Papers by Keyword: CSD Method

Abstract: In this study, (Ba1-x,Srx)TiO3 thin films of various composition ratios were deposited on glazed Al2O3 substrates by the CSD method, and the temperature dependence of the dielectric property was analyzed. The dielectric property of the BST (80/20) thin film annealed at C was highly tunable, and the temperature dependence of the dielectric constant was stabilized at around room temperature. However, this BST (80/20) thin film exhibited intense ferroelectricity. Its tan intensified to 0.0511 in the high-frequency range (1 MHz). After the BST thin film was annealed at 600C, the grain size of the BST thin film was reduced to 40 nm and the ferroelectricity was alleviated. The dielectric constant, tan, and tunability of the BST thin film at 100 kHz were 158, 0.0170, and 39.6 (214 kV/cm, 6.0 V), respectively. The change rate of the dielectric constant, which indicates its temperature dependence, was ±7 or less in the range of -55 to 85C. Therefore, this BST thin film was considered to guarantee a wide operation temperature range for microwave tunable devices.

Abstract: 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.