Anisotropic tuning behavior in epitaxial Ba0.5Sr0.5TiO3 thin films

Hyun, Seung Dam; Lee, J. H.; Kim, S. S.; Char, K.; Park, S. J.; Sok, Junghyun; Lee, E. H.

doi:10.1063/1.1323996

Cited by 48 publications

(21 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The strain in the epitaxial films also affects their local tuning properties. By using a scanning microwave microscope (SMM) method, Hyun et al 53 investigated the effects of different strains on the local tuning properties of epitaxial (Ba 0.5 Sr 0.5 )TiO 3 thin films grown on MgO (001) and LAO (001) substrates. It is interesting to observe remarkably different tuning properties in the planar capacitors measured by SMM.…”

Section: Film Stressmentioning

confidence: 99%

Recent progress of (Ba,Sr)TiO3 thin films for tunable microwave devices

Zhu

Zhou

et al. 2003

Journal of Elec Materi

View full text Add to dashboard Cite

The (Ba 1-x Sr x )TiO 3 (BST) ferroelectric thin films exhibit outstanding dielectric properties, even at high frequencies (Ͼ1 GHz), and large, electric-field dielectric tunability. This feature makes them suitable for developing a new class of tunable microwave devices. The dielectric properties and dielectric tuning property of BST thin films are closely related to the film compositions, substrate types, and post-deposition process. The successful implementation of BST films as high-frequency dielectrics in electrically tunable microwave devices requires a detailed understanding of both their processing and material properties. This paper will review the recent progress of BST thin films as active dielectrics for tunable microwave devices. The technical aspects of BST thin films, such as processing methods, post-annealing process, film compositions, film stress, oxygen defects, and interfacial structures between film and substrate, are briefly reviewed and discussed with specific samples from the recent literature. The major issues requiring additional investigations to improve the dielectric properties of BST thin films for tunable microwave applications are also discussed.

show abstract

Section: Film Stressmentioning

confidence: 99%

Recent progress of (Ba,Sr)TiO3 thin films for tunable microwave devices

Zhu

Zhou

et al. 2003

Journal of Elec Materi

View full text Add to dashboard Cite

show abstract

“…In this work, we investigate the dielectric properties over a very wide range of microwave frequencies ͑45 MHz-50 GHz͒, rather than at the lower, narrower frequency ranges ͑Ͻ10 GHz͒ more commonly studied. [3][4][5] The material investigated is Ba 0.5 Sr 0.5 TiO 3 , which has a Curie temperature ͑T c ͒ around room temperature.…”

Section: Introductionmentioning

confidence: 99%

Microwave properties of Ba0.5Sr0.5TiO3 thin film coplanar phase shifters

Suherman

Jackson

Tse

et al. 2006

Journal of Applied Physics

View full text Add to dashboard Cite

Coplanar waveguide transmission lines have been used to show that the temperature dependent properties of Ba 0.5 Sr 0.5 TiO 3 thin films used for microwave phase shifters in the frequency range 45 MHz-50 GHz are correlated strongly with the microstructure of the films. The highest tunability and figure of merit of the phase shifters were obtained for films with the narrowest ferroelectric-paraelectric phase transition range, lowest mosaic spread, and widest columnar microstructure. The study also showed that the operating temperature plays an important role in achieving the optimum phase shift for microwave applications.

show abstract

“…The small tunability can be interpreted as a result of inplane compressive stress of BaTiO 3 film exhibiting large dielectric anisotropy. Hyun et al [9] reported that the in-plane compressive stress in the BST film with an interdigital electrode decrease the ionic displacement along the electric field parallel to substrate and large tunability should exist near the electrode where the electric field is normal to the substrate since the BST film has distorted tetragonal structure with c/a of 1.009 by in-plane compressive stress. In this work, the measured c/a ratio of epitaxial BaTiO 3 film was 1.04.…”

Section: Resultsmentioning

confidence: 98%

Microwave Dielectric Properties of Ferroelectric BaTiO3 Thin Film

Hyun

Choi

2004

J Electroceram

View full text Add to dashboard Cite

The dielectric properties of c-axis epitaxial BaTiO 3 thin film on LaAlO 3 are investigated at frequencies of 0.5-30 GHz. For the measurements, interdigital capacitors with the Au/Ti electrode configurations of five fingers pairs that are 15 µm wide and spaced 2 µm apart are prepared by photolithography and lift-off patterning. Finger length varies from 20 to 80 µm. The capacitance of epitaxial BaTiO 3 films exhibited no frequency dependence up to 10 GHz with the exception of slightly upward tendency of capacitance in BaTiO 3 film with a finger length of 80 µm due to the self resonant frequency at 20 GHz. The Q-factors of the capacitors, defined as Q = 1/ωCR, are decreased up to 10 GHz with increased frequency. At 10 GHz, the BaTiO 3 film has a tunability [defined as k(V ) = [C(0) − C(V )]C(0)] of 1.5% at 15 V, a loss tangent of ≤0.2 at room temperature. The small tunability can be interpreted as a result of in-plane compressive stress of BaTiO 3 film exhibiting large dielectric anisotropy. For the improvement of tunability and dielectric loss in the interdigital BaTiO 3 capacitor, the tetragonality (c/a) of epitaxial BaTiO 3 film and design of interdigital capacitor should be modified.

show abstract

Anisotropic tuning behavior in epitaxial Ba0.5Sr0.5TiO3 thin films

Cited by 48 publications

References 17 publications

Recent progress of (Ba,Sr)TiO3 thin films for tunable microwave devices

Recent progress of (Ba,Sr)TiO3 thin films for tunable microwave devices

Microwave properties of Ba0.5Sr0.5TiO3 thin film coplanar phase shifters

Microwave Dielectric Properties of Ferroelectric BaTiO3 Thin Film

Contact Info

Product

Resources

About