La doped Ba{sub 1{minus}x}Sr{sub x}TiO{sub 3} thin films for tunable device applications
Pure and La doped Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} thin (BST) films were fabricated via the metalorganic solution deposition technique using carboxylate-alkoxide precursors on Pt{endash}Si substrates. The La doping concentration, from 0 to 10 mol%, was found to have a strong influence on the 750{degree}C postdeposition annealed films material properties. All films possessed a nontextured polycrystalline microstructure with no evidence of secondary phase formation. The pure and 1 mol% 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 mol% La doped BST thin films with respect to that of undoped BST films. The 1 mol% La doped BST film exhibited a lower dielectric constant, (283 vs 450) and enhanced resistivity (31.4{times}10{sup 13}{Omega}cm vs 0.04{times}10{sup 13}{Omega}cm) with respect to that of undoped BST films. The loss tangent and tunability (at 100 kHz) of the 1 mol% La doped BST films were 0.019% and 21% (at E=300kV/cm), respectively. Films doped at concentrations between 5 and 10 mol% possessed under developed microstructures suggesting that higher annealing temperatures and/or longer annealing times are required. The single phase structure of the 5{endash}10 mol% La doped BST films, combined with the beneficial influence of the 1 mol% 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{endash}10 mol% La doped BST thin films.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40203764
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 89; ISSN 0021-8979
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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