Influence of ion current on the growth of carbon films by ion-beam-assisted deposition

Amorphous carbon films have been grown by evaporation of graphite with concurrent assistance of Ar+-ion bombardment. The assisting current was obtained with a 3 cm Kauffman ion gun and was varied between 0 and 15 mA, keeping the evaporation rate and assisting voltage constant. The films have been characterised with Auger electron spectroscopy and Raman spectroscopy. The deposition and post-deposition ion bombardment influence the structure of the films. Bombardment during deposition leads to an increase in the sp(3) content up to 40% with an optimum current value around 10 mA. The additional post-deposition bombardment with Ar+ causes damage to the film structure, reducing the sp3 content and increasing the argon content of the film. (C) 1999 Elsevier Science S.A. All rights reserved.