Characterization of amorphous carbon films deposited by surface wave plasma CVD

Many dangling bonds in hydrogenated amorphous carbon (a-C:H) films are usually generated by bombardments of high-energy ion precursors in typical chemical vapor deposition (CVD). To generate low dangling bonds, a-C:H films should be deposited from low-energy radical species. Surface wave plasma (SWP) generates low-energy and high-density radicals. We prepare a-C:H films using SWP and investigate the relationship between the plasma characteristics and structures of a-C:H films. The microwave of the TM01 mode was introduced through the dielectric window and SWP generate under the dielectric window. An Ar and C₂H₂ plasma mixture mainly consists of neutral radical species, and the electron temperature is as low as 1 eV. Electron density significantly decreases with increasing distance from the dielectric window. The a-C:H films are prepared from these hydrocarbon and carbon low-energy radicals as main precursors. The sp² bonded network cluster size in a-C:H films increase with electron density in SWP. This structure change is the influence of the termination structure of clusters changing to CH from CH₃ and CH₂.