Non-contact electrical measurements of hot and cold domains in silica dielectric breakdown.
Noncontact examination of dielectric breakdown in thin silica layers reveals the stochastic appearance of coexisting stable and "broken" surface domains. Using chemically resolved electrical measurements for resolving electrically these domains, a power law evolution of the hot channels above the percolation critical point is found, approximately (V - V(C))(2/3), accounted for by a model for discharge across a two-phase medium. Consistency with the electrical data is shown, where voltage dependent percolation paths are scanned under controllable termination of the sparklike avalanche processes. Interface effects are found to qualitatively alter the V - V characteristics of high quality layers. Useful applications in studies of stressed insulating components are expected.
Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot 76100, Israel. hagai.cohen@weizmann.ac.il
Hagai
H
Cohen