| An atmospheric pressure plasma source was used to perform plasma-enhanced chemical vapor deposition of aluminum-doped zinc oxide at low temperature (< 250 °C), from the precursors diethylzinc and trimethylaluminum. When the helium plasma included oxygen the growth rate and resistivity of the transparent conducting oxide were much higher than when the plasma included carbon dioxide. It was determined that increasing the substrate temperature to 225 °C and lowering the flow rates of the reactants limits the growth rate, which in turn reduces the resistivity of the film while maintaining optical transparency for use in optical devices.;The same plasma source, mounted on a 2-D translational robot, was used to deposit fluorinated silica glass coatings from triethoxyfluorosilane (TEOFS) and tetramethylcyclotetrasiloxane (TMCTS) in a chamberless environment at the low temperature of 120 °C. It was again found that a decreasing growth rate enhanced the film quality, reducing surface roughness and porosity of the coatings. Films grown with pure TEOFS showed the lowest growth rate, as well as the highest concentration of fluorine atoms and the lowest refractive index.;A novel deposition method was developed using the atmospheric pressure plasma methodologies described above. A linear plasma source, mounted on a translational robot, was used to pre-treat acrylic and glass substrates in a chamberless environment. These substrates were then placed in a chamber containing no water vapor, spin-coated with a thin layer of liquid fluoroalkylsilane precursor in solvent, and treated with a cylindrical plasma source to cure the precursor into a solid thin film. The pretreatment step was necessary to activate the substrate for attachment of the liquid monomer, and the resulting fluorinated silica coating was hydrophobic, with a surface energy of 12 dyn/cm.;The gamut of atmospheric pressure, radio frequency, capacitively coupled plasma source designs have been reviewed. A detailed examination of the physics and chemistry of these non-equilibrium plasmas have been evaluated, especially relating to the alpha-gamma mode transition. This transition occurs when the temporal variation of the sheath thickness surpasses a critical value, be it due to an increase in current density, electron concentration, or a reduction in gap width between the electrodes. Thus certain microplasmas may only operate in the gamma-mode due to their gap size on the order of a few hundred microm or less. The various applications of these plasma sources have also been summarized, and their respective advantages and disadvantages have been discussed. |
