High-impurity molten silicon high-pressure gas-blow separation device and method

Abstract

The invention relates to a high-impurity molten silicon high-pressure gas-blow separation device and a high-impurity molten silicon high-pressure gas-blow separation method. According to the invention, a graphite pedestal is arranged in a furnace body on a lower part. A crucible accommodating polysilicon is arranged on the graphite pedestal. a heating body connected with a system control device is arranged on the periphery in the furnace body. Gas-blow pipes connected with an gas-supply device are arranged above the furnace body. Gas outlet ends of the gas-blow pipes are oriented towards the bottom surface inside the crucible, and are distributed between the crucible center and the crucible inner side surfaces. A polysilicon material is added into the crucible; the chamber of the furnace body is closed; high vacuum is pumped, wherein a vacuum degree is lower than 0.1Pa; heating is carried out such that polysilicon is molten; crystal growth is allowed; through the gas-supply device, hot and cold protective gases are sequentially blew to the top of silicon liquid by using the gas-blow pipes, such that molten silicon is focused to the center and edge of the crucible, and protrusions are formed; solidification is carried out; the material is cooled to a required fetching temperature, and is fetched from the furnace; and the high-density impurity part is removed. With the device and the method, yield can be improved, and cost can be reduced.

Description

technical field [0001] The invention relates to a device and method for polycrystalline silicon purification and ingot casting, in particular to a device and method for separating high-impurity molten silicon by high-pressure gas blowing. Background technique [0002] In the process of polysilicon purification or ingot casting, the top silicon material is an impurity-intensive area. After the silicon ingot is solidified and formed, the impurities will diffuse from the top high-concentration area to the bottom concentration area, thereby affecting the utilization rate of the silicon ingot. After the silicon ingot is solidified and formed, due to the diffusion of impurities, the impurity area expands with time, the height of the cut also increases, and the yield decreases; the usual method is to use a professional cutting machine to cut the silicon ingot The top high impurity area is removed, and the cost of post-processing the top high impurity area is high. Contents of the...

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Problems solved by technology

[0002] In the process of polysilicon purification or ingot casting, the top silicon material is an impurity-intensive area. After the silicon ingot is solidified and formed, the impurities will diffuse from the top high-concentration area to the bottom concentration area, thereby affecting the utilization rate of the silicon ingot.

After the silicon ingot is solidified and formed, due to the diffusion of impurities, the impurity area expands with time, the height of the cut also increases, and the yield decreases; the usual method is to use a professional cutting machine to cut the silicon ingot The top high impurity area is removed, and the cost of post-processing the top high impurity area is high

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