Atomic force microscopic observation at initial growth stage of vacuum-deposited thin film of polyvinylidenefluoride

Abstract

Vinylidenefluoride and tetrafluoroethylene copolymer powder was evaporated to grow a thin film of polyvinylidenefluoride on a Si wafer with the native oxide layer held at 80 °C in a vacuum of 10−5 Torr. Its initial growth process was studied with an atomic force microscope. Some features in the initial film growth stage at 0.2 to 6 nm in its thickness d are: (1) “plateau” and “mountain” islands with the number density in the order of 107 cm−2 grow with the coverage linearly increasing with d; (2) secondary plateau islands grow at d>2 nm; (3) the height was 6, 25, and 1.5 nm for plateau, mountain, and secondary plateau islands, respectively, which was almost independent of d. These are briefly discussed from the viewpoint of the crystallization of bulk polymer and from the thin film growth process.