A balancing method for low Ron and high Vth normally-off GaN MISFET by preserving a damage-free thin AlGaN barrier layer

• Main Authors: Zhang, Jialin, He, Liang, Li, Liuan, Ni, Yiqiang, Que, Taotao, Liu, Zhenxin, Wang, Wenjing, Zheng, Jiexin, Huang, Yanfen, Chen, Jia, Gu, Xin, Zhao, Yawen, He, Lei, Wu, Zhisheng, Liu, Yang
• Format: Conference Proceeding
• Language: English
• Subjects: Aluminum gallium nitride; field-effect mobility; Gallium nitride; GaN MISFET; HEMTs; Logic gates; MISFETs; normally-off; Resistance; thin AlGaN barrier; threshold voltage; Wide band gap semiconductors
• ISSN: 1946-0201
• DOI: 10.1109/ISPSD.2018.8393643

Partially AlGaN recessed scheme based on selective area growth was experimentally demonstrated to improve the performance of normally-off GaN MISFET. The damage-free thin AlGaN barrier layer with lower Al-content in recessed region contributes to a positive V th shift compared with the reference one (from 1.8 V to 2.5 V). At the same time this method realizes a high peak μκΣ of 2033 cm 2 /V·s and a low gate channel sheet resistance of 519 Ω/□ (@V g = 12 V), which is a significant improvement compared with the fully recessed-gate device. The higher Al-contents AlGaN barrier layer regrown in accessed region is adopted to maintain high-conductivity 2DEG transport property. As a result, a maximum drain current of 645 mA/mm and a low on-resistance of 6.8 Ω-mni are obtained. The GaN MISFET also exhibits a low hysteresis, low gate leakage and slight current collapse. This technique could fabricate very promising normally-off GaN devices by designing thickness and Al-content of the controllable-growth thin AlGaN barrier layer.