Aluminum nitride self-supported substrate and preparation method thereof

Abstract

The invention provides an aluminum nitride self-supported substrate and a preparation method thereof, and relates to the technical field of semiconductors. In the case of rapidly growing a high-temperature aluminum nitride layer, an aluminum nitride material is quickly closed when not fully filling gaps between the three-dimensional island structures, thus, gaps between the three-dimensional island structures and not filled with the aluminum nitride material can form a large number of voids which can reduce the contact area between the rapidly grown high-temperature aluminum nitride layer andthe low-temperature aluminum nitride layer. Thus, the rapidly grown high-temperature aluminum nitride layer and an aluminum nitride thick film can be separated from other layers under the effect of lattice mismatch and thermal mismatch strain, thereby obtaining a self-supported substrate. The high-density and small-sized voids facilitate the release of strain to avoid surface cracking, and providea free surface with dislocation discontinuation so as to reduce the cross-dislocation density, and obtain a self-supported substrate with a very low dislocation density. The method has a simple separation process and high yield, and can realize large-scale industrialization of high-quality aluminum nitride self-supported substrates.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an aluminum nitride self-supporting substrate and a preparation method thereof. Background technique [0002] In recent years, the third-generation semiconductor material aluminum indium gallium nitride (AlInGaN) has attracted widespread attention due to its excellent properties such as high temperature resistance, radiation resistance, chemical corrosion resistance, and high luminous efficiency. It has been realized in the fields of blue and white light-emitting diodes and lasers. commercial application. However, the development of optoelectronic devices and electronic devices based on high-aluminum composition aluminum gallium nitride (AlGaN) materials is still slow, and the root cause is the lack of high-quality aluminum nitride (AlN) substrates. Since the direct synthesis of AlN single crystal requires extreme conditions of high temperature and high pressure, it is st...

AI Technical Summary

Problems solved by technology

However, the progress of optoelectronic devices and electronic devices based on high-aluminum composition aluminum gallium nitride (AlGaN) materials is still slow, the fundamental reason is the lack of high-quality aluminum nitride (AlN) substrates

Since the direct synthesis of AlN single crystal requires extreme conditions of high temperature and high pressure, it is still at the level of laboratory research. The produced AlN single crystal is small in size, poor in quality, and high in price, which seriously limits its industrial application.

At present, commercial AlN substrates are mainly grown on heterogeneous substrates such as sapphire, silicon, silicon carbide, and metal substrates. Due to the large thermal mismatch and lattice mismatch between AlN and heterogeneous substrates, at the same time The migration ability of Al atoms is weak, which leads to large strain and high density of dislocations in the AlN epitaxial layer, and the most mainstream sapphire substrate has obvious problems of poor heat dissipation in high-power devices, which will seriously affect Overall device performance

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