Chemically bonded diamondlike films from ion-beam deposition

Low-energy mass-selected C+ ion beams are used to deposit thin carbon films on surfaces of Si(100) and Ni(111) in an UHV environment at room temperature. The films are characterized by Auger electron spectroscopy, x-ray and UV photoelectron spectroscopy, valence level electron energy-loss spectroscopy, K-shell ionization loss spectroscopy, and ellipsometry. The initial monolayer of the deposited film is in the form of a carbide layer which is chemically bonded to the substrate atoms. Over the next several layers deposited, the film evolves gradually through intermediate structures into a diamondlike structure. A phase diagram, prepared as C+ ion dose versus C+ kinetic energy Ek, shows the regions of the different structures. The optimum C+ energy range for formation of the diamondlike structure is 30–175 eV. Below 10 eV the final diamondlike structure has not been attained and above 180 eV there is a sharp increase in the dose required to attain this final structure. Properties of the film, measured in situ, are mentioned.