Connection between morphology and electrical resistivity in AuAl films

AuAl alloys prepared by thermal diffusion on p-type silicon (100) substrates were studied. Au/Al bilayers were prepared with 50%:50% as atomic concentration and 100 nm as total thickness. The formed Au/Al/Si systems were annealed from room temperature (RT) to 400°C in a vacuum oven with Argon atmosphere to form the AuAl alloys by thermal diffusion at different times (1, 2, 4 and 6 h). Prepared alloys were characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and collinear four-probe techniques in order to obtain their morphology, stoichiometry, crystalline structure and electrical resistivity, respectively. An increment in the rms-roughness and grain size values was found with diffusion time. AuAl alloys improve their crystalline structure as demonstrated by the XRD technique. The electrical resistivity of AuAl alloys shows a direct connection with the morphology and the annealing time. Small increase in the resistivity value was obtained in alloyed films as compared with the resistivity reported for individual Au and Al in bulk.