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Epitaxial Growth of BaZn1/3Ta2/3O3 Thin-Films for Microwave Applications

Published online by Cambridge University Press:  10 February 2011

G. Rong ,
L. Tsakalakos ,
J. Browning  and
N. Newman
G. Rong
Affiliation:
ECE Dept., Northwestern University, Evanston, IL 60208
L. Tsakalakos
Affiliation:
Material Science Dept., University of California, Berkeley, CA 94720
J. Browning
Affiliation:
ECE Dept., Northwestern University, Evanston, IL 60208
N. Newman
Affiliation:
ECE Dept., Northwestern University, Evanston, IL 60208
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Abstract

BaZn1/3Ta2/3O3 (BZT) ceramics are widely used in current microwave communication applications due to the material's large-dielectric constant (εr > 25), ultra-low loss tangent (tan δ < 2×10−5 at 2 GHz) and a near-zero temperature-coefficient of resonant frequency (τf∼0). In this paper, we report the first growth of epitaxial BZT thin films. The films are grown on MgO substrates using pulsed laser deposition. X-ray diffraction data indicate the films have a disordered pseudocubic perovskite structure with a small tetragonal distortion (i.e. a = b = 4.100 Å; c = 4.088 Å). An optimized substrate temperature of 575°C results in films which are over 98% oriented in the (001) direction and are relatively smooth (rms roughness of 5.2 Å). X-ray diffraction Φ scans of off-axis (202) reflection show four-fold symmetry, indicating a high degree of in-plane epitaxy, albeit with small angle grain boundaries. The refractive index of epitaxial BZT films is inferred to be 5 from Fabry- Perot fringes in optical transmission spectra. Substrate temperatures during growth are limited to ∼600°C as a result of Zn loss.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 574: Symposia BB – Multicomponent Oxide Films for Electronics , 1999 , 163
Copyright
Copyright © Materials Research Society 1999

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References

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