COMPARISON OF AES AND EXAFS ANALYSIS OF A THIN CU-X AL-Y LAYER ON AL SUBSTRATE

A layer of copper with the thickness of 0.5 mu m was sputter deposited on a commercially available aluminum foil with the thickness of 30 mu m. The composition of elements within the coating was determined with Auger Electron Spectroscopy (AES) depth profiling, while the structur e was determined with Extended X-Ray Absorption Fine Structure (EXAFS) and X-Ray Diffraction (XRD). Samples were exposed to a low pressure w eakly ionized hydrogen plasma with a high H density. Due to extensive recombination of hydrogen atoms on copper surface the samples were hea ted to 300 degrees C so that diffusion of elements within the coating took place. After the plasma treatment, the samples were analyzed with AES and EXAFS again. The AES depth profiles showed that a rather unif orm coating consisting of 66 at.% of Al and 33 at% of Cu was formed. C omparison of the shape of the main Auger LMM peak of pure Cu and that of CuxAly coating showed a substantial difference. The XRD analysis sh owed the presence of crystalline CuAl2 phase. However, the EXAFS analy sis showed that the coating was not a stoichiometric CuAl2 but rather the Cu/Al solid solution rich in CuAl2. (C) 1998 Elsevier Science Ltd. All rights reserved.