Fabrication and properties of Sc-doped BaTiO3 thin film prepared by r.f. magnetron sputtering

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In many previous investigations, microstructure and electric properties of BaTiO3 (BTO) thin films have been shown to depend on type and amount of dopant as well as post-annealing temperature. This study reports the effects of Sc dopant on BT thin films fabricated by r.f. magnetron sputtering on Pt/Ti/SiO2/Si substrates. The BTO films were doped with 0.11at%Sc, 0.28at%Sc and 1.1at%Sc. The post-annealing was performed at 550, 600 and 650�aC. The dielectric constants of pure and Sc-doped BTO thin films are found to increase with increasing annealing temperature, while they decrease with increasing Sc content. The Sc dopant is effective to reduce leakage current as well as dielectric loss compared to the pure BTO film. The lowest leakage current was obtained for the 1.1%Sc-doped BTO thin film. This low leakage current may be attributed to the substitution of Sc in the B sites of BTO lattices, which might have behaved as an electron acceptors. Those Sc-doped films annealed at 650°C showed the high dielectric constant of approximately 347 measured at 1 MHz for 0.11%Sc-doped BTO films and low leakage current density of 5.6×10-8 A/cm2 at an electric field of 250 KV/cm for 1.1%Sc-doped BTO films. The 0.11% and 0.28%Sc-doped films without annealing showed the lower leakage current density of 8.7×10-12 A/cm2 at an electric field of 250 KV/cm.