Microstructure development and dielectric properties of hydrothermal BaTiO3 thin films

Polycrystalline BaTiO3 thin films were processed hydrothermally by reacting TiO2 films at 90 degreesC in alkaline solutions containing Ba2+. Films grown on (100) SrTiO3 suggested that BaTiO3 nucleation occurred at the film-substrate interface as well as the film-a solution interface. As-reacted BaTiO3 films grown on Pt-coated glass substrates had a dielectric constant and tandelta of 80 and 0.20 respectively. Current-voltage (I-V) measurements suggested that the leakage mechanism combined aspects of Poole-Frenkel and Schottky-barrier controlled processes, and had an associated metal/ceramic barrier height of 0.46 eV. Annealing the BaTiO3 films at 200-500 degreesC in air resulted in lower values for dielectric constant, tandelta, and leakage current, and a larger barrier height. (C) 2003 Elsevier Science Ltd. All rights reserved.