Determination of the sp3 C content of a-C films through EELS analysis in the TEM

Electron energy loss spectroscopy (EELS) in a transmission electron microscope (TEM) was employed to estimate the sp3 C content in magnetron sputtered H-free a-C coatings. The deconvolution procedure developed reduces considerably the error which is due to beam point spread function and sample thickness. The methodology has been applied to thin a-C films deposited through RF magnetron sputtering, and determined that, under the present values of ion current to the substrates (< 1 mA/cm2), a variation in energy of the upcoming ions (achieved through a variation in applied substrate bias) has a negligible influence on the C atoms hybridization.