Modeling Methodology for Thermal Stability Factor in Spin Transfer Torque Magneto-Resistive Random Access Memories

This article presents systematic pathways to model the thermal stability factor for magneto-resistive random access memories using atomistic simulations. The model involves constraint Monte Carlo solver to estimate the change in anisotropy energy as a function of the angle of magnetization from the easy axis at real temperatures. The reported modeling methodology has been validated against the hardware (HW) data of GlobalFoundries on the 22FDX technology node. We have clearly explained the routes for proper estimation of the input parameters along with the identification of important tuning parameters in the model. The model is based on a single effective free layer approximation of the magnetic tunnel junction (MTJ) and captures the variations of the thermal stability factor with the variations in free layer thickness, the diameter of the MTJ pillars, and the processing routes.