AINGaN base field effect transistor of high quality MIS structure and manufacturing method thereof

Abstract

The invention relates to the semiconductor device field, discloses a GaN MISFET of high quality MIS grid structure and a manufacturing method thereof and especially relates to an improved method of a MIS interface. The device comprises a substrate, an epitaxial layer, a grid dielectric layer, a source electrode, a drain electrode and a grid electrode, wherein the epitaxial layer, the grid dielectric layer, the source electrode, the drain electrode and the grid electrode are growth on the substrate. The epitaxial layer comprises a first epitaxial growth stress buffer layer, a GaN epitaxial layer and an AIN thin layer. On the epitaxial layer, an area is selected to grow a secondary epitaxial layer and a groove channel is formed. And then, the grid dielectric layer is deposited, grid metal covers the groove channel grid dielectric layer, and two ends of the grid are covered by metal so as to form the source electrode and the drain electrode. The device structure and a manufacturing technology are simple and reliable, the MIS grid interface with high quality can be formed and performance of the GaN MISFET device is increased. The method is important for reducing a channel resistance and improving a threshold voltage stability problem.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, more specifically to a high-quality GaNMISFET structure and a preparation method thereof, and in particular to an improvement method for the interface between a gate dielectric layer and GaN of a GaNMISFET device. Background technique [0002] As a representative of the third-generation wide-bandgap semiconductor materials, GaN materials have superior properties such as large bandgap width, high breakdown electric field strength, large saturated electron drift velocity, and high thermal conductivity. GaN-based power switching devices usually use two-dimensional electron gas with high concentration and high mobility at the interface of AlGaN / GaN heterostructure to work, so that the device has the advantages of small on-resistance and fast switching speed, and is very suitable for making high-power, high-frequency , High temperature power electronic devices. [0003] The realization...

AI Technical Summary

Problems solved by technology

High-quality Si / SiO can be prepared by thermal oxidation in Si-based devices 2 MIS interface structure, however, for GaN-based devices, the introduction of MIS gates adds some additional unfavorable factors, such as interface states, dielectric layer defects, etc., causing device instability problems

The quality of the GaNMIS interface obtained by the current preparation method is generally poor, resulting in a high interface state density and gate dielectric layer defects in the MIS interface system

The bulk oxide of Ga existing at the contact interface between the dielectric layer and GaN is an important factor that induces high interface states, degrades device characteristics, and affects the stability of device operation.

Images