Narrow Results

Various metal film systems, deposited on liquid (silicone oil) substrates by thermal evaporating and DC-magnetron sputtering methods, have been successfully fabricated and the stress relief mechanisms are systematically studied by analyzing the characteristic surface morphologies. The experiment shows that the evaporating metal films can move on silicone oil surfaces freely due to the nearly zero adhesion of solid–liquid interface, which results in spontaneous formation of ordered surface patterns with a characteristic sandwiched structure driven by the internal stress. For the sputtering metal film system, however, the top surface of silicone oil can be modified to form an elastomeric polymer layer on the liquid substrate during deposition. Subsequent cooling of the system creates a higher compressive stress in the film, which is relieved by buckling of the film to form periodic wavy structures because the adhesion of solid–elastomer interface is quite strong.

The growth mechanism and characteristic ordered patterns of iron (Fe) films deposited on the silicone oil surfaces by a DC-magnetron sputtering method are presented in this paper. It is found that as the film thickness increases, the iron atoms deposited on the oil surface first form compact clusters, then transfer to ramified aggregates and web-shaped structures, and finally form a continuous iron film. The average branch width of the ramified aggregates is about 0.34 μm, which is almost independent of the sputtering power, i.e., the deposition rate. In the continuous iron films, large spatially disk-shaped patterns are observed, which result from spontaneous ordered organization of the iron atoms and atomic clusters driven by the internal stress in this nearly free sustained film system.