Modified Ba(1-x)Sr(x)TiO3 Thin Films for Tunable Device Applications
Abstract
Pure and La doped Ba(0.6)Sr(0.4)TiO3 (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 10(exp 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 kV/cm), respectively. Films doped at concentrations between 5 and 10 mole-percent possessed under developed microstructures, suggesting that higher annealing temperatures and/or 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2001
- Accession Number
- ADA393194
Entities
People
- C. W. Hubbard
- Eric H. Ngo
- M. H. Ervin
- Melanie W. Cole
- P. C. Joshi
Organizations
- United States Army Research Laboratory