Epitaxial wafer, epitaxial wafer growth method and high electron mobility transistor

Abstract

The invention provides an epitaxial wafer, an epitaxial wafer growth method and a high electron mobility transistor, the epitaxial wafer comprises a Si substrate, an AlN nucleating layer, a high-resistance buffer layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer and a GaN cap layer which are stacked in sequence, the high-resistance buffer layer comprises a first carbon-doped AlGaN layer, a second carbon-doped AlGaN layer and a third carbon-doped AlGaN layer which are stacked in sequence, and the first carbon-doped AlGaN layer, the second carbon-doped AlGaN layer and the third carbon-doped AlGaN layer are stacked in sequence. The first carbon-doped AlGaN layer is arranged on one side close to the AlN nucleating layer; wherein the doping concentration of the first carbon-doped AlGaN layer is uniformly and gradually changed from high to low, the doping concentration of the second carbon-doped AlGaN layer is constant, and the doping concentration of the third carbon-doped AlGaN layer is uniformly and gradually changed from low to high. Compared with the prior art, the epitaxial wafer provided by the invention not only can realize high resistance, but also has very high crystal quality.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an epitaxial wafer, an epitaxial wafer growth method and a high electron mobility transistor. Background technique [0002] As a third-generation semiconductor material, GaN-based materials have the advantages of large band gap, high electron saturation drift speed, good chemical stability, radiation resistance and high temperature resistance, and easy formation of heterojunctions. , The material of choice for radiation-hardened High Electron Mobility Transistor (HEMT) structures. On the other hand, due to the high carrier concentration and electron mobility of GaN-based heterostructures, its on-resistance is small, and the advantages of its large band gap make it able to withstand high operating voltages. Therefore, GaN-based high electron mobility transistors are also suitable for applications such as high-temperature, high-frequency, high-power devices, and low-loss sw...

AI Technical Summary

Problems solved by technology

However, since the oxygen atoms decomposed from the oxide (such as SiO2) contained on the surface of the Si substrate at high temperature will diffuse to the buffer layer during the growth of the epitaxial layer, the buffer layer will leak, and high resistance cannot be achieved, which will reduce the performance of the device and approach the The two-dimensional electron gas concentration in the channel layer is relatively high, and it is easy to overflow to the buffer layer, which also makes the buffer layer unable to achieve high resistance.

[0004] In order to solve the above problems, in the prior art, the buffer layer is usually doped with high concentration of Fe or C to achieve high resistance and reduce the leakage of the buffer layer, but the high concentration of doping affects the crystal quality of the epitaxial layer. It is not conducive to the improvement of device performance, and although low-concentration doping can improve the crystal quality of the epitaxial layer, it is difficult to achieve high resistance

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