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Humidity Effects on Porous Silica Thin Films

Published online by Cambridge University Press:  10 February 2011

J. R. Kokan  and
R. A. Gerhardt
J. R. Kokan
Affiliation:
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245
R. A. Gerhardt
Affiliation:
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245
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Abstract

Impedance Spectroscopy is being used to study the humidity sensitivity of porous silica thin films. The films are processed via a colloidal sol-gel method which leaves some remnant potassium and sodium. Previous work on bulk porous silica samples processed by the same method showed that the dielectric properties and ac conductivity were very sensitive to changes in humidity. The aim of this work was to determine if the same dependencies could be found in the thin films. The capacitance, dielectric loss, and ac conductivity of the films were measured in a controlled environment chamber from 20–80% RH for frequencies ranging from 10Hz–10MHz. In addition to characterizing films with varying amounts of residual alkali ions obtained through leaching, we have also measured films that were surface doped with controlled amounts of KCl, LiCl, or NaCl. Relative humidity dependencies in the films are not as dramatic as in the bulk samples. The reasons for this behavior are not yet clear, but may be associated with the porosity, thickness, and surface area of the films.

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Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 411: Symposium T – Electricaly-Based Microstructural Characterization , 1995 , 419
Copyright
Copyright © Materials Research Society 1996

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References

REFERENCES

1. Kulwicki, B. M., “Humidity Sensors”, J.Am.Ceram.Soc. 74[4] 697–708 (1991).Google Scholar
2. Yamazoe, N. and Shimizu, Y., “Humidity Sensors: Principles and Applications”, Sensors and Actuators 10, 379–398 (1986).Google Scholar
3. Seiyama, T., Yamazoe, N. and Arai, H., “Ceramic Humidity Sensors”, Sensors and Actuators 4, 85–96 (1983).Google Scholar
4. Fagan, J. G. and Amarakoon, V.S., “Reliability and Reproducibility of Ceramic Sensors. Part III. Humidity Sensors”, Am. Ceram. Soc.BulI. 72[3], 119–130 (1993).Google Scholar
5. Shoup, R.D. and Wein, W.J., “Low Temperature Production of High Purity Fused Silica”, U.S. Patent No. 4059658, Nov. 22, 1977.Google Scholar
6. Gerhardt, R., Kerch, H.M., Long, G.G. and Cosandey, F., unpublished results.Google Scholar
7. Cao, W., Gerhardt, R. and Wachtman, J.B., Jr., “Low Permittivity Porous Silica by a Colloidal Processing Method”, Adv. Ceramics 26, 409–418 (1989).Google Scholar
8. Cao, W., Gerhardt, R. and Wachtman, J.B., Jr., “Dielectric Relaxation of Water Adsorbed on Monolithic Porous Silica Gels”, Ceram. Trans. 8, 175–184 (1990).Google Scholar
9. Cao, W., Gerhardt, R. and Wachtman, J.B., Jr., Mat.Res.Soc.Symp. Proc. 195, 471–476 (1990).Google Scholar
10. Zhang, G., “Effects of Alkali Ions on the Dielectric Properties of Porous Silica Prepared by a Colloidal Processing Method,” M.S. Thesis, The Georgia Institute of Technology, 1993,Google Scholar
11. Gerhardt, R., “Dielectric and Impedance Spectroscopy Revisited: Distinguishing Localized Relaxation from Long Range Conductivity, J. Phys. Chem. Solids 55[12], 1491–1506 (1994).Google Scholar
12. Kokan, J.R., Tadayon, F., Gerhardt, R.A. and Kohl, P.A., “Sol-Gel Processing of Porous Silica Thin Films for Interlevel Dielectrics in Integrated Circuits”, IEEE Proc. 44th Annual Electron Components and Technology Conf, pp. 704–711 (1994).Google Scholar
13. Gerhardt, R.A., Kokan, J.R. and Kohl, P.A., “Low Permittivity Porous Silica Thin Films for MCM-C/D Applications”, in Advances in Ceramics Multi-Chip Module (MCM) and High Performance Electronic Materials (ed. Jones, W.K.), NATO Proc., Kluwer Academic Publishers, pp. 209–219 (1994).Google Scholar
14. Cao, W., Gerhardt, R. and Wachtman, J.B., Jr., “Preparation and Sintering of Colloidal Silica: Alkali Silicate Gels”, J.Am.Ceram.Soc. 71[12], 1108–1113(1988).Google Scholar
15. Meyers, K.S., Zhang, G. and Gerhardt, R., this proceedings.Google Scholar
16. Kerch, H.M., Gerhardt, R. and Grazul, J., “Quantitative Electron Microscopic Investigation of the Pore Structure in 10:90 Colloidal Silica-Potassium Silicate Sol-Gels”, J.Am. Ceram.Soc. 73 [8], 2228–2237 I(1990).Google Scholar
17. Kerch, H.M., Cosandey, F. and Gerhardt, R., “Imaging of Fine Porosity in Colloidal Silica:Alkali Silicate Gels by a Defocus Contrast Technique”, J.Non-Cryst.Solids 152, 18–31 (1993).Google Scholar
18. Conchie, S., “Humidity Sensing–A Cinderella Technology?” Paper Technology, 32[4]43–44 (1991).Google Scholar