Characterization of Mn-Doped Ba_1-xSr_xTiO₃ Thin Films Prepared by the Sol-Gel Method

Undoped and Mn-doped Ba_1-xSr_xTiO₃ (BST) thin films have been fabricated on Pt/Ti/SiO₂/Si by an aqueous acetate sol-gel method. The BST stock solution can be easily mixed with an aqueous metal ion solution and is stable at room temperature. The annealing temperature of the doped and undoped films is between 650-750°C. The x-ray photoelectron spectra (XPS) results show that the Mn 2p_3/2 valence state in the BST is the same as that of the original Mn(II) dopant. The dielectric constant of the BST thin films can be increased to 800, and the loss tangent can be decreased to 0.01 due to the Mn(II) doping. The leakage current of the BST films can also be greatly reduced.