A method of preparing silicon carbide single crystal by using long crystal component

Abstract

The application provides a crystal growth assembly for preparing a single crystal by PVT method, comprising: a crucible and a heating device positioned above the crucible; the heating device is provided with a plurality of concentrically arranged annular heating temperature zones, so that the In the heating and / or crystal growth stage, the axial temperature gradient in the crucible is adjusted by controlling the overall heating temperature of a plurality of concentrically arranged annular heating temperature zones, and by controlling the temperature of each annular heating temperature zone in a plurality of concentrically arranged annular heating temperature zones The heating temperature regulates the radial temperature gradient in the crucible. The device for preparing silicon carbide single crystal provided by this application can control the axial temperature gradient and radial temperature gradient of the temperature field in the crucible to increase the growth rate of the crystal, ensure the stability of the crystal growth environment, and maintain a larger crystal edge diameter ladder, improve edge quality, and obtain larger silicon carbide single crystals at the same time.

Description

technical field [0001] The application belongs to the technical field of single crystal preparation devices, and in particular relates to a crystal growth component for preparing single crystals by PVT method. Background technique [0002] When using the PVT method to prepare silicon carbide single crystals, the silicon carbide seed crystal is fixed on the inner top of the crucible cover and does not move. The crucible is filled with silicon carbide crystal growth raw materials, and the decomposed gas phase of the crystal growth raw materials after sublimation condenses into crystals at the seed crystal. . [0003] However, with the growth of the crystal, the gas-phase transmission distance of the raw material is gradually shortened, and the temperature difference between the crystal growth interface and the raw material interface is gradually reduced. The growth interface is placed in a high-temperature region, which makes the temperature of the growth interface rise. The ...

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Problems solved by technology

[0003] However, with the growth of the crystal, the gas-phase transmission distance of the raw material is gradually shortened, and the temperature difference between the crystal growth interface and the raw material interface is gradually reduced. The growth interface is placed in a high-temperature region, which makes the temperature of the growth interface rise. The temperature gradient in the z-axis direction, that is, the axial temperature gradient gradually decreases, and the decrease of the axial temperature gradient will, on the one hand, lead to slower atmosphere transmission, making it difficult for the ingot to grow thicker; Meteorological composition Si in the interface region m C m As the concentration increases, the probability of interaction will also increase, and in severe cases, polymorphism will occur due to the decrease in the supersaturation of the atmosphere.

[0004] At the same time, during the SiC crystal growth process, with the growth of the crystal edge size, the radial temperature gradient gradually decreases, which leads to the acceleration of the growth rate of the edge region of the crystal. On the one hand, it is easy to produce micropipes, Polytype, edge polycrystalline and other defects, on the other hand, it is difficult to further increase the diameter of the seed crystal

[0005] Therefore, when using the PVT method to prepare silicon carbide single crystals, especially in the crystal growth stage, the instability of the axial temperature gradient and radial temperature gradient limits the improvement of the quality and size of silicon carbide single crystals

Patent CN211497869U provides a crystal annealing treatment device, by setting heaters above, below and around the crucible, so as to eliminate the stress inside the crystal and reduce the probability of crystal cracking, but this device is for the post-treatment of the crystal that has grown , cannot increase the crystal size, nor can it play a role in improving the quality of the boule

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