Investigation of high threshold voltage E-mode AlGaN/GaN MIS-HEMT with triple barrier layer

A comprehensive study on an E-mode AlGaN/GaN MIS-HEMT with triple barrier layer is conducted by Silvaco TCAD software. The effect of geometric parameters of gate dielectric layer, including the length of both sides and the recessed depth, on the device is studied. The simulation results show that the optimized device can reach a high threshold voltage (from 1.24 V to 2.06 V), a large maximum drain current (from 0.925 A/mm to 1.044 A/mm), and a large gate-source capacitance (from 1837 fF/mm to 3100 fF/mm) on the condition that frequency is 1 MHz. Furthermore, based on the analysis of different combinations of the triple structural parameters, two types suitable for specific conditions are concluded, which is helpful to further improve DC and RF characteristics of E-mode AlGaN/GaN MIS-HEMT.