Control of Powder Quality as a Method of Improving the Dielectric Properties of (Ba_0.6,Sr_0.4)TiO_3 Thick Films Fabricated by Aerosol Deposition Method

摘要

(Ba_(0.6),Sr_(0.4))TiO_3 (BST60) thick films were fabricated on Cu substrates by aerosol deposition (AD) method. The quality of the raw powder was checked and optimized to increase the dielectric constant of the fabricated films without the need of a post-film-formation annealing procedure. The carbonate phase has been observed in the raw powder and it was successfully reduced by thermally treating the powder at 900 ℃. The AD-fabricated films obtained from the 900 ℃ thermally-treated powder show a dielectric constant of 200, which is much higher than that of the AD-fabricated films obtained from the raw powders. The leakage currents in the films fabricated from 900℃ thermally-treated powders stay below 10~(-7) A/cm~2 when the applied electric field is less than 500 kV/cm, being at least one order of magnitude smaller than the leakage values in the AD-fabricated films obtained from the raw powder. The above results indicate that thermally treating the powder at 900 ℃ is a satisfactory method of improving the electrical properties of the AD-fabricated BST60 thick films.