Fabrication and electrical characterization of Pt/(Ba,Sr)TiO3/Pt capacitors for ultralarge-scale integrated dynamic random access memory applications

Pt/(Ba,Sr)TiO3/Pt capacitors are fabricated using DC and RF magnetron sputtering processes on thermally oxidized silicon wafers for ultralarge scale integrated dynamic random access memory (ULSI DRAM) applications. (Ba,Sr)TiO3 (BST) thin film deposited at 640 degrees C to 20 nm thickness shows an equivalent SiO2 thickness (t(oxeq)) of 0.35 nm and a leakage current density, measured at an applied voltage of 1.5 V, of about 100 nA/cm(2) . t(oxeq) of the BST film and leakage current density are further decreased to 0.24 nm and 40 nA/cm(2), respectively, by postannealing at 750 degrees C after fabrication of the top electrode.