RF Performance Benchmark of Nanosheets, Nanowires, FinFETs, and TreeFETs

Abstract

RF array performance of stacked nanosheets, stacked nanowires, FinFETs, and TreeFETs are optimized using double-sided gate contact, contact over active-gate, and proposed hybrid layouts. The backend-of-line parasitics up to M3 are included. For the double-sided gate contact, gate resistance increases with the increasing active region width to decrease the maximum oscillation frequency. The gate vias on the active region of contact over active-gate can reduce gate resistance by providing vertical paths for small-signal gate current. Combining the advantages of double-sided gate contact and contact over active-gate, the hybrid can further reduce the gate resistance to improve the maximum oscillation frequency. FinFETs/TreeFETs with the vertical sections of the channel (fin/interbridge) stop the lateral small-signal gate current path to increase gate resistance and thus decrease the maximum oscillation frequency as compared to nanosheets and nanowires. Nanowires adopting the hybrid layout and gate length of 18nm can achieve the highest maximum oscillation frequency of 590GHz due to the lowest gate resistance, the highest electron concentration, and the best gate control.