GaN-based normally-off high-electron-mobility transistor and preparation method thereof

Abstract

The invention discloses a GaN-based normally-off high-electron-mobility transistor and a preparation method thereof. The method comprises the following steps of S1, sequentially preparing a nucleatinglayer (11), a buffer layer (12) and a first high-resistance GaN layer (13) on a substrate (10); S2, preparing a graphical dielectric layer (20) on the first high-resistance GaN layer (13); S3, basedon the graphical dielectric layer (20), growing a ridge-shaped GaN layer (30) in a transverse epitaxial manner, then removing the graphical dielectric layer (20), and forming a ridge-shaped GaN template, wherein the side wall of the ridge-shaped GaN layer (30) is a crystal face or a crystal face; S4, based on the ridge-shaped GaN template, growing a ridge-shaped channel layer (31) and a ridge-shaped barrier layer (32) sequentially in an epitaxial manner, wherein the thickness of the side wall of the ridge-shaped channel layer (31) and the thickness of the side wall of the ridge-shaped barrierlayer (32) are both smaller than the thickness of a platform. According to the transistor prepared by the method, etching loss and injection damage do not exist in a channel region, the influence of the etching damage on the device performance can be effectively avoided, and the GaN-based normally-off high-electron-mobility transistor has high threshold voltage, high saturation current and low on-state resistance.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a GaN-based normally-off high electron mobility transistor and a preparation method thereof. Background technique [0002] Gallium nitride (GaN) material has material performance advantages such as wide band gap and high breakdown field strength, and its unique strong polarization effect can form high-density two-dimensional electron gas (2DEG). These characteristics make GaN very It is suitable for preparing power switching devices. GaN-based power switching devices have many advantages such as high power, high breakdown voltage, high frequency, high temperature resistance, radiation resistance, etc., and have good application prospects in power electronics, wireless base stations, radar, communications and other fields. [0003] Generally, the high electron mobility transistor based on the AlGaN / GaN structure is in the normally-on state due to the existence of 2DEG indu...

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Problems solved by technology

Each method has its own advantages and disadvantages. For example, fluorine ion treatment is inevitable to avoid implantation damage, groove gate is difficult to avoid etching damage, thin barrier threshold voltage is low, and insufficient 2DEG in the source and drain regions affects the device saturation current and on-state resistance, pn The junction gate is limited by the insufficient hole concentration of p-GaN and the threshold voltage is not high enough

Some research groups have also reported groove-shaped or inclined-plane channel devices. The groove-shaped or inclined-plane channel is formed by etching and then epitaxy, but the etching process inevitably causes certain damage, which has a greater impact on device performance.

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