffusion length and affect the performance of photovoltaic devices

It is specifically manifested in the fact that the minority carrier life of silicon wafers made of the above-mentioned silicon single crystal and silicon polycrystalline is relatively low, and ultimately affects the photoelectric conversion efficiency and life of the manufactured crystalline silicon solar cells.

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