Gallium nitride epitaxial wafer and growth method thereof

Abstract

The invention discloses a gallium nitride epitaxial wafer and a growth method thereof. The gallium nitride epitaxial wafer comprises a substrate layer, a buffer layer, a polycrystalline gallium nitride layer, a superlattice buffer layer, a single crystal gallium nitride layer and a gallium nitride epitaxial wafer, sapphire serves as the substrate layer, the buffer layer grows on the substrate layer, the polycrystalline gallium nitride layer grows on the buffer layer, and the single crystal gallium nitride layer grows on the single crystal gallium nitride layer. A superlattice buffer layer grows on the polycrystalline gallium nitride layer, the single crystal gallium nitride layer grows on the superlattice buffer layer, the thickness of the single crystal gallium nitride layer is larger than the thickness of the polycrystalline gallium nitride layer and the thickness of the superlattice buffer layer, and finally a gallium nitride epitaxial layer grows on the single crystal gallium nitride layer. The buffer layer and the polycrystalline gallium nitride layer are adopted to release stress generated by lattice mismatch, the superlattice buffer layer not only can buffer the stress, but also can improve the lattice quality, and the monocrystal gallium nitride layer can improve the quality of the gallium nitride epitaxial wafer and reduce the dislocation density, so that the high-quality gallium nitride epitaxial layer is formed.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a gallium nitride epitaxial wafer and a method for growing the epitaxial wafer. Background technique [0002] As the preparation of gallium nitride epitaxial wafers mainly relies on the epitaxial growth of gallium nitride from sapphire, while the existing epitaxial wafers are formed on sapphire substrates, although a buffer layer is formed, it can buffer the epitaxial wafers and the substrate. However, due to the lattice mismatch between GaN and sapphire substrates, a huge compressive stress is generated, and the stress cannot be fully buffered only through a buffer layer, and the existence of stress will cause warping of the epitaxial wafer. On the other hand, the single buffer layer of AlN or AlGaN makes the crystal quality of GaN not high, and the structure of the epitaxial wafer needs to be further optimized to form a high-quality epitaxial wafer structure. [0003] In summary,...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a gallium nitride epitaxial wafer and a method for growing the epitaxial wafer, which has solved the problem of low quality of the gallium nitride epitaxial wafer prepared by only one layer of buffer layer in the prior art

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