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Bismuth Pyrochlore Films for Dielectric Applications

Published online by Cambridge University Press:  10 February 2011

Wei Ren,
Ryan Thayer,
Clive A. Randall,
Thomas R. Shrout and
Susan Trolier-McKinstry
Wei Ren
Affiliation:
Materials Research Laboratory, Pennsylvania State University, University Park, PA 16802-4801
Ryan Thayer
Affiliation:
Materials Research Laboratory, Pennsylvania State University, University Park, PA 16802-4801
Clive A. Randall
Affiliation:
Materials Research Laboratory, Pennsylvania State University, University Park, PA 16802-4801
Thomas R. Shrout
Affiliation:
Materials Research Laboratory, Pennsylvania State University, University Park, PA 16802-4801
Susan Trolier-McKinstry
Affiliation:
Materials Research Laboratory, Pennsylvania State University, University Park, PA 16802-4801
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Abstract

Bismuth pyrochlore ceramics have modest temperature coefficients of capacitance, good microwave properties, and can be prepared at relatively modest temperatures (∼900 – 1100 °C). This work focuses on the preparation and characterization of thin films in this family for the first time. A sol-gel procedure using bismuth acetate in acetic acid and pyridine, in combination with zinc acetate dihydrate and niobium ethoxide in 2-methoxyethanol was developed. The solution chemistry was adjusted to prepare (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7 and Bi2(Zn1/3Nb2/3)2O7 films. Solutions were spin-coated onto platinized Si substrates and crystallized by rapid thermal annealing. In both cases, crystallization occurred by 550 °C into the cubic pyrochlore structure. (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7 films remained in the cubic phase up to crystallization temperatures of 750 °C, while the structure of the Bi2(Zn1/3Nb2/3)2O7 thin films is dependent of the firing temperature: cubic below 650 °C and orthorhombic above 750 °C. A mixture of cubic and orthorhombic structures is found at 700 °C. The resulting BZN films are dense, uniform, and smooth (rms roughness of < 5 nm). Cubic bismuth zinc niobate films show dielectric constants up to 150, a negative temperature coefficient of capacitance, TCC, (∼ - 400 ppm/°C), tan δ < 0.01, and a field tunable dielectric constant. Orthorhombic films showed smaller dielectric constants (∼80), low tan δ (< 0.01), positive TCC, and field independent dielectric constants. TCC could be adjusted to new 0 ppm/°C using a mixture of orthorhombic and cubic material.

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References

1. Yan, M. F., Ling, H. C., and Rhodes, W. W., J. Am. Ceram. Soc., 73, 1106 (1990).10.1111/j.1151-2916.1990.tb05166.xGoogle Scholar
2. Liu, D., Liu, Y., Huang, S., and Yao, X., J. Am. Ceram. Soc., 76, 2129 (1993).10.1111/j.1151-2916.1993.tb08348.xGoogle Scholar
3. Cann, D. P., Randall, C. A., and Shrout, T. R., Solid State Comm., 100, 529 (1996).10.1016/0038-1098(96)00012-9Google Scholar
4. Wang, X., Wang, H., and Yao, X., J. Am. Ceram. Soc., 80, 2745 (1997).10.1111/j.1151-2916.1997.tb03189.xGoogle Scholar
5. Kagata, H., Inoue, T., Kato, J., and Kameyama, I., Jpn. J. Appl. Phys., 31, 3152 (1992).10.1143/JJAP.31.3152Google Scholar
6. Swartz, S. L., and Shrout, T. R., “Ceramic compositions for BZN dielectric resonators,” U. S. Patent, No. 5449652 (1995).Google Scholar
7. Cann, D. P., “Bismuth pyrochlores for high frequency dielectric applications,” MS Thesis, The Pennsylvania State University (1993).Google Scholar
8. Courtens, E., Phys. Rev. Lett, 52, 69 (1984).10.1103/PhysRevLett.52.69Google Scholar
9. Höchli, U. T., Phys. Rev. Lett., 48, 1494 (1982).10.1103/PhysRevLett.48.1494Google Scholar
10. Bhattacharya, S., Nagel, S. R., Fleishman, L. and Susman, S., Phys. Rev. Lett., 18, 1267 (1982).10.1103/PhysRevLett.48.1267Google Scholar
11. Huser, D., Wenger, L.E., Duyneveldt, A. J. van, and Mydosh, J. A., Phys. Rev. B 27, 3100 (1983).10.1103/PhysRevB.27.3100Google Scholar