THE STRUCTURE OF TETRAHEDRAL AMORPHOUS-CARBON THIN-FILMS

Tetrahedral amorphous carbon (ta-C) thin films were deposited using bo th the filtered cathodic Vacuum are (FCVA) and the pulsed laser are (P LA) deposition techniques. The FCVA deposited films are analysed as a function of ion energy of the deposition species and substrate tempera ture. The films deposited using FCVA as a function of temperature are compared with those deposited using the PLA technique. The microscopic structure of the films is examined using electron microscopy. The den sity, bonding hybridization and chemical composition are obtained by e lectron energy loss spectroscopy (EELS). The data for the diamond-like sp(3) bonding component in the ta-C films clearly show a peak which i s predicted by the subplantation models proposed for the growth of amo rphous carbon films. The structural modifications observed as a functi on of temperature can also be explained using the subplantation model. Under certain deposition conditions used in this study, nanocrystalli tes are observed embedded in the amorphous carbon matrix. The chemical composition of these crystallites is carbon. The microstructure of th e deposited crystals is analysed in terms of lattice spacing and is in dexed to graphite and cubic diamond.