Guide cylinder used in single crystal furnace

Abstract

The invention belongs to the field of solar photovoltaics and particularly relates to a guide cylinder used in a single crystal furnace for Czochralski silicon which is applied in the single crystal furnace. The guide cylinder comprises a cylinder body of which the diameter is gradually reduced from top to bottom and which is made of a multi-layered composite carbon fiber material, wherein the edge of the lower end opening of the cylinder body is provided with a plurality of rotatable gas adjusting devices by virtue of a plurality of adjusting parts, an outer cylinder is arranged at the outer peripheral surface of the cylinder body and a thermal-insulation space is formed between the outer cylinder and the cylinder body and is internally provided with a thermal-insulation material layer. The guide cylinder has the advantages that the gas adjusting devices are controlled by virtue of the adjusting parts to carry out guide adjustment on gas inside the cylinder body, the volatilization of latent heat of crystallization at solid-liquid interfaces of the crystals can be effectively controlled and thus the flatness of the solid-liquid interfaces is effectively maintained and meanwhile, the thermal-insulation effect of the guide cylinder is improved.

Description

technical field [0001] The invention belongs to the field of solar photovoltaics, in particular to a flow guide tube for a single crystal furnace for pulling crystal silicon, which is applied to a single crystal furnace. Background technique [0002] When the single crystal furnace draws single crystal silicon rods, the quartz crucible containing polycrystalline silicon blocks and other raw materials is placed in the graphite crucible holder above the crucible holder, heated and melted in a protective atmosphere, and after the process temperature is adjusted, the seed crystal is guided. The flow tube is inserted into the molten polysilicon liquid, rotates counterclockwise with the crucible and lifts upwards, so that the polysilicon liquid crystallizes and solidifies into single crystal silicon rods according to the order of the silicon atoms of the seed crystal. [0003] At present, the structure of the guide cylinder of the single crystal furnace is a cylindrical structure ...

AI Technical Summary

Problems solved by technology

[0004] However, in the existing structure, because the high-temperature gas flows fast in the guide tube and the flow resistance is small, the solid-liquid interface is concave to the solid side during the crystal growth process. If the depression is too large, it will cause radial inclusions. Oxygen content, resistivity, and native defects fluctuate too much, which makes the response parameter uniformity of the silicon wafer worse

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