TEM and electrical analysis of sputtered barium strontium titanate (BST) thin films on flexible copper substrates

Brian Laughlin, Jon Ihlefeld, Jon Paul Maria

Research output: Contribution to journalConference article

10 Scopus citations

Abstract

Ba0.6Sr0.4TiO3 (BST) films were deposited on copper foils by radio frequency magnetron sputtering. These films will be an integral part of flexible capacitor sheets intended for space borne re-configurable antenna arrays. By the use of controlled pO2 high temperature anneals, the films were fully crystallized in the absence of substrate oxidation. X-ray diffraction and transmission electron microscopy (TEM) showed no existence of copper oxidation (i.e. Cu2O or CuO phases). The deposited BST films exhibit a high permittivity (625) and a low tan δ (0.020) at zero bias and room temperature. A pronounced electrical tunability ratio of 3.5:1 is observed on these devices. Devices show loss tangents as low as 0.003 in fields approaching 400 kV/cm. Electrical field calculations are based on cross-sectional atomic force microscopy (AFM) images that reveal a film thickness of 800 nm. Temperature dependent measurements show a Tmax ∼ 230 K with a diffuse dielectric anomaly. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) analyses indicate a conformal film with a mixed grain morphology and an abrupt Cu/BST interface.

Original languageEnglish (US)
Pages (from-to)301-306
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume784
StatePublished - Dec 1 2003
EventFerroelectric Thin Films XII - Boston, MA, United States
Duration: Dec 1 2003Dec 4 2003

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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