CMOS Compatible Process Integration of SOT-MRAM with Heavy-Metal Bi-Layer Bottom Electrode and 10ns Field-Free SOT Switching with STT Assist

This paper demonstrates a CMOS compatible process integration of spin-orbit torque (SOT) device with a unique bi-layer SOT bottom electrode. An effective spin-Hall angle of 0.27, a median tunneling magneto-resistance ratio of 127% at electrical CD of 57 nm, and a 96% resistance-based MTJ yield on 300 mm scale were achieved. We experimentally validated the two-pulse field-free SOT switching scheme with spin-transfer torque assist at 10 ns. Unlike conventional field-free SOT switching schemes, the demonstrated scheme adds no complexity to process integration.