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 Lg, the gate-source space Lgs, the gate-drain space Lgd, 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 Rc to current-gain cutoff frequency fT is also presented by our simulation. It presents that the fT increases dramatically with the decrease of Lg and Rc while Lgd and Lgs affect fT lightly. Meanwhile, the optimized thickness of AlGaN barrier layer is obtained in our structure.