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 mu m 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 db 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.