The nanostructure evolution during and after magnetron deposition of Au films

The evolution of the nanostructure of magnetron sputtered Au films has been experimentally studied. At a synchrotron-radiation beam line, during growth and subsequent annealing, in-situ X-ray diffraction has been carried out to follow the texture, the grain size, the microstrain and lattice-plane distances. With Bragg–Brentano geometry, only (111) grains, having a (111) plane parallel to the film surface, have been observed, while, with glancing incidence and exit X-ray diffraction, (111)* grains, having one of their (111) planes perpendicular to the film surface, have also been observed. Both during growth and subsequent annealing, the (111) texture changed, and some (111)* grains recrystallized and/or the orientation of the grains changed. The microstrain decreased drastically during the first few minutes of growth (300 A) while, simultaneously, the size of the coherently diffracting domains increased. Subsequently, the microstrain became constant, and the rate of increase of the size of coherently diffracting domains leveled off. Initially, during the first few minutes of annealing, a large decrease in the microstrain was observed simultaneously with a dramatic rise of the size of the coherently diffracting domains. After this initial annealing period, as during film growth, the microstrain became constant, and the rate of increase of the size of coherently diffracting domains leveled off.
The activation energy for the initial growth of the coherent diffracting domains was found to be Q=(0.25 +/- 0.03) eV, and the activation energy for normal grain growth was found to be Q=(0.99 +/- 0.04) eV.
Finally, the thin-film stress was followed during growth and subsequent annealing. A tensile contribution to the stress was observed during island coalescence.