Improvement of DC Performance and RF Characteristics in GaN-Based HEMTs Using SiN[sub.x] Stress-Engineering Technique

• Published in: Nanomaterials (Basel, Switzerland) Vol. 14; no. 18
• Main Authors: Deng, Chenkai, Wang, Peiran, Tang, Chuying, Hu, Qiaoyu, Du, Fangzhou, Jiang, Yang, Zhang, Yi, Li, Mujun, Xiong, Zilong, Wang, Xiaohui, Wen, Kangyao, Li, Wenmao, Tao, Nick, Wang, Qing, Yu, Hongyu
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.09.2024
• Subjects: Chemical vapor deposition; Liquors; Methods; China
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano14181471

In this work, the DC performance and RF characteristics of GaN-based high-electron-mobility transistors (HEMTs) using the SiN[sub.x] stress-engineered technique were systematically investigated. It was observed that a significant reduction in the peak electric field and an increase in the effective barrier thickness in the devices with compressive SiN[sub.x] passivation contributed to the suppression of Fowler–Nordheim (FN) tunneling. As a result, the gate leakage decreased by more than an order of magnitude, and the breakdown voltage (BV) increased from 44 V to 84 V. Moreover, benefiting from enhanced gate control capability, the devices with compressive stress SiN[sub.x] passivation showed improved peak transconductance from 315 mS/mm to 366 mS/mm, along with a higher cutoff frequency (f [sub.t]) and maximum oscillation frequency (f [sub.max]) of 21.15 GHz and 35.66 GHz, respectively. Due to its enhanced frequency performance and improved pinch-off characteristics, the power performance of the devices with compressive stress SiN[sub.x] passivation was markedly superior to that of the devices with stress-free SiN[sub.x] passivation. These results confirm the substantial potential of the SiN[sub.x] stress-engineered technique for high-frequency and high-output power applications, which are crucial for future communication systems.