Characterization of ferroelectric Bi3.25La0.75Ti3O12 thin films prepared by metal organic decomposition method

• Published in: Thin solid films Vol. 478; no. 1-2; pp. 6 - 12
• Main Authors: Kim, Kyoung-Tae, Kim, Chang-Il
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.05.2005; Elsevier Science
• Subjects: BLT; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; FeRAM; Ferroelectric properties; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; MOD; Niobates, titanates, tantalates, pzt ceramics, etc; Physics; Thin Film; MOD; BLT; Ferroelectric properties; Thin Film; FeRAM; Temperature dependence; Scanning electron microscopy; Polarization; Annealing; Inorganic compounds; Transition element compounds; Decomposition; XRD; Rare earth compounds; Experimental study; Bismuth Titanates; Acidic solution; Thin films; Lanthanum Titanates; Perovskite; Lamellar structure; Ferroelectric materials; Crystal growth from solutions; Spin-on coating; Microstructure; Quaternary compounds; Sol-gel process; Ferroelectric hysteresis
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2004.09.042

Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films were prepared using the spin-coating method onto Pt/Ti/SiO2/Si substrate by the metal organic decomposition. Crystallographic properties of BLT films were characterized as a function of annealing temperature. The effect of excess Bi content on the microstructure and ferroelectric properties was also investigated. X-ray diffraction (XRD) results show that predominant Bi4Ti3O12 phase can be obtained at 550 °C, while the films keep randomly oriented structure up to 750 °C. An increase in grain size of BLT films with increasing annealing temperature was observed by the field emission scanning electron microscopy (FE-SEM). The hysteresis loops of BLT films were found to be well defined for temperatures above 600 °C. The remanent polarization decreased when more than 10% of excess Bi has been used in the precursor solution. The films with both Bi deficiency and Bi excess over 10% in the BLT precursor solution annealed at 650 °C showed poor fatigue properties. This was attributed to the structure defects and to the presence of a secondary phase. The films prepared with the Bi content in excess of 10% and annealed at 650 °C exhibited an outstanding hysteresis behaviors with the remanent polarization (2Pr) of 25.66 as well as fatigue-free behavior up to 3.5×109 bipolar cycles.