SOT-MRAM Structure With Composite Oxide Seed Layer for Read Reliability

The patent divides the read and write operations into separate paths: the write path uses the spin orbit torque line to switch magnetization, while the read path uses the magnetic tunnel junction with separate read electrodes. This segmentation prevents write current from damaging the tunnel barrier layer during read operations, resolving the contradiction between structural simplicity and read reliability.

The patent employs a composite metal oxide seed layer consisting of multiple oxide layers (e.g., MgO, AlOx, TaOx) with specific thicknesses and compositions. This composite structure provides optimized spin-current transmission, interface perpendicular magnetic anisotropy, and thermal stability, achieving improved data retention while managing the increase in device complexity through carefully engineered material composition.

The patent optimizes multiple parameters to reduce switching energy while maintaining fast switching speeds: the composite metal oxide seed layer is engineered with specific thicknesses (e.g., 1-5 nm for MgO, 2-10 nm for AlOx) and compositions to maximize spin-current transmission efficiency and interface perpendicular magnetic anisotropy. The spin orbit torque line material (e.g., Pt, Ta, W) and thickness are also optimized to minimize the current required for magnetization switching, thereby reducing energy consumption while achieving sub-nanosecond switching speeds.