This work adopts interface charge engineering to fabricate normally off metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs) on an in situ SiNx/AlGaN/GaN platform using an in situ O3 treatment performed in the atomic layer deposition system. The combination of in situ SiNx passivation and an O3-treated Al2O3/AlGaN gate interface allows the device to provide an excellent breakdown voltage of 1498 V at a low specific on-resistance of 2.02 mΩ cm2. The threshold voltage is increased by 2 V by significantly compensating the net polarization charges by more than five times with O3 treatment as well as reducing the interface traps and improving the high-temperature gate stability. Furthermore, a physical model of fixed charges at the Al2O3/AlGaN interface is established based on dielectric thickness-dependent linear fitting and numerical calculations. The matched device performance and simulated energy band bending elucidate the O3-treated fixed-charge modulation mechanism, providing a practical method for producing normally off GaN MIS-HEMTs.
Interface charge engineering on an in situ SiNx/AlGaN/GaN platform for normally off GaN MIS-HEMTs with improved breakdown performance
JiaQi He, KangYao Wen, PeiRan Wang, MingHao He, FangZhou Du, Yang Jiang, ChuYing Tang, Nick Tao, Qing Wang, Gang Li, HongYu Yu; Interface charge engineering on an in situ SiNx/AlGaN/GaN platform for normally off GaN MIS-HEMTs with improved breakdown performance. Appl. Phys. Lett. 4 September 2023; 123 (10): 103502. https://doi.org/10.1063/5.0169944
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