Control of Microstructure and Orientation in Solution‐Deposited BaTiO₃ and SrTiO₃ Thin Films

Abstract

Columnar and highly oriented (100) BaTiO3 and SrTiO3 thin films were prepared by a chelate‐type chemical solution deposition (CSD) process by manipulation of film deposition conditions and seeded growth techniques. Randomly oriented columnar films were prepared on platinum‐coated Si substrates by a multilayering process in which nucleation of the perovskite phase was restricted to the substrate or underlying layers by control of layer thickness. The columnar films displayed improvements in dielectric constant and dielectric loss compared to the fine‐grain equiaxed films that typically result from CSD methods. Highly oriented BaTiO3 and SrTiO3 thin films were fabricated on LaAlO3 by a seeded growth process that appeared to follow a standard “two‐step” growth mechanism that has been previously reported. The film transformation process involved the bulk nucleation of BaTiO3 throughout the film, followed by the consumption of this matrix by an epitaxial overgrowth process originating at the seed layer. Both BaTiO3 and PbTiO3 seed layers were effective in promoting the growth of highly oriented (100) BaTiO3 films. Based on the various processing factors that can influence thin film microstructure, the decomposition pathway involving the formation of BaCO3 and TiO2 appeared to dictate thin film microstructural evolution.

Enhanced Dielectric and Crystalline Properties in Ferroelectric Barium Titanate Thin Films

“…Stoichiometric barium titanate chemical solutions were formed from a hybrid-chelate chemistry with acetic acid substituted as a solvent [28,29]. Titanium isopropoxide was reacted with 2,4 pentanedione and diethanolamine in molar ratios of 1:2 and 4:1, respectively.…”

Magnetic Properties of Co0.5Zn0.5Fe2O4Nanoparticles Synthesized by a Template-Assisted Hydrothermal Method

“…This is a common occurrence for structures prepared through special synthesis processes. For example, the c/a ratios of some films with c-orientation texture, are all relatively large as reported in literature [15][16][17]. Each lattice cell contains eight …”

“…The orientation degree of the (hk 0 ) plane was calculated from (3) deduced from a formula in literature [15] O hk0 = (I 220 + I 440 )/I 311sample (I 220 + I 440 )/I 311standard .…”

Ink-jet Printed BaTiO3 for Photonics

“…A large exothermic DTA peak between 250 and 650 °C indicates the further decomposition of the precursors, consisting of two main steps in the TGA signal. It is generally accepted that BTO is formed from reaction between TiO 2 and BaCO 3 or from an intermediate such as Ba 2 Ti 2 O 5 CO 3 for aqueous sol-gel precursors [11,17,18]. Given most of the reaction is complete by 650 °C, we believe that the mixed intermediate can play a role here since BaCO 3 reacts only at much higher temperature.…”