Electrical properties of Mg/La, Mg/Nb co-doped (Ba0.7Sr0.3)TiO3 thin filmsprepared by metallo-organic deposition method

(Ba0.7Sr0.3)TiO3 (BST) thin films doped with La, Nb and Mg ions along with an Mg/La, Mg/Nb codopant were prepared on Pt/Ti/SiO2/Si substrates by the m etal-organic deposition method. A decrease of grain size, dielectric consta nt, and leakage current with increasing doping levels was observed for all studied cases. The grain size, dielectric constant and leakage current incr eased with increasing annealing temperatures for specimens doped with a sin gle dopant. However, the leakage current was reduced to a minimum for the c odoped materials at the donor/acceptor compensated concentration and decrea sed with increasing annealing temperatures. The decreased leakage current o f the codoped materials could be explained by the additional barrier height and width of the insulating layer caused by the defect dipoles around grai n boundaries.