Electrical Properties of Bi2Ti2O7 Thin Films Grown at Low Temperature by the Pulsed Laser Deposition

Abstract

A crystalline Bi2Ti2O7 (B2T2) film with a high dielectric constant (epsilon(r)) of 67.2 was formed even at 300 degrees C when the oxygen pressure (OP) exceeded 600 mTorr, even though the Bi4Ti3O12 target was used. The Mn-doping improved the electrical properties of the B2T2 films by producing the doubly ionized, extrinsic oxygen vacancies, which reduced the number of intrinsic oxygen vacancies. The B2T2 film containing 20 mol% of Mn ions, which was annealed under an OP of 75.0 Torr, exhibited a low leakage current density of 5 x 10(-7) A/cm(2) at 0.5 MV/cm(2) and a large epsilon(r) (similar to 73) with a low tan delta (similar to 1.3%).