Resistive Switching Behaviors of HfO₂ Thin Films by Sol–Gel Spin Coating for Nonvolatile Memory Applications

In this study, we reported the fabrication of a transparent resistive random access memory device based on the Ag/HfO 2 /indium tin oxide (ITO) capacitor structure and its resistive switching characteristics. The X-ray diffraction and Fourier transform infrared spectra demonstrated that the as grown HfO 2 thin films were monoclinic in structure. The morphological analysis revealed a uniform, smooth surface morphology of the thin films. The fabricated Ag/HfO 2 /ITO memory device exhibited the characteristic of bipolar resistive switching under a consecutive dc sweeping voltage of ±2 V. The mechanism of the resistive switching in the fabricated memory device is examined on the basis of the reversible formation/rupture of the conducting filament in the oxygen-deficient HfO 2 layer.