Activation energy of an asymmetrical, radio frequency discharge with methane

Growth Mechanism of Oxygen-Containing Functional Plasma Polymers

“…It might be assumed that lower gas flow rates enhance the incorporation of film-forming intermediates due to longer residence times. Similar results were already observed for asymmetric RF discharges with CH 4 , [51] but not for HMDSO discharges, which show higher overall deposition rates of the film-forming species and allow remote plasma deposition. [57,59,60] As a further investigation, we calculated the energy density e for the two experimental series with 8 and 16 sccm C 2 H 4 using Equation (1).…”

“…[51,53] Similar results were obtained by Corbella et al [54,55] For hydrocarbon plasmas, it could be demonstrated that mainly plasma chemistry affects the deposited mass over a broad parameter range yielding dense barrier coatings. [49,[56][57][58][59] Despite the fact that the same apparent activation energy is obtained for both experimental series shown in Figure 3, the actual mass deposition rate per monomer flow is seen to vary with the actual C 2 H 4 flow rate.…”

“…[51] The macroscopic parameter W/F (given at standard conditions) represents the energy invested per particle within the active plasma zone and can easily be converted to (kJ Á mol À1 ) or (eV) using the ideal gas law. [52] Equation (2) yields a linear increase within an Arrhenius-type plot, where the (negative) slope is equal to E a , the apparent activation barrier.…”

Macroscopic control of plasma polymerization processes

“…Moreover, the expansion of the active plasma zone now directly depends on the external plasma parameters such as power input W, pressure p, and gas composition. For volume-dominated discharges (e.g., hydrocarbons or mixtures of monomers with carrier gases at sufficiently low pressure) V dis ≈ V gas might still be assumed, thus, the variation of d act with W and p can be examined [18]. The expansion of the active plasma zone can be obtained from the luminosity distribution assuming that radiation scales with excitation processes.…”

“…1, W/F might be kept constant while increasing the monomer flow (and thus the power input) to obtain higher deposition rates. However, this results in broadening of the active plasma zone [18]. A thorough examination of d act (W, F) for methane discharges at constant pressure (7.5 Pa) reveals that the width of the active plasma zone reliably scales with power input (Fig.…”