Fabrication of normally-off AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors by photo-electrochemical gate recess etching in ionic liquid

• Published in: Applied physics express Vol. 9; no. 8; pp. 84102 - 84104
• Main Authors: Zhang, Zhili, Qin, Shuangjiao, Fu, Kai, Yu, Guohao, Li, Weiyi, Zhang, Xiaodong, Sun, Shichuang, Song, Liang, Li, Shuiming, Hao, Ronghui, Fan, Yaming, Sun, Qian, Pan, Gebo, Cai, Yong, Zhang, Baoshun
• Format: Journal Article
• Language: English
• Published: The Japan Society of Applied Physics 01.08.2016
• ISSN: 1882-0778; 1882-0786
• DOI: 10.7567/APEX.9.084102

We characterized an ionic liquid (1-butyl-3-methylimidazolium nitrate, C8H15N3O3) as a photo-electrochemical etchant for fabricating normally-off AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs). Using the ionic liquid, we achieved an etching rate of ∼2.9 nm/min, which is sufficiently low to facilitate good etching control. The normally-off AlGaN/GaN MIS-HEMT was fabricated with an etching time of 6 min, with the 20 nm low-pressure chemical vapor deposition (LPCVD) silicon nitride (Si3N4) gate dielectric exhibiting a threshold voltage shift from −10 to 1.2 V, a maximum drain current of more than 426 mA/mm, and a breakdown voltage of 582 V.