Electrical characteristics of (Ba,Sr)TiO 3 films accounted by partially depleted model

Abstract

We investigated the leakage current versus voltage ( I–V) characteristics, the capacitance versus thickness of (Ba 0.5Sr 0.5)TiO 3 film ( C–t) characteristics, and the relaxation currents of sputtered (Ba 0.5Sr 0.5)TiO 3 films with the thickness of 40–166 nm. The I–V characteristics can be explained by the partially depleted model especially when the thickness of (Ba 0.5Sr 0.5)TiO 3 film exceeds 62 nm. The C–t characteristics indicate that the relative dielectric constant in the internal layer (out of the depletion layer) does not change by applied voltages. This can be explained by assuming that the electric field is concentrated at the partially depleted layer, and that the relative dielectric constant in the depletion layer decreases in accordance with the increasing of applied voltage. The relaxation currents may be explained by assuming that the relative dielectric constant in the depletion layer decreases in accordance with the increasing of applied voltage.