Method for manufacturing polycrystalline silicon used for solar battery

A technology for solar cells and manufacturing methods, which is applied in the growth of polycrystalline materials, final product manufacturing, chemical instruments and methods, etc., and can solve the problems that the technology has not reached industrialized production, the scale is small, and the technology has not been fully disclosed.

Inactive Publication Date: 2008-02-13
李绍光
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the technology disclosed in the above-mentioned patent documents has the following problems: (1) the impurity content in the product, especially the main impurities B and P, cannot reach the solar level standard; (2) the technical parameters of the process, especially its important technical parameters Not yet sure, at least its technology has not been fully disclosed; (3) the scale of the embodiments is very small, which shows that its technology has not yet reached the level of industrial production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Step 1: Use chemically pure industrial silicon and SiO with a purity of more than 99.68% 2 High-purity quartz powder with a content of 99.98% is used as a raw material, and the two are ground into fine powder and placed in a pressure lower than 10 -4 Heat up to 1250°C in a vacuum furnace held in a tray, and keep it warm for 1 to 3 hours to obtain gaseous silicon monoxide, slowly lower the temperature to 1180°C, and then rapidly cool to room temperature to obtain solid silicon monoxide;

[0026] Step 2: Put the solid silicon monoxide at a pressure lower than 10 -5 Heating to 1450°C in the vacuum furnace held by the supporter and holding the temperature for 1 to 3 hours. At this time, the disproportionation reaction of silicon monoxide in the furnace produces molten silicon and solid silicon dioxide. After the silicon melt is separated from the solid silicon dioxide, the temperature is slowly lowered to obtain silicon powder;

[0027] Step 3: Grind and sieve the silicon...

Embodiment 2

[0033] Step 1: Use chemically pure industrial silicon and SiO with a purity of more than 99.68% 2 High-purity quartz powder with a content of 99.98% is used as a raw material, and the two are ground into fine powder and placed in a pressure lower than 10 -4 Heat up to 1300°C in a vacuum furnace held in a tray, keep it warm for 2 to 4 hours to obtain gaseous silicon monoxide, slowly lower the temperature to 1180°C, and then rapidly cool to room temperature to obtain solid silicon monoxide;

[0034] Step 2: Put the solid silicon monoxide at a pressure lower than 10 -6 Heating to 1500°C in the vacuum furnace held in the support, and keeping it warm for 2 to 4 hours, at this time, the disproportionation reaction of silicon monoxide in the furnace produces molten silicon and solid silicon dioxide. After the silicon melt is separated from the solid silicon dioxide, the temperature is slowly lowered to obtain silicon powder;

[0035] Step 3: Grind and sieve the silicon powder and p...

Embodiment 3

[0040] Step 1: Use chemically pure industrial silicon and SiO with a purity of more than 99.68% 2 High-purity quartz powder with a content of 99.98% is used as a raw material, and the two are ground into fine powder and placed in a pressure lower than 10 -4 Heat up to 1250-1300°C in a vacuum furnace held in a tray, keep it warm for 2-4 hours to obtain gaseous silicon monoxide, slowly lower the temperature to 1180-1200°C, and then rapidly cool to room temperature to obtain solid silicon monoxide;

[0041] Step 2: Put the solid silicon monoxide at a pressure lower than 10 -5 Heating to 1450-1500°C in the vacuum furnace held by the supporter, and holding the temperature for 2-3 hours. At this time, the disproportionation reaction of silicon monoxide in the furnace produces molten silicon and solid silicon dioxide. After the silicon melt is separated from the solid silicon dioxide, the temperature is slowly lowered to obtain silicon powder;

[0042] Step 3: Grind and sieve the s...

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PUM

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Abstract

A method of preparing a polycrystalline silicon for solar batteries adopts combined means of silicon monoxide disproportionation, acid dipping separation and vacuum melting and processes by the following procedures: (1) the silicon monoxide is made from chemical pure industrial silicon and high purity sand quartz. (2) the high purity silicon is obtained by disproportionation of the silicon monoxide. (3)impurities boron and phosphorus in the silicon are removed by soaking with aquafortis. (4) the high purity silicon is further purified by melting of a vacuum electro beam furnace, and parts with impurities heavily gathered in a cast ingot are cut. (5) nitrogen or nitrogen plus hydrogen is fed into a plasma furnace for melting, so as to further remove the rest boron, phosphorus and other impurities, and conduct directional solidification. (6)the outer skin and parts with impurities heavily gathered of the cast ingot are cut, and finally the high purity silicon which is above 6N pure and applicable to solar batteries is obtained. The invention rejects the technical route of the Siemens method, prevents environment pollution, improves safety of production, and is good for promotion and application in China.

Description

technical field [0001] The invention belongs to the technical field of silicon purification, and in particular relates to a method for manufacturing polysilicon for solar cells by using an electron beam furnace and a plasma furnace to remove impurities in industrial silicon. Background technique [0002] Solar cells can use the photovoltaic effect to directly convert solar energy into DC power, which can provide human beings with inexhaustible clean and renewable energy, and has a very bright development prospect. Among solar cells, silicon cells are currently the most widely used. The silicon material that can be used to manufacture solar silicon cells must have a silicon content above 6N (ie 99.9999%), wherein the carbon and oxygen content must be below 0.5-1ppmw, and the content of other impurities such as boron, phosphorus, iron, aluminum, and titanium must be low. Must drop below 0.01ppmw, so as to ensure the required photoelectric conversion efficiency. [0003] At p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/06C01B33/037C01B33/039
CPCY02E10/546C01B33/037C01B33/021H01L31/182Y02P70/50
Inventor 李绍光
Owner 李绍光
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