Crystalline Phases and Ferroelectric Properties of Sputtered BiFeO3 Thin Films Cooled in Pure O2 and Mixed Ar/O2 Atmospheres

The fabrication of high-quality epitaxial BiFeO 3 (BFO) thin films is critical for their integrated device applications. This work demonstrates a modification of two cooling atmospheres, i.e., pure O 2 and mixed Ar/O 2 , on the crystalline phase and electrical properties of BFO thin films prepared by radio-frequency magnetron sputtering. A good epitaxial growth of BFO thin films with a coexistence of dominant rhombohedral ( R ) and partial tetragonal ( T ) phases is identified by XRD analyses. Compared to an extremely small amount of (100)-oriented T phase detected in the BFO thin film cooled in mixed Ar/O 2 , an increased amount of T phase with (001) orientation is observed in the film cooled in pure O 2 . In addition, compared with the poor electrical properties, including leakage, dielectric behavior, and ferroelectric polarization, of the BFO film cooled in mixed Ar/O 2 , the film cooled in pure O 2 exhibits the improved electrical properties, e.g., a low leakage current ( J