Preparation process of a carbon/carbon composite material crucible for single crystal silicon furnace

Abstract

The invention discloses a preparation technology of a carbon / carbon composite material crucible for a monocrystalline silicon furnace, and the preparation technology comprises the following steps of: adopting a polyacrylonitrile nitrile base carbon fiber-woven performing body, taking mixed gas of natural gas, propylene, liquefied petroleum as a carbon source and nitrogen or argon as carrier gas, in a uniform temperature thermal field formed by a vertical pot type deposition furnace, timely switching the upper gas charging and lower gas charging of a pipeline, due to the pressure difference of the gas inside and outside the crucible, and in combination with a uniform temperature method, a differential-pressure method and a compulsive gas current method, realizing the quick densifying of the whole crucible blank body, wherein after 300-350 hours, the intensity of the crucible can reach to more than 1.6g / cm<3>, compared with the conventional free deposition technology, the preparation technology can be used for greatly shortening the deposition time, and reduces the production cost. After being mechanically machined, the crucible is used for a thermal field of the monocrystalline silicon furnace, compared with the hot isostatic pressure graphite crucible, the carbon / carbon composite material crucible has the advantages that the service life is prolonged by 3-5 times, the cost performance is obviously better than that of the graphite crucible, and the production cost and labor intensity of the monocrystalline silicon are greatly reduced.

Description

technical field [0001] The invention relates to a preparation process of a carbon / carbon composite material crucible for a single crystal silicon furnace. Background technique [0002] At present, the equipment used to prepare monocrystalline silicon is a Czochralski monocrystalline silicon furnace. The specific production process is to put high-purity polycrystalline silicon powder in a quartz crucible, and then put the quartz crucible into a graphite crucible with a heating bottom. In the monocrystalline silicon furnace, hydrogen or argon is introduced as a protective gas to heat and melt the silicon powder. The temperature is generally controlled at 1400°C-1700°C. The seed crystal of monocrystalline silicon is inserted into the melt through the guide tube. The crystal pulling rod and the crucible rotate in reverse motion, so that crystal grains are continuously precipitated in the melt of polycrystalline silicon powder, and are regularly arranged around the seed crystal a...

AI Technical Summary

Problems solved by technology

[0004] In industry, the free CVD or CVI process is generally used, that is, the preform is placed freely in the deposition furnace, the gas enters from the bottom and is discharged from the top, and the preparation density is 1.5g / cm 3 For the above carbon / carbon composite materials, the reaction time is more than 600 hours, and the relative cost is relatively high; if the combination of deposition process and impregnation process is adopted, on the one hand, the process is cumbersome, on the other hand, the obtained composite material is due to the matrix carbon structure inside the fiber. Inconsistency makes the thermophysical properties of the material itself different, which affects the life of the material