Development and characteristic analysis of enhancement-mode recessed-gate AlGaN/GaN HEMT

• Published in: Science in China Series E: Technological Sciences Vol. 51; no. 6; pp. 784 - 789
• Main Authors: Hao, Yue, Wang, Chong, Ni, JinYu, Feng, Qian, Zhang, JinCheng, Mao, Wei
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science in China Press 01.06.2008
• Subjects: Engineering; threshold voltage; enhacement-mode high electron mobility transistors; recessed-gate; AlGaN/GaN
• ISSN: 1006-9321; 1862-281X
• DOI: 10.1007/s11431-008-0088-7

Fabrication of enhancement-mode high electron mobility transistors on AlGaN/GaN heterostructures grown on sapphire substrates is reported. These devices with 1 μm gate-length, 10 nm recessed-gate depth, 4 μm distance of source and drain exhibit a maximum drain current of 233 mA/mm at 1.5 V, a maximum transconductance of 210 mS/mm, and a threshold voltage of 0.12 V. The threshold voltage of these devices increased to 0.53 V after 500°C 5 min annealing in N 2 ambient. The saturation drain current and transconductance of 15 nm recessed-gate depth reduced compared to those of 10 nm recessed-gate depth, but the threshold voltage increased to 0.47 V. The relations between threshold voltage, controlling ability of gate and recess depth were validated by testing C-V structures on AlGaN/GaN heterostructures with different etching depth.