The effect of annealing temperature on the structure and dielectric properties of (Ba0.6Sr0.4)TiO3 thin films

Ba_0.6Sr_0.4TiO₃ thin films were prepared on LaAlO₃ substrates by sol-gel method. The effects of annealing temperature on the structure and dielectric properties were studied. The microstructure was examined by XRD, SEM and AFM. It was observed that as the annealing temperature increased, films were crystallized in preferential (001) orientation. When annealed at 1100°C, the films reveal agglomeration structure, and surface roughness increase. By the measurement, we found that the dielectric properties strongly depend upon annealing temperature. The higher the annealing temperature, the lower dissipation factor and the larger tunability will be. At the same thickness, the tunability of the films annealed at 1100°C enhanced to 46.9% (DC bias electric field of 80KV/cm) and the dissipation factor is 0.008 at 1 MHz.