Pulsed laser deposition of nanocrystalline SiC films

Thin SiC films were grown on (1 0 0) Si substrates at temperatures from 400 to 1000 °C under various CH4 pressures by the pulsed laser deposition (PLD) technique using a KrF excimer laser. After deposition, films were in situ annealed at their deposition temperature under 500 mbar of CH4 for 1.0-1.5 h. X-ray reflectivity investigations showed that films exhibited mass densities similar to SiC single crystal samples, while symmetrical and grazing incidence X-ray diffraction investigations found that films deposited at 800 °C or higher substrate temperatures were nanocrystalline. Modeling of spectroscopic ellipsometry measurements indicated that the refractive index values were similar to those reported for bulk SiC, while X-ray photoelectron spectroscopy investigations found that films contained in bulk a relatively low oxygen concentration of around 1.0 at.%. Nanoindentation results showed that the deposited SiC films were very hard, with hardness values above 40 GPa for films deposited at temperatures higher than 800 °C.