Numerical study of 2DEG carrier density of quaternary AlInGaN-based T-gate MOSHEMT grown on UWBG-β-Ga2O3 substrate

This paper presents a numerical simulation study of an E-mode AlInGaN/AlN/GaN metal oxide semiconductor high electron mobility transistor (MOSHEMT) grown on an ultra-wide bandgap beta oxide gallium substrate (UWBG-β-Ga2O3) using the two-dimensional device simulator Silvaco-Atlas. The study investigates the influence of aluminum (x) and indium (y) concentrations and the downscaling of the AlxInyGazN barrier layer on various electrical characteristics, including polarization, 2D electron gas (2DEG) concentration, sheet charge density, threshold voltage, and Ion/Ioff ratio. The impact of introducing an AlN spacer layer is also examined. The results demonstrate that increasing the alloy composition and barrier thickness leads to significantly improved analog performance, accompanied by a reduction in the threshold voltage. Notably, an optimal 20nm-Al0.80In0.18Ga0.02N barrier grown over β-Ga2O3 substrate achieves a high 2DEG carrier density of 1.54 × 1013 cm-2, a positive threshold voltage of 1.09 V, and a higher Ion/Ioff ratio of around 5. 5 × 1012.The proposed numerical simulation model proves to be well-suited for the investigation of quaternary nitride-based MOSHEMTs grown on UWBG-β-Ga2O3 substrates, offering valuable insights prior to device manufacturing.