Extremely steep switch of negative-capacitance (NC) Nanosheet (NS) GAA-FETs and FinFETs are experimentally presented with SS avg SS =22/14 mV dec and SS avg SS =38/21 mV dec, respectively. The sub-60m V/dec current magnitude of sub-60mV/dec is >4 and ∼5 decades for NC-NSGAA and NC-FinFET, respectively. Both NC-NSGAA and NC-FinFET exhibit extremely steep switch behavior due to FET scale down to nano-scale and comparable domain size of polycrystalline HZO. The dramatic current switch with steep slope is measured with only several dipole domains flipping over with gate voltage applied. The apparent Negative-DIBL and NDR (Negative Differential Resistance) are observed due to strong NC boost. The SS depends on WFin/L ratio, and W Fin < L is the solution to achieve sub-60m V/dec. The super-steep slope on current behavior still occurs after multiple DC sweep. The uniform size of each NS for stacked NC-NSGAA is an important issue to optimize the NC effect with SS =19 mV/ dec due to single TNS for capacitance matching by modeling.