Resistive memory switching in ultrathin TiO₂ films grown by atomic layer deposition

Electric field controlled forming free and unipolar resistive memory switching was observed in Au/TiO₂/Pt devices containing ultrathin TiO₂ films of thickness ~ 4 nm grown by atomic layer deposition. These devices showed a large resistance ratio of ~ 10³ between high and low resistance states along with appreciable time retention for ~ 10⁴ seconds and endurance. The spread of reset and set voltages was from ~ 0.4-0.6 V and 1.1-1.5 V respectively with a clear window between them. The resistive switching mechanism was explained based on conductive filamentary model.