Morphology and electrical properties of ultra thin PTFE film prepared with RF sputtering

PTFE (polytetrafluoroethylene) film is an excellent insulating material. It also has good hydrophobicity and superior chemical stability. But it is difficult to make good thin films (thickness<10 μm). We have obtained ultra thin film (thickness<1 μm) with the RF sputtering method. The electric strength of 7.9 nm-thick film is about 7 MV/cm which is much higher than that of a conventional PTFE film. The conduction currents may be Schottky type in a high field region. The contact angle of an thin PTFE film is the almost same as that of a conventional PTFE film and it is 100° at a room temperature. This also means that the morphology of the ultra thin PTFE film (thin PTFE film) is similar to that a conventional PTFE film. The results of the electron spectroscopy for chemical analysis (ESCA) and the X ray diffraction revealed the thin PTFE film is an amorphous rich compound polymer