| AVS 61st International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS+2D-WeA |
| Session: | Plasma Processing for 2D Materials, Coating, and Surface Modification |
| Presenter: | Nicolas Vandencasteele, Université Libre de Bruxelles, Belgium |
| Authors: | J. Hubert, Université Libre de Bruxelles, Belgium N. Vandencasteele, Université Libre de Bruxelles, Belgium C. Poleunis, Université catholique de Louvain, Belgium J. Mertens, Université Libre de Bruxelles, Belgium A. Delcorte, Université catholique de Louvain, Belgium P. Bertrand, Université catholique de Louvain, Belgium F.A.B. Reniers, Université Libre de Bruxelles, Belgium |
| Correspondent: | Click to Email |
The deposition of PTFE like films by argon atmospheric plasma using various precursors, liquid at room temperature, is presented. Those compounds are: Perfluorohexane (C6F14), a fully saturated monomer, perfluoro(2-methylpent-2-ene) (C6F12) containing one unsaturated bond and Perfluorotributylamine (C12F27N), containing a central nitrogen atom to which 3 fully saturated perfluorobutyl chains are attached. The influence of the monomer structure as well as the electrical parameter of the plasma (AC or pulsed DC) on the films chemistry and deposition rate is studied.
PTFE like films are of interest because of their low surface energy which gives them interesting properties such as easiness of cleaning etc.
The surface composition of the films is studied by X-Ray Photoelectron Spectroscopy (XPS) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The surface energy of the films is studied by Water Contact Angle (WCA). The films thickness is determined by profilometry, and the composition of the plasma phase is analyzed by atmospheric Mass Spectrometry (atm-MS) and Optical Emission Spectroscopy (OES).
Results
Very similar atomic composition and surface energies are obtained for the tested range of experimental parameters. Difference in composition, depending on the precursor used, can however be detected in the high resolution C1s peak (XPS). The signature of the precursor can also be detected in the atm-MS results of the plasma phase. OES measurements on the other hand do not allow to easily differentiate the various precursors. The main species detected other than Ar are F and CF2. The combination of the gas phase analysis and the films composition suggest a small fragmentation of the monomer in the plasma. Indeed as the initial structure of the precursor can still be detected in the deposited films we can conclude that the chemical structure of the polymerizing species must be close to the one of the initial molecule.
Differences in deposition speed depending on the precursor type and/or the plasma type (AC or DC) are evidenced by profilometry measurements. As expected the precursor containing the unsaturated bond has a higher deposition rate. Thicker films exhibit slightly higher contact angle values (∼140°) than thinner ones (∼130°). This cannot be attributed to the chemical composition of the films as they are very similar but can be explained by the increased roughness of the thicker samples.
The overall composition of the films can only be slightly modified by changing the precursor structure or the plasma parameters. The deposition speed is the main parameters linked to both the precursors structure and the plasma parameters.