Material Stack Design With High Tolerance to Process-Induced Damage in Domain Wall Motion Device

We have developed a three-terminal domain wall motion (DWM) device. We found that its performance was significantly degraded by ion irradiation to the DWM materials under conventional etching conditions with Ar/NH3/CO gas mixture plasma for the device fabrication. To avoid this process-induced damage (PID), we fabricated and optimized a new material stack, in which a thin Ta layer is inserted on top of the capping layer of the DWM layer We found that the new stack effectively prevented a decrease in DWM layer coercivity, an increase in the critical current, and a decrease in the switching probability owing to the high-etch selectivity of Ta. As a result, the switching property of the DWM cell was greatly improved by the newly developed DWM stacks with high tolerance to PID.