Operational Improvement of AlGaN/GaN High Electron Mobility Transistor by an Inner Field-Plate Structure

Hyeon-Tak Kwak,Kyu-Won Jang,Sang-Heung Lee,Hyun-Jung Kim,Hyung Yoon,Jong-Won Lim,Seung-Bo Chang,Hyun-Seok Kim

doi:10.3390/app8060974

Abstract

In this study, a high-performance AlGaN/GaN high electron mobility transistor (HEMT) is presented to improve its electrical operation by employing an inner field-plate (IFP) structure. Prior to the IFP structure analysis, we compared the measured and simulated direct current characteristics of the fabricated two-finger conventional T-shaped gate HEMTs. Then, the AlGaN/GaN HEMT with a drain-side field plate (FP) structure was suggested to enhance the breakdown voltage characteristics. The maximum breakdown voltage recorded with a 0.8 μm stretched FP structure was 669 V. Finally, the IFP structure was interfaced with the gate head of the device to compensate the radio frequency characteristics, choosing the optimum length of the drain-side FP structure. Compared to the 0.8 μm stretched FP structure, the IFP structure showed improved frequency characteristics with minimal difference to the breakdown voltage. The frequency variation caused by changing the passivation thickness was also analyzed, and the optimum thickness was identified. Thus, IFP AlGaN/GaN HEMT is a promising candidate for high-power and high-frequency applications.

Highlights

Gallium Nitride (GaN) is widely used for wireless telecommunications and radar systems because of its superior material and electronic properties, such as wide bandgap (3.4 eV) and high breakdown field (2–3.3 MV/cm) [1,2,3]
High electron mobility transistors (HEMTs) based on the AlGaN/GaN heterostructure show excellent performance owing to the two-dimensional electron gas (2-DEG) in the channel region
The AlGaN/GaN heterostructure was grown on a (111) silicon substrate by metal-organic chemical vapor deposition. It consists of a 2-μm-thick acceptor-doped GaN buffer layer, a 100-nm-thick i-GaN

Summary

Introduction

Gallium Nitride (GaN) is widely used for wireless telecommunications and radar systems because of its superior material and electronic properties, such as wide bandgap (3.4 eV) and high breakdown field (2–3.3 MV/cm) [1,2,3]. These characteristics make GaN more practicable for high-voltage and high-temperature applications than many other materials, such as silicon or gallium arsenide [4]. High electron mobility transistors (HEMTs) based on the AlGaN/GaN heterostructure show excellent performance owing to the two-dimensional electron gas (2-DEG) in the channel region. For class A HEMT operation [8,9,10], the AC maximum power (P) is described in Equation (1), P=

Methods

Discussion

Conclusion