Consideration of space charge effect on electrical breakdown of poly-p-phenylene sulfide films

The space charge effects on electrical breakdown were investigated on PPS (poly-p-phenylene sulfide) films with three different thicknesses, 6, 13, and 25 mu m. The difference between impulse and DC breakdown strengths suggested the effect of space charge. The larger space charge effect appeared in the thinner samples. The effect of DC prestress on the breakdown strength was investigated. The positive space-charge accumulation was directly probed by the laser-induced-pressure-pulse technique. The amount of space charge and its penetration depth were estimated to be about 10/sup -7/ C/cm/sup 2/ and 10 mu m from the anode (homo space charge), respectively, under 1-2 MV/cm at 30 degrees C. Both were insensitive to the sample thickness.<>