Device and method for preparing high-quality large-diameter SiC single crystal

Abstract

The invention discloses a device and a method for preparing a high-quality large-diameter SiC single crystal, which belong to the field of SiC crystal growth, the device comprises a crucible, a thermal insulation layer, a heating device and a porous graphite barrel; wherein the crucible is positioned in the thermal insulation layer; the heating device is located on the outer side of the thermal insulation layer; the seed crystal and a porous graphite barrel are positioned in the crucible and are coaxial with the crucible; according to the invention, a transportation mode of the SiC growth components is from raw materials on the outer side of the crucible to seed crystals on the inner side of the crucible, the crystal growth process is a natural expanding process, expanding of the diameterof the crystal is not limited, meanwhile, the crystal grows along a non-polar growth face, and the penetration dislocation density is greatly reduced compared with that of the crystal growing along aC axis; C particles generated by the SiC raw material which is heated and carbonized next to the crucible wall are effectively blocked by the SiC raw material on the inner side and the porous graphitelayer, so that C inclusions in the crystal are reduced, and the quality of the crystal is effectively improved.

Description

technical field [0001] The invention relates to the field of SiC crystal growth, in particular to a high-quality and large-diameter SiC single crystal preparation device and method. Background technique [0002] In recent years, SiC has become an ideal material for making high-frequency, high-power, high-temperature-resistant and radiation-resistant devices, so the growth of high-quality SiC matrix materials has become a research hotspot. In terms of SiC single crystal growth technology, at present, physical vapor transport (PVT) is mainly used in the world to grow SiC single crystal. like figure 1 As shown, the seed crystal is fixed on the top inside the crucible, and the raw material is on the bottom inside the crucible. The induction coil surrounds the graphite crucible on the outside to heat the side wall of the graphite crucible, and the raw material at the bottom is vaporized by heat and decomposed into Si, Si 2 C, SiC 2 At this time, the raw material is in the hig...

AI Technical Summary

Problems solved by technology

At this time, the temperature at the edge of the crystal is lower, that is, a certain radial temperature gradient, but because of the lower temperature at the edge of the crystal, the sublimated SiC component is easy to nucleate at the graphite ring and other foreign materials next to the crystal. , thus growing into SiC polycrystalline, resulting in the failure of diameter expansion

Therefore, the problem of diameter expansion has always been the bottleneck hindering the growth of large-diameter SiC crystals.

At the same time, SiC grown by the traditional PVT method grows along the C-axis polar plane, while when SiC grows along the non-polar growth plane, it shows completely different growth kinetics and defect generation mechanism compared with the growth along the C-axis polar plane. The threading dislocation density is greatly reduced compared to growing along the C-axis

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