Grain Size Effect on Dielectric and Piezoelectric Properties of Alkoxy-Derived BaTiO3-Based Thin Films

Lead- and bismuth-free Ba(Ti1-x Zr x )O3 (BTZ) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by the chemical solution deposition (CSD) process. The BaTiO3 and BTZ005 thin films fabricated by the conventional process were observed to have a remarkable difference in grain size along the depth of the thin film. The microstructure of the BaTiO3 and BTZ005 thin films was improved by additional sintering process, and their grain sizes were increased to about 60 and 40 nm, respectively, by additional sintering at 800°C for 1 h. The dielectric constant ε r and piezoelectric constant d 33 of the BaTiO3 thin film consisting of large grains by the additional sintering at 800°C for 1 h were found to be about 375 and 14.5 pm/V. But, ε r and d 33 of the BTZ005 thin film changed negligibly with increasing of the grain size.