Scaln/gan high electron mobility transistor and method of making same

Abstract

The invention relates to a ScAlN / GaN high electron mobility transistor and a manufacturing method thereof, and mainly solves the problems of current leakage at the homogeneous epitaxial interface and low operating frequency of existing nitride microwave power devices. It includes a substrate, a nucleation layer, a GaN channel layer, an AlN insertion layer and a ScAlN barrier layer from bottom to top, and an InAlN cap layer is arranged between the insertion layer and the barrier layer; The barrier protection layer and the insulating gate dielectric layer are provided with ohmic contact regions for making source and drain electrodes on both sides of the InAlN cap layer to the insulating gate dielectric layer. The nucleation layer, GaN channel layer, AlN insertion layer and InAlN cap layer in this structure are grown by MOCVD; ScAlN barrier layer and barrier protection layer are grown by MBE. The invention has no parasitic leakage at the homogeneous epitaxial interface, high operating frequency of the device, high output current density and simple manufacturing process, and can be used for high-frequency microwave power amplifiers and microwave millimeter-wave integrated circuits.

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...

AI Technical Summary

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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