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Low Sintering Temperature of CuO-Fluxed Ag(Nb, Ta)O3 Dielectric Ceramics

Published online by Cambridge University Press:  01 February 2011

Chiping Wang ,
Thomas Shrout ,
Gaiying Yang ,
Hyo-Tae Kim ,
Do-Kyun Kwon  and
Michael T. Lanagan
Chiping Wang
Affiliation:
Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802
Thomas Shrout
Affiliation:
Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802
Gaiying Yang
Affiliation:
Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802
Hyo-Tae Kim
Affiliation:
New Functional Materials Research Department, Korea Institute of Ceramic Eng. and Tech.
Do-Kyun Kwon
Affiliation:
Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802
Michael T. Lanagan
Affiliation:
Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802
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Abstract

Solid solutions in the Ag(NbxTa1−x)O3 (where 0 ≤ × ≤ 1) system exhibit excellent dielectric properties at microwave frequency including high dielectric constant (200<k<400), low loss (tanΔ ∼ 0.004) and a composition controlled temperature coefficient of capacitance (TCC). For Ta-rich and Nb-rich solid solutions, the TCC values are negative and positive, respectively, and two-phase mixtures provided an average TCC close to zero. Series, parallel, and logarithmic mixing rules were applied to predict dielectric constant and TCC of polyphase assemblages (45wt%Ag(Nb0.65Ta0.35)O3+55wt% Ag(Nb0.35Ta0.65)O3) yielded an average dielectric constant of 450 and a TCC of 180ppm/°C. Microstructure analysis revealed that a CuO-rich liquid remains at the grain boundary and transmission electron microscopy shows that the CuO resides at triple points. Ag(NbxTa1−x)O3 ceramics were successfully integrated into LTCC for embedded capacitors. The addition of CuO lowered the sintering temperature to below 900°C and a low TCC was maintained for fine grained microstructures.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 783: Symposium B – Materials, Intergration, and Packaging Issues for High-Frequency Devices , 2003 , B1.3
Copyright
Copyright © Materials Research Society 2004

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References

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