Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Origin of the dielectric dead layer in nanoscale capacitors


Capacitors are a mainstay of electronic integrated circuits and devices, where they perform essential functions such as storing electrical charge, and blocking direct current while allowing alternating currents to propagate. Because they are often the largest components in circuits, extensive efforts are directed at reducing their size through the use of high-permittivity insulators such as perovskite-structure SrTiO3 (refs 1, 2), which should provide more capacitance per unit area of device. Unfortunately, most experiments on thin-film SrTiO3 capacitors have yielded capacitance values that are orders of magnitude smaller than expected3. The microscopic origin of this reduced capacitance, which is often discussed in terms of a low-permittivity interfacial ‘dead layer’4, is not well understood. Whether such a dead layer exists at all, and if so, whether it is an intrinsic property of an ideal metal–insulator interface or a result of processing issues such as defects and strains, are controversial questions. Here we present fully ab initio calculations of the dielectric properties of realistic SrRuO3/SrTiO3/SrRuO3 nanocapacitors, and show that the observed dramatic capacitance reduction is indeed an intrinsic effect. We demonstrate the existence of a dielectric dead layer by calculating the dielectric profile across the interface and analyse its origin by extracting the ionic and electronic contributions to the electrostatic screening. We establish a correspondence between the dead layer and the hardening of the collective SrTiO3 zone-centre polar modes, and determine the influence of the electrode by repeating our calculations for Pt/SrTiO3/Pt capacitors. Our results provide practical guidelines for minimizing the deleterious effects of the dielectric dead layer in nanoscale devices.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: Inverse permittivity profile and induced electrostatic potentials.
Figure 2: Infrared absorption spectrum of the SrRuO 3 /SrTiO 3 capacitor and decomposition into bulk polar modes.
Figure 3: Influence of the ionic contribution to the screening on the magnitude of the dead layer.


  1. Scott, J. F. High-dielectric constant thin films for dynamic random access memories (DRAM). Annu. Rev. Mater. Sci. 28, 79–100 (1998)

    Article  ADS  CAS  Google Scholar 

  2. Nagaraj, B. et al. (Ba,Sr)TiO3 thin films with conducting perovskite electrodes for dynamic random access memory applications. Appl. Phys. Lett. 74, 3194–3196 (1999)

    Article  ADS  CAS  Google Scholar 

  3. Mead, C. A. Anomalous capacitance of thin dielectric structures. Phys. Rev. Lett. 6, 545–546 (1961)

    Article  ADS  CAS  Google Scholar 

  4. Zhou, C. & Newns, D. M. Intrinsic dead layer effect and the performance of ferroelectric thin film capacitors. J. Appl. Phys. 82, 3081–3088 (1997)

    Article  ADS  CAS  Google Scholar 

  5. Sinnamon, L. J., Bowman, R. M. & Gregg, J. M. Investigation of dead-layer thickness in SrRuO3/Ba0.5Sr0.5TiO3/Au thin-film capacitors. Appl. Phys. Lett. 78, 1724–1726 (2001)

    Article  ADS  CAS  Google Scholar 

  6. Black, C. T. & Welser, J. J. Electric-field penetration into metals: consequences for high-dielectric constant capacitors. IEEE Trans. Electron Devices 46, 776–780 (1999)

    Article  ADS  CAS  Google Scholar 

  7. Natori, K., Otani, D. & Sano, N. Thickness dependence of the effective dielectric constant in a thin film capacitor. Appl. Phys. Lett. 73, 632–634 (1998)

    Article  ADS  CAS  Google Scholar 

  8. Saad, M. M. et al. Intrinsic dielectric response in ferroelectric nano-capacitors. J. Phys. Condens. Matter 16, L451–L456 (2004)

    Article  CAS  Google Scholar 

  9. Sinnamon, L. J., Saad, M. M., Bowman, R. M. & Gregg, J. M. Exploring grain size as a cause for “dead-layer” effects in thin film capacitors. Appl. Phys. Lett. 81, 703–705 (2002)

    Article  ADS  CAS  Google Scholar 

  10. Plonka, R., Dittmann, R., Pertsev, N. A., Vasco, E. & Waser, R. Impact of the top-electrode material on the permittivity of single-crystalline Ba0.7Sr0.3TiO3 thin films. Appl. Phys. Lett. 86, 202908 (2005)

    Article  ADS  Google Scholar 

  11. Dawber, M. & Scott, J. F. Models of electrode-dielectric interfaces in ferroelectric thin-film devices. Jpn. J. Appl. Phys. 41, 6848–6851 (2002)

    Article  ADS  CAS  Google Scholar 

  12. Vendik, O. G., Zubko, S. P. & Ter-Martirosayn, L. T. Experimental evidence of the size effect in thin ferroelectric films. Appl. Phys. Lett. 73, 37–39 (1998)

    Article  ADS  CAS  Google Scholar 

  13. Sirenko, A. A. et al. Soft-mode hardening in SrTiO3 thin films. Nature 404, 373–376 (2000)

    Article  ADS  CAS  Google Scholar 

  14. Finnis, M. W. The theory of metal-ceramic interfaces. J. Phys. Condens. Matter 8, 5811–5836 (1996)

    Article  ADS  CAS  Google Scholar 

  15. Stengel, M. & Spaldin, N. A. Ab-initio theory of metal-insulator interfaces in a finite electric field. Preprint at (2005).

  16. Antons, A., Neaton, J. B., Rabe, K. M. & Vanderbilt, D. Tunability of the dielectric response of epitaxially strained SrTiO3 from first-principles. Phys. Rev. B 71, 024102 (2005)

    Article  ADS  Google Scholar 

  17. Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994)

    Article  ADS  Google Scholar 

  18. Junquera, J., Zimmer, M., Ordejón, P. & Ghosez, Ph. First-principles calculation of the band offset at BaO/BaTiO3 and SrO/SrTiO3 interfaces. Phys. Rev B 67, 155325 (2003)

    Article  ADS  Google Scholar 

  19. Baroni, S., de Gironcoli, S. & Corso, A. D. Phonons and related crystal properties from density-functional perturbation theory. Rev. Mod. Phys. 73, 515–562 (2001)

    Article  ADS  CAS  Google Scholar 

  20. Baldereschi, A., Baroni, S. & Resta, R. Band offsets in lattice-matched heterojunctions: a model and first-principles calculations for GaAs/AlAs. Phys. Rev. B 61, 734–737 (1988)

    ADS  CAS  Google Scholar 

  21. Giustino, F. & Pasquarello, A. Theory of atomic-scale dielectric permittivity at insulator interfaces. Phys. Rev. B 71, 144104 (2005)

    Article  ADS  Google Scholar 

  22. Junquera, J. & Ghosez, Ph. Critical thickness for ferroelectricity in perovskite ultrathin films. Nature 422, 506–509 (2003)

    Article  ADS  CAS  Google Scholar 

  23. Spaldin, N. A. Fundamental size limits in ferroelectricity. Science 304, 1606–1607 (2004)

    Article  CAS  Google Scholar 

  24. Fong, D. D. et al. Ferroelectricity in ultrathin perovskite films. Science 304, 1650–1653 (2004)

    Article  ADS  CAS  Google Scholar 

  25. Ghosez, Ph. & Junquera, J. in Handbook of Theoretical and Computational Nanotechnology (eds Rieth, M. & Schommers, W.) (American Scientific Publisher, Stevenson Ranch, California, 2006)

    Google Scholar 

  26. Hwang, C. S. Thickness-dependent dielectric constants of (Ba,Sr)TiO3 thin films with Pt or conducting oxide electrodes. J. Appl. Phys. 92, 432–437 (2002)

    Article  ADS  CAS  Google Scholar 

  27. Gerra, G., Tagantsev, A. K., Setter, N. & Parlinski, K. Ionic polarizability of conductive metal oxides and critical thickness for ferroelectricity in BaTiO3 . Phys. Rev. Lett. 96, 107603 (2006)

    Article  ADS  CAS  Google Scholar 

  28. Kim, D. J. et al. Polarization relaxation induced by a depolarization field in ultrathin ferroelectric BaTiO3 capacitors. Phys. Rev. Lett. 95, 237602 (2005)

    Article  ADS  CAS  Google Scholar 

  29. Sai, N., Kolpak, A. M. & Rappe, A. M. Ferroelectricity in ultrathin perovskite films. Phys. Rev. B 72, 020101(R) (2005)

    Article  ADS  Google Scholar 

Download references


We thank A. De Vita, Ph. Ghosez, J. Junquera, R. Ramesh, R. Seshadri, J. F. Scott and S. Stemmer for discussions. This work was supported by the National Science Foundation's Division of Materials Research, through the Condensed Matter and Materials Theory Program; computations were performed on the DataStar machine at the San Diego Supercomputer Center.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Massimiliano Stengel.

Ethics declarations

Competing interests

Reprints and permissions information is available at The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Stengel, M., Spaldin, N. Origin of the dielectric dead layer in nanoscale capacitors. Nature 443, 679–682 (2006).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing