Dielectric properties of SrTiO3 capacitor using TiN bottom electrode and effects of SrTiO3 film thickness

SrTiO3 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 SrTiO3 capacitors is studied. At the substrate temperature of 400 degrees C, a relative dielectric constant of 120 is obtained for SrTiO3 films with a thickness of 150 nm and the maximum capacitance of 15 nF/mm(2) is obtained at the SrTiO3 film thickness of 12 nm. The TiN bottom electrode is found to be oxidized during SrTiO3 film deposition, and the oxidized layer is suggested to be rutile-TiO2, with a relative dielectric constant of 80, through comparisons with Au/SrTiO3/TiN and Au/SrTiO3/Pt capacitors. The thickness of oxidized TiN is found to grow logarithmically with increasing SrTiO3 thickness.