Effect of Barrier Layer Thickness on AlGaN/GaN Double Gate MOS-HEMT Device Performance for High-Frequency Application

In this work, we have examined the effect of the AlGaN barrier layer thickness (d _b) of 0.5 μm gate length AlGaN/GaN heterostructure double gate (DG) MOS-HEMT device using 2D Atlas TCAD Silvaco simulation tools. Simulation of various important device parameters such as V_t , DIBL and also, transfer characteristics have been thoroughly analyzed with different d _b. We have also performed RF analysis to analyze the important figure of merits (FOMs) like f_T , g_m and also, gate capacitance with the variation in d _b. The drain current of the device increases with d _b while electrostatic control is decreased. After a certain limit of d _b, the short channel effect comes into play the role significantly in overall device performance. Furthermore, the threshold voltage of the device shifted towards more negative with the increase in d _b. However, with the decrease in d _b, C _gs and g_m are found to be increased as a result of the decrease in distance between the channel and gate, finally, it provides better gate control. So, the variation of d _b is the tradeoff between the electrostatic gate control and drain current. Hence, selection of d _b is significantly critical as it influences the device performance.