RADIOFREQUENCY (RF) PLASMA-ETCHING OF GRAPHITE WITH OXYGEN - A SCANNING TUNNELING MICROSCOPE STUDY

The surface topography of highly oriented pyrolytic graphite (HOPG) after exposure to a radio-frequency (RF) oxygen plasma has been studied using scanning tunnelling microscopy (STM) in ambient air. The STM images obtained show that the HOPG surface after etching in an oxygen RF plasma is remarkably different from that of the freshly cleaved material. The resultant topographical features are found to be strongly dependent on the etching conditions used. The layer-by-layer etching of graphite by an oxygen RF plasma revealed in the high resolution STM images obtained is attributed to the structural characteristics of graphite and to the synergistic effects of oxygen ion bombardment and atomic oxygen reactions.