LASER-ASSISTED CHEMICAL-VAPOR-DEPOSITION OF GRAPHITE

Photolysis of naphthalene-1,4,5,8-tetracarboxylic acid dianhydride vapor using a beam from a KrF (248 nm) excimer laser focused onto a silicon substrate gives a carbon film. Analysis of the film by Auger electron spectroscopy gave three peaks at 268, 255, and 241 eV which confirms the graphitic nature of the carbon deposit. Raman spectroscopy in the reflectance mode gives a narrow band at 1577 cm-1, similar to single crystal or highly ordered pyrolytic graphite; however, this band is accompanied by a weaker band at 1350 cm-1 which indicates there is some disorder in the graphitic structure. The use of the laser-assisted process allows the deposition of high-purity graphite films without heating the substrate, whereas the conventional thermal process requires deposition temperatures of 800-degrees-C and annealing at 2000-degrees-C to obtain a similar quality film.