A High Performance MRAM Cell Through Single Free-Layer Dual Fixed-Layer Magnetic Tunnel Junction

As technology size scales down, magnetic tunnel junctions (MTJs) as a promising technology are becoming more and more sensitive to process variation, especially in oxide barrier thickness. Process variation particularly affects the cell resistance and the critical switching current for the smaller dimensions. This article proposes an MTJ cell with one free and two pinned layers, which highly improves the process variation robustness. By employing the spin transfer torque (STT)-spin-Hall effect (SHE) switching method, our proposed MTJ cell improves the switching speed and lowers the switching power consumption. Per simulations, an MRAM cell built with the proposed MTJ cell offers up to 36% lower total power consumption, up to 32% higher write performance, and 35% higher read performance over the previous state-of-the-art MRAMs. Also, the error rate resulting from process variation is 1.4%, which is about one-tenth of the best examples reported in the literature.