Magnetic Stray Field Induced Variability of the Switching Characteristics of Spin-Transfer Torque Magnetic RAMs

Spintronic and Monte Carlo simulations and statistical analysis show that stray fields resulting from intracell and intercell coupling significantly impact the switching variability of spin transfer torque-magnetic random access memory (STT-MRAM) devices. It is shown that such variations can be controlled or mitigated by exploiting the exchange coupling between interlayers of the device stack. Tapering of the device sidewalls resulting from etching can also be utilized to control the variability of switching characteristics of STT-MRAMs.