Method for preparing polysilicon

Abstract

The invention relates to a method for producing polysilicon comprising the following steps: reacting industrial silicon with chlorine hydride to generate trichlorosilane; reacting the purified trichlorosilane with hydrogen gas to generate the polysilicon; collecting tail gases mainly including the hydrogen gas, chlorine hydride, dichIorosilane, trichlorosilane and silicon tetrachloride; adding pressure to and cooling the tail gases, and carrying out a gas-liquid separation to the hydrogen gas, the chlorine hydride and the dichIorosilane from the liquid trichlorosilane and the silicon tetrachloride; leaching the hydrogen gas, the chlorine hydride and the dichIorosilane by a liquid state silicon tetrachloride, thereby removing the impurities such as chlorine hydride, solid impurities and perchlorosilane or the like; separating the hydrogen gas from the chlorine hydride and the dichlorosilane by a liquid state absorbent; desorbing the chlorine hydride and the dichlorosilane out from the liquid state absorbent through heating; separating the chlorine hydride from the dichlorosilane by controlling the pressure and / or temperature; and separating the trichlorosilane from the silicon tetrachloride by controlling the temperature and / or the pressure. The inventive method can recover and utilize the tail gas, and increases the output and the efficiency.

Description

technical field [0001] The invention relates to a method for industrially producing polysilicon, more specifically, to a method for producing polysilicon capable of dry recovery and utilization of tail gas. Background technique [0002] Polycrystalline silicon is the raw material for preparing monocrystalline silicon, which is ultimately used in the production of integrated circuits and electronic devices. It is one of the basic raw materials with the largest consumption and the highest purity requirements in the information industry. It is also a product and industry that the country encourages the development of. [0003] The world's advanced polysilicon production technology has always been monopolized by companies from the United States, Japan, and Germany. Each company has its own technical secrets and technical characteristics. After continuous research and development, it has formed its own production process. Set out, strictly control technology transfer and monopoli...

AI Technical Summary

Problems solved by technology

However, during the water washing process, impurity gases such as oxygen and carbon dioxide in the water will pollute the hydrogen, so a large amount of recovered hydrogen needs to be purified again

In addition, the hydrolysis of chlorosilane during the washing process produces sewage, which requires further treatment, resulting in environmental pollution and large material consumption.

At the same time, the generated hydrogen has not been fully utilized, which not only wastes energy, increases costs, but also causes environmental pollution.

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