Influence of irradiation on the thermally stimulated depolarization currents of polyimide films

Thermally stimulated depolarization (TSD) currents and temperature dependences of the conductivity of non-irradiated, irradiated and irradiated and heated polyimide (PI) films (Kapton, Du Pont) were studied. The films were irradiated by the electrons with energy 900 keV. The experimental results were analysed on the base of different models describing the processes of charge accumulation and relaxation. It was observed that the charge relaxation occurred due to electrical conductivity of the dielectric both in non-irradiated and irradiated samples. It was shown that direct correlation between the conductivity of the films and the TSD currents exists.