Preparation method of polycrystalline silicon

A polysilicon preparation and polysilicon technology, applied in chemical instruments and methods, silicon compounds, sustainable manufacturing/processing, etc., can solve the problems of decreasing silicon deposition rate, affecting average deposition rate and reduction power consumption, etc. The effect of reducing the energy consumption of polysilicon deposition

Active Publication Date: 2012-07-11
新疆戈恩斯能源科技有限公司
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Problems solved by technology

The main means to solve the atomization are: reducing the current, reducing the amount of material feed, increasing the ratio of hydrogen and trichlorosilane, etc. The basic point is to solve the fog from the perspective of reducing the gas phase thermal decomposition reaction rate of trichlorosilane. However, this also leads to a decrease in the silicon deposition rate, which in turn affects the average deposition rate and reduction power consumption. This is a situation that polysilicon manufacturers do not want to see.

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  • Preparation method of polycrystalline silicon
  • Preparation method of polycrystalline silicon

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Embodiment 1

[0039] The polysilicon deposition reaction was carried out in the same steps as Comparative Example 1, while HCl was preheated to 200°C at a certain rate and continuously added to the feed tube so that the ratio of HCl / TCS in the reaction gas was about 5% by mole. . After starting the reaction, keep the surface temperature of the silicon core at 1080-1100°C. After the trichlorosilane and hydrogen are heated to 200°C, they are passed into the reactor. The initial flow rate of the trichlorosilane is 2Nm3 / h, which increases to 42Nm3 / h at a constant speed and remains constant, and the speed-up time is 30h. The initial hydrogen flow rate was 13Nm3 / h, which gradually increased to 189Nm3 / h. During the whole deposition process, the molar ratio of hydrogen to trichlorosilane gradually decreased from 6.5 to 4.5. When the reaction time reaches 40-50 hours, there is no atomization phenomenon in the reactor, and the feed amount, proportion and surface temperature of the silicon rods conti...

Embodiment 2

[0041] The polysilicon deposition reaction was carried out in the same steps as in Comparative Example 1. After starting the reaction, keep the surface temperature of the silicon core at 1080-1100°C. After the trichlorosilane and hydrogen are heated to 200°C, they are passed into the reactor. The initial flow rate of the trichlorosilane is 2Nm3 / h, which increases to 42Nm3 / h at a constant speed and remains constant, and the speed-up time is 30h. The initial hydrogen flow rate was 13Nm3 / h, which gradually increased to 189Nm3 / h. During the whole deposition process, the molar ratio of hydrogen to trichlorosilane gradually decreased from 6.5 to 4.5. When the reaction time reaches 40-50 hours, atomization occurs in the reactor. At this time, continue to keep the feed amount, proportion and surface temperature of the silicon rod unchanged, slowly open the HCl valve, and continuously Add it into the feed pipe so that the ratio of HCl / TCS in the reaction gas is about 10% (mole), react...

Embodiment 3

[0043] The polysilicon deposition reaction is carried out by adopting the method of the present invention. The raw materials trichlorosilane and hydrogen are mixed and heated to 200°C, and then passed into the reactor. The initial flow rate of trichlorosilane is 2Nm3 / h, which increases to 42Nm3 / h at a constant speed and remains constant, and the initial flow rate of hydrogen gas is 13Nm3 / h, which gradually increases To 189Nm3 / h, after reacting at 1100°C for 20h at a high temperature, feed HCl gas (preheated to 200°C) with a flow rate of 2Nm3 / h and 6% trichlorosilane into the reactor. After another 30 hours of reaction, the silicon core grows to a diameter of about 65mm, and HCl gas with a percentage of 18% of trichlorosilane is introduced. After another 30 hours of reaction, the silicon core grows to a diameter of about 100mm, and HCl gas with a percentage of 15% of trichlorosilane is introduced. The reaction was continued for 10 h, and the feed amount of HCl gas was kept con...

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Abstract

The invention discloses a preparation method of polycrystalline silicon. The method comprises the following steps of: undergoing a chemical vapor deposition reaction on trichlorosilane and high-purity hydrogen serving as raw materials at the high temperature of 1,050-1,250 DEG C and under the pressure of 0-0.8 MPa in a reduction furnace reactor; and depositing polycrystalline silicon on the surface of a heat-emitting silicon core. The method is characterized in that: 0.1-20 percent of hydrogen halide gas is introduced into a reduction furnace in a chemical vapor deposition process. According to method, silicon powder produced in the bulk phase of the reduction furnace can be suppressed effectively, an atomization phenomenon is eliminated, heat produced by reacting can be applied to deposition of polycrystalline silicon, the energy utilization efficiency and silicon depositing rate are increased, and the reaction temperature and the halogenated silane concentration are not required to be lowered; and due to etching of hydrogen halide on the surface of a silicon stick, the surface appearance is improved, and a dense polycrystalline silicon stick is obtained.

Description

technical field [0001] The invention relates to a method for preparing polysilicon, in particular to a method for preparing polysilicon by adding oxidizing gas to reduce atomization and improve the surface appearance of products. Background technique [0002] Polysilicon is the most important raw material for the photovoltaic industry and the electronics industry, and its application requires extremely high purity. Generally speaking, the purity of solar-grade polysilicon needs to reach more than 6 nines (more than 99.9999%), and the purity of electronic-grade polysilicon needs to reach more than 9 nines (more than 99.9999999%). Today, the mainstream polysilicon preparation methods mainly include: improved Siemens method, silane method, metallurgical method, sodium reduction method, zinc reduction method, etc. Among them, the polysilicon produced by the improved Siemens method accounts for more than 80% of the world's total output, and its core process is three Hydrogen sil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/035
CPCY02P20/10
Inventor 江宏富钟真武
Owner 新疆戈恩斯能源科技有限公司
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