Carbon-carbon composite guide cylinder of CZ silicon crystal growing furnace and preparation method thereof

Abstract

The invention discloses a carbon-carbon composite guide cylinder of a CZ silicon crystal growing furnace and a preparation method thereof. The cylinder body of the carbon-carbon composite guide cylinder of the CZ silicon crystal growing furnace consists of a surface coating, a carbon-carbon composite layer and a carbon-carbon composite central layer. The preparation method of the carbon-carbon composite guide cylinder comprises the following steps: (1) designing and manufacturing a mold of the guide cylinder; (2) designing the shape and size of carbon fiber felt and cutting and blanking according to the size; (3) preparing a blank; (4) curing the blank; (5) performing CVD densification; (6) demolding the guide cylinder and polishing the surface of the guide cylinder; (7) performing secondary CDV densification; (8) machining the end parts of the guide cylinder and finishing the rest surface of the guide cylinder; (9) subjecting the finished guide cylinder to surface anti-oxidization, anti-erosion and anti-corrosion coating processing; and (10) subjecting the guide cylinder to drying and high-temperature purification processing. The guide cylinder product of the invention has the advantages of high service reliability, long service life and convenient replacing operation; and the preparation method can improve the rate of finished crystals and reduce the energy consumption of crystal pulling by about 10 percent.

Description

technical field [0001] The invention relates to a CZ silicon crystal growth furnace guide tube and a preparation method thereof, in particular to a CZ silicon crystal growth furnace carbon-carbon composite integral guide tube and a preparation method thereof. Background technique [0002] About 85% of monocrystalline silicon is produced by CZ Czochralski method. The size of silicon crystal rods is becoming larger and larger. In order to ensure the quality of silicon crystals, save energy, and reduce carbon dioxide emissions, the thermal field of silicon crystal growth furnaces generally uses guide tubes. The guide tube mainly acts as a guide for high-temperature gas. Therefore, it is required to have good heat resistance and certain mechanical properties; There is an appropriate temperature gradient along the axial direction between the rod and the silicon liquid in the crucible. At present, the guide tube of CZ silicon crystal growth furnace is mostly a combined guide tub...

AI Technical Summary

Problems solved by technology

Due to the low strength of graphite products, poor high-temperature thermal shock performance, high thermal conductivity, and short service life, it is generally used for about 2 months, frequently replaced, and low in purity; The size of the guide tube also increases accordingly. Therefore, the material consumption of the graphite guide tube increases, the yield rate of the processing process is low, and it is easy to be damaged during transportation, handling, and use. Requirements for the performance and reliability of the draft tube

[0003] Chinese Patent Application No. 200610043187.9 discloses "Preparation method of thermal field carbon / carbon guide tube for single crystal silicon drawing furnace" and "Single crystal furnace guide tube and its production process" disclosed in No. 200810030750.8 both involve carbon / carbon composite The preparation method of the material guide tube consumes a lot of raw materials, and the service life of the prepared guide tube is also short

And 200810030750.8 discloses "single crystal furnace guide tube and its production process", in the preparation process, the surface layer and the inner layer are separated by expanded graphite paper or sulfuric acid paper as the retarding layer, so the guide tube prepared by it still has density Gradient, which affects its service life even more

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