AVS 47th International Symposium
    Surface Engineering Tuesday Sessions
       Session SE-TuP

Paper SE-TuP1
General Rule to Predict Under-layer Segregation on Film Surface

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: Y.-R. Aparna, National Research Institute for Metals, Japan
Authors: M. Yoshitake, National Research Institute for Metals, Japan
Y.-R. Aparna, National Research Institute for Metals, Japan
K. Yoshihara, National Research Institute for Metals, Japan
Correspondent: Click to Email
Film deposition with multi-layer structure is widely utilized in many industrial fields such as electronic device and magnetic film. Diffusion and reaction of under-layer metal sometimes cause troubles and considerable efforts are made to prevent diffusion and reaction. In catalysis field, on the other hand, surface segregation of one component in alloys or bi-layer thin film is decisive factor for its catalytic ability. We studied surface segregation of under-layer metal on the top of a film in a vacuum with Auger electron spectroscopy (AES) and/or X-ray photoelectron spectroscopy (XPS). When surface segregation of under-layer metal was observed, no significant interfacial reaction between under-layer and top layer was detected. Metallic films of sub-micron or micron order thickness were deposited on polished metallic substrates. Al, Ti, Cr, Ni, Cu, Nb and Fe were used as a substrate material, and Al, Ti, Cr, Cu, Zr, Nb and Fe were used as a film material. More than 25 combinations of film-substrate materials have been investigated. From the viewpoint of phase diagram, three types of combinations are included in those combinations, i.e., two elements in solid solution, two elements in separation, and two elements in an intermetallic compound. General rule to predict under-layer segregation on film surface is discussed based on adsorption energy. This rule is quite different from that for segregation in bulk alloy.