Exploring the impact of AlGaN barrier thickness and temperature on normally-on GaN HEMT performance

Abstract

We study varying barrier thicknesses in GaN/AlGaN HEMTs as well as the effect of temperature fluctuation on device functionality theoretically. Structures A, B, C, D, and E are designed each with barrier thickness 16 nm, 19 nm, 22 nm, 25 nm, and 28 nm respectively. The impact of barrier thickness on the surface barrier height, strain relaxation and 2DEG concentration is explained including GaN HEMT’s drain and transfer properties. At elevated temperatures, the polar-optical phonon dispersion is the predominant process. Yet, at lower temperatures, the interface-roughness (IFR) and alloy disorder dispersion both satisfactorily account for the calculated mobilities.