STRUCTURE OF DIAMOND AND DIAMOND-LIKE CARBON THIN-FILMS GROWN BY HOT-FILAMENT CHEMICAL-VAPOR-DEPOSITION TECHNIQUE

Micro-crystalline diamond (MCD) and diamond like carbon (DLC) thin fil ms were deposited on silicon (100) substrates by hot-filament CVD proc ess using a mixture of CH4 and H-2 gases at substrate temperature betw een 400-800 degrees C. The microstructure of the films were studied by X-ray diffraction and scanning electron microscopy. The low temperatu re deposited films were found to have a mixture of amorphous and cryst alline phases. At high temperatures (>750 degrees C) only crystalline diamond phase was obtained. Scanning electron micrographs showed facet ed microcrystals of sizes up to 2 mu m with fairly uniform size distri bution. The structure of DLC films was studied by spectroscopic ellips ometry technique. An estimate of the amount of carbon bonds existing i n sp(2) and sp(3) form was obtained by a specially developed modelling technique. The typical values of sp(3)/sp(2) ratio in our films are b etween 1.88-8.02.