When energy is introduced to gases in the form of DC Arc or radio frequency power, electrons will be accelerated and collide with gas molecules, in which gas molecules will be partially dissociated, excited and even ionized to form reactive neutrals and energetic ions.  In confined plasmas, ions will be accelerated across a plasma-surface boundary layer and form directional ions. By tuning plasma conditions, the fraction of gas molecules dissociation and ionization, ion energy and ion directionality can be manipulated for applications ranging from semiconductor materials processing to chemical engineering applications.  In particular, plasma can be used for reactive ion etch and plasma enhanced chemical vapor deposition (PECVD) in semiconductor materials processing, and it can be introduced to heterogeneous catalysis, reaction engineering, and nano-structured functional materials synthesis in chemical engineering applications.

In plasma etching of semiconductor materials, isotropic reactive neutral radicals will be adsorbed onto semiconductor materials surface, energetic directional ions will bombard the surface and enhance the surface reactions, and hence anisotropic etch behavior is achieved.  A fundamental understanding of plasma chemistry and plasma-surface interaction is critical to optimize plasma physics and chemistry and plasma reactor configuration to form continuously shrinking nano-structured semiconductor device features.  In the applications of PECVD, the introduction of plasma can help to manipulate the reactive gas composition, and provide extra knobs to tune the film deposition properties, such as conformality, film stress and quality.

When plasma is introduced to a chemical engineering process, it can help to enhance the mass transfer and/or reaction kinetics.  For instance, when plasma is introduced to heterogeneous catalysis, the surface reaction kinetics can be enhanced.  Specifically, the activation energy of surface reactions could be reduced effectively as the gaseous reactants have been partially dissociated into reactive radicals and will be adsorbed to catalyst surfaces in forms of reactive radicals.  Moreover, the energetic ions across plasma-surface boundary layer will bombard the surface and help break chemical bonds of adsorbed reactive species on catalyst surfaces, and consequently enhance the surface reaction kinetics and also desorption of reaction products.  In addition, UV light emitted by the plasma discharge can also expedite the chemical bonding breaking and enhance the surface reaction kinetics. 

In this presentation, the characteristics and advantages of low temperature plasmas and the applications in semiconductor materials processing and chemical engineering processes will be covered.  Proposals of plasma applications in materials processing, micro-and nano-structured functional materials, catalysis and catalyst synthesis, chemical reaction engineering, and biological applications will also be discussed.