Reverse gate bias-induced degradation of AlGaN/GaN high electron mobility transistors

• Published in: Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena Microelectronics and nanometer structures processing, measurement and phenomena, 2010-09, Vol.28 (5), p.1044-1047
• Main Authors: Chang, Chih-Yang, Anderson, Travis, Hite, Jennifer, Lu, Liu, Lo, Chien-Fong, Chu, Byung-Hwan, Cheney, D. J., Douglas, E. A., Gila, B. P., Ren, F., Via, G. D., Whiting, Patrick, Holzworth, R., Jones, K. S., Jang, Soohwan, Pearton, S. J.
• Format: Article
• Language: English
• ISSN: 1071-1023; 2166-2746; 1520-8567; 2166-2754
• DOI: 10.1116/1.3491038

A threshold reverse bias of ∼ 21   V was observed leading to a sharp increase in the gate current of AlGaN/GaN high electron mobility transistors biased at low source-drain voltage (5 V). The gate current increases by one to two orders of magnitude at this bias, corresponding to an electric field strength around 1.8   MV   cm − 1 . The gate current increased by roughly five orders of magnitude after step-stressing the gate bias from 10 to 42 V in 1 V increments for 1 min at each bias. The drain current was also decreased by ∼ 20 % after this step-stress cycle. The photoluminescence and electroluminescence intensity from the semiconductor is decreased along the periphery of the gate region after stressing and transmission electron microscopy shows a thin native oxide layer under the gate and this disappears as the gate metal reacts with the underlying AlGaN.