The structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) deposition was investigated by high-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray photoelectron spectroscopy. Results of the plasmon excitation energy shift and through-thickness elemental concentration show a multilayered a-C film structure comprising an interface layer consisting of C, Si, and, possibly, SiC, a buffer layer with continuously increasing sp 3 fraction, a relatively thicker layer (bulk film) of constant sp 3 content, and an ultrathin surface layer rich in sp 2 hybridization. A detailed study of the C K-edge spectrum indicates that the buffer layer between the interface layer and the bulk film is due to the partial backscattering of C+ ions interacting with the heavy atoms of the silicon substrate. The results of this study provide insight into the minimum thickness of a-C films deposited by FCVA under optimum substrate bias conditions. Copyright © 2013 Materials Research Society.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research was funded by the Computer Mechanics Laboratory (CML) and the UCB-KAUST Academic Excellence Alliance (AEA) Program. TEM and XPS studies were performed at the National Center for Electron Microscopy and the Molecular Foundry, respectively, of the Lawrence Berkeley National Laboratory.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.