Failure mechanisms of polyimide and perfluoroalkoxy films under high frequency pulses

Breakdown behaviors of polyimide and perfluoroalkoxy high temperature films under unipolar and bipolar repetitive pulses are investigated. A bipolar 20 kV, 20 kHz pulse generator with fast dV/dt pulse risetime has been designed and built to study the impact of pulse frequency, pulse rise time, and pulse polarity and pulse duty cycles on breakdown strength of these films films. Space charge injection and decay processes are also investigated. Possible failure mechanisms are discussed.