Segregation and sputter effects on perfectly smooth (111) and (100) surfaces of AuAg alloys studied by AES

Epitaxial Au-Ag alloy films of (111) and (100) orientation are prepared on Ag substrates for an AES study of the surface composition occurring after annealing and Ar ion sputtering. To characterize microtopography and structure of the alloy surfaces supplementary measurements are carried out by TEM and LEED. A correct quantitative AES analysis is guaranteed via extensive calibration experiments. In cases of (111) surfaces the analysis gives clear evidence of Ag segregation during annealing and of Ag depletion during sputtering, respectively. In cases of (100) surfaces, however, no unambiguous quantitative proof of the effects is possible since the surface structure changes with the concentration which probably influences both, surface composition and parameters of Auger emission.