Junction Design Strategy for Si Bulk FinFETs for System-on-Chip Applications Down to the 7-nm Node

DC/AC characteristics of Si bulk FinFETs including middle-of-line levels are precisely investigated using well-calibrated 3-D device simulations for system-on-chip applications. Scaling the fin widths down to 5 nm effectively enhances gate-to-channel controllability and improves RC delay, but a dramatic increase in band-to-band tunneling currents from source-to-drain does not satisfy low-power application in the 7-nm node. All lightly-doped extension regions as a solution could improve band-to-band tunneling currents and total gate capacitances because of better short-channel immunity and lower parasitic capacitances, respectively. Using systematic TCAD-based RC calculation, we suggest optimized overlap/underlap lengths in the 7-nm node FinFETs to overcome the scaling limitations.