On the Mechanism of Dielectric Breakdown of Solids

The mechanism of dielectric breakdown in solids, according to recent experimental evidence, involves the creation of a gaseous channel through the dielectric. The high conductance of breakdown appears to be associated with this channel, not with conduction through the solid itself. The central problem in the theory of dielectric breakdown in solids is thus to explain the development, in a strong electric field, of a macroscopic gaseous channel through the dielectric before the large change of conductance characteristic of dielectric breakdown. Recent experimental results will be reviewed and a gaseous model of breakdown in solids will be described in terms of four stages: Formative, Tree Initiation, Tree Growth and Return Streamer. The model is still in the stage of phenomenological development.