Pulsed laser deposition creates high-quality PTFE films

Researchers at the Johannes Kepler University (Linz, Austria) have used pulsed laser deposition for the fabrication of high-quality thin films of polytetrafluoroethylene (PTFE, or Teflon). Deposition was performed from sintered-powder PTFE targets by means of 248-nm krypton fluoride excimer-laser radiation. Metallic, semiconducting, and insulating substrates were used. The background atmosphere was argon. The deposited films are pure Teflon and highly crystalline and consist of large spherulites with diameters of up to more than a millimeter. Because of the outstanding physical and chemical properties of PTFE, such films are desirable for many applications, for example as a low-dielectric-constant material in microelectronics, as an electret in electroacoustics and electromechanics, and as an inert coating in biomedical applications. Negatively charged films exhibit an exceptional charge stability with practically no decrease of the surface potential up to 225°C in open-circuit thermally stimulated discharge. Contact Dieter Bäuerle atdieter.baeuerle@jk.uni-linz.ac.at.