Self-supporting gallium nitride layer and preparation method thereof

Abstract

The invention provides a self-supporting gallium nitride layer and a preparation method thereof. The preparation method at least comprises the following steps: providing a substrate; forming a first gallium-containing decomposed layer, a decomposed blocking layer, a second gallium-containing decomposed layer and a graphical mask layer on the substrate in sequence, wherein a plurality of openings are formed in the graphical mask layer; carrying out thermal annealing, so that the first gallium-containing decomposed layer and the second gallium-containing decomposed layer are partially decomposed and reconstructed, and a first decomposed and reconstructed layer internally provided with a plurality of first holes, a second decomposed and reconstructed layer internally provided with a plurality of first holes and gallium nitride crystal seed layers positioned inside the openings are formed respectively; carrying out thermal growth, so that the gallium nitride crystal seed layers grow, and a gallium nitride layer is formed on the graphical mask layer; and carrying out cooling, so that the gallium nitride layer is automatically peeled off from the substrate so as to obtain the self-supporting gallium nitride layer. The preparation method is relatively low in preparation process requirement, and quick self-peeling for the gallium nitride layer can be realized, so that the self-supporting gallium nitride layer with high finished product rate can be obtained.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a self-supporting gallium nitride layer and a preparation method thereof. Background technique [0002] The third-generation semiconductor materials are also called wide-bandgap semiconductors because their energy bandgap is generally greater than 3.0 electron volts. Compared with traditional silicon-based and gallium arsenide-based semiconductor materials, wide-bandgap semiconductors (such as silicon carbide, gallium nitride, aluminum nitride, and indium nitride, etc.) have unique bandgap ranges, excellent optical and electrical properties The properties and excellent material properties can meet the working requirements of high-power, high-temperature, high-frequency and high-speed semiconductor devices, and have a wide range of applications in the automotive and aviation industries, medical care, communications, military, general lighting and semiconductor devices worki...

AI Technical Summary

Problems solved by technology

Among them, laser lift-off technology is often used to separate gallium nitride grown on sapphire substrates. However, laser lift-off has high requirements on the flatness of gallium nitride crystals, and it is not easy to lift off larger-sized gallium nitride crystals; self-lift-off technology The stress generated by the thermal mismatch acts on the specific connection between the epitaxial GaN crystal and the heterogeneous substrate to make the epitaxial layer and the template fracture and separate. However, the thermal stress generated in the existing self-stripping process often causes the nitride The gallium epitaxial layer is broken, or the epitaxial layer cannot be peeled off. The self-stripping technology has high requirements for the growth process of the gallium nitride crystal, the design and production of the patterned substrate, and the yield of a complete gallium nitride crystal obtained by self-stripping is low; Mechanical stripping is the use of mechanical grinding to remove foreign substrates. However, mechanical stripping is suitable for low hardness and fragile foreign substrates; chemical etching stripping uses chemical agents that can remove foreign substrates and are not easy to corrode gallium nitride. To remove the foreign substrate on the back, chemical stripping requires the thermal stability of the foreign substrate to be good and easy to corrode

It can be seen from the above that the laser lift-off process, the mechanical lift-off process and the chemical etching lift-off process all need to perform an additional lift-off process after the gallium nitride growth process is completed, which increases the process steps and process complexity, thereby increasing the cost. At the same time, the laser lift-off process, mechanical stripping process, and chemical etching stripping process all have strict requirements on heterogeneous substrates, and their universality is poor; although the existing self-stripping process can realize self-striping of heterogeneous substrates and gallium nitride, the stripping The quality of gallium nitride will be affected during the process, and the yield rate is low

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