Experimentally Validated Gate-Lag Simulations of AlGaN/GaN HEMTs Using Fermi Kinetics Transport

• Published in: IEEE transactions on electron devices 2023-02, Vol.70 (2), p.435-442
• Main Authors: Miller, Nicholas C., Grupen, Matt, Islam, Ahmad E., Albrecht, John D., Frey, Dave, Young, Richard, Lindquist, Miles, Green, Andrew J., Walker, Dennis E., Chabak, Kelson D.
• Format: Article
• Language: English
• Subjects: AlGaN/gallium nitride (GaN) high-electron-mobility transistor (HEMT); Aluminum gallium nitrides; Capacitors; Conduction bands; Electric potential; Fermi kinetics transport (FKT); Gallium nitride; Gallium nitrides; gate lag; HEMTs; High electron mobility transistors; Kinetics; Logic gates; MODFETs; Semiconductor devices; Simulation; technology computer-aided design (TCAD); Transistors; Trapping; trapping effects; Voltage; Voltage measurement
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2022.3229291

This article presents for the first time a direct connection between gate lag observed in drain current transient measurements of gallium nitride (GaN) high-electron-mobility transistors (HEMTs) and traps located in the barrier of the transistor epitaxy. Semiclassical numerical simulations are presented using the Air Force Research Laboratory's (AFRL's) Fermi kinetics transport (FKT) solver and are validated with drain current transient measurements. Capacitance-voltage ( {C} - {V} ) and conductance-voltage ( {G} - {V} ) measurements are also presented to provide further insights into the trap location used in the FKT simulations. These simulations indicate that equivalent defects located specifically at the AlGaN barrier/GaN cap interface of an AFRL GaN HEMT with a density of 7.5\times 10^{{12}} cm−2 and positioned 1.464 eV below the GaN cap conduction band edge were the salient traps linked to the gate-lag phenomenon. The study highlights the importance of experimentally benchmarked device simulation for trapping analysis in GaN HEMTs and may provide significant insights into device engineers for mitigating trapping effects in state-of-the-art GaN technologies.