PERPENDICULAR SPIN TRANSFER TORQUE MEMORY (PSTTM) DEVICES WITH ENHANCED STABILITY AND METHOD TO FORM SAME

摘要

A material layer stack for a pSTTM memory device includes a magnetic tunnel junction (MTJ) stack, a oxide layer, a protective layer and a capping layer. The MTJ includes a fixed magnetic layer, a tunnel barrier disposed above the fixed magnetic layer and a free magnetic layer disposed on the tunnel barrier. The oxide layer, which enables an increase in perpendicularity of the pSTTM material layer stack, is disposed on the free magnetic layer. The protective layer is disposed on the oxide layer, and acts as a protective barrier to the oxide from physical sputter damage during subsequent layer deposition. A conductive capping layer with a low oxygen affinity is disposed on the protective layer to reduce iron-oxygen de-hybridization at the interface between the free magnetic layer and the oxide layer. The inherent non-oxygen scavenging nature of the conductive capping layer enhances stability and reduces retention loss in pSTTM devices.