Dielectric properties of (Ba,Sr)TiO 3 thin films with varied microstructures prepared by the chemical solution deposition method for thin-film capacitors and ferroelectric varactors

We prepared epitaxially grown three-axis-oriented (Ba 0.7 S 0.3 )TiO 3 thin films on (100) platinum-coated (100) MgO single-crystal substrates by the chemical solution deposition method, using a solution derived from Ba(CH 3 COO) 2 , Sr(CH 3 COO) 2 , and Ti(O-i-C 3 H 7 ) 4 . Microstructures of fabricated thin films depend strongly on the fabrication process, especially on the annealing condition. A (Ba,Sr)TiO 3 thin film fabricated with an annealing temperature of 1073K was found to be a single crystal by transmission electron microscopy. The single-crystal (Ba,Sr)TiO 3 thin film exhibited a (100) three-axis-orientation, which followed the (100) orientation of the platinum electrode on the MgO single-crystal substrate. A (100) three-axis-oriented (Ba,Sr)TiO 3 thin film may be useful for preparing a thin-film capacitor.