GaN-based field effect transistor with high quality MIS structure and preparation method of GaN-based field effect transistor

Abstract

The invention belongs to the semiconductor material and device field and discloses a GaN-based field effect transistor with a high quality MIS structure and a preparation method of the GaN-based field effect transistor, in particular, a GaN MISFET device gate dielectric layer and an improvement method of a dielectric layer and GaN interface. The device includes a substrate, an epitaxial layer grown on the substrate as well as a gate electrode, a source electrode, a drain electrode and an insulating layer; the epitaxial layer includes a stress buffer layer which is formed through primary epitaxial growth, a GaN epitaxial layer as well as a second epitaxial layer and a third epitaxial layer which are grown on selective regions on the GaN epitaxial layer; a GaN/AlGaN heterostructure is formed through secondary epitaxial growth, and groove channels are formed; an AlN thin layer is formed through third epitaxial growth; the AlN thin layer is partially oxidized so as to form an AlN/oxide dielectric layer stack structure; gate metal covers the groove channels; a source electrode region and a drain electrode region are formed at two ends; and the source electrode region and the drain electrode region are covered with metal, so that the source electrode and the drain electrode can be formed. The device and preparation process of the invention are simple and reliable. With the preparation method adopted, the high quality MIS structure can be formed, and the performance of the GaN MISFET device can be improved. The preparation method can play a key role in decreasing the electric leakage of the gate electrode, decreasing the resistance of the channels and stabilizing threshold voltage.

Description

Technical field [0001] The invention relates to the technical field of semiconductor device preparation, and discloses a high-quality GaNMISFET structure and a preparation method thereof, in particular to a gate dielectric layer of a GaNMISFET device and a method for improving the interface with GaN. Background technique [0002] GaN semiconductor materials have the advantages of large forbidden band width, high breakdown electric field, high saturated electron drift speed and high thermal conductivity. GaN-based power switching devices usually use high-concentration and high-mobility two-dimensional electron gas at the AlGaN / GaN heterostructure interface to work, so that the device has the advantages of small on-resistance and fast switching speed, and becomes ideal for the next generation of power switching devices. alternatives. [0003] The realization of high-performance normally-off switching devices is an important challenge faced by GaN power electronic devices, and is cur...

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Problems solved by technology

Under different bias voltages on the gate, these interface states and defect charges will be charged and disc

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