In this paper temperature and frequency dependence of dielectric properties and their relation to dc electrical conduction current of polysiloxaneimide thin films in high temperature region were studied and their mechanisms were discussed.
As temperature rises, dielectric dissipation factor (tanδ) increased, especially tanδ in the low frequency region markedly increased even at relatively low temperature. Dielectric constant showed little dependence on temperature. Temperature dependence of dc conduction current almost obeyed Ahrenius-formula. Based on these results, the mechanism of ac conduction was discussed. The analysis revealed that the ac conduction loss due to the mobile carrier becomes prominent at higher temperature and at lower frequency, and the ac inherent loss such as dipole relaxation loss are conspicuous at lower temperature and at higher frequency.