Resistive switching behaviors of a co-sputtered zinc silicate thin film (ZnO and SiO₂ targets) have been investigated. We fabricated an Ag/ZnSiO_x/highly doped n-type Si substrate device by using an RF magnetron sputter system. X-ray diffraction pattern (XRD) indicated that the Zn₂SiO₄ was formed by a post annealing process. A unique morphology was observed by scanning electron microscope (SEM) and atomic force microscope (AFM). As a result of annealing process, 50 nm sized nano clusters were formed spontaneously in 200~300 nm sized grains. The device showed a unipolar resistive switching process. The average value of the ratio of the resistance change between the high resistance state (HRS) and the low resistance state (LRS) was about 106 when the readout voltage (0.5 V) was achieved. Resistance ratio is not degraded during 50 switching cycles. The conduction mechanisms were explained by using Ohmic conduction for the LRS and Schottky emission for the HRS.

In this study, we observed current-voltage characteristics of the MIM (metal-insulator-metal) structure. The WOx material was used between metal electrodes as the oxide insulator. The structure of the Al/WOx/TiN shows bipolar resistive switching and the operating direction of the resistive switching is clockwise, which means set at negative voltage and reset at positive voltage. The set process from HRS (high resistance state) to LRS (low resistance state) occurred at - 2.6 V . The reset process from LRS to HRS occurred at 2.78 V . The on/off current ratio was about 10 and resistive switching was performed for 5 cycles in the endurance characteristics. With consecutive switching cycles, the stable Vset and Vreset were observed. The electrical transport mechanism of the device was based on the migration of oxygen ions and the current-voltage curve is following (Ohm``s Law → Trap-Controlled Space Charge Limited Current → Ohm``s Law) process in the positive voltage region.