Optical studies of hydrogenated amorphous carbon plasma deposition

Abstract

Optical emission spectroscopy was applied to study the rf glow discharge in hydrocarbons used for the deposition of amorphous hydrogenated carbon (a-C:H). The optical data in conjunction with mass spectrometric measurements show that the species found in the glow region are very specific for the hydrocarbon used (e.g., benzene), but they are not directly related to the structure of the a-C:H film deposited. In the vicinity of the negatively self-biased cathode strong emission from CH is observed, irrespective of which hydrocarbon is used. The excited CH radicals are shown to result from fragmentation of the impacting hydrocarbon molecules. We conclude that this fragmentation upon impact is the key mechanism for the formation of hard a-C:H, irrespective of the type of hydrocarbon used for the deposition.

Amorphous, Hydrogenated Carbon Films and Related Materials: Plasma Deposition and Film Properties

“…The experimental setup has been described elsewhere [16,22]. To get insight into the plasma-chemical processes occuring in hydrocarbon rf discharges, the mass distribution of positive ions in the plasma has been measured by means of a differentially pumped quadrupole mass-spectrometer (OMA).…”

“…Since the mass distribution of positive ions depends critically on the type of hydrocarbon, this loss of structure must occur at the plasma-substrate interface. In order to investigate the interaction between the hydrocarbon plasma and the growing a-C:H films, spatially resolved optical emission spectroscopy has been applied [22,23]. Optical emission spectra were taken from different hydrocarbon discharges used for the deposition of a-C:H films.…”

Plasma Polymer-Metal Composite Films

“…Recently, mass spectroscopic and spatially resolved OES studies of an rf discharge in C 6 H 6 at 3 Pa and U B = -1000 V have shown that the dominant positive ions are C 6 H 6 + [66]. These ions are extracted from the plasma glow, accelerated by the sheath potential and after impact at the substrate they are broken into fragments.…”

Spectroscopic visualization of CH in methane/hydrogen plasmas for synthesis of carbonaceous materials and surface micromorphology

“…Tahara et al reported diamond-like carbon (DLC) films prepared by plasma-assisted CVD [3]. Many studies have been performed on the synthesis mechanisms of the DLCs, which are very attractive materials for hard manufacturing tools and excellent electrical insulating films [4][5][6][7][8][9]. However, the interaction between a plasma and a substrate target surface is not clear because particle-species compositions, temperatures and densities of the plasma as well as plasma behaviors near the surface cannot easily be measured even with recent advanced diagnostic methods [3].…”