Structural and dielectric properties of epitaxial (Ba,Sr)TiO3 films on c-Al2O3 with ultra-thin TiN sacrificial template

Abstract

Using ultra-thin TiN sacrificial template, the epitaxial (Ba,Sr)TiO 3 [BST] films on c-Al2O3 were grown by pulsed laser deposition. TiN epitaxially grew on c-Al2O3 with (111) orientation, which promoted the (111) epitaxial growth of upper BST films. The obtained epitaxial BST films showed significantly larger dielectric constant compared with polycrystalline films directly deposited on c-Al 2O3 over the wide temperature range. By inserting the TiN template, the temperature corresponding to maximum dielectric constant of BST films was shifted up by 50 K, which is mainly due to the in-plane tensile strain induced by the difference in thermal expansion coefficients of BST and c-Al2O3. © 2011 The Ceramic Society of Japan.