High-temperature secondary annealing method for silicon carbide crystal

Abstract

The invention belongs to the field of silicon carbide single crystal growth, and particularly discloses a high-temperature secondary annealing method of a silicon carbide crystal. The method comprises the following steps of: loading the crystal, heating the crystal by using a sectional heating program, wherein heating to 1300-1500 DEG C is conducted in the first stage and heating to 2000 DEG C is conducted in the second stage, preserving heat and ensuring that a temperature fluctuation range is within 2000 +/-1 DEG C; conducting cooling by adopting a step cooling program, wherein cooling is conducted for 10 hours at a speed that power is reduced by 200 W per hour, and then cooling is conducted for 10 hours at a speed that the power is reduced by 400 W per hour; and decreasing the power to 0 within 10 hours, fully cooling the crystal in a crystal furnace for 24 hours, and then taking the crystal out. According to the high-temperature secondary annealing method of the silicon carbide crystal in the invention, stress can be better released and further development of the stress can be avoided by adopting the three sections of heating, heat preservation and cooling, and the temperature can be accurately controlled to meet a temperature requirement required by heat preservation through temperature control; and in a cooling stage, slow high-temperature cooling and fast low-temperature cooling are guaranteed through staged cooling, and regeneration after stress release is avoided while time is shortened.

Description

technical field [0001] The invention belongs to the field of silicon carbide single crystal growth, and in particular relates to a high-temperature secondary annealing method for silicon carbide crystals. Background technique [0002] As a third-generation wide bandgap semiconductor material, silicon carbide has the advantages of wide bandgap, high critical breakdown electric field, high thermal conductivity, high carrier saturation concentration, stable chemical properties, high hardness, and wear resistance. Silicon carbide devices are used in aviation , Aerospace exploration, nuclear energy development, petroleum, geothermal drilling exploration, automobile engine and other fields have important applications. At present, the process for growing silicon carbide single crystals is mainly physical vapor transport (PVT), which has complete equipment and mature technology, but the silicon carbide crystals grown by physical vapor transport have serious defects and many residual...

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Problems solved by technology

At present, the process for growing silicon carbide single crystals is mainly the physical vapor transport method (PVT), which has complete equipment

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