Diffuse neutron reflectivity and AFM study of interface morphology of an electro-deposited Ni/Cu film

摘要

We present a detailed study of the interface morphology of anelectro-deposited (ED) Ni/Cu bilayer film by using off-specular (diffuse)neutron reflectivity technique and Atomic Force Microscopy (AFM). The Ni/Cubilayer has been electro-deposited on seed layers of Ti/Cu. These two seedlayers were deposited by magnetron sputtering. The depth profile of density inthe sample has been obtained from specular neutron reflectivity data. AFM imageof the air-film interface shows that the surface is covered by globular islandsof different sizes. The AFM height distribution of the surface clearly showstwo peaks [Fig. 3] and the relief structure (islands) on the surface in thefilm can be treated as a quasi-two-level random rough surface structure. Wehave demonstrated that the detailed morphology of air-film interfaces, thequasi-two level surface structure as well as morphology of the buriedinterfaces can be obtained from off-specular neutron reflectivity data. We haveshown from AFM and off-specular neutron reflectivity data that the morphologiesof electro-deposited surface is distinctly different from that ofsputter-deposited interface in this sample. To the best of our knowledge thisis the first attempt to microscopically quantify the differences inmorphologies of metallic interfaces deposited by two different techniques viz.electro-deposition and sputtering.