Fabrication and Crystallization Behavior of BNN Thin Films by H-MOD Process

  • Lou, Junhui (Department of Materials Science and Engineering, Yeungnam University) ;
  • Lee, Dong-Gun (Department of Materials Science and Engineering, Yeungnam University) ;
  • Lee, Hee-Young (Department of Materials Science and Engineering, Yeungnam University) ;
  • Lee, Joon-Hyung (Department of Inorganic Materials Engineering, Kyungpook National University) ;
  • Cho, Sang-Hee (Department of Inorganic Materials Engineering, Kyungpook National University)
  • Published : 2003.08.22

Abstract

$Ba_2NaNb_5O_{15}$, hereafter BNN, thin films are attractive candidates for nonvolatile memory and electro-optic devices. In the present work, thin films that have different contents of Ba, Na and Nb have been prepared by H-MOD technique on silicon and Pt substrates. XRD and SEM were used to investigate the phase evolution behavior and the microstructure of the films. It was found that the films of about 450nm thick were crack-free and uniform in microstructure. Nb content strongly influenced the phase formation of the films, where low temperature phase was always formed at the stoichiometric BNN composition. However, the amount of low temperature phase decreased with the increase of excess Nb content, and the single phase (orthorhombic tungsten bronze structure) BNN thin film was obtained at the temperature as low as $750^{\circ}C$ for samples with excess niobium. From this study, the sub-solidus phase diagram below $850^{\circ}C$ for $BaO-Na_2O-Nb_2O_5$ ternary system is proposed.

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