Gate structure, manufacturing method of gate structure, and enhanced semiconductor device

Abstract

A gate structure, a manufacturing method of the gate structure, and an enhanced semiconductor device relate to the semiconductor technology field. The gate structure includes a channel layer, a barrier layer arranged on the channel layer, a cap layer arranged on the barrier layer, and a gate electrode layer arranged on the cap layer. The cap layer has a crystal polarization orientation which is opposite to the barrier layer. A cap layer material with an opposite polarity orientation of the barrier layer is used so that an interface between the barrier layer and the cap layer has extremely strong negatively polarized charges and a conduction band energy level is bent upwardly. The conduction band energy level of the barrier layer and the channel layer is raised above a Fermi level, a two-dimensional electron gas/two-dimensional cavity gas at the interface between the barrier layer and the channel layer can be effectively exhausted so as to increase a turn-on voltage. Simultaneously, different chemical properties of different crystal polarization orientations are used to realize self-termination wet etching of a gate pattern so as to increase uniformity and repeatability of device manufacturing.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, in particular to a gate structure, a manufacturing method of the gate structure and an enhanced semiconductor device. Background technique [0002] Due to the large band gap of gallium nitride (GaN) materials, power semiconductor devices based on GaN materials can have higher breakdown voltage and higher power density than traditional silicon (Si)-based power devices; Using the inherent polarization characteristics of GaN materials, a two-dimensional electron gas channel with high concentration and high electron mobility can be formed, so it can have a higher switching frequency than traditional silicon-based power devices. AlGaN / GaN high-mobility transistors (HEMTs) with a planar structure based on GaN's high withstand voltage and high-frequency characteristics have a wide range of application requirements in the high-voltage and high-frequency fields. [0003] In the prior art, ...

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Problems solved by technology

The turn-on voltage of the device depends on the hole concentration in the p-type gate, and a higher turn-on voltage requires a higher hole concentration, but since p-GaN or p-AlGaN is usually doped with magnesium (Mg), and The doping concentration and activation rate of Mg are limited, resulting in insufficient hole concentration, which in turn leads to a low turn-on voltage of the device (less than 3V).

[0004] In device manufacturing, the patterning of the p-type gate is usually formed by ion etching. However, due to the lack of effective selective etching process between the p-GaN or p-AlGaN layer and the AlGaN layer under the gate, it is difficult to precisely control The thickness and uniformity of etching lead to non-uniform turn-on voltage and on-resistance of devices on the entire wafer, and the manufacturing process repeatability is also poor

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