Method for producing polysilicon with silicon tetrafluoride reduced by plasmas

Abstract

The invention discloses a method for producing polysilicon with silicon tetrafluoride reduced by plasmas, specifically comprising the following steps: pumping the mixture of the silicon tetrafluoride gas and hydrogen as the raw materials into a plasma reactor filled with hydrogen, heating the silicon tetrafluoride gas and hydrogen to 1200-3500 DEG C instantaneously under the action of the plasmas and the silicon tetrafluoride gas and hydrogen carrying out chemical reaction to produce the polysilicon solid and the hydrogen fluoride gas; the produced polysilicon solid and hydrogen fluoride gas and the unreacted silicon tetrafluoride gas and hydrogen jointly entering into a gas-solid separation device, separating the polysilicon solid from the gases, the purity being more than 99.9999% and producing the finished product; and the hydrogen fluoride gas and the unreacted silicon tetrafluoride gas and hydrogen jointly entering into a condenser, condensing the hydrogen fluoride gas to liquid and the silicon tetrafluoride gas and hydrogen returning to the plasma reactor. The method has the advantages of novel and reasonable process routes, low equipment requirements, easy industrialization realization and low energy consumption.

Description

technical field [0001] The invention relates to a method for producing polysilicon, more specifically a method for producing polysilicon or polysilicon wafers by using silicon tetrafluoride and hydrogen as raw materials. Background technique [0002] As is well known, there are many methods for producing polysilicon used as a raw material for semiconductors or solar power cells, and some of them have been industrially practiced. [0003] For example, the patent application with the application number 200710121059 "Method for Producing Polysilicon" discloses a method: using industrial silicon and hydrogen chloride as raw materials to react to generate trichlorosilane; purifying the trichlorosilane and reacting it with hydrogen , so as to reduce and generate polysilicon; collect the tail gas generated in the process of generating trichlorosilane, purifying trichlorosilane and generating polysilicon, and recycle after treatment. [0004] The patent application with the applica...

AI Technical Summary

Problems solved by technology

[0010] 1. The investment is huge; the investment per ton of polysilicon production capacity is as high as 1 million yuan or more

[0011] 2. Low utilization rate of raw materials

[0012] 3. High energy consumption

[0013] 4. High production cost

[0014] 5. It is difficult to deal with tail gas or by-products

[0015] 6. Serious environmental pollution

[0016] 7. Poor product quality

[0017] 8. Some gases in the production process are flammable and explosive, prone to explosion accidents, and poor in safety

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