Purification apparatus and method for solar energy level polysilicon

A solar-grade, purification method technology, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of high cost, waste of environment, large amount of slag, etc., and achieve considerable market prospects, convenient operation, and low investment. Effect

Inactive Publication Date: 2009-01-14
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

U.S. Patent No. 6,368,403 B1 adopts air blowing slagging and other processes for purification, which mainly removes B, C, and O, and the removal effect is very good, but due to the large amount of slag required by this process, the cost is increased and the by-product slag Phase cannot be reused, causing a lot of waste and environmental pollution

Method used

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  • Purification apparatus and method for solar energy level polysilicon
  • Purification apparatus and method for solar energy level polysilicon
  • Purification apparatus and method for solar energy level polysilicon

Examples

Experimental program
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Effect test

Embodiment 1

[0044] Embodiment 1: Start the heater of the resistance wire heating holding furnace, and set the temperature according to the upper, middle and lower temperature sections as 1415°C, 1200°C, and 1000°C respectively. Put 50kg of polycrystalline silicon (block) into a graphite crucible, close the vacuum chamber, and turn on the mechanical rotary vane pump. When the vacuum degree of the vacuum chamber reaches 10Pa, the induction coil is powered on with an alternating current at 50kW until the silicon is completely melted. Turn on the power of the oil diffusion pump for preheating. When the temperature of the silicon liquid reaches 1800°C, lower the rotary aeration device to the surface of the silicon liquid for preheating, and after 10 minutes, inject 99% Ar+2% O from the inlet of the aeration device. 2 , and then put the aeration device in the graphite crucible at a position 10mm from the bottom, start the rotation button, aerate while rotating and stirring, the rotation speed i...

Embodiment 2

[0045] Embodiment 2: technological process is with embodiment 1. The temperature of the upper, middle and lower temperature zones of the resistance wire heating and holding furnace is set at 1500°C, 1350°C, and 1150°C; the raw material is 100kg of bulk polysilicon, the AC power is 80kW, and the temperature of the silicon liquid reaches 1700°C for ventilation and rotation. The ventilation device was preheated for 5 minutes, 99% Ar+3% water vapor was introduced, the rotation speed was 60 rpm, the ventilation volume was 2.5 L / min, and the ventilation time was 45 minutes. Vacuum up to 3.9×10 -2 Pa, the vacuum melting time is 90min, and the stainless steel lifting rod drives the mold to move downward at a speed of 20mm / h. After the directional solidification is completed, break the vacuum to take out the silicon ingot, cut off 1 / 10 of the upper part, and measure the P content of the polysilicon by plasma inductively coupled mass spectrometer (ICP-MS) to be 0.05ppmw, the B content ...

Embodiment 3

[0047] Technological process is with embodiment 1. The temperature of the upper, middle and lower temperature zones of the resistance wire heating and holding furnace is set at 1600°C, 1350°C, and 1150°C; the raw material is 180kg of powdered polysilicon, the AC power is 100kW, and the temperature of the silicon liquid reaches 1500°C for ventilation and rotation. The ventilation device was preheated for 8 minutes, 98% Ar+1% water vapor was introduced, the rotation speed was 120 rpm, the ventilation volume was 1 L / min, and the ventilation time was 90 minutes. Vacuum up to 1.2×10 -2 pa, the vacuum melting time is 90min, and the stainless steel lifting rod drives the mold to move downward at a speed of 20mm / h. After the directional solidification is completed, break the vacuum and take out the silicon ingot, cut off 1 / 10 of the upper part, and measure the P content of the polysilicon by a plasma inductively coupled mass spectrometer (ICP-MS) to be 2.8ppmw, the B content to be 4....

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Abstract

Disclosed are a purification device as well as a purification method of solar-grade polysilicon, relating to a polysilicon, which provides a purification device and a purification method of solar-grade polysilicon characterized by low cost, high purity, simple process, easy operation and suitability for large-scale production. The purification device is equipped with a vacuum system, a melting system and a directional solidification system; wherein the vacuum system is provided with a mechanical rotary vane pump, a lobed element pump and an oil diffusion pump, and the melting system is provided with a vacuum chamber, a secondary feeder, an observation window, a rotary ventilation device which can be raised and lowered, an induction coil and a graphite crucible; and the directional solidification system is disposed at the lower part of the vacuum chamber and is equipped with an electric resistance-wire heating and holding furnace, a graphite mold, a holding furnace frame, a water-cooled copper tray and an elevating lever which can control speed. The metal silicon is treated by induction heating to be molten, the oxidizing gas is fed under conditions of low vacuum and high temperature to remove boron, and then under conditions of high temperature and high vacuum to remove phosphorus, and finally the molten silicon solution is poured into a directional mold to strictly conduct directional solidification to remove metal impurities.

Description

technical field [0001] The invention relates to polysilicon, in particular to a purification device and a purification method for solar-grade polysilicon. Background technique [0002] The so-called "purification" refers to removing the impurity elements in the matrix through appropriate physical and chemical processes according to the physical and chemical properties of the matrix elements or impurity elements. [0003] For silicon used as a semiconductor material, at present, the most mature and large-scale production process is the Siemens method or the modified Siemens method. This type of process first reduces silica through C to obtain industrial silicon with a purity of at least 98%, and then reacts industrial silicon with HCl at a high temperature of about 1400°C to form SiHCl 3 (or SiCl 4 ), after distillation and purification, use high-purity H in Siemens reactor (or fluidized bed) 2 Reduction can obtain high-purity polysilicon with a purity up to 12N. Up to no...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 罗学涛郑淞生蔡靖陈文辉陈朝
Owner XIAMEN UNIV
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