Electron evaporation of carbon using a high density plasma

High-density plasmas are often used either in the preparation of thin films or for the modification of surfaces. However, except for collision-driven chemical reactions the electrons present are not used, although electron bo mbardment hearing of the work piece nearly always occurs. Principally it is the ions and neutrals that are utilised for material processing. By suitab le biasing of a conducting source material the electrons can be extracted f rom a high-density low-pressure plasma to such an extent that evaporation o f this source material can be achieved. Due to the presence of the plasma a nd the flux of electrons a large proportion of the evaporant is expected to be ionised. We have used this novel arrangement to prepare thin films of c arbon using a resonant high-density argon plasma and a water-cooled rod of high purity graphite. Multiple substrates were used both outside of, and im mersed in, the plasma. We report the characteristics of the plasma (electro n temperature and density, the ion energy and flux, and optical emission sp ectra), the deposition process (the evaporation rate and ion/neutral ratio) , and the film properties (IR and UV/Vis absorption spectra, Raman spectra, elemental analysis, hardness and refractive index). (C) 2000 Elsevier Scie nce S.A. All rights reserved.