Structure and electrical properties of Ba_0.67Sr _0.33TiO₃ thin film fabricated by sol-gel based composite technique

A sol-gel based novel technique is used to fabricate Ba _0.67Sr_0.33TiO₃ (BST) thin films with thickness up to several microns. In this technique, surface-modified fine BST particles are dispersed in a sol-gel precursor solution. The pH value of the precursor solution is modified to achieve high zeta potential for the dispersed powder, hence a very stable and uniform slurry can be produced. The slurry is then spin-coated onto Pt/Ti/SiO₂/Si substrate, pre-heated and annealed as in conventional sol-gel process. The resulting films show well-developed dense polycrystalline structure with uniform grain distribution. The metal-BST-metal structure of the films displays good dielectric properties.