Glow Characterization in Low-Pressure Radio-Frequency $\hbox{CH}_{2} \hbox{F}_{2}$ and $\hbox{C}_{2}\hbox{H}_{2}\hbox{F}_{4}$  Plasma Deposition Systems
The glow characteristics and deposited film structures of fluorocarbon monomers in radio-frequency glow discharges are investigated using CH<sub>2</sub>F<sub>2</sub> and C<sub>2</sub>H<sub>2</sub>F<sub>4</sub>, which were compared to hydrocarbon monomer such as CH<sub>4</sub>. The glow was characterized and investigated by optical photography, optical emission spectroscopy, and Fourier transform infrared spectrometry. The glow differences were attributed to the nature of the luminous gas phase in respect to polymer-forming species.
Glow characterization in direct current plasma polymerization of trimethylsilane
Plasma polymerization of trimethylsilane (TMS) was carried out in a direct current (dc) glow discharge and was investigated by optical photography and plasma diagnostic techniques including optical emission spectroscopy and residual gas analysis. The nature of the glow formed in TMS discharge, which deposited plasma polymers, was significantly different from that of a simple gas such as Ar. In an Ar discharge, the dominant glow was the well known negative glow, which developed at a distinctive distance from the cathode, whereas the cathode surface remained in the dark space. In strong contrast to this situation, in TMS dc discharge the dominant or primary glow was the cathode glow, which appeared at the cathode surface. At a similar location where the Ar negative glow appeared, a very feeble glow as a secondary glow was also observed in TMS glow discharge. The deposition results and plasma diagnosis data evidently indicated that in TMS glow discharge, the cathode glow resulted from the low-energy electron-impact dissociation of TMS molecules that creates polymerizable species, but the negative glow was related to nonpolymerizable species such as hydrogen atoms and molecules. In this article, the cathode glow formed in glow discharges of organic compounds was designated as the dissociation glow according to its underlying plasma reactions.
Effects of Cathode and Anode on Deposition of Trimethylsilane in Glow Discharge
DC cathodic polymerization of trimethylsilane (TMS) was carried out in plasma reactors with and without using anode assembly. In DC cathodic polymerization, the TMS plasma polymers are mainly deposited on the cathode (substrate) surface. As a result, fast deposition of TMS plasma polymers was easily achieved in DC cathodic polymerization as compared with AF or RF plasma polymerization. DC cathodic polymerization without using anode assembly has its advantageous features that the size and number of substrates (as cathodes) are not restricted by the size and the location of anode assembly. It was found that the maximum deposition rate on the cathode surfaces was obtained without anode assembly. The DC cathodic polymerization of TMS was conducted also in a large volume reactor with multiple cathodes (substrates). The same deposition mechanisms for DC cathodic polymerization with a single cathode also apply to the multiple cathodes. Uniform deposition on each cathode could be obtained with appropriate spacing of multiple cathodes and by adjusting the operational parameters, which are based on the current density and the system pressure.