First Demonstration of High-Power GaN-on-Silicon Transistors at 40 GHz

In this letter, high-output-power-density GaN-based high-electron-mobility transistors grown on a 100-mm silicon substrate is demonstrated for the first time at 40 GHz. The use of an optimized double heterostructure based on ultrathin barrier AlN/GaN allows both high current density and low leakage current, resulting in high-frequency performance (f_max close to 200 GHz). Furthermore, the control of the trapping effects on these highly scaled devices enabled to set a first benchmark at 40 GHz with 2.5 W/mm at V_DS = 15 V, mainly limited by RF losses and thermal issues. These results show that an AlN/GaN/AlGaN heterostructure grown on silicon substrate is a viable technology for cost-effective high-power millimeter-wave amplifiers fully compatible with standard Si-based devices.