Gallium nitride single crystal with extremely low dislocation density and flux growth method thereof

Abstract

The invention discloses a method for growing a gallium nitride single crystal with an extremely low dislocation density by a flux process. The method comprises: setting a patterned masking film on a gallium nitride substrate; using the gallium nitride substrate as a seed crystal, and utilizing a liquid phase epitaxy method for growing to obtain a low-dislocation-density gallium nitride single crystal; and performing dislocation selective etching on the low-dislocation-density gallium nitride single crystal, performing landfilling treatment on corrosion regions to obtain a gallium nitride single crystal containing landfills, using the gallium nitride single crystal containing the landfills as a seed crystal, and utilizing a liquid phase epitaxy method for growing to obtain the gallium nitride single crystal with the extremely low dislocation density. Compared with the prior art, the method can obtain the gallium nitride single crystal with the extremely low dislocation density by a two-step method based on a flux method liquid phase epitaxial growth process, the process is simple and easy to operate, the cost is low, and the method can realize large-scale production of the gallium nitride single crystal with the extremely low dislocation density.

Description

technical field [0001] The invention relates to a method for preparing a nitride single crystal, in particular to a method for growing a very low dislocation density gallium nitride single crystal by a flux method. Background technique [0002] The growth of gallium nitride (GaN) single crystal by the flux method (Na Flux method) has many advantages, and it is currently one of the internationally recognized growth technologies that can realize the industrial production of high-quality, large-size GaN single crystal. GaN single crystal with low dislocation density is an important basic guarantee for obtaining high-performance and high-reliability GaN optoelectronic devices and microwave power devices. In the flux growth system, the dislocations in the epitaxial GaN crystal mainly come from the epitaxial substrate used in the initial growth stage. Therefore, how to effectively realize the annihilation and proliferation suppression of dislocations in the substrate during the e...

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Problems solved by technology

The seed crystal used for liquid phase epitaxy growth of gallium nitride single crystal by flux method is usually epitaxial gallium nitride on heterogeneous substrate (GaN on SiC / Al 2 o 3 ) or freestanding GaN (Freestanding-GaN), by controlling the growth conditions, GaN can be mainly grown in a three-dimensional island-like growth mode in the early stage of growth, and then the dislocations in the three-dimensional islands can be annihilated by island merging. However, this method is only suitable for high dislocation density (threading dislocation density 10 6 ~10 8 / cm 2 ) GaN substrates are effective, but not effective for GaN substrates with lower dislocation density

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