ScAlN/GaN high-electron-mobility transistor and manufacturing method thereof

Abstract

The invention relates to an ScAlN / GaN high-electron-mobility transistor and a manufacturing method thereof, which mainly solve the problems of electric leakage and low working frequency of a homoepitaxy interface of an existing nitride microwave power device. The ScAlN / GaN high-electron-mobility transistor comprises a substrate, a nucleating layer, a GaN channel layer, an AlN insertion layer and an ScAlN barrier layer from bottom to top, wherein an InAlN cap layer is arranged between the insertion layer and the barrier layer; a barrier protection layer and an insulated gate dielectric layer are sequentially arranged at the upper part of the barrier layer, and ohmic contact regions for manufacturing a source electrode and a drain electrode are arranged on two sides from the InAlN cap layerto the insulated gate dielectric layer. A nucleating layer, a GaN channel layer, an AlN insertion layer and an InAlN cap layer in the structure are grown by adopting MOCVD; and the ScAlN barrier layerand the barrier protection layer are grown by adopting MBE. Homoepitaxial interface parasitic electric leakage is avoided, the working frequency of the device is high, the output current density is large, the manufacturing process is simple, and the transistor can be used for a high-frequency microwave power amplifier and a microwave millimeter wave integrated circuit.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices, and in particular relates to a high electron mobility transistor, which can be used for making microwave power amplifiers and microwave millimeter wave monolithic integrated circuits. Background technique [0002] GaN heterojunction materials have excellent properties such as wide bandgap, high critical breakdown field strength, high electron saturation drift velocity, and two-dimensional electron gas with high electron mobility characteristics produced by strong spontaneous and piezoelectric polarization effects. The properties of materials have been extensively studied, and they have unique advantages in the application of high-frequency, high-power, and high-efficiency solid-state microwave power devices. Since the first GaN high electron mobility transistor (HEMT) prototype device was successfully prepared in 1993, relevant researchers at home and abroad have conducted extensive...

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Problems solved by technology

[0004] One is that in the process of heteroepitaxial GaN materials, high-density dislocation defects are inevitably generated, which will form leakage channels when the device works at high voltage for a long time, reducing the breakdown voltage of the device and deteriorating reliability;

[0005] The second is that there is a large lattice mismatch and tensile strain in the AlGaN barrier layer and the GaN channel layer. When the device works at high voltage, an inverse piezoelectric effect occurs in the AlGaN barrier layer, forming lattice defects and reducing device reliability;

[0006] The third is that the two-dimensional electron gas concentration generated by the polarization effect at the AlGaN / GaN heterojunction interface is not high enough, which limits its application in the field of high-frequency and high-power devices;

[0007]Fourth, if the AlGaN barrier layer is not protected, surface states will be generated on the surface of the barrier layer, which will reduce the concentration of two-dimensional electron gas and affect the current and power output characteristics of the device

[0008] Fifth, the thick AlGaN barrier layer needs to increase the gate length to effectively control the channel two-dimensional electron gas, which limits the improvement of the operating frequency of HEMT devices

[0009] Sixth, the source-drain electrodes are made directly on the surface of the AlGaN barrier layer. The ohmic contact resistance of the source-drain region is very high, which affects the current and power output characteristics of the device.

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