Sol-gel based zirconium dioxide dielectrics by oxygen-annealing at low temperature for highly stable and robust flexible resistive random access memory

In this paper, flexible resistive random access memory (ReRAM) operating at 4 V with sol-gel based zirconium oxide (ZrO2) film at 200 °C is demonstrated. The memory performance of solution-processed ReRAM can be improved by utilizing oxygen-annealing, which results in high-quality metal-oxide dielectric films with suppressed oxygen vacancies. The effects of oxygen-annealing on metal-oxide bonding states are investigated to explain the origin of the improved switching performance in ReRAM. In addition, the conduction mechanism underlying the charge transport in solution-processed ReRAM by oxygen-annealing at 200 °C is investigated in a comparison to that of ReRAM annealed at 400 °C in air. The activation energy of solution-processed ReRAM is determined by an Arrhenius plot from temperature-dependent measurements in the range of 120–300 K. Finally, highly stable and robust flexible ReRAM without a passivation film against cyclic bending tests with curvature radiuses of 10 to 5 mm is demonstrated. We believe that this work provides a practical and effective approach by which to improve the device performance of ReRAM with sol-gel based metal-oxide dielectrics through oxygen-annealing at low temperature, compatible with flexible substrates.