Accession Number:

ADA393194

Title:

Modified Ba(1-x)Sr(x)TiO3 Thin Films for Tunable Device Applications

Descriptive Note:

Final rept. May 2000-Nov 2001

Corporate Author:

ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE

Report Date:

2001-06-01

Pagination or Media Count:

29.0

Abstract:

Pure and La doped Ba0.6Sr0.4TiO3 BST thin films were fabricated via the metalorganic solution deposition technique using carboxylate-alkoxide precursors on Pt-Si substrates. The La doping concentration, from 0-10 mole-percent, was found to have a strong influence on the 750 deg C post deposition annealed films material properties. All films possessed a nontextured polycrystalline microstructure with no evidence of secondary phase formation. The pure and 1 mole-percent La doped films exhibited a uniform microstructure suggestive of a fully developed film at this annealing temperature. Improved dielectric and insulating properties were achieved for the 1 mole-percent La doped BST thin films with respect to that of undoped BST films. The 1 mole-percent La doped EST film exhibited a lower dielectric constant 283 vs. 450 and enhanced resistivity 31.4 x 10 exp 13 Omega-cm vs. 0.04 x 10exp 13 Omega-cm with respect to that of undoped BST films. The loss tangent and tunability at 100 kHz of the 1 mole-percent La doped BST films were 0.019 and 21 at E 300 kVcm, respectively. Films doped at concentrations between 5 and 10 mole-percent possessed under developed microstructures, suggesting that higher annealing temperatures andor longer annealing times are required. The single phase structure of the 5 and 10 mole-percent La doped BST films, combined with the beneficial influence of the 1 mole-percent La doping on the BST films dielectric and insulating properties, suggest potential for further enhancement of the films material properties after optimization of the thermal treatments for the 5 and 10 mole-percent La doped BST thin films.

Subject Categories:

  • Inorganic Chemistry
  • Electrical and Electronic Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE