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

Abstract

The present disclosure provides a gallium nitride-based high electron mobility transistor epitaxial wafer and a preparation method thereof, belonging to the technical field of semiconductors. The gallium nitride-based high electron mobility transistor epitaxial wafer includes a substrate and a buffer layer, a high-resistance buffer layer, a channel layer, an AlGaN barrier layer, and a cap layer stacked on the substrate, and the cap layer includes A first semiconductor layer and a second semiconductor layer stacked in sequence, the first semiconductor layer is P-type doped In x Ga 1‑x N / MgN superlattice structure, 0<x<1, the second semiconductor layer is P-type doped Al y Ga 1‑y N / In z Ga 1‑z N superlattice structure, 0<y<1, 0<z<1. The epitaxial wafer can increase the doping concentration of Mg in the cap layer to form an enhancement type HEMT and at the same time improve the crystal quality of the enhancement type HEMT epitaxial wafer.

Description

technical field [0001] The present disclosure relates to the technical field of semiconductors, and 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. It has very important application value in the field of high temperature electronic devices. [0003] HEMTs typically include a chip and source, drain, and gate electrodes 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 implementation of ...

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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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