PROTRUSIONS ON THE SURFACE OF GRAPHITE CATHODE USED IN THE TETRAHEDRAL AMORPHOUS-CARBON FILM DEPOSITION

We report the growth of protrusions on the surface of graphite cathode in a pulsed plasma are-discharge method, which is used for producing tetrahedral amorphous carbon (ta-C) films. The bonding structure of th e protrusions were studied using the electron spectroscopy for chemica l analyses (ESCA) method and the protrusions were found to consist of pure graphite. The morphology of the protrusions was studied using a s canning electron microscope (SEM). The growth of the protrusions is no n-beneficial since ii diminishes the carbon plasma yield in a short ti me (similar to 1 h:) to a level too low for any practical application. This effect can be eliminated in situ by mechanical abrasion of the s urface of the graphite cathode. (C) 1998 Elsevier Science S.A.