Enhanced dielectric and crystalline properties in ferroelectric barium titanate thin films

A chemical solution synthesis technique incorporating barium titanate and a high-temperature liquid phase is developed. In a temperature range conventional to thin-film growth, the presence of the liquid phase dramatically enhances grain growth, densification, and overall crystalline quality. By controlling the liquid-phase stoichiometry and molar fraction, thin films with grain sizes greater than 10 mu m that pronounce X-ray peak splitting, low loss, and permittivity values in excess of 3000 at room temperature can be produced. These properties are comparable, and in some cases superior, to those observed in well-prepared bulk barium titanate. As such, the historical difficulty in reproducing bulklike properties in polycrystalline barium titanate is overcome. These results have broad implications for the expanded use of ferroelectric thin films by demonstrating bulk properties in thin layers and by providing a means of achieving these properties with low thermal budgets.