Negative resistance behavior and reproducible resistance switching were found in polycrystalline TiO2 films. The TiO2 thin films were deposited on Pt/Ti/SiO2/Si substrates at room temperature by radio frequency (rf) reactive magnetron sputtering using a 4N Ti target. A PtOx layer was sputtered in the middle of the TiO2 thin films. Then, the PtOx was reduced to form Pt nanocrystals by RTN 500℃, 3min. The crystalline phase and microstructure of TiO2 thin films embedded with Pt nanoparticles were investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), Henergy-dispersive x-ray spectroscopyH (EDX), and field-emission scanning electron microscopy (FE-SEM). Electrical properties of the Pt/ TiO2- Pt nanocomposite/ Pt capacitor were measured by Keithley 4200 Semiconductor Parameter Analyzer.
Our result shows that the thin films exhibit the bipolar resistive switching characteristics. The endurance and retention properties of pure TiO2 thin films were not satisfying, and these drawbacks were greatly improved by embedding the Pt nanocrystals into the TiO2 thin films. The embedded Pt nanocrystals could effectively reduce the fluctuation of set voltage, reset voltage, set current, and reset current, especially in the case of depositing the PtOx for 1min. The retention measurement exhibits the improvement of performance with the increasing Pt nanocrystals until the case of depositing PtOx for 4min. In the case, a continuous layer of Pt was formed which affects the resistance switching and causes the I-V characteristics become abnormal. Not only both of the HRS and LRS were below 100Ω with a low ratio of HRS/ LRS, but also a bad retention was measured.
Therefore, the embedding of Pt nanocrystals with proper and uniform size could greatly improve the property of resistance switching of TiO2 thin films.

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