Effect of deposition temperature on the microstructure and electrical properties of Ba0.8Sr0.2TiO3 thin films deposited by radio-frequency magnetron sputtering

Ba0.8Sr0.2TiO3 (BST) nanocrystalline thin films were deposited on n-type silicon substrates by radio-frequency magnetron sputtering technique at various deposition temperatures. X-ray diffraction confirmed that the deposited BST films were polycrystalline possibly due to recrystallization. Scanning electron microscopy study showed the evidence of resputtering in the films deposited at a high substrate temperature (600 °C). The electrical properties of the films were measured using an aluminum/BST/silicon metal-insulator-semiconductor capacitor configuration. Annealing seemed to enhance the dielectric constant of the as-deposited film. The film deposited at 300 °C showed the highest dielectric constant. Three-dimensional Monte-Carlo simulation confirmed that 300-350 °C would be the optimum deposition temperature range for the sputtering of BST films.