Formation and annihilation of Cu conductive filament in the nonpolar resistive switching Cu/ZrO2:Cu/Pt ReRAM

We report a ZrO₂-based resistive memory composed of a thin Cu doped ZrO₂ layer sandwiched between Pt bottom and Cu top electrode. The Cu/ZrO₂:Cu/Pt shows excellent nonpolar resistive switching behaviors, such as free-electroforming, high ON/OFF resistance ratio (10⁶), fast Set/Reset speed (50 ns/100 ns), and reliable data retention (>10 years). The temperature-dependent switching characteristics show that a metallic filamentary channel is responsible for the low resistance state. Further analysis reveals that the physical origin of this metallic filament is the nanoscale Cu conductive filament. On this basis, we propose that the set process and the reset process stem from the electrochemical reactions in the filament, in which a thermal effect is greatly involved.