Demonstration of ultralow bit error rates for spin-torque magnetic random-access memory with perpendicular magnetic anisotropy

Bit error rates below 10$^{-11}$ are reported for a 4-kb magnetic random access memory chip, which utilizes spin transfer torque writing on magnetic tunnel junctions with perpendicular magnetic anisotropy. Tests were performed at wafer level, and error-free operation was achieved with 10 ns write pulses for all nondefective bits during a 66-h test. Yield in the 4-kb array was limited to 99% by the presence of defective cells. Test results for both a 4-kb array and individual devices are consistent and predict practically error-free operation at room temperature.