Electrical properties of ultra thin polymer films

Abstract

Ultra thin polyamide (PA) films (thickness: 2/spl sim/3 nm) were deposited on a glass substrate by the vacuum evaporation method. The evaporated PA thin film was annealed at 200/spl deg/C for one hour in nitrogen. The FT-IR spectrum of the ultra thin film agreed well with that of a conventional PA film, which suggests that the structure of the two types of film is similar. The binding energies of O/sub 1s/ and C/sub 1s/ spectra shift to the higher energy side. This means that the thin PA film was slightly oxidized in the evaporation process. The breakdown strength and electrical conduction of the thin PA film were discussed. The conduction currents of 2.3 nm-thick film were measured under an applied DC field of 2.5 V, which corresponds to 10 MV/cm. No self healing breakdown occurs until 8 MV/cm. This value is much higher than the breakdown strength of a conventional PA film (2.4 MV/cm). The conduction mechanism of the thin film annealed in vacuum is discussed.