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Method for manufacturing polysilicon and method for manufacturing silicon tetrachloride

A manufacturing method, a technology of silicon tetrachloride, applied in the direction of silicon compounds, silicon halide compounds, chemical instruments and methods, etc., can solve the problems of reduced yield of titanium tetrachloride and silicon tetrachloride, and achieve impurity Ingredient suppression, effective manufacturing effect

Inactive Publication Date: 2012-09-19
JNC CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] However, titanium tetrachloride is generated inside the fluidized bed, and if oxygen is supplied to the above-mentioned parts, the titanium tetrachloride generated in the fluidized bed will be oxidized by oxygen to return to titanium oxide, and the yield of titanium tetrachloride will decrease. , so it is not preferred
Therefore, when silicon dioxide is used as a raw material, it is also expected that the yield of silicon tetrachloride will decrease similarly to the above, and there is still room for improvement in the supply method of oxygen.

Method used

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  • Method for manufacturing polysilicon and method for manufacturing silicon tetrachloride
  • Method for manufacturing polysilicon and method for manufacturing silicon tetrachloride
  • Method for manufacturing polysilicon and method for manufacturing silicon tetrachloride

Examples

Experimental program
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Effect test

Embodiment 1

[0137] use figure 2 In the shown device, under the conditions shown below, in the chlorination step, silicon dioxide is used as a raw material to produce silicon tetrachloride, which is reduced with metal zinc vapor in the reduction step to produce solid polysilicon. In addition, zinc chloride, which is by-produced in the reduction reaction, is electrolyzed into metal zinc and chlorine gas in the electrolysis step, metal zinc is recycled as a reducing agent for silicon tetrachloride, and chlorine gas is recycled as a chlorinating agent for silicon dioxide . Furthermore, the polysilicon produced in the reduction step is melted, and high-purity silicon is deposited on the high-purity seed crystal.

[0138] 1. Chlorination step

[0139] 1) Raw material

[0140] The following raw materials were used to form granules of 1 to 2 mm for the chlorination reaction.

[0141] (1) Silica: purity 98wt%, particle size after pulverization 5μm

[0142] (2) Coke: purity 90wt%, particle ...

Embodiment 2

[0166] The silica and coke before pulverization in Example 1 were blended at a molar ratio of 1:2, put into a ball mill, pulverized by a pulverizer, and the particle diameters of silica and coke were changed by changing the pulverization time. Next, after adding 25% of TEOS to the silica and coke, granules were formed using a granulator. Then, after heating and drying the above-mentioned granules, the granules were sized to 0.5 mm to 1 mm, and then a chlorination test was performed using a fixed bed to confirm the production of silicon tetrachloride.

[0167] The reaction rate index of silica was calculated by the above formula (1), and the reaction rates confirmed under various test conditions are summarized in Table 1.

[0168] It was confirmed that silicon tetrachloride was efficiently produced by subjecting granules composed of silica having a particle diameter of 5 μm or less and coke having a particle diameter of 10 μm or less to the chlorination reaction. Among them, i...

Embodiment 3

[0172] In Example 2, various molar ratios of silica and coke constituting the granules were changed, and the influence on the production state of silicon tetrachloride was investigated. The results are shown in Table 2. When the molar ratio of coke to silica is 1.0 to 4.0, the utilization rate of chlorine gas is 90% or more, showing good reactivity. However, when the molar ratio of coke to silica was 0.5, the utilization rate of chlorine gas decreased to 50%.

[0173] Wherein, the utilization rate of chlorine is defined as the molar ratio (%) of the amount of chlorine calculated from the recovered silicon tetrachloride relative to the amount of input chlorine. It was confirmed from this Example that the molar ratio of coke constituting the granules to silica is preferably in the range of 1.0 to 4.0.

[0174] [Table 2]

[0175]

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Abstract

Provided is a method for manufacturing polysilicon and silicon tetrachloride. The polysilicon manufacturing process used in said method is energy-efficient and can use an inexpensive raw material, the supply of which is stable. The chlorination reaction in said process proceeds smoothly and post-chlorination impurities are minimized. The provided method comprises: a chlorination step which generates silicon tetrachloride by chlorinating granules comprising silicon dioxide and a carbon-containing substance; a reduction step which generates polysilicon by using a reducing metal to reduce the silicon tetrachloride; and an electrolysis step which generates chlorine gas and a reducing metal by performing molten-salt electrolysis on a reducing metal chloride generated as a by-product from the reduction step. In the chlorination step, chlorine gas is supplied to the silicon dioxide and the carbon-containing substance in the presence of oxygen gas in order to react said substances. The reducing metal generated in the electrolysis step is reused as the reductant for the silicon tetrachloride in the reduction step, and the chlorine gas generated in the electrolysis step is reused in the chlorination step.

Description

technical field [0001] The present invention relates to a method for producing silicon tetrachloride using silicon dioxide as a raw material, and a method for producing polysilicon using the silicon tetrachloride. In the present invention, especially without going through the chlorination step of metal silicon as in the past, silicon dioxide is directly chlorinated to generate silicon tetrachloride, and the resulting silicon tetrachloride is reduced with a reducing agent metal to obtain high-purity silicon tetrachloride. polysilicon. Background technique [0002] Polycrystalline silicon has been attracting attention from the viewpoint of utilization of the amount of sunlight that has been active in recent years, and has attracted attention particularly as a raw material for solar cells. [0003] Conventionally, the Siemens method has been widely known as a step for producing high-purity polysilicon for silicon cells for solar cells, which is characterized in that metal sili...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/02C01B33/033C01B33/107
CPCC01B33/10721C01B33/025C01B33/033C01B33/035C01B33/02C01B33/107
Inventor 笼桥亘堀川松秀垣內康辅
Owner JNC CORP
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