Abstract:

Low temperature plasmas (temperature of ions and neutrals are about 300 K or higher) have wide applications in thin film deposition etching and material surface treatment, because of their efficient generation of active neutral species and energetic ions. The concentration of these particles, produced by electron impact processes (ionization, dissociation and excitation) are strongly dependent on electron energy. In most cases, the electrons are not in thermal equilibrium and their energy distribution function (EEDF) is not a Maxwellian. Therefore, investigation of EEDF and its dependence on plasma parameters, such as RF frequency, RF power, discharge pressure, gas composition, etc., is one of the important research topics in low temperature plasma physics.

Plasma sheath is formed at any plasma-surface interface, due to the huge difference of mobilities between electrons and ions. There is a large electrical potential difference between the plasma and the surface. This potential difference accelerates the ions, which bombarding the surface with an energy from a few eV to several hundred eV. Studying sheath dynamics can provide important insight on ion energetics.
 
 
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