Optimization and High‐Frequency Performance Evaluation of AlGaN/GaN High‐Electron‐Mobility Transistors Aspect Ratio Scaling for Millimeter‐Wave Applications

This work presents the optimization and performance evaluation of AlGaN/GaN high‐electron‐mobility transistors (HEMT) devices through comprehensive Technology Computer‐Aided Design (TCAD) simulations. The conventional experimental device is accurately calibrated to serve as a baseline for analysis. The barrier thickness T B is analyzed from 25 to 4 nm, and energy band analysis indicated that a thickness between 25 and 7 nm is optimal for creating a strong two‐dimensional electron gas (2DEG). The analysis of sheet carrier density further supported the selection of 7 nm as the preferred T B . Simultaneously, gate length L G scaling from 250 to 100 nm is conducted to assess its impact on device performance. The optimized device achieved a peak transconductance g m of 534 mS mm −1 , an 67% improvement over the conventional design. The device also achieved a maximum cut‐off frequency f T of 74 GHz and a maximum oscillation frequency f max of 97 GHz. These results demonstrate that the optimized device structure is highly suitable for advanced communication.