A super-large self-supporting gallium nitride single crystal and its preparation method

Abstract

The invention provides a method for preparing a super-large self-supporting gallium nitride single crystal, comprising the following steps: (1) providing a substrate; (2) forming a thin AlN layer on the upper surface of the substrate; (3) forming a thin layer of AlN on the upper surface of the substrate Forming an AlN nano-column layer on the AlN thin layer, the nano-column layer is uniformly arranged, and the direction and thickness are consistent; (4) growing a two-dimensional GaN layer with high lateral ductility on the top of the AlN nano-column layer; (5) Continuously growing a thick GaN single crystal film on the GaN layer; (6) lowering the temperature, peeling off the GaN single crystal thick film from the substrate to form a self-supporting crystal. The invention has the characteristics of low cost, high yield, and obvious stress absorption. At the same time, the size of the self-supporting gallium nitride single crystal suitable for preparation is larger, which solves the difficult problem of difficult preparation of ultra-large-sized gallium nitride single crystal.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an ultra-large self-supporting gallium nitride single crystal and a preparation method thereof. Background technique [0002] GaN is a typical representative of the third-generation wide-bandgap semiconductors. It has been widely used in semiconductor lighting, microwave power devices, and power electronic devices, showing great application prospects. The most ideal substrate for gallium nitride growth is naturally gallium nitride single crystal material. Such homoepitaxial (that is, the epitaxial layer and the substrate are the same material) can greatly improve the crystal quality of the epitaxial film and reduce the dislocation density. , Improve the working life of the device, improve the luminous efficiency, and increase the working current density of the device. However, gallium nitride single crystal growth is difficult and expensive, and large-scale homoepitaxial ...

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Problems solved by technology

[0005] However, such methods have disadvantages: 1. High cost, requiring expensive equipment and index processes such as lithography machines or MOCVD; 2. Additional equipment and processes are required, resulting in poor process control performance and reduced yield; 3. Absorbing stress The effect is not very significant

At present, the largest GaN self-supporting substrate in the industry is about 4 inches, which is far from reaching the size of heterogeneous substrates such as silicon, sapphire, and silicon carbide, such as 8 inches or even larger.

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