Polycrystalline ZrO 2 and yttria-stabilized ZrO 2 thin films have been deposited on Pt/Ti/SiO 2/Si substrates by pulsed-laser-deposition methods. Pt/ZrO 2/Pt and Pt/YSZ/Pt capacitor structures show giant conductivity switching behaviors which can be utilized for nonvolatile memory devices, Maximum on/off ratio of 10 6 and good endurance even after 10 5 times conductivity switching are observed in a typical Pt/ZrO 2/Pt whose ZrO 2 film has been deposited at 100°C and at an oxygen pressure of 50 mTorr. The Pt/ZrO 2/Pt structure exhibits two ohmic behaviors in the low-voltage region (V < 1.4 V), depending on the value of previously applied high voltage, and Schottky-type conduction in the high-voltage region (1.4 V < V < 8,9 V), It seems that conductivity switching behaviors in our Pt/ZrO 2/Pt structure result from changes in both the Schottky barrier and the bulk conductivity controlled by applied voltages. A Pt/YSZ/Pt capacitor structure has more stable reset voltage and current state than a Pt/ZrO 2/Pt capacitor structure. Moreover, a Pt/YSZ/Pt capacitor structure shows higher conductivity than a Pt/ZrO 2/Pt capacitor structure, which may result from substitution of Y 3+ ions for Zr 4+ ions.
|Journal||Journal of the Korean Physical Society|
|Issue number||SUPPL. 2|
|State||Published - Sep 2005|