The effects of solvents on the formation of Ba0.65Sr0.35TiO3 thin films derived by sol–gel processing

The sol–gel method was used to synthesize Ba0.65Sr0.35TiO3 thin films. Two synthesis routes with two different solvents, ethylene glycol methyl ether and methyl ethyl glycol, were used and compared. Ba0.65Sr0.35TiO3 thin films were deposited on Si substrates by using spin coating technique. The as-deposited dry films were treated with rapid thermal annealing. The effects of solvents on the grain size, morphology, surface roughness, and the phase formation of the Ba0.65Sr0.35TiO3 thin films were studied. Investigation of these films shows that the microstructures of Ba0.65Sr0.35TiO3 thin films prepared from sols using methyl ethyl glycol were more homogeneous and denser; the root mean square (RMS) of the film can reach ∼3 nm when annealed at 750 °C.