REACTION AND DIFFUSION AT CU/AL INTERFACES STUDIED USING GLANCING-ANGLE EXTENDED X-RAY-ABSORPTION FINE-STRUCTURES

We present studies on Cu-Al thin-film interfaces using the glancing-angle extended x-ray-absorption fine structure (EXAFS) technique. This depth-sensitive technique reveals a thin initial interfacial reaction, which is difficult to observe by conventional probes. Exposure of the interface to oxygen appears to create a reaction barrier, which breaks down after high-temperature annealing. The interfacial structure is found to be multiphased, but not a simple combination of the standard phases. Data analysis also shows evidence of grain-boundary diffusion of the Cu. The grain- boundary environment surrounding Cu seems to be very disordered and contributes little to the measured EXAFS. © 1990 The American Physical Society.