A HIGH PERFORMANCE MTJ ELEMENT FOR CONVENTIONAL MRAM AND FOR STT-RAM AND A METHOD FOR MAKING THE SAME

摘要

A STT-RAM MTJ that minimizes spin-transfer magnetization switching current is disclosed. The MTJ has a MgO tunnel barrier layer formed with a natural oxidation process to achieve a low RA and a Fe or Fe/CoFeB/Fe free layer which provides a lower intrinsic damping constant than a CoFeB free layer. A Fe, FeB, or Fe/CoFeB/Fe free layer when formed with a MgO tunnel barrier and a CoFeB AP1 pinned layer in a MRAM MTJ stack annealed at 360°C provides a high dR/R (TMR) > 100% and a substantial improvement in read margin with a TMR/Rp_cov = 20. High speed measurement of 100 nm x 200 nm oval STT-RAM MTJs has shown a Jc0 for switching a Fe free layer is one half that for switching an amorphous Co40Fe40B20 free layer.