Improvement of dielectric loss tangent of Al₂O₃ doped Ba_0.5Sr_0.5TiO₃ 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 Ba_0.5Sr_0.5TiO₃ thin films for tunable microwave devices. Journal of Applied Physics, 95(3) pp. 1416–1419.

DOI: https://doi.org/10.1063/1.1638615

Abstract

Al₂O₃ doped Ba_0.5Sr_0.5TiO₃ (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).

Viewing alternatives

Metrics

Item Actions

Export

You can export this page using these formats Digital Object Identifier - DOI

About

• Item ORO ID
• 23060
• Item Type
• Journal Item
• 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 or School
• Faculty of Science, Technology, Engineering and Mathematics (STEM)
• Copyright Holders
• © 2004 American Institute of Physics
• Depositing User
• Kok Boon Chong