Fabrication, Characterization, and Comparison of Oxygen-Rich Organic Films Deposited by Plasma- and Vacuum-Ultraviolet (VUV) Photo-Polymerization

Thin organic films with oxygen-bearing functional groups (hydroxyl, carboxyl, ...) were prepared by "co-polymerizing'' gas mixtures of ethylene (C2H4) and one of several O-containing oxidizer molecules, O-2, CO2, or N2O. This was done either by vacuum-ultraviolet (VUV) photo-polymerization or by low-pressure r.f. plasma-assisted CVD. The gas mixture ratio, R, permits one to control total oxygen concentration, [O], as well as the relative proportions of the various functionalities. Analyses were performed by XPS (with or without chemical derivatization using TFAA to determine [-OH] content), and IRRAS-FTIR. Temporal and structural stability (mass change) of deposits under exposure to air or water was examined; altogether, data confirmed different reaction pathways for VUV and PECVD.