Hostname: page-component-8448b6f56d-m8qmq Total loading time: 0 Render date: 2024-04-18T23:59:22.148Z Has data issue: false hasContentIssue false
  • English
  • Français

Models for Electronic Conduction Across Ceramic Grain Boundaries

Published online by Cambridge University Press:  28 February 2011

L. C. Burton
L. C. Burton*
Affiliation:
College of EngineeringVirginia Polytechnic Institute and State UniversityBlacksburg, VA 24061
Get access

Abstract

Electronic current flow over grain boundary potential barriers for low resistance grains is first reviewed. It is then shown that if the resistance of the grains increases and/or grain size is reduced, the grains may be totally depleted of mobile charge. The grain boundary barrier is thus reduced to (D/2W)2 of its original large grain value, D being grain width and W the full space charge width. For high resistivity grains satisfying the relation D ≪ 2W, the conduction band becomes essentially flat. Phenomena formerly caused by grain boundary potential barriers (varistor and PTC effects seen in semiconducting ceramic) will be greatly reduced, or eliminated.

Commercial COG and X7R MLC capacitors exhibit a transition from super-ohmic to ohmic behavior at high voltages, paralleling the behavior of the varistor. Two possible mechanisms that could account for this are varistor-like grain boundary behavior, or space charge limited diffusion current.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 60: Symposium L – Defect Properties and Processing of High-Technology Nonmetallic Materials , 1985 , 179
Copyright
Copyright © Materials Research Society 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. O’Dwyer, J. J., The Theory of Electrical Conduction and Breakdown in Solid Dielectrics, Oxford Press (1973).Google Scholar
2. Kao, K. C. and Hwang, W., Electrical Transport in Solids, Pergamon Press (1981)Google Scholar
3. Lampert, M. A. and Mark, P., Current Injection in Solids, Academic Press (1970).Google Scholar
4. Kazmerski, L. L. (ed.), Polycrystalline and Amorphous Thin Films and Devices, Academic Press (1980).Google Scholar
5. Harbeke, G. (ed.), Polycrystalline Semiconductors, Springer-Verlag (1985).CrossRefGoogle Scholar
6. Yan, M. F. and Heuer, A. H. (eds.), Additives and Interfaces in Electronic Ceramics, Adv. in Ceramics vol. 7, American Ceramic Society (1983).Google Scholar
7. Levinson, L. M. and Hill, D. C. (eds.), Grain Coundary Phenomena in Electronic Ceramics, Adv. in Ceramics vol. 1, American Ceramic Society (1981).Google Scholar
8. Pike, G. E. and Seager, C. H., The DC Voltage Dependence of Semiconductor Grain-Boundary Resistance, J. Appl. Phys. 50, 3414 (1979).CrossRefGoogle Scholar
9. Sze, S. M., Physics of Semiconductor Devices, John Wiley & Sons (1981).Google Scholar
10. Seager, C. H. and Pike, G. E., Grain Boundary States and Varistor Behavior in Solicon Bicrystals, Appl. Phys. Lett. 35, 709 (1979).CrossRefGoogle Scholar
11. Morris, W. G., Physical Properties of the Electrical Barriers in Varistors, J. Vac. Sci, Technol. 13, 926 (1976).CrossRefGoogle Scholar
12. Mahan, G. D., Levinson, L. M. and Philip, H. R., Theory of Conduction in ZnO Varistors, J. Appl. Phys. 50, 2799 (1979).CrossRefGoogle Scholar
13. Hower, P. L. and Gupta, T. K., A Barrier Model for ZnO Varistors, J. Appl. Phys. 50, 4847 (1979).Google Scholar
14. Burton, L. C., Voltage Dependence of Activation Energy for Multilayer Ceramic Capacitors, to appear in IEEE Transactions CHMT, Dec. 1985.CrossRefGoogle Scholar
15. Bagley, B. G., The Field Dependent Mobility of Localized Electronic Carriers, Sol. State Commun. 8, 345 (1970).CrossRefGoogle Scholar
16. Kao, K. C. and Rashwan, M. M., On The Thermal Activation Energy for High-Field Electric Conduction in Dielectric Liquids, IEEE Trans. Electr. Insul. Vol. EI–13, 86 (1978).CrossRefGoogle Scholar
17. Loh, E., A Model of DC Leakage in Ceramic Capacitors, J. Appl. Phys. 53, 6229 (1982).CrossRefGoogle Scholar
18. Eda, K., Iga, A. and Matsuoka, M., Degradation Mechanism of Non-Ohmic Zinc Oxide Ceramics, J. Appl. Phys. 51, 2678 (1980).CrossRefGoogle Scholar
19. Gupta, T. K. and Carlson, W. G., A Grain Boundary Defect Model for Instability/Stability of a ZnO Varistor, to appear in J. Mater. Sci.Google Scholar