Transient conduction in insulators at high fields

Abstract

Transient and steady-state conduction in insulators at high fields are studied through a one-carrier single trap level insulator model. It is found that at high fields the conduction-band (electron) density generally produces a negligible field distortion. Therefore, attention is focused on calculating the spatial and temporal behavior of the trapped electron distribution. This behavior, during the initial transient, is dominated under high-injection conditions by trapping and under low-injection conditions by detrapping. By relating the trapped electron distribution to externally measured currents and voltages the trap density and capture cross section can be determined under trapping conditions and the trap depth and insulator dynamic dielectric constant determined under detrapping conditions. Extending the measurements to steady-state conditions facilitates determining the injecting contact-current-field relations and the attempt-to-escape frequency. Thus, all of the parameters of this model are uniquely determinable by experiment. This model has been successfully applied to the study of silicon nitride.