Normally off AlGaN/GaN FinFET devices on Si substrate

A FinFET device architecture is effective in realising normally off operation in Al_xGa_(1-x)N/GaN HEMTs with low on resistance and increased gate control. This paper discuses simulation and experimental study of normally off Al_xGa_(1-x)N/GaN FinFET devices. Atlas silvaco simulator is used to carry out electrostatic simulations to demonstrate normally off operation in Al_xGa_(1-x)N/GaN FinFETs, by considering the tri-gate induced depletion effect on 2DEG. FinFET devices are fabricated with the understanding gained from simulation studies. The fin width, height and length of the fabricated device were 80 nm, 70 nm abd 1.5 μm respectively. The fabricated device exhibited a threshold voltage of 2.5 V with a maximum drain current of 260 mA/mm at a gate overdrive voltage of 2.5 V. A maximum field effect mobility of 130 cm²/Vs is achieved for the fabricated FinFET device.