A physics-based statistical model for reliability of STT-MRAM considering oxide variability

A physics-based statistical model considering oxide thickness (Tox) variability is proposed for evaluating the impact of time-dependent dielectric breakdown (TDDB) on the performance of spin-transfer torque magneto-resistive random access memory (STT-MRAM). The statistics of breakdown events are captured by the percolation theory, physics-based analytical model for successive break down (BD) and 1-D non-equilibrium Green's function (NEGF). Using the proposed model, we examine Tox-dependence of STT-MRAM performance distribution, such as tunneling magneto-resistance ratio (TMR) and critical current (IC). Simulation results clearly show that oxide variability needs to be taken into account for better lifetime prediction. The proposed model has been validated with experimental data.

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