Two-dimensional device simulation for radio frequency performance of AlGaN/GaN HEMT

In order to obtain better high frequency performance for GaN-based devices, we investigate the influence of the gate length L_g, the gate-source space L_gs, the gate-drain space L_gd, and the thickness of barrier AlGaN on frequency performance of AlGaN/GaN high electron mobility transistors (HEMTs) using silvaco TCAD simulation. Besides, the importance of Ohmic contact resistance R_c to current-gain cutoff frequency f_T is also presented by our simulation. It presents that the f_T increases dramatically with the decrease of L_g and R_c while L_gd and L_gs affect f_T lightly. Meanwhile, the optimized thickness of AlGaN barrier layer is obtained in our structure.