Integration of artificial SrTiO3/BaTiO3 superlattices on Si substrates using a TiN buffer layer by pulsed laser deposition method

Epitaxial SrTiO3(STO)/BaTiO3(BTO) artificial superlattices, STO, BTO, and (Ba-0.5,Sr-0.5)TiO3 (BSTO) thin films have been grown on TiN-buffered Si (0 0 1) substrates by pulsed laser deposition method and their dielectric properties were studied. The crystal orientation, epitaxy nature, and microstructure of epitaxial oxide thin films were investigated using X-ray diffraction and transmission electron microscopy. Thin films were prepared with laser fluence of 3 and 2J/cm(2), repetition rate of 8 and 10 Hz, substrate temperature of 700 and 650 degrees C for TiN and oxide, respectively. The TiN buffer layer and oxide thin films were grown with cube-on-cube epitaxial orientation relationship of [1 1 0](0 0 1)(film)parallel to[1 1 0](00 1)(TiN)parallel to[1 1 0](0 0 1)(si). The dielectric constants of BTO, STO, BSTO, and STO/BTO superlattice epitaxial thin films with 1 nm/1 nm periodicity were shown to be as high as 300, 410, 520, and 680 at the frequency of 100kHz, respectively. (c) 2006 Elsevier B.V. All rights reserved.