Synergistic Effect of Hybrid Polarized Spin Currents Enables Sub-Nanosecond and Energy-Efficient Field-Free Switching on a Wafer-Scale Platform

Abstract Spin–orbit torque magnetoresistive random access memory (SOT-MRAM) exhibits intrinsic potential for next-generation magnetic memory, whereas robust wafer-level field-free switching (FFS) of nanosized perpendicular magnetic tunnel junctions (pMTJ) remains a critical challenge for practical applications. Here, we present a robust FFS of 90 nm pMTJs on 300 mm wafers driven by the synergistic effect of y- and z-polarized spin currents generated at the antiferromagnetic (AFM)/nonmagnetic (NM) interface. Experimental results demonstrate that an appropriate combination of both y- and z-spin polarizations is able to significantly improve the FFS performance. 90 nm pMTJ arrays are fabricated on 300 mm wafers, where a mean tunnel magnetoresistance ratio (TMR) of 140%, an endurance of exceeding 1012 cycles, and a robust field-free SOT switching at sub-nanosecond (down to 0.2 ns) are simultaneously achieved. Robust FFS is observed at temperature up to 100 °C, and the switching polarity remains unchanged after 1T magnetic field disturbance. With the assistance of the voltage-controlled magnetic anisotropy (VCMA) effect, the switching current density is reduced by 20% and the switching energy can be as low as 0.35 pJ/bit. This work paves the way for SOT-MRAM toward commercialization.