Bipolar and unipolar resistive switching modes in Pt/Zn0.99Zr0.01O/Pt structure for multi-bit resistance random access memory

In this work, we report the coexistence of bipolar resistive switching (BRS) and unipolar resistive switching (URS) modes in Pt/Zn0.99Zr0.01O/Pt structure device. After the forming process, this device with URS behavior exhibits either URS mode in the same direction or BRS mode in the opposite direction during the reset process. Controllable multi-state resistances in the low and high resistance states for the BRS mode were obtained by imposing different compliance currents (Icc) and the span of voltage sweeping in the reset process (Vstop). These results suggest that our devices have high potential for the next generation of nonvolatile memory applications.