Microstructure and Dielectric Properties of Barium Strontium Titanate Multilayer Thin Films Prepared by The Sol-Gel Method
|關鍵字:||鈦酸鍶鋇;多層膜;溶膠-凝膠法;中間相;Barium Strontium Titanate;Multilayer films;Sol-Gel Method;Intermediate Phase|
Ba1-xSrxTiO3 (BST) multiplayer thin films were spin-coated on Pt/Ti/SiO2/Si(100) substrates by the sol gel method and heat-treated in air at temperatures ranging from 500 to 800oC. The microstructure of the multilayer thin films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The dielectric constants and the leakage current densities were measured using a semiconductor parameter analyzer. The addition of strontium to the BaTiO3 lattice increased the grain size of the crystallized films. The fact that grain size increased with the constant of strontium may be attributed to the higher growth rate due to the more rapid diffusion of the Sr2+ ion, which has a smaller ionic radius than Ba2+. Effects of formamide additives on powder and film properties were also investigated. HRTEM investigations show that the gel films crystallize as an intermediate carbonate phase, Ba2-2xSr2xTi2O5CO3. A dielectric constants of 323 and leakage current density of 5.21×10-6A/cm2 were measured for the Ba0.9Sr0.1TiO3/Ba0.5Sr0.5TiO3 multilayered thin films with the formamide additive after annealing 650℃ for 1hr and the dielectric constant (219) of various stacking Ba0.5Sr0.5TiO3/Ba0.9Sr0.1TiO3 multilayered thin films were smaller than that of Ba0.9Sr0.1TiO3/Ba0.5Sr0.5TiO3 and leakage current density (5.21x 10-6 A/cm2 ) were larger.
|Appears in Collections:||Thesis|