Kinetics of evaporation of Cu beaded films on sapphire

Kinetics of evaporation of beaded Cu films from a sapphire substrate at 2-3 x 10(-8) mbar were investigated by means of Auger electron spectroscopy in the temperature range 893-978 K. Measuring the time dependence of the normalized Auger intensity of Cu, we concluded that the process is controlled by a surface reaction at the perimeters of beads. From the temperature dependence of the initial and final parts of these curves we were able to determine the energy of activation of the desorption of Cu and of the surface reaction as well.