Critical Review Atmospheric plasmas for thin film deposition: A critical review Delphine Merche, Nicolas Vandencasteele, François Reniers ⁎ Université Libre de Bruxelles, Faculty of Sciences, Analytical and Interfacial Chemistry Department, Avenue F. D. Roosevelt 50, B-1050 Brussels, Belgium abstract article info Available online 21 January 2012 Keywords: Atmospheric plasma Deposition APECVD Organic coatings Inorganic coatings Hybrid coatings Plasma-polymerization An overview of the possibilities of atmospheric plasma for the deposition of inorganic and organic coatings is presented. Some particularities of the atmospheric discharges and their consequences on the synthesis of films are presented and discussed. © 2012 Published by Elsevier B.V. Contents 1. Introduction and historical background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4219 2. Atmospheric pressure plasma for the deposition of coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4221 3. Basic facts about atmospheric plasmas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4223 4. The pressure–distance constraint in atmospheric plasma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4226 5. Coatings deposited by atmospheric plasmas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4226 6. Synthesis of hybrid coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4227 7. Co-deposition: organic sulfonated membranes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4227 8. Polymerization using atmospheric pressure plasmas: general mechanisms and experimental parameters. . . . . . . . . . . . . . . . . . . 4228 9. Effect of the power on coatings properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4229 10. Effect of the nature of the plasma gas and of the nature of the substrate material on the chemical structure of an organic coating . . . . . . . 4229 11. Post-discharge or “in discharge” plasma polymerization? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4230 12. Pulsed plasmas at atmospheric pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4230 13. Effect of the injection mode on the resulting chemistry of a coating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4231 14. Comparison: coatings under vacuum/liquid/plasma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4232 15. Deposition rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4233 16. Nucleation in the gas phase or at the gas substrate interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4234 17. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4234 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4234 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4234 1. Introduction and historical background Plasmas, a word proposed by Langmuir [1], are often called the 4th state of matter and represent 97% of the universe. A commonly accept- ed definition is that a plasma is a partially or fully ionized gas. Although at the beginning, plasmas were considered as a topic of fundamental re- search for physicists; very quickly, the energy available in a plasma dis- charge was thought to be useful for applications. In parallel, the deposition of coatings has always been a technological and fundamental challenge for academia and industry. More specifically, in order to modify the surface properties of a material, scientists have developed many technologies to deposit the appropriate coatings on essentially every substrate. The challenges are numerous: control of the chemistry and structure of the layer, adhesion of the layer on a sub- strate, deposition rate, geometric concerns, minimizing the energy injected…. It was therefore normal that sooner or later, the energy available in a plasma discharge was used to help depositing a coating. In the first part of this introduction, we will briefly describe some other major existing deposition techniques. We will then introduce atmospheric plasmas, and basic concerns about plasmas in general, while stressing the particularities of atmospheric plasmas. Thin Solid Films 520 (2012) 4219–4236 ⁎ Corresponding author. E-mail address: freniers@ulb.ac.be (F. Reniers). 0040-6090/$ – see front matter © 2012 Published by Elsevier B.V. doi:10.1016/j.tsf.2012.01.026 Contents lists available at SciVerse ScienceDirect Thin Solid Films journal homepage: www.elsevier.com/locate/tsf