Solving the BEOL compatibility challenge of top-pinned magnetic tunnel junction stacks

Abstract

For the first time, we report on 400°C compatible top-pinned perpendicular magnetic tunnel junction (MTJ) stacks with dual MgO free layer for STT-MRAM applications. Using a texture-inducing parallel-coupling barrier layer (TICPB), we enforce the pinning layer and control diffusion, which enables BEOL compatibility while keeping TMR as high as 184%. In addition, we demonstrate that using such synthetic ferro-magnetic stack (SFM) design with TICPB layer allows a free layer off-set control and a switching current of 3.8 MA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in 25 nm e-CD devices.