Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-29T17:48:59.850Z Has data issue: false hasContentIssue false
  • English
  • Français

Leakage Current Experiments in STO and BST Thin Films

Published online by Cambridge University Press:  11 February 2011

Herbert Schroeder  and
Sam Schmitz
Herbert Schroeder
Affiliation:
Institut für Elektrokeramische Materialien im Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
Sam Schmitz
Affiliation:
Institut für Elektrokeramische Materialien im Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
Get access

Abstract

We have performed experiments on steady state leakage currents through insulating thin films of high permittivity dielectrics such as strontium-titanate (STO) and barium-strontium-titanate (BST) in order to contribute to the understanding of the mechanism limiting the current. Furthermore, as BST is a candidate as a dielectric in the capacitor of future Gb-generation DRAM cells, the absolute value of the current in dependence of external parameters is interesting for the application.

Besides external parameters such as applied voltage and temperature we have investigated the dependence on dielectric film thickness between 20 nm and 150 nm with symmetrical Pt electrodes. For some selected films the influence of asymmetric electrodes has also been investigated: While the bottom electrode was always Pt, the top electrodes were Pt, Au and Al. An epitaxial STO film with oxide electrode bottom electrode has also been tested.

The main results are as follows:

The field dependence of the leakage current quite often shows a linear behavior in a “Schot-tky”-plot, i.e. log (current density) vs. sqrt (applied field). At constant applied field the thinner films show much lower leakage currents than the thicker ones. The leakage currents increase using Pt, Au and Al as cathode, respectively. The leakage in the epitaxial STO film is much smaller with an oxide electrode (SrRuO3) as cathode than with a platinum one.

All these results will be discussed within a modified model, in which the current is bulk-limited, and compared to numerical simulation results of this model.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 748: Symposium U – Ferroelectric Thin Films XI , 2002 , U6.2
Copyright
Copyright © Materials Research Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1] Kotecki, D.E. et al., IBM J. Res. Develop. 43, 367 (1999)Google Scholar
[2] Dietz, G.W., Schumacher, M., Waser, R., Streiffer, S.K., Basceri, C., Kingon, A.I., J. Appl. Phys. 82, 2359 (1997).Google Scholar
[3] Shin, J.C., Park, J., Hwang, C.S., and Kim, H.J., J. Appl. Phys. 86, 506 (1999)Google Scholar
[4] Baniecki, J.D. et al. J. Appl. Phys. 89, 2873 (2001).Google Scholar
[5] Saha, S. and Krupanidhi, S.B., Appl. Phys. Lett. 79, 111 (2001)Google Scholar
[6] Watanabe, K. et al., Integrated Ferroelectrics 21, 241 (1998)Google Scholar
[7] Schroeder, H., Schmitz, S., and Meuffels, P., “Simulation of steady state leakage current …”, this volume.Google Scholar
[8] Hoffmann, S. et al., Mat. Res. Soc. Symp. Proc. 474, 9 (1997)Google Scholar
[9] Fitsilis, F. et al., Mat. Res. Soc. Symp. Proc. 655, CC9.4.1 (2001)Google Scholar
[10] Schmitz, S. and Schroeder, H., Scientific Report 2000/2001, Institute for Solid State Research (IFF), Forschungszentrum Jülich, p. 139 (2001) and to be published.Google Scholar
[11] Sze, S.M., Physics of Semiconductor Devices, (2nd ed., John Wiley & Sons, New York, 1981)Google Scholar
[12] Zhou, C. and Newns, D.W., J. Appl. Phys. 82, 3081 (1997)Google Scholar
[13] Basceri, C., Streiffer, S.K., Kingon, A.I. and Waser, R., J. Appl. Phys. 82, 2497 (1997).Google Scholar
[14] Ellerkmann, U., Liedtke, R., and Waser, R., Ferroelectrics 271, 315 (2002).Google Scholar
[15] Schmitz, S., Thesis RWTH Aachen, 2002.Google Scholar
[16] Denk, I., Münch, W., and Maier, J., J. Am. Ceram. Soc. 78, 3265 (1995).Google Scholar