Asymmetric resistive switching processes in W:AlO_x/WO_y bilayer devices

Asymmetric resistive switching processes were observed in W:AlO_x/WO_y bilayer RRAM devices. During pulse programming measurements, the RESET speed is in the range of hundreds of microseconds under -1.1 V bias, while the SET speed is in the range of tens of nanoseconds under 1.2 V bias. Electrical measurements with different pulse conditions and different temperatures were carried out to understand these significant differences in switching time. A redox reaction model in the W:AlO_x/WO_y device structure is proposed to explain this switching time difference.