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Preparation method of high-purity polycrystalline silicon wafer

A polysilicon wafer and polysilicon technology, applied in the field of solar cells, can solve the problems of high cutting loss and high comprehensive cost of cutting and processing, and achieve the effects of improving conversion efficiency, ensuring product qualification rate, and reducing production costs

Active Publication Date: 2018-11-02
ZHEJIANG HANDU PHOTOELECTRIC TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The silicon wafers used in solar cells are mainly processed by mechanical cutting technology to make traditional large-diameter single crystal silicon wafers. This processing method has the outstanding disadvantages of cutting loss as high as 50% and high comprehensive cost of cutting and processing.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] In the embodiment of the present invention, the preparation method of high-purity polycrystalline silicon wafer comprises the following steps:

[0021] 1) Put the silicon material into a high-temperature furnace and heat it to 1300°C in a dust-free environment to keep the silicon material at the bottom of the furnace from melting, so that the silicon material remaining at the bottom of the furnace can better guide the crystal growth and control the crystal growth. Grain requirements, thereby reducing dislocations and defects, and improving product purity; polysilicon is produced through the above steps.

[0022] 2) Cut the polysilicon, and clean the surface of the cut polysilicon with a cleaning agent to effectively remove the pollutants on the surface of the silicon wafer, so that the surface of the silicon wafer is clean and uniform, which is beneficial to the texture of the silicon wafer and improves the surface purity. Product conversion efficiency is effectively im...

Embodiment 2

[0025] In the embodiment of the present invention, the preparation method of high-purity polycrystalline silicon wafer comprises the following steps:

[0026] 1) Put the silicon material into a high-temperature furnace and heat it to 1380°C in a dust-free environment to keep the silicon material at the bottom of the furnace from melting, so that the silicon seed crystals left at the bottom of the furnace can better guide the crystal growth and control the crystal growth. Grain requirements, thereby reducing dislocations and defects, and improving product purity; polysilicon is produced through the above steps.

[0027] 2) Cut the polysilicon, and clean the surface of the cut polysilicon with a cleaning agent to effectively remove the pollutants on the surface of the silicon wafer, so that the surface of the silicon wafer is clean and uniform, which is beneficial to the texture of the silicon wafer and improves the surface purity. Product conversion efficiency is effectively im...

Embodiment 3

[0030] In the embodiment of the present invention, the preparation method of high-purity polycrystalline silicon wafer comprises the following steps:

[0031] 1) Put the silicon material into a high-temperature furnace and heat it to 1320°C in a dust-free environment to keep the silicon material at the bottom of the furnace from melting, so that the silicon material remaining at the bottom of the furnace can better guide the crystal growth and control the crystal growth. Grain requirements, thereby reducing dislocations and defects, and improving product purity; polysilicon is produced through the above steps.

[0032] 2) Cut the polysilicon, and clean the surface of the cut polysilicon with a cleaning agent to effectively remove the pollutants on the surface of the silicon wafer, so that the surface of the silicon wafer is clean and uniform, which is beneficial to the texture of the silicon wafer and improves the surface purity. Product conversion efficiency is effectively im...

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PUM

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Abstract

The invention discloses a preparation method of a high-purity polysilicon wafer; silicon material is put in a high-temperature smelting furnace and is heated in a dust-free environment to 1300-1380 DEG C, and keeping the silicon material at the bottom of the high-temperature smelting furnace to not melt so as to obtain polysilicon; cutting the polysilicon, and cleaning the surface of the cut polysilicon with a cleaning agent, wherein the cleaning agent is made from, by weight, 40-50 parts of a surfactant and 22-30 parts of a chelating agent; adding an additive and a boron curing agent into the cleaned polysilicon, and treating at 700-800 DEG C for 10 min, cleaning to acquire the high-purity polysilicon; key impurity elements such as boron, hard to remove and capable of affecting minority carrier lifetime and conversion efficiency decrease in solar cell materials, the purified polysilicon wafer is less than 1 ppm in B concentration, conversion efficiency of the polysilicon wafer is increased, and the finished wafer is up to 99.9999% in qualification rate, product yield is guaranteed, and production cost is reduced.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a method for preparing high-purity polycrystalline silicon wafers. Background technique [0002] High efficiency and low cost are the main trends in the development of solar cells. Polycrystalline silicon solar cells are low in price and high in conversion efficiency, and have become a research hotspot in the international photovoltaic field. [0003] Polysilicon is a form of elemental silicon. When molten elemental silicon is solidified under supercooled conditions, silicon atoms are arranged in the form of diamond lattices to form many crystal nuclei. If these crystal nuclei grow into crystal grains with different crystal plane orientations, these crystal grains combine to crystallize into polycrystalline silicon. . Polycrystalline silicon can be used as the raw material for pulling single crystal silicon, and the difference between polycrystalline silicon and single cry...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B28/04C30B29/06C30B33/00
CPCC30B28/04C30B29/06C30B33/00
Inventor 王勇
Owner ZHEJIANG HANDU PHOTOELECTRIC TECH CO LTD