Epitaxial Bi-layered perovskite ferroelectric thin film heterostructures by large area pulsed laser deposition

Abstract

Epitaxial thin films of Bi4Ti3O12, SrBi2Ta2O9 and BaBi4Ti4O15 have been epitaxially deposited onto 3-inch substrates by large area pulsed laser deposition. The out-of-plane orientation of the layers is characterized by a FWHM of the rocking curve Δωin the range of 0.9° to 2.1° and their in-plane orientation by a FWHM of the phi-scan ω π ranging from 3° to 4.5°. The composition is uniform across the whole 3-inch wafer and a thickness uniformity in the range of 5 to 10% of the mean thickness has been achieved. The ferroelectric properties of the Bi-layered perovskite layers depend strongly on their microstructure and crystallographic orientation. The remnant polarization of SrBi2Ta2O9 films is ranging from Pr = 0.2 μC/cm2 for films having only c-oriented crystallites to Pr = 1 μC/cm2 for films containing a substantial fraction of crystallites with their c-axis in the plane of the film.