A kind of method for heterogenous growth of aln on sic seed crystal by pvt method

Abstract

The invention discloses a method for heterogeneously growing AlN on a SiC seed crystal by using a physical vapor transport method. A crucible structure including a vapor-saturated microcavity is designed, and the interior of the microcavity can be evacuated and inflated; The vapor-saturated microcavity suppresses the forward decomposition and sublimation of SiC in the initial stage and realizes the growth of AlN. The lateral sublimation of SiC in the initial stage is suppressed by the adhesive covering with weak pores, and the AlN polycrystalline spacer is gradually back-sublimated and deposited on the surface of SiC; After the sublimation of the polycrystalline spacer disappears, the Al atoms obtained by the sublimation of the AlN source powder are transported to the growth surface; The AlN binder sublimates away from the crucible area, so that the SiC is sublimated and decomposed laterally, and the SiC seed crystal layer gradually disappears, thereby obtaining an AlN seed crystal without SiC. By adopting the method of the invention, crack-free AlN seed crystals with high single crystal rate and low impurity content can be obtained.

Description

technical field [0001] The invention relates to the technical field of crystal growth, in particular to a method for heterogeneously growing AlN on a SiC seed crystal by using a physical vapor transport method (PVT method). Background technique [0002] The lattice mismatch and thermal mismatch between AlN (aluminum nitride) and high Al composition AlGaN (aluminum gallium nitride) are very small. Reduce the dislocation density of the epitaxial layer to improve the lattice quality. Therefore, AlN single crystal has become the optimal substrate for epitaxial growth of AlN and AlGaN structures to fabricate deep ultraviolet optical elements. At the same time, AlN single crystal has many excellent properties, including high breakdown field strength, high thermal conductivity, high hardness, excellent electrical properties, etc. It is one of the important substrate materials for the preparation of power electronic devices that work under extreme conditions such as high temperature...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the above-mentioned problems in the prior art, the present invention provides a new method for heterogeneously growing AlN on SiC seed crystals by physical vapor transport method (PVT method), which is a bonding method using vapor-saturated microcavity and AlN AlN powder (the main component is AlN powder, which can be sublimated similar to AlN source powder) inhibits the initial decomposition and sublimation of SiC while promoting the middle and late sublimation of SiC to prepare the growth technology of large-sized AlN seed crystals, which can significantly improve the heterogeneous growth on SiC single crystals The existing methods of obtaining AlN seed crystals with the same size have problems such as low single crystal rate of AlN seed crystals, high impurity content, poor crystal quality and cracks

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