Induced effects by DC electrical current cycling on aluminum thin films

Aluminum thin films deposited by free evaporation on silicon substrates were studied by X-ray diffraction and Auger electron spectroscopy. The crystalline behavior was analyzed by X-ray grazing incidence, when DC current cycles (0.1-1.2 A) along the metallic films were applied in situ. The intensity, Full Width Height Medium (FWHM), and the crystal parameter changes as current is applied, due to the film relaxation and thermal expansion. It was found that Al thin films behave as an elastic system when the electrical current is cycling. Stresses due to the differential thermal dilatation of film are analyzed as a function of the current flow (Joule effect). Also, the aluminum oxide layer, formed on the surface of the metallic film, plays an important role on the oscillating process found on aluminum films due to the number of applied current cycles.