Electrical properties of Mg doped (Ba0.5Sr0.5)TiO3 thin films

The microstructures and electrical characteristics of Mg doped (Ba0.5Sr0.5) TiO3 (BSTM) thin films were investigated as a function of Mg content. Also the multi-layered structure, BSTM/BST/BSTM was proposed to improve both of the leakage current and dielectric constant. With increasing Mg content, th e perovskite peak intensity slightly decreased and grains became smaller. F or the films above 15 mol% Mg, the secondary phase (MgTi2O5) was observed i n X-ray diffraction (XRD) patterns. The dielectric constant decreased with increasing Mg content, while leakage current decreased up to 10 mol% Mg and then increased with further addition, which were explained by the effect o f grain size and charge compensation. For the BSTM/BST/BSTM multi-layered f ilms, the leakage current dramatically decreased without reduction of the d ielectric constant when the thicknesses of BSTM and BST were 70 mn and 210 nm, respectively. These results confirm that a promising BST thin film capa citor can be obtained by introduction of Mg modified multi-layer structure.