Local Epitaxial Growth of (103) One-Axis-Oriented SrBi₂Ta₂O₉ Thin Films Prepared at Low Deposition Temperature by Metalorganic Chemical Vapor Deposition and Their Electrical Properties

Abstract

We compared a directly crystallized SrBi 2 Ta 2 O 9 (SBT) film with one crystallized by solid-phase reaction from the fluorite phase prepared by metalorganic chemical vapor deposition (MOCVD). The region of the Bi/Ta mole ratio showing large remanent polarization (2Pr) was narrow for the film directly crystallized from the gas phase compared with that crystallized by solid-phase reaction. Moreover, the Bi/Ta mole ratio showing the maximum 2Pr value differed according to the preparation method used. The crystallinity and the orientation of the SBT phase directly crystallized from the gas phase were strongly influenced by those of the substrate; the (103)-oriented SBT grains directly crystallized from the gas phase grew hetero-epitaxially on (111)-oriented Pt grains. As a result, the direct crystallization of the film from the gas phase lowered the crystallization temperature of the SBT phase and resulted in a (103) one-axis-oriented film.