Low Frequency Electrical Conduction in Thin Polyimide Films Prepared by Vapor Deposition Polymerization

Abstract

Two kinds of thin polyimide films are prepared by vapor deposition polymerization. One is annealed in air, and the other is annealed in a vacuum during imidization procedure. In this paper, electrical conduction in the two kinds of samples have been investigated with low frequency voltage, and the difference between them have been discussed from the view point of ionic conduction. The samples annealed in air shows lead of current phase that due to the accumulated ionic space charge in the vicinity of Al oxide layer at Al-polyimide boundary. The samples annealed in a vacuum shows lower conductivity and an anomalous current peak. The mechanism responsible for the peak has been discussed in terms of diffusion and drift of space charges accumulated near the electrode.