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 P_r = 0.2 μC/cm² for films having only c-oriented crystallites to P_r = 1 μC/cm² for films containing a substantial fraction of crystallites with their c-axis in the plane of the film.

Keywords:

• Thin Films
• Perovskites
• Microstructure
• Ferroelectric properties