Microstructure and properties of sol-gel derived Pb(Zr0.3Ti 0.7)O3 thin films on GaN/sapphire for nanoelectromechanical systems

Wei Cao, Sandwip Dey

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Highly (111) oriented, phase-pure perovskite Pb(Zr0.3Ti 0.7)O3 (or PZT 30/70) thin films were deposited on single-crystal, (0001) wurtzite GaN/sapphire substrates using the sol-gel process and rapid thermal annealing. The phase, crystallinity, and stoichiometry of annealed PZT films were evaluated by X-ray diffraction and Rutherford backscattering spectroscopy. The atomic force microscopy revealed a smooth PZT surface (rms roughness 1.5 nm) with striations and undulations possibly influenced by the nature of the underlying GaN surface. The cross-sectional field-emission scanning electron microscopic images indicated a sharper PZT/GaN interface compared to that of sol-gel derived PZT on (111) Pt/TiO 2/SiO2/(100) Si substrates. The capacitance-voltage (C-V) characteristics for PZT in the Pt/PZT/GaN (metal-ferroelectric-semiconductor or MFS) configuration were evaluated as a function of annealing temperature and applied voltage. The observed C-V hysteresis stemmed from trapped charge at defect sites within PZT. Also, the lower capacitance density (C/A = 0.35 μF/cm2, where A is the area of an electrode) and remnant polarization (P r 4 μC/cm2) for PZT in the MFS configuration, compared to the values for PZT in the MFM configuration (Pt/PZT/Pt), were attributed to the high depolarization field within PZT.

Original languageEnglish (US)
Pages (from-to)389-395
Number of pages7
JournalJournal of Sol-Gel Science and Technology
Volume42
Issue number3
DOIs
StatePublished - Jun 1 2007

Keywords

  • Ferroelectric
  • GaN
  • Pb(ZrTi)O
  • Sol-gel
  • Thin film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Chemistry(all)
  • Biomaterials
  • Condensed Matter Physics
  • Materials Chemistry

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