Fabrication of carbonaceous thin films and clusters using the low temperature rf plasma generated under atmospheric pressure

Abstract

We have developed new plasma generators to make low temperature material processing possible in open air conditions. The torch-type generator is a cylindrical plasma generator which is composed of a metal needle acting as the cathode at the center and a grounded cylindrical anode. The inner surface of the anode was lined with a thin insulator nozzle. Sheet- and disk-type generators have capacitively coupled electrodes, and their plasma gas flows are parallel and perpendicular, respectively, to the electrodes. Low temperature homogeneous plasma was generated between the anode and cathode by applying rf voltage to the cathode under constant flow of He or Ar at atmospheric pressure. Due to such additional advantages as simple operation and low maintenance cost, the low temperature plasma generated under atmospheric pressure can provide useful applications to surface coating and modification, etching, sputtering film deposition, and non-equilibrium and nano-materials synthesis. Among a variety of applications of this unique plasma, we report here the synthesis of carbon films and clusters by the chemical vapor deposition of hydrocarbons admixed in plasma. The products ranged from hydrogen-rich polymer films to amorphous and glassy carbons, as well as to fullerenes, depending on the source gases and plasma conditions.