Crystal structure and dielectric property of epitaxially grown (Ba, Sr)TiO3 thin film prepared by molecular chemical vapor deposition

Epitaxially grown (Ba, Sr)TiO3 thin films were prepared on (100)MgO and (100)Pt parallel to (100)MgO substrates by molecular chemical vapor deposition (MOCVD). The lattice parameter increased with increasing Ba/(Ba + Sr) ratio in the film and was higher than the reported value for bulk (Ba, Sr)TiO3. The dielectric constant at room temperature reached the maximum value at a lower Ba/(Ba + Sr) ratio compared to the reported one for bulk (Ba, Sr)TiO3. The temperature showing the maximum dielectric constant was higher than the reported value for bulk (Ba, Sr)TiO3. These results can be explained by the compressive stress applied to the film under the cooling process after the deposition.