Multifinger embedded T-shaped gate graphene RF transistors with high ratio

Gate resistance plays a key role in determining the maximum oscillation frequency f_MAXof all radio frequency transistors. This letter presents a new graphene device structure having multiple-finger T-shaped gates embedded in the substrate. The structure possesses several advantages over conventional top gate structures, including low gate resistance, low parasitic capacitance, scalable gate dielectric, and simple interconnect wiring. With 1 V drain bias, f_MAX up to 20 GHz, and sim 25\%$-43% higher than the current gain cutoff frequency f_T, is achieved from devices with a channel length down to 250 nm.