Method for purifying polysilicon by adopting electron beam to carry out fractionated smelting

An electron beam melting furnace, polysilicon technology, applied in chemical instruments and methods, silicon compounds, sustainable manufacturing/processing, etc., can solve the problems of hindering the volatilization of phosphorus impurities, removing unfavorable impurities, and large silicon evaporation, and reducing evaporation. Loss, reduce removal efficiency, good purification effect

Inactive Publication Date: 2011-08-10
DALIAN LONGSHENG TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Electron beams are used in metallurgical smelting to melt and purify materials. The known invention patent application number is 200810011631.8. Electron beams are used to smelt and remove impurity phosphorus in polycrystalline silicon. However, during the electron beam smelting process, the electron beams continue to have a large beam current Melting polysilicon, in this process, not only the amount of silicon evaporation is relatively large, but also a large amount of silicon vapor generated by continuous smelting with a large beam will hinder the volatilization of phosphorus impurities, causing the phosphorus impurities to flow back, which is not conducive to the removal of impurities

Method used

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  • Method for purifying polysilicon by adopting electron beam to carry out fractionated smelting
  • Method for purifying polysilicon by adopting electron beam to carry out fractionated smelting

Examples

Experimental program
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Embodiment 1

[0013] The first step of material preparation: Take 500g of polysilicon material with a phosphorus content of 0.001%, wash it with deionized water for 4 times, put it in a drying box and dry it at 50°C, put the polysilicon material into an electron beam melting furnace for melting in the crucible;

[0014] The second step of pretreatment: Use a vacuum pump to vacuum the electron beam melting furnace to below 0.0018Pa; water-cool the melting crucible with cooling at the bottom, and keep the temperature at 40°C; preheat the electron gun, set the high voltage to 30kV, and preheat the high pressure for 5 After 10 minutes, turn off the high voltage, set the beam current of the electron gun to 100mA, and perform preheating. After 15 minutes of preheating, turn off the beam current of the electron gun;

[0015] The third step of purification: turn on the high voltage and beam current of the electron gun, and after stabilization, use the electron gun to bombard the polysilicon materia...

Embodiment 2

[0017] The first step of material preparation: Take 500g of polysilicon material with a phosphorus content of 0.0013%, wash it with deionized water for 4 times, put it in a drying box and dry it at 50°C, put the polysilicon material into an electron beam melting furnace for melting in the crucible;

[0018] The second step of pretreatment: Use a vacuum pump to vacuum the electron beam melting furnace to below 0.0018Pa; water-cool the melting crucible with cooling at the bottom, and keep the temperature at 40°C; preheat the electron gun, set the high voltage to 30kV, and preheat the high pressure for 5 After 10 minutes, turn off the high voltage, set the beam current of the electron gun to 200mA, and perform preheating. After preheating for 10 minutes, turn off the beam current of the electron gun;

[0019] The third step of purification: turn on the high voltage and beam current of the electron gun, and after stabilization, use the electron gun to bombard the polysilicon mater...

Embodiment 3

[0021] The first step of preparing materials is the same as in Example 1;

[0022] The second step of pretreatment: Use a vacuum pump to vacuum the electron beam melting furnace to below 0.0018Pa; water-cool the melting crucible with cooling at the bottom, and keep the temperature at 40°C; preheat the electron gun, set the high voltage to 28kV, and preheat the high pressure for 10 After 10 minutes, turn off the high voltage, set the electron gun beam current to 150mA, and perform preheating. After 15 minutes of preheating, turn off the electron gun beam current;

[0023] The third step of purification: turn on the high voltage and beam current of the electron gun, and after stabilization, use the electron gun to bombard the polysilicon material with high phosphorus content with a beam current of 300mA. Adjust the beam current to 260mA for melting, melt for 8 minutes after melting, reduce the beam current to 0mA again, repeat the operation of 300mA beam current electron beam me...

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Abstract

The invention belongs to the technical field of purification of polysilicon by a physical metallurgical technology. A method for purifying the polysilicon by adopting an electron beam to carry out fractionated smelting comprises the following steps: firstly preparing a material; placing a cleaned and dried silicon material into an electronic beam smelting furnace; carrying out preprocessing; carrying out water cooling on a crucible and preheating an electronic gun; and finally purifying, i.e. melting and smelting for a certain time by adopting the electron beam with a small beam current of 200 to 300mA, then reducing the beam current to zero, smelting the polysilicon for a certain time by the small beam current of 200 to 300mA and stopping the beam current after a silicon ingot is completely darkened and silicon steam is condensed back into a molten pool, repeatedly repeating the operation of smelting small beam current and stopping beam current, and finally carrying out cooling and condensing to obtain a polysilicon ingot with low phosphorus content. The method has the obvious effects that due to the adoption of the technology of carrying out electro beam fractionated smelting, the evaporation loss of silicon is reduced; the method has good purifying effect, stable technology, simple process, short period and high production efficiency; energy is saved; and consumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of purifying polysilicon by physical metallurgy technology, and particularly relates to a method for melting and removing impurity phosphorus in polysilicon by electron beam. Background technique [0002] In a society where energy is scarce and low-carbon environmental protection is advocated, solar energy, as an environmentally friendly new energy, has great application value. Solar cells can convert solar energy into electrical energy, and solar-grade polysilicon materials are important raw materials for solar cells. Therefore, the preparation technology of solar-grade polysilicon materials is particularly important. At present, the main technical routes for preparing solar-grade polysilicon materials worldwide include: improved Siemens method, silane method, and metallurgical method. The principle of the improved Siemens method is to use high-purity hydrogen to reduce high-purity trichlorosilane on a hig...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
CPCY02P20/10
Inventor 谭毅战丽姝邹瑞洵郭校亮
Owner DALIAN LONGSHENG TECH CO LTD
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