Ultra-Fast SOT-MRAM Cell with STT Current for Deterministic Switching

This paper presents a spin-orbit torque magnetic random access memory (SOT-MRAM) using perpendicular-anisotropy magnetic tunnel junction (p-MTJ). In spite of conventional p-MTJ based SOT-MRAMs which need an external magnetic field to achieve a deterministic switching, the proposed cell uses a spin-torque transfer (STT) current where we show that the cell needs only two access transistors. This can solve the thermal instability, complexity and process variation sensitivity issues of the conventional SOT-MRAMs. In addition, it maintains the advantage of conventional p-MTJ based SOT-MRAMs such as ultra-fast switching and enhanced reliability of the MTJ. Our simulation results show that the proposed SOT-MRAM can achieve 3.3X and 2.8X faster and energy efficient write operation in comparison with the conventional SOT-MRAMs.