NiOx gate oxide for enhanced thermal stability of threshold voltage in GaN MIS-HEMTs up to 400 °C

Mritunjay Kumar; Ganesh Mainali; Vishal Khandelwal; Saravanan Yuvaraja; Manoj Kumar Rajbhar; Dhanu Chettri; Haicheng Cao; Xiao Tang; Xiaohang Li

doi:10.1063/5.0251561

NiOx gate oxide for enhanced thermal stability of threshold voltage in GaN MIS-HEMTs up to 400 °C

M Mritunjay Kumar G Ganesh Mainali (Advanced Semiconductor Laboratory, Electrical and Computer Engineering Program, CEMSE Division, King Abdullah University of Science and Technology (KAUST) 1 , Thuwal 23955-6900,) V Vishal Khandelwal (Department of Electrical and Computer Engineering, King Abdullah University of Science and Technology 2 , Thuwal 23955-6900,) S Saravanan Yuvaraja (Advanced Semiconductor Laboratory, Electrical and Computer Engineering Program, CEMSE Division, King Abdullah University of Science and Technology (KAUST) 1 , Thuwal 23955-6900,) M Manoj Kumar Rajbhar (Advanced Semiconductor Laboratory, Electrical, and Computer Engineering Program, CEMSE Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900,) D Dhanu Chettri (Advanced Semiconductor Laboratory, Electrical and Computer Engineering Program, CEMSE Division, King Abdullah University of Science and Technology (KAUST) 1 , Thuwal 23955-6900,) H Haicheng Cao (Advanced Semiconductor Laboratory, Electrical and Computer Engineering Program, CEMSE Division, King Abdullah University of Science and Technology (KAUST) 1 , Thuwal 23955-6900,) X Xiao Tang X Xiaohang Li (Advanced Semiconductor Laboratory, Electrical and Computer Engineering Program, CEMSE Division, King Abdullah University of Science and Technology (KAUST) 1 , Thuwal 23955-6900,)

Abstract

This study demonstrates the high-temperature operation of AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs) based on nickel oxide (NiOx) as an intermediate gate oxide, achieving stable performance up to 400 °C. Compared to the control sample with only an SiNx gate dielectric, the proposed device exhibited significant improvements: (1) enhanced thermally induced VTH stability, (2) a flat transconductance (gm) curve indicating improved linearity, and (3) lower and stable drain-to-source saturation voltage (VDS,sat). Notably, the ΔVTH shift for D-mode MIS-HEMT with NiOx was effectively reduced to ∼+0.4 V, compared to ∼−1.4 V in the control sample, over a temperature range from 25 to 400 °C. This improvement is attributed to hole carrier generation in the NiOx layer, which increases the depletion region and stabilizes the stored charge underneath the gate at high temperatures. This work demonstrates that the NiOx gate oxide layer significantly enhances VTH stability and linearity in GaN MIS-HEMT, ensuring reliable and stable device operation at high temperatures.

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Article Details

Journal Applied Physics Letters

Volume / Issue Vol. 126, Issue 21

Published May 26, 2025

DOI 10.1063/5.0251561

ISSN 0003-6951

Publisher American Institute of Physics

Journal Info

Applied Physics Letters

American Institute of Physics

ISSN: 0003-6951 Physical Sciences

Authors (9)

M

Mritunjay Kumar

G

Ganesh Mainali