Structural analysis of Cu-In alloy films with XPS depth profiling by ion etching

The structural changes of sequentially evaporated thin Cu-In films on molybdenum substrate were studied by the depth profiling technique in an XPS apparatus. Pure metal materials were deposited by vacuum evaporation at room temperature. A specimen of the film was sputter-etched in situ after the deposition with Ar ion beams to obtain the depth profile. Another specimen of the film was annealed at 120degreesC for 1 h, and the depth profile was taken. The transient characteristics of signal appearance/disappearance of elements of film/substrate were different before-and-after the annealing. The behavior was discussed based on the film structure whether it was in a layered form or in an island form. It was suggested that the observed profiles for films prior to the annealing could be explained as a layered one, but they became island-like structure of alloys after the annealing. Films of various indium composition were also examined. The tendency of island formation was stronger for films with higher indium content. On films whose In composition was more than 70%, indium islands were also formed. (C) 2004 Elsevier Ltd. All rights reserved.