In this work, we report high breakdown characteristics of AlN/GaN/InGaN coupling channel HEMTs (CC-HEMTs) using by silicon nitride (SiN_x) passivation layer removal and backfill technique (PRB). Owing to the modulated barrier stress and blocked interface leakage path, the fabricated HEMTs exhibit excellent electrical characteristics, including a high breakdown voltage of 340 V. The small-signal measurements revealed that the current gain cutoff frequency (f_T) and maximum oscillation frequency (f_max) are 12.3 and 35.9 GHz, respectively. A high Johnson’s figure of merit (JFoM) of 4.2 THz•V is achieved, benchmark against state-of-the-art (SOA) report of existing GaN HEMTs platform. These results have proved that the great potential of AlN/GaN/InGaN CC-HEMTs with reasonable device design applied for the next generation radio frequency front-end modules (FEMs) and power conversion integrated circuits.    

AlN barrier,high breakdown field,coupling channel,Gallium nitride,HEMT