Single-nanometer CoFeB/MgO magnetic tunnel junctions with high-retention and high-speed capabilities

Abstract

Making magnetic tunnel junctions (MTJs) smaller while meeting performance requirements is critical for future electronics with spin-transfer torque magnetoresistive random access memory (STT-MRAM). However, it is challenging in the conventional MTJs using a thin CoFeB free layer capped with an MgO layer because of increasing difficulties in satisfying the required data retention and switching speed at smaller scales. Here we report single-nanometer MTJs using a free layer consisting of CoFeB/MgO multilayers, where the number of CoFeB/MgO interfaces and/or the CoFeB thicknesses are engineered to tailor device performance to applications requiring high-data retention or high-speed capability. We fabricate ultra-small MTJs down to 2.0 nm and show high data retention (over 10 years) and high-speed switching at 10 ns or below in sub-5-nm MTJs. The stack design proposed here proves that ultra-small CoFeB/MgO MTJs hold the potential for high-performance and high-density STT-MRAM.

Advanced Modeling and Simulation of Multilayer Spin–Transfer Torque Magnetoresistive Random Access Memory with Interface Exchange Coupling

“…This structure typically includes a CoFeB reference layer (RL) and a free layer (FL), separated by a MgO tunnel barrier (TB) or a non-magnetic spacer (NMS). These components are instrumental in achieving high-density memory cells through enhanced perpendicular magnetic anisotropy [7,8] and reduced cell diameters [9,10]. Such advancements are pivotal in the miniaturization of memory cells, aligning with the trend toward higher density and efficiency in memory technologies.…”