Normally off AlGaN/GaN FinFET devices on Si substrate

Abstract

A FinFET device architecture is effective in realising normally off operation in AlxGa(1-x)N/GaN HEMTs with low on resistance and increased gate control. This paper discuses simulation and experimental study of normally off AlxGa(1-x)N/GaN FinFET devices. Atlas silvaco simulator is used to carry out electrostatic simulations to demonstrate normally off operation in AlxGa(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.