Polycrystalline silicon ingot casting process

Abstract

The invention discloses a polycrystalline silicon ingot casting process, comprising the following steps of: 1) heating monatomic silicon until the monatomic silicon is melted; 2) cooling the molten monatomic silicon and solidifying the molten monatomic silicon, and performing nucleation, thereby forming a silicon ingot; and 3) performing multiple times of annealing on the silicon ingot, wherein the annealing temperatures are reduced gradually. In this way, the silicon ingot is subjected to multiple times of annealing, so that thermal stress formed between two adjacent annealing temperatures can be reduced accordingly and the thermal stress in the silicon ingot is eliminated a plurality of times; and compared with once annealing in the prior art, the thermal stress in the silicon ingot can be effectively reduced.

Description

technical field [0001] The invention relates to the technical field of solar energy, and more specifically, relates to a polysilicon ingot casting process. Background technique [0002] Polycrystalline silicon is a form of elemental silicon. When molten elemental silicon solidifies under supercooled conditions, silicon atoms are arranged in the form of diamond lattices to form many crystal nuclei, and these nuclei grow into crystal grains with different crystal plane orientations. These crystal grains Joined together to form polysilicon. The process of producing solar photovoltaic products in the solar photovoltaic industry includes polycrystalline silicon ingots, cutting into pieces, making cells and packaging them into solar modules. It can be seen that polycrystalline silicon ingots are an important part of the solar photovoltaic industry and the first choice for the production of solar photovoltaic products. link. [0003] Among them, the polysilicon ingot casting proc...

AI Technical Summary

Problems solved by technology

In this way, after the heat preservation is completed at about 1370°C, a large thermal stress will still be generated when cooling at a certain speed. If the cooling speed is reduced, the production cycle will be correspondingly extended and the production efficiency will be reduced.

Images