Pre-breakdown conduction in polymeric films

Fundamental understanding of carrier mobility-related pre-breakdown phenomena in dielectrics provides insights into high field transport phenomena as well as associated aging and onset of charge injection instability. A system for measuring resistive current through a planar dielectric film during a linear ramp voltage to breakdown has been developed to address the limits of conventional steady-state approaches in which the sample typically fails prior to achieving steady state current at around sixty percentage of the breakdown field. With this technique, pre-breakdown conduction in polypropylene, polystyrene and polyethylene-terephthalate thin films with varying molecular structures, crystallinity, chain orientation were studied extensively under room and elevated temperatures. The ability to measure resistive current up to breakdown will advance the fundamental understanding of conduction mechanisms in polymeric dielectrics and provide a basis for material engineering for improved high field performance.