Micro-structured electrode arrays:: atmospheric pressure plasma processes and applications

Micro-structured electrode (MSE) arrays allow to generate large-area uniform glow discharges over a wide pressure range up to atmospheric pressure. The electrode dimensions in the micro-range realized by means of modern micro-machining and galvanic techniques are small enough to generate sufficiently high electric field strengths to ignite gas discharges applying only moderate radio frequency (13.56 MHz) voltages (80-390 V in Ne, He, Ar and N-2). The non-thermal plasma system is characterized by a special probe measuring the electric parameters. Possible industrial applications of the MSE arrays are plasma chemistry (e.g. waste gas decomposition) and surface modification of materials. Using an MSE based micro-reactor the abatement of the greenhouse gas CF4 was performed with decomposition rates of over 90% at a pressure of 100 mbar in He and N-2. The decomposition of waste gases in the plasma was monitored online with quadrupole mass spectrometry. At atmospheric pressure in He the abatement rate of CF4 is still over 70%. Other applications realized in our lab are thin film deposition of diamond-like carbon layers and SiO2 layers on various substrates and sterilization of food packaging materials. (C) 2003 Elsevier Science B.V. All rights reserved.