Study of the dielectric and ferroelectric properties of chemically processed BaxSr1-xTiO3 thin films

Polycrystalline BaxSr1-xTiO3 (x = 0.4 and 0.8) thin films with a perovskite structure were prepared by the polymeric precursor method on a platinum-co ated silicon substrate. High-quality thin films with uniform composition an d thickness were successfully produced by dip-coating and spin-coating tech niques. The resulting thin films prepared by dip and spin-coating showed a well-developed dense polycrystalline structure with uniform grain size dist ribution. The metal-BST-metal structure of the thin films displays good die lectric and ferroelectric properties. The ferroelectric nature to BaxSr1-xT iO3 (x = 0.8) thin film, indicated by butterfly-shaped C-V curves and confi rmed by the hysteresis curve, showed 2P(r) = 5.0 muC/cm(2) and E-c = 20 kV/ cm. The capacitance-frequency curve reveals that the dielectric constant ma y reach a value of up to 794 at 1 kHz. On the other hand, the BaxSr1-xTiO3 (x = 0.4) thin films had paraelectric nature and dielectric constant and th e dissipation factor at a frequency of 100 kHz were 680 and 0.01, respectiv ely, for film annealed at 700 degreesC. In addition, an examination of the film's I-V curve at room temperature revealed the presence of two conductio n regions in the BaxSr1-xTiO3 (x = 0.4 and 0.8) thin films, showing ohmic-l ike behavior at low voltage and a Schottky-emission or Poole-Frenkel mechan ism at high voltage. (C) 2001 Elsevier Science B.V. All rights reserved.