Adoption of the Wet Surface Treatment Technique for the Improvement of Device Performance of Enhancement-Mode AlGaN/GaN MOSHEMTs for Millimeter-Wave Applications.

Chun Wang,Yi-Fan Tsao,Yu-Chiao Chen,Yueh-Chin Lin,Chang-Fu Dee,Edward-Yi Chang,Heng-Tung Hsu

doi:10.3390/ma14216558

Abstract

In this work, a low-power plasma oxidation surface treatment followed by Al2O3 gate dielectric deposition technique is adopted to improve device performance of the enhancement-mode (E-mode) AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOSHEMTs) intended for applications at millimeter-wave frequencies. The fabricated device exhibited a threshold voltage (Vth) of 0.13 V and a maximum transconductance (gm) of 484 (mS/mm). At 38 GHz, an output power density of 3.22 W/mm with a power-added efficiency (PAE) of 34.83% were achieved. Such superior performance was mainly attributed to the high-quality Al2O3 layer with a smooth surface which also suppressed the current collapse phenomenon.

Highlights

The quest for a high-capacity 5G network for increased data transmission requires wide bandwidth and high signal-to-noise ratio (SNR) to maintain the quality of service (QoS) of the system
Several approaches were reported for the development of E-mode devices
An imperfect layer caused by the environment pollutants, the native oxide, and the bombardment damage ical composition after applying the wet surface treatment

Summary

Introduction

The quest for a high-capacity 5G network for increased data transmission requires wide bandwidth and high signal-to-noise ratio (SNR) to maintain the quality of service (QoS) of the system. Since the spectrum below 20 GHz has been crowded with commercial applications, allocation of bandwidth wide enough to accommodate the required channel capacity is almost impossible. Successful demonstrations of the depletion-mode (D-mode) devices have been reported in [1,2,3]. Since the devices require only positive supply, the complexity of the biasing network can greatly be reduced. Fluorine plasma treatment was applied to insert negative charges into the barrier layer, resulting in a positive shift with the threshold voltage as a depletion region was formed in the 2DEG channel

Methods

Discussion

Conclusion