Preparation of (Ba, Sr)TiO3 Thin Films on Glazed Alumina Substrate and Analysis of their Electric Properties

The (Ba0.6Sr0.4)TiO3 (BST) thin films were formed on a Pt bottom electrode/glazed-Al2O3 substrates by a chemical solution deposition (CSD) method. The BST films were annealed at temperatures between 600 and 800°C in a rapid thermal annealing (RTA) process and grown at each temperature with a random orientation. The grain size of the BST films enlarged and the electrical properties of the BST films improved as the annealing temperature rose. The grain size of the film annealed at 800°C enlarged to be 80 nm. The averaged surface roughness Ra was 2.927 nm, which resulted in a favorable degree of planarity. The dielectric constant and loss tangent of the film at 1 MHz were 403 and 0.049, respectively. The film also displayed a high degree of tunability, which was 58.3% (at 429 kV/cm). These results indicated that high-quality BST thin films could be formed on an extremely cheap glazed-Al2O3 substrates.