PULSED-LASER DEPOSITION AND BORON-BLENDING OF DIAMOND-LIKE CARBON (DLC) THIN-FILMS

Diamond-like carbon (DLC) films, both pure and doped with boron, were prepared by pulsed laser deposition (PLD) with a XeCl excimer laser em ploying polycrystalline graphite and boron carbide targets. As substra tes served silicon (111) wafers. The deposition parameters such as the laser intensity, vacuum, supporting gas conditions, substrate tempera ture, target-substrate distance, substrate combination and composition could be controlled independently, and thus, were used to modify the film properties and composition. Optical emission diagnostics of the l aser plasma was performed at various locations between the target and the substrate. In the high power regime (> 10(8) W cm(-2)), pulsed las er evaporation resulted in the emission of excited C-2 molecule radica ls. High incident energies were necessary for surmounting potential ba rriers to the formation of sp(3) bonds. Films with the highest sp(3) c ontent were formed with small distance between target and substrate, h igh laser intensities (I approximate to 10(9) W cm(-2)), and low base pressures (< 10(-5) mbar). The room temperature laser-deposited films showed a single broad laser Raman band peaked around 1530 cm(-1) typic al for unhydrogenated diamond-like a-C films. Coevaporation of a B4(C) target led to a-C:B films exhibiting laser Raman spectra practically similar to the a-C films.