The surface structure factor of evaporated Cu films

Abstract

The surface structure factor of a deposited film is calculated. The calculation takes into account the competing mechanisms of roughening by the random nature of the deposition and flattening by surface diffusion. The surface structure factor has been measured by diffuse optical scattering for Cu films deposited by thermal evaporation in UHV. The shape of the surface roughness momentum distribution of the unannealed films is determined by both the film and the nature of the substrate. The film roughness spectrum dominates for k > 4 × 10 −4 A ̊ −1 and is relatively constant. Comparison of the measured and calculated magnitude of the surface structure factor shows that the minimum correlation length is of the order of magnitude of the grain size. The surface roughness amplitude increases upon annealing due to grain boundary grooving and hillock formation.