Characterization of internal boundary layer capacitors based upon barium titanate and strontium titante
Abstract
The nature of ceramic microstructure and the electrical properties of individual grains and junctions was determined by STEM, microprobe analysis and microscale electrical measurements. The chemical compositions of the resistive boundary regions were different from those of the grains. Additives were concentrated in the boundary regions, forming resistive layers. Limited diffusion of the counterdopants into the grain subsurface formed an interfacial compensation layer between the insulating intergranular layer and the semiconducting grains. The electrical behavior of this intermediate layer was found to be similar to that of a depletion layer. Ceramic microstructures was approximated by a three-layer n-c-i-c-n model and representive equivalent circuit, which was used to explain the voltage dependence of the dielectric constant and dispersion behavior. Fine grain microstructures developed by liquid phase sintering techniques were suitable for high dielectric constant multilayer capacitors, based upon internal boundary layer phenomena, and these capacitors and stable dielectric characteristics.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- August 1981
- Bibcode:
- 1981PhDT.........8P
- Keywords:
-
- Barium Titanates;
- Capacitors;
- Ceramics;
- Strontium Titanates;
- Boundaries;
- Electrical Properties;
- Microstructure;
- Sintering;
- Solid-State Physics