Current transport dynamics and stability characteristics of the NiOx based gate structure for normally-off GaN HEMTs. (24th November 2022)

• Record Type: Journal Article
• Authors: Du, Yonghao; Xu, Weizong; Gong, Hehe; Ye, Jiandong; Zhou, Feng; Ren, Fangfang; Zhou, Dong; Chen, Dunjun; Zhang, Rong; Zheng, Youdou; Lu, Hai
• Is Part Of: Journal of physics. Volume 55:Number 47(2022)
• Publication Date: 2022-11-24
• Subjects: normally-off GaN HEMT -- p-NiOx -- gate current -- gate stability; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac9146
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: The application of p-type oxide typified with NiO x as cap layer in AlGaN/GaN high electron mobility transistor for normally-off operation has specific benefits, including etching free fabrication process, high hole density and elimination of Mg dopants diffusion effects. This work presents a device configuration exploration combining the p-NiO x gate cap layer and a thin AlGaN barrier layer. Calculation method for the threshold voltage has been discussed, which obtains good consistence with the experimental measurements. In addition, a nitrogen based post-annealing process was developed to improve the film stoichiometry for elevated gate controllability, realizing normally-off operation with enhanced channel conduction capability. The current transport dynamics in the gate stack as coupled with the NiO x /AlGaN interface states have also been studied, where a deep level trap was recognized in dominating the gate current characteristics and the gate stability performance under different forward gate bias conditions.