A kind of algan film epitaxially grown on aluminum substrate and preparation method thereof

Abstract

The invention provides an epitaxial growth AlGaN film on an aluminum substrate and a preparation method of the AlGaN film. The method comprises the following steps: (1) taking an Al substrate and carrying out annealing treatment on the surface of the Al substrate; and (2) carrying out epitaxial growth of the AlGaN film, with an Al (111) surface as an epitaxial surface, ablating a GaN target by a laser light for epitaxial growth of the AlGaN film on the Al substrate treated in the step (1). The method utilizes the advantages of Al (111): the lattice mismatch between the Al (111) substrate and the AlGaN (0002) is relatively small, is 8.9%-11.4% and is beneficial to nucleation and growth of the AlGaN material. According to the method, Al atoms in the Al substrate diffuse to crystal lattices of the GaN, so that the high-quality AlGaN film with different Al components can be simply and efficiently prepared; and the grown AlGaN film can play an important role in the manufacturing field of an ultraviolet detector, an ultraviolet LED and the like.

Description

technical field [0001] The invention relates to the field of semiconductor thin films, in particular to an AlGaN thin film epitaxially grown on an aluminum substrate and a preparation method thereof. Background technique [0002] AlGaN material has good high temperature stability, high dielectric breakdown strength, excellent mechanical strength, and the band gap can be adjusted from 3.4 to 6.2eV by changing the Al composition, thus covering the ultraviolet band with a wavelength of 365-200nm. It has important applications in ultraviolet detectors, ultraviolet LEDs and HEMTs devices. [0003] However, there are still problems in the preparation of AlGaN materials. First of all, due to the large lattice mismatch between the AlGaN epitaxially grown substrate and AlGaN, the AlGaN material grown by epitaxial growth has a high defect density; secondly, the substrate grown by epitaxial growth has low thermal conductivity, which is not conducive to AlGaN heat dissipation of the d...

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Problems solved by technology

[0003] However, there are still problems in the preparation of AlGaN materials

First of all, due to the large lattice mismatch between the AlGaN epitaxially grown substrate and AlGaN, the AlGaN material grown by epitaxial growth has a high defect density; secondly, the substrate grown by epitaxial growth has low thermal conductivity, which is not conducive to AlGaN Heat dissipation of the device

Thirdly, when AlGaN with a high Al composition is epitaxially grown by metal organic vapor phase epitaxy (MOCVD), which is a relatively common epitaxy technology at present, due to the combination of trimethylaluminum (TMAl) and NH 3 The irreversible pre-reaction between them makes it difficult for Al atoms to enter the crystal lattice, resulting in poor quality of epitaxially grown films; while using molecular beam epitaxy (MBE) to grow AlGaN, the Al crucible needs to be maintained above 720 °C, otherwise the Al crucible is easy to break ; so AlGaN epitaxial growth with controllable Al composition is also difficult

Finally, for AlGaN epitaxial growth, the bond energy of Ga-N is 2.2eV, while the bond energy of Al-N is 2.88eV, therefore, Al atoms have a larger viscosity and lower mobility than Ga atoms, making it difficult to perform Two-dimensional growth, resulting in poor quality epitaxially grown AlGaN crystals

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