Ion-Bombardment of X-Ray Multilayer Coatings - Comparison of Ion Etching and Ion Assisted Deposition

TitleIon-Bombardment of X-Ray Multilayer Coatings - Comparison of Ion Etching and Ion Assisted Deposition
Publication TypeJournal Article
Year of Publication1991
AuthorsE.J Puik, M.J van der Wiel, H. Zeijlemaker, J. Verhoeven
JournalApplied Surface Science
Date PublishedApr
ISBN Number0169-4332

The effects of two forms of ion bombardment treatment on the reflectivity of multilayer X-ray coatings were compared: ion etching of the metal layers, taking place after deposition, and ion bombardment during deposition, the so-called ion assisted deposition. The ion beam was an Ar+ beam of 200 eV, and the multilayer coatings studied were W-C, Ni-C and W-Si. Cu K-alpha reflection measurements (lambda = 0.154 nm) of Ni-C and W-C multilayer coatings having ion etched metal layers showed considerably higher reflectivities than those of coating having as-deposited layers; a factor 2.5 and 4, respectively. Ion etching of tungsten layers in W-Si coatings did not result in enhanced reflectivities. We applied ion assisted deposition to nickel in Ni-C multilayer coatings. We observed enhanced in-situ soft X-ray reflectivities of ion assisted deposited nickel layers with respect to as-deposited layers. However, the observed increases were less than those obtained by ion etching, which we ascribe to bombardment-induced intermixing at the underlying Ni-C interfaces. Finally we demonstrate that during ion assisted deposition and ion etch rates are not additive, but that the ion etch rate increases. The indicates that during deposition a number of atoms are temporarily loosely bound to the surface.



Go back one page.