Sputtering Deposition of (BaxSr1-x) TiO3 Thin Films for Microwave Waveguide Devices

Barium strontium titanate (Ba
x
,Sr
1-x
)TiO
3
films are expected to be utilized for microwave integrated circuit devices; therefore, the preparation of highly crystalline BST films has been investigated. In this study, we attempted to prepare (Ba
x
,Sr
1-x
)TiO
3
films on MgO and sapphire substrates by sputtering under various conditions. It was revealed that BST films could be obtained at lower substrate temperatures on sapphire substrates, and sputtering gases with low oxygen composition were preferred to improve dielectric properties.