ABSTRACTAmorphous carbon films were deposited onto (100) Si crystals and onto ultra-pure Al foils by dc-magnetron sputtering with different Ar plasma pressures, from 0.17 to 1.4 Pa. We investigate the voids structure and the voids density in these films by means of small angle x-ray scattering (SAXS) and mass spectrometry of effused gases. The analysis of the effusion spectra provided clear evidence that films deposited at lower pressures are compact, while the films deposited at higher pressure present a more open structural arrangement, confirming density results obtained by using ion beam techniques. SAXS results reveal that the fraction of open volumes increases with the plasma pressure: a direct correlation between film density and open volume fraction is found. These different film microstructures could be explained by the existence of different bombarding regimes during film growth
