Growth and morphology of magnetron sputter deposited silver films

Silver thin films (1–10 nm thick) were deposited on titanium by magnetron sputtering. We study the effect of the current (20–65 mA) and the argon pressure (5–20 mtorr) on the films morphology. Their structure is characterized by electron spectroscopy for chemical analysis (ESCA) and atomic force microscopy (AFM). The ESCA data are analysed by means of the quases™ code. The data are fitted by means of a model in which the surface is assumed to be composed of two kinds of features: islands and a thin layer. It is shown that the islands coverage coefficient may attain 95%. The films are also characterized by AFM. It appears that the surface roughness is important, due to the roughness of the initial Ti film. A comparison of the AFM and quases™ results shows that the structure is such that clusters of Ti are covered by a thin layer of Ag. The space between Ti clusters is filled with clusters of Ag. The coverage and the thickness of the films depend on the deposition rate and the total argon pressure.