Dielectric breakdown of solids by electron avalanches

摘要

While the sequence of events leading to electric breakdown in gases is today fairly well understood, research in the case of solids asks still the basic question about the mechanisms causing the destruction of dielectrics under high field-strength. This lag in advance is partly inherent in the experimental difficulties of handling such fields, and partly-due to the complexities of the solid state. Solid insulation may suffer breakdown in various ways, by thermal activation of charge carriers or chemical decomposition, by dendrite formation or electron trapping, and finally, when these types of destruction are avoided, by electronic impact ionization. It is the purpose of the present paper to re-evaluate the mechanism of this last and limiting breakdown type in the light of new evidence.