Pipeline for nitrogen crystal pulling and nitrogen-doping single crystal pulling process

Abstract

The invention provides a pipeline for nitrogen crystal pulling, wherein the pipeline includes an argon control pipeline and a nitrogen control pipeline. The argon control pipeline is respectively connected with a subchamber and a main chamber of a single crystal furnace. The nitrogen control pipeline is connected with the subchamber and the main chamber of the single crystal furnace. The argon control pipeline is provided with an argon intake pipeline, and the nitrogen control pipeline is provided with a nitrogen intake pipeline. The pipeline has the beneficial effects that the pipeline for nitrogen crystal pulling has simpler structure and is easy to install. Meanwhile, the pipeline structure with the structure can separate argon from nitrogen, and can control the input of nitrogen and argon respectively. The pipeline also has a flowmeter, so the input flow quantity of nitrogen and argon can be controlled from time to time, then the volume proportion of argon and nitrogen in the single crystal furnace is controlled, the furnace pressure of the single crystal furnace is ensured, and the quality of pulled single crystals is ensured.

Description

technical field [0001] The invention belongs to the technical field of Czochralski single crystal, and in particular relates to a pipeline for pulling crystal with nitrogen gas and a process for pulling a nitrogen-doped single crystal. Background technique [0002] Existing Czochralski single crystal furnaces use high-purity argon as a protective gas to pull single crystals. The industrial method for preparing high-purity argon is generally the cryogenic air separation method. The proportion of argon in the air is less than 0.93%; the gas source is scarce , high production cost. The methods for industrially preparing high-purity nitrogen include cryogenic air separation nitrogen production, pressure swing adsorption nitrogen production, and membrane separation nitrogen production. Production costs are low. If it is possible to use nitrogen instead of argon as a protective gas to pull single crystals, it will not only break the limitation of a single gas source, but also re...

AI Technical Summary

Problems solved by technology

[0003] Argon is a monoatomic molecule, a typical inert gas, and does not react with silicon during the single crystal pulling process; nitrogen is a diatomic molecule, not an inert gas, chemically inactive, and can react with certain substances at high temperatures Chemical reaction; nitrogen will not react with liquid silicon when it is above 1300°C, but it will react with solid silicon to form infusible silicon nitride, which floats on the surface of molten silicon and affects crystal formation

[0004] The existing nitrogen-doped Czochralski single crystal furnace realizes the whole process of single crystal growth equal diameter + finishing + shutdown and uses nitrogen. The added nitrogen pipeline can only supply gas to the auxiliary chamber of the single crystal furnace, and cannot realize the furnace during the isolation process. At present, only argon can be used for isolation; if the main pipes of argon and nitrogen are directly replaced under the condition that the current gas circuit structure remains unchanged, then the entire process of crystal pulling will be switched to nitrogen atmosphere; but Nitrogen will not react with liquid silicon when it is above 1300°C, but it will react with solid silicon to form infusible silicon nitride, which floats on the surface of molten silicon and affects crystallization, and in the existing technology, the process of melting alone cannot be realized Use argon, nitrogen for the rest of the stages

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