Ionization mechanism of the electrical degradation (breakdown) of polymer dielectric films

A physical mechanism is proposed explaining rapid (for a time of $\sim$10$^{-7}$ s) increase in the current during an electrical breakdown of polymer dielectrics. Accumulation of positive molecular ions and electrons in a local region of a polymer as a result of field ionization of macromolecules is considered as the formation of quasi-neutral plasma in which the effect of Debye screening of charges occurs, leading to a decrease in the molecule ionization potential, which, in turn, accelerates the formation of unbound charges in the polymer. It is shown that the occurrence of these interrelated processes, the rates of which increase in time, leads, at a certain stage, to an explosive change in the polymer properties. A self-accelerating process has been revealed leading to an increase in the concentration of quasi-free charges, the development time of which is comparable to the time of breakdown evolution.