Interfacial roughness of multilayered TiN/ZrN coatings

TiN/ZrN multilayers with nominal modulation periods of 8.5, 12.5 and 16.5 nm and total thicknesses ranging between 60 nm and 1.5 mu m were prepared by combined DC and RF magnetron sputtering. These coatings were deposited on polished Si substrates. The multilayer period was evaluated by X-ray diffraction (XRD) in the low angle region. Several orders of multilayer reflections are present in these diffraction patterns, exhibiting a pronounced attenuation, which in turn indicates a moderate degree of interfacial roughness. The interface roughness was studied as a function of the number of bilayers and of the modulation period by Rutherford Backscattering Spectrometry (RBS). An increase of the average interlayer roughness with the thickness and with the modulation period was observed. (C) 1998 Elsevier Science B.V.