Highly scalable STT-MRAM with 3-dimensional cell structure using in-plane magnetic anisotropy materials

Abstract

Novel spin transfer torque MRAM cells with three dimensional freelayer structures were suggested for the high density memory below 20nm technology node. By folding the freelayer to a special geometry, the 3D MTJ Cell structure retains large freelayer volume without an increase of cell foot-print, scaling down the MRAM cells even with in-plane magnetic anisotropy materials. From the micromagnetic calculation with Nudged Elastic Band (NEB) method, we confirmed the thermal stability over 60 in 3D MTJ cell with 15×30 nm2 area.