GaN-based double-layer passivation groove gate enhanced MIS-HEMT device and preparation method thereof

Abstract

The invention discloses a GaN-based double-layer passivation groove gate enhanced MIS-HEMT device and a preparation method thereof.The device comprises a substrate, a nucleating layer, a buffer layer, a channel layer and a barrier layer which are sequentially arranged from bottom to top, and the two sides of the barrier layer are provided with a first isolation area and a second isolation area respectively; a drain electrode and a source electrode are arranged on the inner sides of the first isolation region and the second isolation region respectively, at least one part of the drain electrode and at least one part of the source electrode are embedded in the barrier layer, and the lower surfaces of the drain electrode and the source electrode are in contact with the channel layer; a gate region groove is formed in the barrier layer between the drain electrode and the source electrode, and the inner surface of the gate region groove and the upper surface of the barrier layer are coated with double-layer passivation layers; and a gate electrode is arranged on the double-layer passivation layer in the groove of the gate region. The insulating layer is formed in the direction perpendicular to the channel through the double passivation layers, transportation of carriers in the perpendicular direction is blocked, and the device has the advantages of being low in interface state defect density, small in PBTI effect and stable in threshold voltage.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices, in particular to a GaN-based double-layer passivation groove gate enhanced MIS-HEMT device and a preparation method thereof. Background technique [0002] High Electron Mobility Transistor (HEMT) based on AlGaN / GaN has excellent properties of high temperature resistance and high voltage resistance, and is widely used in the fields of power electronics, wireless communication and radio frequency. With the continuous improvement of device performance requirements in various application fields, there are still some gate electrode reliability problems in AlGaN / GaN-based HEMT devices that need to be solved urgently. [0003] The gate electrode of the conventional GaN-based Schottky HEMT has serious leakage, and due to the existence of a large number of dislocations and defects in the GaN material, the charges are recombined by the surface states, resulting in a serious current collapse p...

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Problems solved by technology

[0003] The gate electrode leakage of the conventional GaN-based Schottky HEMT is serious, and because there are a large number of dislocations and defects in the GaN material itself, the charge is recombined by the surface state, resulting in serious current collapse.

In order to solve this problem, it has been proposed to use Al 2 o 3 、SiN 4 The method of MIS (metal-insulator-semiconductor)-HEMT with a dielectric passivation layer such as SiO2 as the gate insulating layer, although to a certain extent suppressed the leakage of the gate electrode of the device and improved the problem of current collapse, but in the gate electrode The insulating layer dielectric below also causes certain reliability problems in the device, resulting in a decrease in the current cut-off frequency of the device, and an increase in the PBTI (positive bias temperature instability, positive bias temperature instability) effect, thus making the GaN-based MIS-HEMT device Wide application is limited

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