A kind of hemt epitaxial structure and preparation method thereof

Abstract

The invention discloses a HEMT epitaxial structure and a preparation method thereof, belonging to the field of semiconductor photoelectric technology. The nano-nickel layer has high material activity and can grow well on the substrate, and the AlN layer can also grow well on the nano-nickel layer. The nano-nickel layer grown directly on the substrate can play a good role in connecting the substrate and AlN. The role of the layer is conducive to improving the quality of the AlN layer grown on the nano-nickel layer. Due to the existence of multiple island structures, there is a certain slope on the island structure. When the AlN layer grows vertically on the substrate gradually toward the direction away from the first surface of the substrate, the AlN layer will simultaneously face the direction parallel to the first surface. The direction of growth is lateral. When the AlN layer grows vertically and laterally, dislocation defects in different directions will be generated in the AlN layer, and part of the dislocation defects generated during the vertical growth of the AlN layer will offset some of the dislocation defects generated during the lateral growth of the AlN layer. The reduction of defects can improve the crystal quality of the AlN layer and improve the quality of the resulting HEMT.

Description

technical field [0001] The invention relates to the field of semiconductor optoelectronic technology, in particular to a HEMT epitaxial structure and a preparation method thereof. Background technique [0002] HEMT (High Electron Mobility Transistor, High Electron Mobility Transistor) is a heterojunction field effect transistor, which is widely used in various electrical appliances. The HEMT epitaxial structure is the basis for the preparation of HEMT devices. The current HEMT epitaxial structure includes a substrate and an AlN layer, a nano-nickel layer, a GaN layer, an AlGaN barrier layer, and a GaN capping layer stacked on the substrate in sequence. The substrate can be It is silicon carbide substrate, sapphire substrate or single crystal silicon substrate. [0003] Among them, the AlN layer and the nano-nickel layer can act as a buffer between the substrate and the GaN layer, improving the quality of the GaN layer grown on the silicon carbide substrate, sapphire substra...

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Problems solved by technology

However, due to the unsatisfactory quality of the AlN layer and the nano-nickel layer grown on the substrate, the crystal quality of the finally grown GaN layer is not good enough, which affects the quality of the HEMT.

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