Preparation method for improving quality of high electron mobility transistor epitaxial wafer

Abstract

The invention provides a preparation method for improving the quality of a high-electron-mobility transistor epitaxial wafer, and belongs to the technical field of semiconductor devices. The first AlN layer and the second AlN layer are sequentially grown on the substrate, the growth temperature of the second AlN layer is 100-300 DEG C higher than that of the first AlN layer, stress is released, and quality is improved. In the process of growing the second AlN layer, Ar is used as carrier gas for growth, plane movement of Al atoms is promoted, and the growth uniformity is improved. For the AlN film layer formed in the process of growing the second AlN layer, H2 treatment is carried out under the high temperature condition to reduce dislocation, the quality of the second AlN layer is improved, and the quality of the first AlN layer, the quality of the second AlN layer and the growing AlGaN buffer layer can also be improved. The quality improvement of the bottom layer structure can improve the quality of the high-electron-mobility transistor epitaxial wafer which finally grows continuously on the bottom layer structure.

Description

technical field [0001] The disclosure relates to the technical field of semiconductor devices, in particular to a preparation method for improving the quality of high electron mobility transistor epitaxial wafers. 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 wafer is the basis for preparing HEMT devices. The HEMT epitaxial wafer includes a substrate and an AlN layer, an AlGaN buffer layer, a GaN channel layer, an AlGaN barrier layer, and a GaN capping layer stacked on the substrate in sequence. [0003] When the AlN layer is grown on the substrate, since the Al atoms have a high surface adhesion coefficient, the surface migration ability of the Al atoms is relatively weak during the growth process of the AlN layer or the AlGaN layer with a high Al composition. Enough energy migrates to the lowest-...

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Problems solved by technology

The two adjacent three-dimensional islands that continue to grow and merge will generate tensile stress, which may cause roughness and even cracks on the surface of the epitaxial layer

The quality of the AlN layer and AlGaN buffer layer grown directly on the substrate is poor, and the poor quality of the bottom layer will lead to the quality of the final high electron mobility transistor epitaxial wafer.

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