Domain Matched Epitaxial Growth of Dielectric Thin Films

Abstract

Epitaxial Ba0.5Sr0.5TiO3 (BST) thin films have been grown by pulsed laser deposition on (0001) Al2O3 substrate with ZnO as buffer layer. The X-ray ω-2θ, Φ-scan and reciprocal space mapping indicate epitaxial nature of BST thin films. The domain matched epitaxial growth of BST thin films over ZnO buffer layer was confirmed using Fourier-filtered HRTEM images of the film–buffer interface. The incorporation of ZnO buffer layer effectively suppressed the lattice mismatch and promoted domain matched epitaxial growth of BST thin films. Dielectric studies were conducted by fabricating coplanar interdigital capacitors on the epitaxial BST thin films. Epitaxial BST thin films show significantly improved tunable performance over polycrystalline thin films.