Method for changing solidifying crucible bottom layering manner in electron-beam polycrystalline silicon purification

A technology of polysilicon and electron beams, which is applied to the growth of polycrystalline materials, chemical instruments and methods, and single crystal growth. Consumption, improve the effect of quality

Inactive Publication Date: 2017-06-27
DALIAN UNIV OF TECH QINGDAO NEW ENERGY MATERIALS TECH RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this kind of bottoming method can effectively protect the crucible, the silicon raw material needs to be irradiated with high-power electron gun for a long time, and the energy consumption is high; at the same time, there is unmelted silicon raw material at the bottom of the product silicon ingot, which needs to be cut and removed, which increases the cost and reduces the yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A method for changing the method of laying the bottom of a polycrystalline silicon solidification crucible for electron beam purification, specifically comprising the following steps:

[0020] A. Spread 3 kg of polycrystalline silicon wafers with a purity of 5N, a P content of 0.9ppmw, a total metal content of 0.9ppmw, a Fe content of 0.4ppmw, an Al content of 0.2ppmw, and a thickness of 7mm of other metals less than 0.25ppmw on the bottom of the solidification crucible, and then in the polysilicon Spread 5kg of polysilicon fragments on the chip to prevent the electron beam from directly irradiating the crucible through the gap between the silicon chips and damaging the crucible;

[0021] B. Preheat three electron guns, of which 2 electron guns irradiate the melting crucible, and the other electron gun irradiates the solidification crucible, preheat for 30 minutes, and enter the silicon material melting stage after preheating is completed;

[0022] C. Melting of silicon...

Embodiment 2

[0031] The various steps of a method for changing the method of laying the bottom of the solidified crucible for electron beam purification polysilicon described in this embodiment are all the same as in Embodiment 1, and the different technical parameters are:

[0032] 1) The thickness of the polysilicon wafer in step A is 8 mm, and 2 kg of the polysilicon wafer is added; the purity of the polysilicon wafer is 6N, the P content is 0.8 ppmw, the total metal content is 0.8 ppmw, the Fe content is 0.3 ppmw, the Al content is 0.15 ppmw, and the other metal contents are less than 0.2 ppmw; Add 3kg of polysilicon fragments;

[0033] 2) In step B, the electron gun is preheated for 20 minutes;

[0034] 3) Melting the silicon material for 10 minutes in step D;

[0035] 4) In the step F, transport 65kg of raw materials to the smelting crucible;

[0036] 5) Melting the silicon material for 10 minutes in step H.

Embodiment 3

[0038] The various steps of a method for changing the method of laying the bottom of the solidified crucible for electron beam purification polysilicon described in this embodiment are all the same as in Embodiment 1, and the different technical parameters are:

[0039] 1) The thickness of the polysilicon wafer in step A is 10 mm, and 5 kg of the polysilicon wafer is added; the purity of the polysilicon wafer is 7N, the P content is 0.7 ppmw, the total metal content is 0.7 ppmw, the Fe content is 0.25 ppmw, the Al content is 0.1 ppmw, and the other metal contents are less than 0.15 ppmw; Add 7kg of polysilicon fragments;

[0040] 2) In step B, the electron gun is preheated for 40 minutes;

[0041] 3) Melting the silicon material for 30 minutes in step D;

[0042] 4) In the step F, transport 70kg of raw materials to the smelting crucible;

[0043] 5) Melting the silicon material for 30 minutes in step H.

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Abstract

A method for changing solidifying crucible bottom layering manner in electron beam polycrystalline silicon purification belongs to the field of electron-beam melting and comprises the following steps: layering 3 Kg of polycrystalline silicon wafers (with thickness of 7-10 mm) at the bottom of a solidifying crucible, and layering 5 Kg of polycrystalline silicon fragments on the polycrystalline silicon wafers; preheating electron guns; gradually increasing the power of an electron gun for irradiating a smelting crucible to 250 KW and the power of an electron gun for irradiating the solidifying crucible to 50 KW, and melting silicon; increasing the power of the electron gun for irradiating the solidifying crucible to 200 KW, and melting silicon; turning off the electron gun for irradiating the smelting crucible, outpouring silicon liquid, and increasing the power of the electron gun for irradiating the solidifying crucible to 250 KW; increasing the power of the electron gun for irradiating the smelting crucible to 250 KW, and melting and smelting silicon; and turning off the electron gun for irradiating the smelting crucible, outpouring silicon liquid, turning on the electron gun, keeping the power at 250 KW for 10 min, keeping the power at 200 KW for 2 min, keeping the power at 150 KW for 3 min, keeping the power at 120 KW for 5 min, keeping the power at 100 KW for 7 min, keeping the power at 80 KW for 8 min, keeping the power at 50 KW for 12 min, keeping the power at 30 KW for 16 min, keeping the power at 20 KW for 20 min, decreasing the power to 0 KW, and reducing the electron beam for solidifying. The method disclosed by the invention can increase product yield, and reduce the energy consumption of electron beam polycrystalline silicon purification.

Description

technical field [0001] The invention belongs to the technical field of electron beam smelting, and in particular relates to a method for changing the method of laying the bottom of a crucible for solidification of polysilicon purified by electron beams. Background technique [0002] At present, when electron beams are used to purify polysilicon, 15kg of silicon raw materials are added to the water-cooled solidification crucible as a bottom layer and melted with high-power irradiation of an electron gun to protect the crucible. Although this kind of bottom laying method can effectively protect the crucible, the silicon raw material needs to be irradiated with high-power electron gun for a long time, and the energy consumption is high. At the same time, there is unmelted silicon raw material at the bottom of the product silicon ingot, which needs to be cut and removed, which increases the cost and reduces the yield. Therefore, there is an inevitable demand for a bottoming meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/06C30B28/04
CPCC30B28/04C30B29/06
Inventor 孟剑雄王峰姚玉杰李鹏廷
Owner DALIAN UNIV OF TECH QINGDAO NEW ENERGY MATERIALS TECH RES INST CO LTD
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