Argon/tetramethysilane PECVD: From process diagnostic and modeling to a-Si:C:H hard coating composition

Challenges in the characterization of plasma polymers using XPS

“…Mainly focused on vacuum plasmas, a growing number of studies using mass spectrometry (MS) to characterize the gas phase during plasma deposition of organic [25,[36][37][38] and inorganic [39][40][41][42][43] coatings as well as during plasma etching/ablation of polymer surfaces [44,45] can be found in the literature. The above-cited references attest that, although MS does not provide direct, unambiguous chemical information due to possible fragmentation in the ionization chamber, one can easily discern fragmentation and/or oligomerization phenomena as soon as (in)organic molecules (precursor or monomer) are subjected to plasma discharges.…”

Plasma diagnostics for pulsed-dc plasma-polymerizing para-xylene using QMS and OES

“…The peak recorded at 516 nm ascribed to C 2 * [19]. The emission lines of CH species (CH + at 422 nm and CH at 431 nm) come from the dissociation products of CH x [8,14,20]. The peaks at 312 nm can be ascribed to OH which should come from the gas recombination of oxygen plasma species (O + and O 2 + ) and hydrogen plasma species (H + and H 2 ) [22].…”

“…In the present study, neutral particles were first ionized under the effect of electron-impact ionization to produce C 8 H 10 + and Ar + (monomer and carrier gas respectively), following preferential bond-breaking dissociation (between CH 3 group and parent molecule H 3 C-C 6 H 4 -CH 3 , as frequently observed in other material systems [8,[11][12][13]) to form larger molecules (C 8 H 9 and C 7 H 7 ) accompanied with smaller molecules (H and CH 3 ). This explains the presence of two major groups of molecular species in our plasma space which can be seen in Fig.…”

“…It was found that all the chemical species in plasma space persisted at different f p and ω p , and only the intensity of each species can be affected by changing f p and ω p . The larger-molecule group consisted of C 8 , H 2 , H + , Ar + and Ar ++ (mainly composed of residual gases, fully dissociated molecules from the para-xylene monomer and argon carrier gas). The decreased peak intensity in the mass spectra of those larger molecules, indicating a decreased amount of larger molecules, was found as a function of ω p .…”

“…As such, it is necessary to investigate the glow discharge plasma system using para-xylene monomer gas. Among those plasma diagnostics available for exploring plasma space, mass spectrometry is mostly used to identify active species produced in plasma space during the deposition process [8]. However, optical emission spectrometry (OES) is an in situ, widespread diagnostic technique with a simple set-up for easy identification of the active species involved in the film growth [9,10].…”