Crystallization process of polycrystalline silicon and ingot casting process of polycrystalline silicon

Abstract

The invention provides a crystallization process of polycrystalline silicon and an ingot casting process of polycrystalline silicon. The crystallization process comprises the following steps: when a silicon material is in the state of coexistence of solid silicon and liquid silicon, the temperature of the top of an ingot furnace is kept so as to continuously melt solid silicon, and the temperature of the top in the ingot furnace is gradually lowered to enable the liquid silicon to be subjected to recrystallization to form the polycrystalline silicon ingot. The crystallization treatment is performed to the liquid silicon, when the silicon material is in the state of mixing of solid and liquid, so the temperatures of liquid silicon in all the ingot furnaces are basically the same, latent heat of the liquid silicon is the same, and therefore the crystallization velocity of the liquid silicon is enabled to be stable, the crystallization stability of liquid silicon is improved, and the properties of solar cells manufactured by the polycrystalline silicon ingot is improved. Meanwhile, the crystallization process of the polycrystalline silicon has the characteristics of simple process and high production efficiency.

Description

technical field [0001] The invention relates to the technical field of solar cells, and more specifically, to a polycrystalline silicon crystallization process and a polycrystalline silicon ingot casting process. Background technique [0002] With the rapid development of the photovoltaic industry, polycrystalline silicon ingot furnaces have been widely used in the photovoltaic power generation industry due to their high production capacity and high quality stability of the products (polycrystalline silicon ingots and quasi-monocrystalline silicon ingots). [0003] The ingot casting process of polysilicon includes five process steps: heating, melting, crystallization (directional crystallization), annealing, and cooling. The high-purity polysilicon material is placed in the quartz crucible of the ingot furnace, and after the above-mentioned process steps, it is finally grown into a polysilicon ingot for the production of solar cells. [0004] When producing polycrystalline ...

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Problems solved by technology

[0005] The present invention aims to provide a polysilicon crystallization process and a polysilicon ingot casting process to solve the problems of unstable crystallization speed and poor crystallization stability of liquid silicon in the prior art

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