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Improvement of dielectric loss tangent of Al2O3 doped Ba0.5Sr0.5TiO3 thin films for tunable microwave devices

Chong, K. B.; Kong, L. B.; Chen, L. F.; Yan, L.; Tan, C. Y.; Yang, T.; Ong, C. K. and Opsipowicz, T. (2004). Improvement of dielectric loss tangent of Al2O3 doped Ba0.5Sr0.5TiO3 thin films for tunable microwave devices. Journal of Applied Physics, 95(3) pp. 1416–1419.

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Al2O3 doped Ba0.5Sr0.5TiO3 (BST) thin films, with different Al2O3 contents, were deposited on (100) LaAlO3 substrates by the pulsed laser deposition technique to develop agile thin films for tunable microwave device applications. The dielectric properties of Al2O3 doped BST films were determined with a nondestructive dual resonator near 7.7 GHz. We demonstrated that the Al2O3 doping plays a significant role in improving the dielectric properties of BST thin films. The Al2O3 doping successfully reduced the dielectric loss tangent (tan δ) from 0.03 (pure BST) to 0.011 (Al2O3 doped BST). Reduction in the loss tangent also leads to reduction in the dielectric constant and dielectric tunability. Our results showed that the BSTA4 film remains tunability=15.9%, which is sufficient for tunable microwave devices applications. Consequently, the Al2O3 doping improved the figure of merit (K) for the BST films from K=7.33 (pure BST) to K=14.45 (Al2O3 doped BST).

Item Type: Journal Item
Copyright Holders: 2004 American Institute of Physics
ISSN: 0021-8979
Extra Information: This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 23060
Depositing User: K B Chong
Date Deposited: 16 Sep 2010 10:47
Last Modified: 08 Oct 2016 08:09
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