AlGaN Channel High Electron Mobility Transistors with Ultra-Low Drain-Induced-Barrier-Lowering Coefficient

The conventional AlGaN/GaN high electron mobility transistor (HEMT), the AlGaN/GaN/AlGaN HEMT, and the Al_xGa_1?xN/Al_yGa_1?yN HEMT are fabricated on sapphire substrates to study the drain-induced barrier-lowering (DIBL) effect. It is found that the Al_xGa_1?xN/Al_yGa_1?yN HEMT with AlGaN channel has the lowest DIBL coefficient of 6.7 mV/V compared with the other two HEMTs. This is attributed to the best two-dimensional electron gas confinement of the Al_xGa_1?xN/Al_yGa_1?yN structure. This opinion is further confirmed by the conduction band diagrams and electron distribution calculated from the one-dimensional Poisson–Schr?dinger equation.