A kind of gan HEMT device and preparation method

Abstract

The invention relates to the technical field of semiconductor devices, and discloses a GaN HEMT device and a preparation method thereof, including a substrate, a GaN epitaxial layer and a gate dielectric layer are sequentially arranged on the upper surface of the substrate from bottom to top, and a GaN epitaxial layer and a GaN epitaxial layer are also included. The grid, the source electrode and the drain electrode in layer contact; the gate dielectric layer includes a first gate dielectric layer and a second gate dielectric layer with different properties; a first gate groove is opened on the first gate dielectric layer, and a first gate groove is opened on the second gate dielectric layer A second gate groove is opened, and the position of the first gate groove corresponds to the position of the second gate groove; the gate includes gate metal filling the first gate groove and the second gate groove, and a gate cap arranged on the upper surface of the second dielectric layer; Source and drain electrodes are located on both sides of the gate. The present invention can effectively reduce gate parasitic capacitance and improve device frequency characteristics by providing gate grooves with steep sidewalls and double-groove structures at the corresponding positions of two gate dielectric layers with different properties.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a GaN HEMT device and a preparation method. Background technique [0002] At present, GaN HEMT (High Electron Mobility Transistor) devices have excellent power and frequency characteristics, high breakdown and low noise characteristics, and are widely used in mobile communications, radar and other fields. In order to improve the frequency characteristics of GaN HEMT devices, it is not only necessary to shorten the length of the gate, but also to reduce the parasitic parameters of the device, such as: parasitic capacitance, parasitic inductance, parasitic resistance, etc. Reducing the square resistance of the material and shortening the distance between the source electrode and the drain electrode are the main ways to reduce the parasitic resistance. When the distance between the source electrode and the drain electrode is reduced, the overlay of the gate becomes th...

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Problems solved by technology

[0003] The purpose of the embodiments of the present invention is to provide a GaN HEMT device and its preparation method, aiming to solve the problem that when the distance between the source electrode and the drain electrode of the GaN HEMT device is reduced, fluctuations in the gate overlay process lead to changes in parasitic parameters, thereby affecting the frequency characteristics of the device. , which uses the double-groove structure gate groove prepared in the gate dielectric layer to avoid parasitic parameter changes caused by gate overlay process fluctuations, thereby reducing process difficulty and improving process stability and device frequency characteristics

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