Dielectric and Structural of BST Thin Films with Ce-doped prepared by Sol-gel method for Phase shifters

Phase shifters 응용을 위한 Sol-gel 법으로 제작된 BST 박막의 Ce 첨가에 따른 구조적, 유전적 특성

The dielectric and electrical characteristics of Ce doped (Ba0.6Sr0.4)TiO3 (BST) thin films were investigated as a function of Ce content. Both atomic force microscopy (AFM) and x-ray diffraction (XRD) analysis showed that increasing the Ce doping ratio causes the decrease in grain size while the surface remains smooth and crack-free. The dielectric properties of the Ce doped BST films were found to be strongly dependent on the Ce contents. The dielectric constant and dielectric loss of the BST films decreased with increasing Ce content. However, it was also found that, compared with undoped films, the increase of Cecontent improves the leakage-current characteristics. The improvement of the electrical properties of Ce-doped BST films may be related to the decrease in the concentration of oxygen vacancies. The figure of merit (FOM) reached the maximum value of 48.9 at the 1 mol % of Cedoping. The dielectric constant, loss factor, and tunability of the 1 mol% Ce doped Ba0.6Sr0.4TiO3 thin films were 320, 0.011, and 46.3%, respectively.