Conductivity Switching Behaviors in ZrO₂ and YSZ Films Deposited by Pulsed Laser Depositions

Abstract:

Polycrystalline ZrO2 and yttria-stablilized ZrO2 thin films have been deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition methods. Pt/ZrO2/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 106 and good endurance even after 105 times conductivity switching are observed in a typical Pt/ZrO2/Pt whose ZrO2 film has been deposited at 100 °C and an oxygen pressure of 50 mTorr. The Pt/ZrO2/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/ZrO2/Pt structure result from the 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/ZrO2/Pt capacitor structure. Moreover, a Pt/YSZ/Pt capacitor structure shows higher Conductivity than a Pt/ZrO2/Pt capacitor structure, which may result from substitution of Y3+ ions for Zr4+ ions.

• Periodical: Key Engineering Materials (Volumes 306-308)
• Pages: 1301-1306
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.306-308.1301
• Online since: March 2006
• Authors: S.H. Kim, I.S. Byun, I.R. Hwang, J.S. Choi, B.H. Park, S. Seo, Man Jong Lee, D.H. Seo, E.J. Jeoung, D.-S. Suh, Y.S. Joung, I.K. Yoo
• Keywords: Conductivity, PLD, Switching, YSZ, Zro₂

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DOI: 10.1063/1.1377617