GaN-based high-electron-mobility transistor epitaxial wafer and preparation method thereof

Abstract

The invention provides a GaN-based high-electron-mobility transistor epitaxial wafer and a preparation method thereof, and belongs to the technical field of semiconductors. The GaN-based high-electron-mobility transistor epitaxial wafer comprises a substrate, a buffer layer, a high-resistance buffer layer, a channel layer, an AlGaN barrier layer and a cap layer, wherein the buffer layer, the high-resistance buffer layer, the channel layer, the AlGaN barrier layer and the cap layer are stacked on the substrate; the cap layer comprises a first semiconductor layer and a second semiconductor layer which are stacked in sequence; the first semiconductor layer is of a P-type doped InxGa1-xN / MgN superlattice structure, wherein x is larger than 0 and is smaller than 1; the second semiconductor layer is of a P-type doped AlyGa1-yN / InzGa1zN superlattice structure, wherein y is larger than 0 and smaller than 1, and z is larger than 0 and smaller than 1. According to the epitaxial wafer, the doping concentration of Mg in the cap layer can be improved, an enhanced HEMT is formed, and meanwhile, the crystal quality of the enhanced HEMT epitaxial wafer is improved.

Description

technical field [0001] The disclosure relates to the technical field of semiconductors, in particular to a gallium nitride-based high electron mobility transistor epitaxial wafer and a preparation method thereof. Background technique [0002] HEMT (High Electron Mobility Transistor, High Electron Mobility Transistor) based on AlGaN (aluminum gallium nitride) / GaN (gallium nitride) heterostructure has high current density, critical breakdown voltage and electron mobility. The field of high temperature electronic devices has very important application value. [0003] A HEMT typically includes a chip and a source, drain, and gate located on the chip. Chips are obtained from epitaxial wafers. The structure of a gallium nitride epitaxial wafer generally includes a substrate and a buffer layer, a high-resistance buffer layer, a GaN channel layer, an AlGaN barrier layer, and a cap layer sequentially stacked on the substrate. The common heterojunction growth process for realizing ...

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Problems solved by technology

[0004] The P-type GaN cap layer is currently mainly doped with Mg, but Mg doped has the problem of being easily passivated by H, resulting in high activation energy. The ionization rate of Mg is very low, and a high doping concentration is required to achieve P-type GaN.

At the same time, due to the large lattice mismatch between the GaN layer and the silicon carbide substrate, sapphire substrate or single crystal silicon substrate, it is easy to generate stress, which makes the crystal quality of the final GaN-based epitaxial wafer grown Poor, and the crystal quality of the epitaxial wafer is poor, which will also affect the doping of Mg in the P-type GaN cap layer

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