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Microstructural instability in single-crystal thin films

Published online by Cambridge University Press:  31 January 2011

A. Seifert
Affiliation:
Materials Department, College of Engineering, University of California, Santa Barbara, Santa Barbara, California 93106
A Vojta
Affiliation:
Materials Department, College of Engineering, University of California, Santa Barbara, Santa Barbara, California 93106
J. S. Speck
Affiliation:
Materials Department, College of Engineering, University of California, Santa Barbara, Santa Barbara, California 93106
F. F. Lange
Affiliation:
Materials Department, College of Engineering, University of California, Santa Barbara, Santa Barbara, California 93106
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Abstract

Epitaxial PbTiO3 thin films were produced from a mixed Pb–Ti double-alkoxide precursor by spin-coating onto single crystal (001) SrTiO3 substrates. Heat treatment at 800 °C produces a dense and continuous, epitaxial lead titanate film through an intermediate Pb-Ti fluorite structure. A microstructural instability occurred when very thin single crystal films were fabricated; this instability caused the films to become discontinuous. Scanning electron microscopy and atomic force microscopy observations show that single crystal films with a thickness less than ∼80 nm developed holes that expose the substrate; thinner films broke up into isolated, single crystal islands. The walls of the holes were found to be (111) perovskite planes. A free energy function, which considered the anisotropic surface energies of different planes, was developed to describe the microstructural changes in the film and to understand the instability phenomenon. The function predicted that pre-existing holes greater than a critical size are necessary to initiate hole growth, and it predicted the observed morphological changes in the current system. Morphological stability diagrams that explain the stability fields for different film configurations, i.e., either completely covered, with holes, or single crystal islands, can be calculated for any film/substrate system.

Type
Articles
Copyright
Copyright © Materials Research Society 1996

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References

REFERENCES

1.Gimpl, M. L., McMaster, A. D., and Fuschillo, N., Appl. Phys. 35 (12), 3572 (1964).CrossRefGoogle Scholar
2.Cane, W. M., Spratt, J. P., and Hershinger, L. W., J. Appl. Phys. 37 (5), 2085 (1966).Google Scholar
3.Hummel, R. E., De Hoff, R.T., Matts-Goho, S., and Goho, W.M., Thin Solid Films 78 (1), 1 (1981).CrossRefGoogle Scholar
4.Bachmann, L., Sawyer, D. L., and Siegel, B. M., J. Appl. Phys. 36 (1), 304 (1966).CrossRefGoogle Scholar
5.Mazur, V. A. and Goldiner, M. G., Phys. Lett. A 137 (5), 69 (1989).CrossRefGoogle Scholar
6.Jiran, E. and Thompson, C. V., Thin Solid Films 208 (1), 23 (1992).CrossRefGoogle Scholar
7.Wu, N. L. and Phillips, J.J. Appl. Phys. 59 (3), 3572 (1986).CrossRefGoogle Scholar
8.Srolovitz, D. J. and Safran, S. A., J. Appl. Phys. 60 (1), 247 (1986).CrossRefGoogle Scholar
9.Srolovitz, D. J. and Safran, S. A., J. Appl. Phys. 60 (1), 255 (1986).CrossRefGoogle Scholar
10.Miller, K. T., Lange, F. F., and Marshall, D. B., J. Mater. Res. 5, 157 (1990).CrossRefGoogle Scholar
11.Seifert, A., Lange, F. F., and Speck, J. S., J. Mater. Res. 10, 680 (1995).CrossRefGoogle Scholar
12.Gurkovich, S. R. and Blum, J. B., in Ultrastructure Processing of Ceramics, Glasses and Composites, edited by Hench, L. L. and Ulrich, D. R. (Wiley-Interscience, New York, 1984), p. 152.Google Scholar
13.Herring, C., Phys. Rev. 82 (4), 87 (1951).CrossRefGoogle Scholar
14.Mullins, W. W., J. Appl. Phys. 30 (1), 77 (1959).CrossRefGoogle Scholar
15.Srolovitz, D. J. and Goldiner, M. G., J. Metal (3), 31 (1995).Google Scholar
16.Winterbottom, W. L., Acta Metall. 15 (2), 303 (1967).CrossRefGoogle Scholar
17.Wulff, G., Z. Krist allogr. 34, 449 (1901).Google Scholar
18.Lange, F. F., in Proc. Recrystallization '92, edited by Fuentes, M. and Sevillano, J. G. (Trans. Tech. Publications, Brooksfield, VT, 1992), p. 81.Google Scholar
19.Lupis, C. H. P.Chemical Thermodynamics of Materials (North-Holland, New York, 1983), p. 368.Google Scholar