Interface Structures and Epitaxial Behavior of Ferroelectric (Ba,Sr)TiO3 Thin Films

Author： Chen C. L. Garrett T. Lin Y. Jiang J. C. Meletis E. I. Miranda F. A. Zhang Z. Chu W. K.

ISSN： 1058-4587

Source： Integrated Ferroelectrics, Vol.42, Iss.1, 2002-01, pp. : 165-172

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Abstract

Perovskite Ba_0.6Sr_0.4TiO₃ thin films were epitaxially grown on (001) LaAlO₃ and (001) MgO by using pulsed laser ablation. The films are single crystal cubic structure with interface relationship of (001)_BST // (001)_MgO and <100>_BST // <100>_MgO for the films on (001) MgO and (001)_BST // (001)_LAO and <100>_BST // <100>_LAO. High-resolution transmission electron microscopy studies indicated that the initially grown layer of the film on both (001) MgO and (001) LAO is TiO₂ monolayer. Equally spaced misfit dislocations were found to form at the interface to release the lattice mismatch energy. Physical property measurements show that the films exhibit excellent room temperature dielectric behavior with very low dielectric loss of 0.007 and very large tenability of 45% at 1 MHz. The figure of merit of 60°/dB has been achieved for the microwave phase shifter operated at 24 GHz and room temperature.