In this tutorial I will review the complex process of plasma deposition. Plasma deposition is an example of a deposition process in which the gas is activated, i.e. the presence of reactive species (radicals, ions and excited species) is key to the understanding of the film growth process. I will review the measurement of the reactive species by means of cavity ring down spectroscopy and threshold ionization mass spectrometry in a remote plasma. Another important aspect of film growth (or etching) is the plasma-surface interaction of the reactive species, i.e. the reaction probility of a reactive specie with the film growth surface and which is in most cases unknown. Several advanced experiments to determine this reaction probability under film growth conditions will be discussed. To unravel the physical and chemical processes occuring during the plasma-surface interaction, the film surface under plasma processing conditions needs to be characterized. Novel surface diagnostics, which employ the principle of photon-in-photon-out and thus are non-intrusive in nature, such as second harmonic generation and evanescent wave cavity ring down spectroscopy, will be discussed shortly.

Low temperature plasmas are fascinating medium where electrons, ions and reactive neutral species can coexist under a steady state but non-equilibrium conditions. Selective heating of electrons by electromagnetic fields and a slow energy transfer in elastic collisions are responsible for a large difference between electron and heavy particle temperatures. Deposition of thin films from these low temperature plasmas is interplay of several mechanisms. Energetic electrons generate reactive species in ionization, dissociation and excitation collisions with “cold” molecules. Surface reactions and surface diffusion of these reactive species result in formation of a condensate on the plasma-facing surface. Ions accelerated through the sheath on the edge of the plasma bombard the surface, modify significantly film properties and bring anisotropy into the film growth. High deposition rates and excellent and unique film properties in many applications can be achieved with these so-called Plasma Enhanced CVD processes. Basic principles of plasma chemistry, plasma/surface interaction and thin film growth will be discussed and selected examples of PECVD processes at low and atmospheric pressure will be shown in this lecture.

After a short review on polymeric surfaces properties, illustrations of the different surface treatments applied in polymer chemistry will be given. The discussion will be focused on a comparison between the cold plasma chemistry and the more classical treatments such as chemical, abrasive ones.
The efficiency of the plasma treatment will be related to the interactions between the different reactive species of the plasma phase and the polymer surface. These interactions induce four types of reactions onto the polymer surface: first of all activation, i.e. surface radicals formation, then cross-linking, degradation and functionalization. All these reactions take place, but their rates depend on the nature of polymer surface and of the plasma phase. An attention is also pointed out on the ageing properties of the modified surface.
Bioapplications of plasma-treated surface or plasma-deposited layers will be also described. The 3 types of plasma techniques, i.e. plasma modification, plasma deposition and plasma followed by grafting reaction are used for the fabrication of tools, medical devices and biomaterials. Depending on the application, bioadhesion of cells and biomolecules is either looked for or avoided. Since the mechanisms of bioadhesion depend on the characteristics of the surface : hydrophilic or hydrophobic, acid-base …; modifying the surface by a specific treatment will alter and therefore control the bioadhesion . Illustration will be given on anti-fouling process, sterilization and improvement of the biofilms formation. We will show how the plasma chemistry is powerful for the synthesis of biomimicking devices and sensors.