In this paper, we demonstrate the integration of local oxidation and metal-gate strain technologies to induce 3.3%/5.6 GPa uniaxial tensile strain/stress in 2 μm long suspended Si nanowire MOSFETs, the highest process-based stress record in MOSFETs until now, by elastic local buckling. Significant stress level modulation in the channel from 1.2 to 5.6 GPa on a single wafer is demonstrated for the first time by varying the NW width. The GAA Si NW MOSFET with 5.6 GPa uniaxial tensile stress is characterized and the electron mobility enhancement is reported.