High-performance normally-off GaN field effect transistor and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor device fabrication, in particular to a high-performance normally-off GaN field effect transistor and a preparation method thereof. The device includes a substrate, an epitaxial layer, a gate dielectric layer, a gate pole, a drain pole and a source pole grown on the substrate. The epitaxial layer includes an epitaxially grown stress buffer layer and a GaN channel layer, masks are only retained in a gate region by mask patterning and etching processes, after mask residues and surface smears in an access region are removed by in-situ etching, an AlGaN/GaN heterojunction structure is grown in a selective region to form a trench channel. A gate metal covers the trench channel, both ends of the transistor form a source region and a drain region, and metals cover the source region and the drain region to form the source pole and the drain pole. The structure of the high-performance normally-off GaN field effect transistor is simple, the preparation process is simple and reliable, the in-situ etching of the access region can reduce defect impurities introduced in the access region of the transistor in a mask preparation process,thereby obtaining a high-quality access region interface and ensuring the secondary epitaxial AlGaN/GaN heterojunction structure quality so as to improve the conduction performance of the normally-off GaN field effect transistor.

Description

technical field [0001] The invention relates to the technical field of semiconductor device preparation, more specifically, to a high-performance normally-off GaN field effect transistor and a preparation method thereof. Specifically, it relates to an improved method for preparing a secondary growth interface of an access region of a recess gate normally-off GaN field effect transistor by selective region epitaxy. Background technique [0002] As a representative of the third-generation semiconductor materials, GaN has the characteristics of large band gap, high critical breakdown electric field strength, high power density and high carrier saturation velocity. GaN power switching devices can greatly increase the upper limit operating frequency while maintaining the low noise performance and high rated power of metal semiconductor field effect transistors, and have the advantages of higher operating voltage, higher power density and high temperature resistance. GaN-based de...

AI Technical Summary

Problems solved by technology

The introduction of too many impurities will deteriorate the quality of the secondary epitaxial heterostructure, reduce the two-dimensional electron gas concentration of the conductive channel in the access region, and is not conducive to the improvement of device conduction performance

Therefore, it is necessary to seek a method for optimizing the interface quality of the access region of the normally-off GaN field-effect transistor to overcome the shortcomings of introducing defect impurities into the device access region caused by the selective area growth method, so as to obtain high-performance normally-off GaN field effect transistor

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