Memory Switching in Aluminum-Aluminum Oxide-Aluminum Thin Film Devices

In thin (300-1500 A.) Al-Al2O3-Al films, the stable low-frequency (60 Hz) voltage-current characteristics obtained in the high-resistivity state (off-state) depended on the electrode area (A). By increasing the peak-to-peak value of the applied sinusoidal voltage beyond a certain threshold (Vth), switching to a highly conductive (20-60 ohms) state (on-state) occurred, the on-resistance (Ron) of which did not depend on A; Ron increased with increasing temperature, indicating its metallic nature. By applying a high-voltage (about 50 V) pulse (less than 5 microsec), the switch was returned to its original off-state. Since Vth did not decrease on repeated cycling, the metallic filaments were probably dissolved completely each time.--CA.