Properties of Ba0.5Sr0.5TiO3 thin films prepared by water-based sol-gel process

A new liquid source using water as a solvent was studied to prepare Ba0.5Sr0.5TiO3 (BST) thin films by Sol-Gel technique. DTA/TGA methods were employed to analyze this water-based BST liquid source gel. XRD results show that the film exhibits a completely pure perovskite phase. SEM photographs show that the thickness of the films is homogeneous, and the grain size of the thin films annealed at 650 degrees C for 20min is about 200nm. It is found that the thickness of the film plays an important role in the dielectric properties of the BST films. The BST films of one layer with the thickness of 1250 Angstrom have better dielectric properties than those of the multilayers. The dielectric constant and dielectric loss for single layer BST films are 330 and 0.043 at 1kHz, respectively.