Reduction of the Gate Leakage Current in Binary-trench-insulated Gate AlGaN/GaN High-electron-mobility Transistors

We propose a binary-trench-insulated (BTI) gate structure for reducing the gate leakage current without sacrifice of the transconductance in GaN high-electron-mobility transistors (HEMTs), and its physics-based simulation results are compared with conventional GaN HEMTs and metal-insulator-semiconductor high-electron-mobility-transistors (MIS-HEMTs) with Si3N4 insulators. The gate insulator of AlGaN/GaN BTI-HEMTs consists of two laterally contacting materials with different dielectric constants. The two parallel trench-insulators are composed of oxide and high-k dielectric materials of the same thickness and located within the AlGaN barrier layer. Simulation results clearly indicate that the gate leakage current in the proposed BTI-HEMT is significantly decreased by about two and six orders of magnitude compared to that of the conventional HEMT and MIS-HEMTs. In addition, we observe approximately 57.7% and 15.6% improvements in the maximum drain current density (I-D,I-max) and 40.8% and 65.4% improvements in the maximum transconductance (g(m,max)) at zero gate bias condition, respectively, as compared to those of the conventional-HEMTs and MIS-HEMTs.