Annealing technique of cast polycrystalline silicon

An annealing process, polysilicon technology, applied in the direction of polycrystalline material growth, crystal growth, post-processing details, etc., can solve the problems of no mass production practicability, no obvious advantages in cost control, no obvious contribution to product quality, etc., to achieve enhanced Effect of annealing, reduction of annealing temperature and time, effect of thermal stress reduction

Inactive Publication Date: 2015-06-10
HUNAN RED SUN PHOTOELECTRICITY SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This technology has great damage to the furnace body and is not practical for mass production
At the same time, there is no obvious contribution to improving product quality, and there is no obvious advantage in cost control

Method used

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  • Annealing technique of cast polycrystalline silicon

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Experimental program
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Effect test

Embodiment 1

[0022] The embodiment of the present invention provides an annealing process for polysilicon ingots. The annealing process uses a G5 type ingot furnace to cast polysilicon ingots. A G5 quartz crucible is selected, and the charge weight is 500Kg. Ingot process, the annealing process is performed after the crystal growth process is completed. In the first step of the annealing stage, set the temperature control mode, and use 90 minutes to reduce the temperature in the crucible from 1410 ° C to 1250 ° C, and at the same time move the heat insulation cage from the position of 20 cm to the position of 8 cm. After the first step of annealing is completed, the temperature inside the crucible reaches 1250°C, and the temperature at the bottom of the crucible reaches 1000°C. In the second step of the annealing stage, set the temperature control mode, and use 20 minutes to reduce the temperature in the crucible from 1250°C to 1200°C, and at the same time move the heat insulation cage fro...

Embodiment 2

[0025] The embodiment of the present invention provides an annealing process for polysilicon ingots. The annealing process uses a G5 type ingot furnace for high-efficiency polysilicon ingots. A G5 quartz crucible is selected, and the charge weight is 600Kg. Ingot casting process, the annealing process is performed after the crystal growth process is completed. In the annealing step, set the temperature control mode, use 180 minutes to reduce the temperature in the crucible from 1390 °C to 920 °C, and set the moving speed of the heat insulation cage to 6 cm / h. At the end of the annealing, the temperature inside the crucible reaches 920°C, the temperature at the bottom of the crucible reaches 900°C, and the cooling procedure is entered.

[0026] After calculation and verification, the running time of polycrystalline silicon ingots is shortened by 3 hours compared with the normal process, and the electricity cost is saved by 300Kw h. The obtained polycrystalline silicon ingots pa...

Embodiment 3

[0028] The embodiment of the present invention provides an annealing process for polysilicon ingots. The annealing process uses a G6 type ingot furnace for similar monocrystalline silicon ingots. A G6 quartz crucible is selected, and the charge weight is 800Kg, which is sent into the ingot furnace and vacuumized. Finally, the ingot casting process is run, and the annealing process is performed after the crystal growth program is completed. In the first step of the annealing stage, set the temperature control mode, and use 90 minutes to reduce the temperature in the crucible from 1400°C to 1200°C, and at the same time move the heat insulation bottom plate from the 24cm position to the 2cm position. In the second step of the annealing stage, set the power control mode, use 120 minutes to reduce the temperature from 1200 ° C to 950 ° C, and at the same time move the heat insulation cage from the position of 2 cm to the position of 10 cm. After the second step of annealing is comp...

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Abstract

The invention relates to an annealing technique of cast polycrystalline silicon, which uses a polycrystalline silicon ingot casting furnace, wherein the polycrystalline silicon ingot casting furnace comprises a heat insulation cage and a heat insulation base plate arranged below the heat insulation cage, a crucible is arranged in the heat insulation cage, and the external surface of the bottom of the crucible is provided with a graphite base plate. After the polycrystalline silicon growth step in the crucible, the height of the heat insulation cage or heat insulation base plate is lowered or enhanced to adjust the distance between the heat insulation cage and heat insulation base plate, so that the temperature in the crucible drops at the rate of 0.5-5 DEG C/minute, and the crucible bottom temperature fluctuation does not exceed 50 DEG C; and when the difference between the temperature in the crucible and the temperature of the crucible bottom is within 50 DEG C, the annealing is completed. The crucible bottom temperature is the temperature below the crucible bottom graphite protecting sheet. The technique reduces the back diffusion of impurities, greatly enhances the yield of the silicon bulk, and saves the energy consumption.

Description

technical field [0001] The invention relates to an annealing process of cast polycrystalline silicon. Background technique [0002] In the solar photovoltaic field, crystalline silicon accounts for more than 90% of the entire solar photovoltaic field due to its raw material source and preparation cost advantages. In the preparation process of crystalline silicon, polysilicon ingot technology plays a dominant role. The polysilicon ingot and silicon wafer manufacturing process technology is to use a large heat exchange ingot furnace, apply directional solidification technology, control the input and output of heat, and grow polysilicon ingots under a lower temperature gradient. The usual ingot process flow is: heating , melting, crystal growth, annealing and cooling. In order to obtain excellent silicon ingots, a suitable crystal growth process is required, but the annealing process after the crystal growth is completed is also very important. [0003] During the silicon cr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/06C30B33/02C30B28/06
CPCC30B29/06C30B28/06C30B33/02
Inventor 明亮段金刚黄美玲谭晓松瞿海斌陈国红蔡先武
Owner HUNAN RED SUN PHOTOELECTRICITY SCI & TECH
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