Stack gate enhanced GaN high-electron-mobility transistor containing ferroelectric gate dielectric and preparation method

Abstract

The invention discloses a stack gate enhanced GaN high-electron-mobility transistor containing a ferroelectric gate dielectric, which mainly solves a problem of poor reliability of the existing similar devices. The stack gate enhanced GaN high-electron-mobility transistor comprises a substrate, an AlN nucleation layer, a GaN buffer layer, an AlN insertion layer, an AlGaN barrier layer, a GaN cap layer, an SiN passivation layer, a gate dielectric layer and an SiN protection layer from the bottom up, wherein the SiN passivation layer is provided with a concave structure, the inner wall of the concave structure and the surface of the SiN passivation layer are provided with the gate dielectric layer, the gate dielectric layer comprises an AlN or Al2O3 dielectric insertion layer and an HfZrO ferroelectric layer, two ends of the GaN buffer layer are provided with a source electrode and a drain electrode respectively, the middle of the gate dielectric layer is provided with a gate electrode, the source electrode and the drain electrode are provided with a metal interconnection layer, and the gate electrode and the gate dielectric layer at the surface of the passivation layer are covered with the SiN protection layer. According to the invention, the reliability of the device is improved, gate leakage of the enhanced device is reduced, and the transistor can be used as a switching device requiring high threshold voltage.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and in particular relates to a method for preparing a laminated gate enhanced GaN high electron mobility transistor, which can be used as a switching device requiring a relatively large threshold voltage. Background technique [0002] GaN has the characteristics of large band gap, high critical field strength, high thermal conductivity, high carrier saturation rate, etc., and is widely used in high temperature, high frequency and microwave power devices. The high two-dimensional electron gas density and high electron mobility in the AlGaN / GaN heterostructure make it have a very good application prospect in high-power microwave devices. [0003] Due to the high two-dimensional electron gas density, AlGaN / GaN are usually depletion devices, showing normally-on characteristics. From the perspective of simplifying circuit design and safety, enhanced devices have better potential. As a power...

AI Technical Summary

Problems solved by technology

Whether it is groove etching or fluorine ion implantation, it will cause a certain degree of damage to devices and materials.

Although the damage can be reduced or repaired by some methods, it cannot be completely eliminated. The damage caused by etching and ion implantation will affect the characteristics and reliability of the device to a certain extent.

[0010] Secondly, the controllability of the threshold is poor

Since the etching rate and the dose of fluorine ion implantation do not have a stable corresponding relationship with the threshold, the repeatability of the process is not good, and the controllability of the threshold is poor.

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