A statistical study of magnetic tunnel junctions for high-density spin torque transfer-MRAM (STT-MRAM)

Abstract

We demonstrated a robust magnetic tunnel junction (MTJ) with a resistance-area product RA=8 ω-μm 2 that simultaneously satisfies the statistical requirements of high tunneling magnetoresistance TMR > 15σ(R p), write threshold spread σ(Vw)/<Vw> <7.1%, breakdown-to-write voltage margin over 0.5V, read-induced disturbance rate below 10 -9, and sufficient write endurance, and is free of unwanted write-induced magnetic reversal. The statistics suggest that a 64Mb chip at the 90-nm node is feasible.