Nitrogen surface enhanced composite barrier layer gallium nitride-based heterojunction field effect transistor

Abstract

The invention provides a nitrogen surface enhanced composite barrier layer gallium nitride-based heterojunction field effect transistor, which comprises a substrate, a gallium nitride buffer layer, agallium nitride channel layer, a source electrode, a drain electrode, a grid electrode, an N+ type semiconductor layer, a passivation layer and a composite barrier layer, wherein the composite barrierlayer includes an aluminum nitride layer and a composite structure formed by a gallium nitride layer and an aluminum gallium nitride layer, and the gallium nitride layer is located below the aluminumgallium nitride layer. According to the invention, the nitrogen surface enhanced gallium nitride-based heterojunction field effect transistor is realized through the composite barrier layer structure, and the polarization strength of a channel under the gate is reduced through introducing the composite barrier layer material of aluminum gallium nitride and gallium nitride under the gate, so thatthe three-dimensional electron gas channel is depleted. When the gate voltage is increased in the positive direction, the depletion region of the channel layer under the gate is narrowed, so that thethree-dimensional electron gas channel is enabled to be opened. The field effect transistor solves the problem of nitrogen surface enhanced characteristic, has higher saturation drain current comparedwith a groove gate structure and the like, and avoids the influences such as defects caused by doping.

Description

technical field [0001] The invention relates to the epitaxial structure of microelectronic devices, in particular to the field of gallium nitride heterojunction field effect transistors. Background technique [0002] Wide bandgap gallium nitride (GaN)-based heterojunction field effect transistor (HFET) is a kind of field effect transistor, the material used is a heterojunction structure, and the two-dimensional electron gas ( 2DEG) form a conductive channel. Gallium nitride heterojunction field effect transistor has the advantages of high critical breakdown electric field, fast electron saturation speed, high thermal conductivity and excellent frequency characteristics, and has become a strong candidate for the next generation of power semiconductor devices. [0003] Nitride wurtzite structure crystals have two polarities of Ga plane and N plane, and the physical and chemical properties of different polar planes show obvious differences, so the two polarities are not equiva...

AI Technical Summary

Problems solved by technology

These two methods can effectively realize the high-threshold enhanced operation of the device, but the groove gate structure has high requirements on the etching process, and the etching damage will seriously affect the channel mobility of carriers; although the epitaxial cap layer The process is simple and controllable, and has no effect on channel mobility, but the introduction of a cap layer under the gate will inevitably reduce the gate control capability of the device, resulting in the degradation of the subthreshold characteristics of the device

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