Local slope evolution during thermal annealing of polycrystalline Au films

The morphological evolution of thermally annealed polycrystalline gold films was studied in terms of several statistical parameters of the growing surface, determined by x-ray diffraction and scanning probe microscopy, including roughness, in-plane and out-of-plane grain size and local slope distributions. The morphology transformations occur as a result of the balance of attractive and repulsive interactions between surface structures emerging at different length scales, which comprise a competition between stress relaxation via surface currents and strain generation. This balance is responsible for the formation of large multigrain structures via the bundling with in-plane reorientation of neighbouring grains, related to attractive interaction on the short length scale, and the generation of grooves and surface discontinuities between structures repelling each other, on longer length scales. These results shed light on the surface phenomena occurring during post-growth annealing of T-zone structured, polycrystalline gold films.