Epitaxial Ba0.5Sr0.5TiO3 thin films for microwave phase shifters

A tunable phase shifter was fabricated with epitaxial Ba0.5Sr0.5TiO3 (BST) thin film and gold coplanar waveguide. BST thin film of the thickness similar to0.5 mum was deposited by laser ablation on the MgO(001) single crystalline substrate. Gold electrode of the thickness similar to2 mum was pre pared by the sequence of thermal evaporation, electroplating, and wet etching. Epitaxial quality of the BST thin film was confirmed by X-ray diffraction. The microwave performance of phase shifter was measured at room temperature in the frequency range of 8 similar to 12 GHz, and with applied bias voltage of up to 30 V. Effect of Mn dopant in the epitaxial films was also considered.