Excess source and drain (S/D) recess depth (T SD) variations were analyzed comprehensively as one of the most critical factors to DC/AC performances of sub 5-nm node Si-Nanosheet (NS) FETs for system-on-chip (SoC) applications. Variations of off-, on-state currents (I off , I on) in three-stacked NS channels and parasitic bottom transistor (tr pbt), gate capacitance (C gg), intrinsic switching delay time (τ d), and static power dissipation (P static) are investigated quantitatively according to the T SD variations. More S/D dopants diffuse into the tr pbt with the deeper T SD , so the I off and I on increase due to raised current flowing through the tr pbt. Especially, the I off of PFETs remarkably increases above the certain T SD (T SD,critical) compared to NFETs. Furthermore, the I on contribution of each channels having the T SD,critical is the largest at the top NS channel and the tr pbt has the ignorable I on contribution. Among the NS channels, the top (bottom) NS channel has the largest (smallest) I on contribution due to its larger (smaller) carrier density and velocity for both P-/NFETs. The C gg also increases with the deeper T SD by increasing parasitic capacitance, but fortunately, the τ d decreases simultaneously due to the larger increasing rate of the I on than that of the C gg for all SoC applications. However, the P static enormously increases with the deeper T SD , and low power application is the most sensitive to the T SD variations among the SoC applications. Comprehensive analysis of the inevitable tr pbt effects on DC/AC performances is one of the most critical indicators whether Si-NSFETs could be adopted to the sub 5-nm node CMOS technology.