PULSED-LASER DEPOSITION OF SIC FILMS ON FUSED-SILICA AND SAPPHIRE SUBSTRATES

350-nm-wavelength laser ablation of ceramic SiC targets has been used to deposit SiC films on fused silica and R-cut sapphire at substrate t emperatures from 300 to 1150-degrees-C. The films deposited above 800- degrees-C show (111) and (222) x-ray-diffraction bands from crystal pl anes parallel to the substrate. The bandwidths decrease and the integr ated intensities increase with deposition temperature. The crystallite dimension for the highest-temperature films is in the order of 50 nm. The diffraction peaks are absent for the films deposited at the lower temperatures. Analysis of optical transmission spectra of the high-te mperature films shows a lowest-energy gap near 2.2 eV which is the val ue for cubic SiC. The low-temperature films show smaller and variable gaps. The room-temperature resistivities of the former are low, from 0 .02 to 0.1 OMEGA cm whereas the latter are insulating. Film thicknesse s and deposition rates ranging from 0.2 to over 0.6 angstrom/pulse are obtained from the spectra and by monitoring of the interference oscil lations in the infrared emission through the film during deposition.