Physics Colloquium - Low Temperature Plasma-Surface Interactions with Complex Materials: Inorganic, Liquid and Organic (Living) Surfaces

Mark Kushner

University of Michigan

Plasma surface interactions are indispensable in materials processing over a large range of applications and a wide range of pressures.  Tremendous progress has been made in optimizing reactive fluxes in low pressure plasmas (a few to tens of mTorr) to produce surface features in microelectronics fabrication.  Tradeoffs between damaging fluxes and rapid rates of etching or deposition are based on understanding of how incident reactive fluxes affect both the surface and sub-surface of the materials.  These investigations continue to provide unexpected results.  The recent discovery of VUV photon stimulated etching of Si and aging of porous materials by VUV photons has refocused attention on the influence of plasma generated, short wavelength fluxes on materials processing.  At the other extreme is the use of atmospheric pressure plasmas for modification and functionalization of organic materials and liquids.  Those organic materials now include living tissue – the discipline of plasma medicine.  Plasma modification of metals, semiconductors and organic polymers is typically desired only on the top surface.  Plasma treatment of liquids and living tissue is intended to influence processes well below the surface.  Using results from computational investigations, we will discuss the common themes (e.g., real-time-control) in this broad range of low temperature plasma-surface interactions.  Examples will be taken from microelectronics fabrication, polymer processing and plasma medicine.