Letter | Published:

Individually addressable epitaxial ferroelectric nanocapacitor arrays with near Tb inch−2 density

Nature Nanotechnology volume 3, pages 402407 (2008) | Download Citation

Abstract

Ferroelectric materials have emerged in recent years as an alternative to magnetic and dielectric materials for nonvolatile data-storage applications1,2,3,4,5. Lithography is widely used to reduce the size of data-storage elements in ultrahigh-density memory devices6,7,8,9. However, ferroelectric materials tend to be oxides with complex structures that are easily damaged by existing lithographic techniques, so an alternative approach is needed to fabricate ultrahigh-density ferroelectric memories. Here we report a high-temperature deposition process that can fabricate arrays of individually addressable metal/ferroelectric/metal nanocapacitors with a density of 176 Gb inch−2. The use of an ultrathin anodic alumina membrane as a lift-off mask makes it possible to deposit the memory elements at temperatures as high as 650 °C, which results in excellent ferroelectric properties.

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Acknowledgements

H. Han is grateful for the award of a fellowship of the German Academic Exchange Service (DAAD) and for support by DFG and KRF. Financial support from the Volkswagen Foundation (Project I/80897) and partly from the Brain Korea 21 Program is also acknowledged. We are thankful to S. Swatek and N. Schammelt for TEM sample preparation. We also thank R. Hillebrand for discussions on statistical analyses for the size distribution and 2D ordering of ferroelectric nanocapacitors.

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Affiliations

  1. Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle, Germany

    • Woo Lee
    • , Andriy Lotnyk
    • , Markus Andreas Schubert
    • , Stephan Senz
    • , Marin Alexe
    • , Dietrich Hesse
    •  & Ulrich Gösele
  2. Department of Materials Science & Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, 790-784 Pohang, Korea

    • Hee Han
    •  & Sunggi Baik
  3. Korea Research Institute of Standards and Science (KRISS), Yuseong, 305-340 Daejon, Korea

    • Woo Lee

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Correspondence to Woo Lee.

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DOI

https://doi.org/10.1038/nnano.2008.161

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