Gallium nitride high electron mobility transistor and preparation method and application thereof

Abstract

The invention provides a gallium nitride high-electron-mobility transistor and a preparation method and application thereof. The transistor comprises a substrate, a gallium nitride epitaxial layer, an aluminum gallium nitride barrier layer, an aluminum oxide dielectric layer, an unoxidized p-type gallium nitride layer, an oxidized p-type gallium nitride layer, a source electrode, a drain electrode and a grid electrode. The preparation method comprises the following steps: (1) forming an active region on a gallium nitride epitaxial wafer; (2) carrying out high-density oxygen plasma treatment on the device to sequentially form an oxidized p-type gallium nitride layer and an alumina dielectric layer; (3) etching the unoxidized p-type gallium nitride layer on the surface of the source and drain regions, growing metal, and respectively and independently forming a source electrode and a drain electrode; (4) performing rapid thermal annealing on the device to form ohmic contact; and (5) depositing gate metal on the surface of the unoxidized p-type gallium nitride layer to form a gate, thereby obtaining the gallium nitride high-electron-mobility transistor. According to the invention, the high-temperature and high-voltage tolerance and the electrical performance of the device are improved, and the damage caused by the etching of the p-type gallium nitride layer is avoided.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and relates to a transistor, in particular to a gallium nitride high electron mobility transistor and its preparation method and application. Background technique [0002] Materials such as gallium nitride (GaN) and silicon carbide (SiC) are called third-generation semiconductors because of their advantages in wide bandgap physical properties. Gallium nitride high electron mobility transistors (GaN HEMTs) are used in high-speed, high-temperature, It has huge potential application value in high-voltage scenarios. GaN HEMT conducts electricity through the high-concentration two-dimensional electron gas (2DEG) generated by the piezoelectric effect and polarization effect between the AlGaN epitaxial layer and the GaN layer. It has the characteristics of high mobility and small on-resistance, and the electron mobility is as high as 1500 -2000cm 2 / (V·s). [0003] The 2DEG channel of GaN HEMT...

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Problems solved by technology

[0005] At present, the device structure optimization under high temperature and high pressure conditions in this field mainly includes the following three schemes: (1) Hydrogen passivation: use hydrogen to passivate the p-GaN layer, so that hydrogen ions and Mg ions in the p-GaN layer form Mg- H bond, so as to achieve the purpose of passivating the p-GaN layer. However, due to the instability of the Mg-H bond, the hydrogen passivation method cannot achieve reliable performance under high temperature conditions, that is, this method loses the ability to withstand high temperatures ; (2) Oxygen passivation: By growing an AlN layer between the p-GaN layer and the AlGaN layer, it is convenient to control the oxidation time, but the AlN thin layer of about 1-5nm cannot improve the breakdown resistance of the device as a semiconductor material; (3) Full etching of the p-GaN layer: remove the p-GaN layer between the source, drain and gate by etching, but the difficulty of this method is to precisely control the etching depth and reduce the surface roughness after etching degree, and to avoid etching damage to the lattice caused by etching, such stable process conditions often require harsh environments and long-term debugging

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