Polycrystalline silicon ingot preparation process and polycrystalline silicon ingot thereof

Abstract

The invention provides a polycrystalline silicon ingot preparation process and a polycrystalline silicon ingot thereof, which relate to the technical field of solar cell ingot casting. The process comprises the steps of loading, heating and melting, crystallizing, annealing and cooling. The process is characterized in that during the later period of heating and melting, a heat insulation cage is gradually arisen to the first height, and a pulling plate is opened; the rising speed of the heat insulation cage is controlled, the heat insulation cage is gradually adjusted to the second height fromthe first height and then stops rising, and the pulling plate is controlled to be gradually opened to a set opening degree in cooperation with the height of the heat insulation cage and then stopped;the annealing time is controlled to be 130 to 140minutes. The invention further provides the polycrystalline silicon ingot prepared by adopting the process. According to the preparation process provided by the invention, the ingot casting period is shortened, the yield is improved, the energy consumption is reduced, meanwhile, the prepared polycrystalline silicon ingot has no frozen silicon or whole ingot laceration after being extracted, and the detection result shows that the red-region length is reduced and the ingot casting yield is improved.

Description

Technical field [0001] The invention relates to the technical field of solar cell ingot casting, in particular to a preparation process of polycrystalline silicon and a polycrystalline silicon ingot. Background technique [0002] Polysilicon is a form of elemental silicon. When molten elemental silicon solidifies under supercooling conditions, silicon atoms are arranged into many crystal nuclei in the form of a diamond lattice. If these crystal nuclei grow into crystal grains with different crystal plane orientations, these crystal grains combine to crystallize into polysilicon . The raw materials of polycrystalline silicon are easily available and the conversion efficiency is high. The area utilization efficiency in the module is also superior to that of monocrystalline silicon wafers, and it has become the most important photovoltaic material. The use of silicon materials to make solar cell modules requires a series of complex processing processes. Among them, the preparation...

AI Technical Summary

Problems solved by technology

Poor annealing process will directly affect the stress distribution inside the finished ingot, and have a great impact on the quality of the finished polysilicon ingot

The current annealing process requires high temperature and long-term heat preservation, which promotes the high-temperature solid-phase diffusion of impurities, increases the length of the red zone, and reduces the minority carrier lifetime.

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