Composite structure AlN seed crystal for PVT and preparation and application thereof

Abstract

The invention provides a composite structure AlN seed crystal for PVT, the AlN seed crystal sequentially comprises an aluminum nitride seed wafer, a back sealing film and an AlN thick film from top to bottom, the two faces of the aluminum nitride seed wafer are polished faces, and the roughness of the back face of the aluminum nitride seed wafer is smaller than 2 nm; the back sealing film is a combination of one or more layers of any one of W, Mo, Ta, WC, TaC, BN and diamond, and is formed on the back surface of the aluminum nitride seed wafer through a coating method; and the AlN thick film covers the back sealing film through a film coating method, and the thickness of the AlN thick film is 0.5-5 mm. The invention provides a method for preparing the composite-structure AlN seed crystal and application of the composite-structure AlN seed crystal in PVT epitaxial growth of an AlN crystal. The density of various defects (cracks, dislocations and air holes) can be effectively reduced, and the crystal growth quality is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor material preparation, in particular to a method for improving the quality of aluminum nitride crystals. Background technique [0002] For half a century, the development and application of the first and second-generation semiconductor electronic devices have reached their limits, and the third-generation semiconductor has attracted widespread attention in the field of modern science and technology because of its superior material properties. Aluminum nitride (AlN), as one of the representative materials of the third-generation semiconductors, has a band gap as high as 6.2eV, high breakdown field strength, high electron migration rate, and excellent thermal conductivity and radiation resistance. (LED), laser diode (LD), microwave radio frequency devices, high-temperature / high-power electronic devices are high-quality substrates, and have broad application prospects in semiconductor lighting, ...

AI Technical Summary

Problems solved by technology

Compared with homoepitaxial technology, cracks and dislocations are mainly optimized by optimizing the temperature distribution around the seed crystal and reducing the radial temperature gradient. Stress, resulting in a large number of defects such as initial dislocations

At the same time, the reduction of the radial temperature gradient will reduce the rate of crystal diameter expansion and reduce the crystal growth efficiency.

The method of reducing the internal pores of the crystal can be to strengthen the adhesion between the seed crystal and the back support and minimize the gap between them, but it cannot be avoided well, and the machining accuracy such as warpage cannot reach the level of less than microns

In addition, there is also a solution through chemical bonding, but it will affect the purity and quality of the crystal

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