Crystal structure and dielectric property of bismuth layer-structured dielectric films with c-axis preferential crystal orientation

Yuki Mizutani, Takanori Kiguchi, Toyohiko J. Konno, Hiroshi Funakubo, Hiroshi Uchida

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13 Citations (Scopus)

Abstract

Thin films of bismuth layer-structured dielectrics (BLSDs), CaBi4Ti4O15, and SrBi4Ti4O15, were prepared by a chemical solution deposition (CSD) technique on various substrates, such as (111)Pt/TiO2/(100)Si, (100)LaNiO 3/(111)Pt/TiO2/(100)Si, and (100)SrRuO3//(100) SrTiO3 substrates. Conductive perovskite oxide LaNiO3 with (100) preferential crystal orientation was introduced into the interface between the BLSD film and the (111)Pt/TiO2/(100)Si substrate to control the crystal orientation of BLSD by lattice matching between pseudo-perovskite blocks in the BLSD crystal and the (100)LaNiO3 plane with the perovskite structure. The (00/) planes of BLSD crystals were preferentially oriented on the substrate surface of the (100)LaNiO 3/(111)Pt/TiO2/(100)Si, whereas randomly-oriented BLSD crystals with lower crystallinity were only obtained on the surface of (111)Pt/TiO2/(100)Si substrate. The (001)-oriented BLSD films exhibited the leakage current densities below 10-7A/cm2 at ±50 kV/cm, which is significantly lower than those for randomly-oriented films, above 10-6 A/cm2, The room-temperature dielectric constants (εr)p of CaBi4Ti4O15 and SrBi4Ti4O15 thin films on the (100)LaNiO3/(111)Pt/TiO2/(100)Si substrate were both approximately 250, while those on the (100)SrRuO3//(100)SrTiO 3 substrate were approximately 220. The temperature dependence of the capacitances for the CaBi4Ti4O15 and SrBi 4Ti4O15 films on the (100)LaNiO 3/(111)Pt/TiO2/(100)Si substrate were approximately+17 and +10%, respectively, in the temperature range from 25 to 400 °C. These values were slightly larger than those of epitaxial BLSD films, but smaller than those of (Ba,Sr)TiO3 films.

Original languageEnglish
Article number09MA02
JournalJapanese journal of applied physics
Volume49
Issue number9 PART 2
DOIs
Publication statusPublished - 2010 Sep

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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