EELS and ELNES studies of nano-scale nitride multilayers deposited by unbalanced magnetron sputtering

High spatial resolution chemical analysis and imaging of a CrAlYN/CrN multi-layer coating was performed using sub-nanometer probe electron energy loss spectroscopy in a spherical aberration corrected scanning transmission electron microscope. Analysis indicated the CrN layers to be near stoichiometric with a relative Cr/N ratio of 1.050.1 while the CrAlYN layers gave a Cr/N ratio of 0.590.02. Analysis of the energy loss near edge structure at the nitrogen K-edge was performed. The experimentally determined fine edge structure in electron energy loss spectra were compared with theoretically determined spectra, calculated using electron density functional theory. For the CrN layers the best match between the direct experimental analysis and the simulated edges corresponds to stoichometric CrN consistent with the quantitative analysis while the best match for the CrAlYN layers was to (Cr0.5Al 0.5)N.