Specimen development for evaluating electrical properties and study of breakdown mechanism on extremely thin PEN film

To understand the breakdown mechanism of extremely thin Polyethylene Naphthalate (PEN) film, the conduction current and the breakdown strength (Fb) were measured using the modified method. In addition, the surface temperature and the conduction current up to the breakdown were observed. The aluminum (Al) sheets were placed between the brass electrode and the evaporated electrode on extremely this PEN film. The conduction current exhibits the positive temperature dependence like that of a normal polymer. The DC-Fb and AC-Fb (Fb : Breakdown strength) increased with decrease of the film thickness. The AC-Fb in RMS value was lowest and the Imp-Fb highest. The local heating was observed before the breakdown. From these results, it was suggested that the thermal breakdown process might be preferable process rather than the electronic process.