Polysilicon purification method and crucible and purification device used for polysilicon purification

Abstract

A polysilicon purification method includes the following steps: impurity containing low purity polysilicon is maintained to be fusion state for a period of time in a crucible; the polysilicon liquid in fusion state is gradually cooled and solidified from the bottom to the top through relative move of the crucible and an induction coil arranged at the periphery of the crucible in a surrounding way;and the solidified polysilicon after cooling is taken out from the crucible and is purified by mechanical cutting. The invention also discloses a crucible used for polysilicon purification and a purification device provided with the crucible. The invention has the advantages that the polysilicon purification method and device has strong operability, low cost, no secondary pollution in purification process and the like.

Description

technical field [0001] The invention relates to a polysilicon purification (or refining) production process, in particular to a polysilicon purification method, a polysilicon purification crucible and purification equipment with the crucible. Background technique [0002] In recent years, energy and environmental issues, such as the massive consumption of traditional fossil energy and global warming, have attracted global attention. In this context, the global photovoltaic industry is developing rapidly, and the demand for silicon as a material for silicon solar cells is increasing rapidly. This has led to a shortage of silicon materials and high prices, which has become a bottleneck for the development of the photovoltaic industry. Improving polysilicon output and quality and reducing costs are the development direction of polysilicon industry. [0003] At present, the large-scale production of polysilicon at home and abroad mainly adopts chlorination purification technol...

AI Technical Summary

Problems solved by technology

However, the relatively high investment in purification using these equipments is reflected in the following two aspects: first, the investment in the equipment itself and supporting equipment is relatively large; High, such as high-purity quartz or graphite crucibles used in the production process, the price is very expensive

And it is not easy to increase the output of a single furnace, because when the required internal volume of the quartz or graphite crucible increases, the cost of manufacturing the quartz or graphite crucible increases geometrically

Although no consumables such as crucibles are used in the purification process of the zone furnace, the output of a single furnace is low and the production efficiency is low

3. These production processes will inevitably cause secondary pollution to high-purity silicon. Traditional processes, such as using graphite crucibles, can easily cause secondary pollution to metallurgical silicon due to the volatilization of graphite

This method takes a long time to process, and the furnace must be turned down during the process, which increases the possibility of pollution

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