ION-BEAM-ASSISTED DEPOSITION OF NONHYDROGENATED A-SI-C FILMS

Amorphous silicon carbide (a-Si:C) films were prepared by low-energy i on-beam-assisted deposition (IBAD) in an attempt to remove structural defects in the ''lattice'' and improve the electrical characteristics of the film. The ion beam was generated by electron cyclotron resonanc e from an ultra high-purity argon plasma. The deposition environment w as first evacuated to a very high vacuum to eliminate all but trace am ounts of water vapour and other gases so that improvements in the elec trical and (or) structural properties of the film would be attributabl e to the influence of the densification by ion bombardment and not to contaminants. The IBAD process does improve the film characteristics b y reducing the density of localized states at the Fermi level and the porosity of the film. However, even though these films have the best e lectrical characteristics obtained thus far for these kind of films, n one of them exhibited device quality and none were observed to be phot oconducting. A large density (approximate to 1 at.%) of implanted argo n atoms may be limiting the reduction in the defect density that might otherwise be achievable.