Dielectric Properties of SrTiO₃ Capacitor Using TiN Bottom Electrode and Effects of SrTiO₃ Film Thickness

Abstract

SrTiO 3 thin films are prepared on TiN bottom electrodes by rf magnetron sputtering, and the effect of the oxidation of the TiN electrodes on dielectric properties of SrTiO 3 capacitors is studied. At the substrate temperature of 400°C, a relative dielectric constant of 120 is obtained for SrTiO 3 films with a thickness of 150 nm and the maximum capacitance of 15 nF/mm 2 is obtained at the SrTiO 3 film thickness of 12 nm. The TiN bottom electrode is found to be oxidized during SrTiO 3 film deposition, and the oxidized layer is suggested to be rutile-TiO 2 , with a relative dielectric constant of 80, through comparisons with Au/SrTiO 3 /TiN and Au/SrTiO 3 /Pt capacitors. The thickness of oxidized TiN is found to grow logarithmically with increasing SrTiO 3 thickness.