Highly Uniform Bipolar Resistive Switching With Al2O3 Buffer Layer in Robust NbAlO-Based RRAM

The bipolar resistive switching characteristics of atomic-layer-deposited NbAlO-based devices have been investigated for nonvolatile memory applications. With the help of a thin Al2O3 buffer layer, highly uniform and reproducible bipolar resistance switching cycles could be observed. Four typical multilevel operations, with resistances being at 1000, 350, 145, and 75 Omega, respectively, are also successfully demonstrated by varying the current compliance during the set process. The resistance ratios of high-resistance state to low-resistance state are more than 10(3) within 5000 cycles during the test without any degradation. Moreover, the estimated retention lifetime at room temperature is sufficiently long to fulfill the typical ten-year requirement. Considering its excellent memory switching behavior, a resistance switching device composed of a NbAlO film with a thin Al2O3 buffer layer is a possible candidate to be integrated into future memory processes.