SHIFT OF THE BOUNDARY OF A BEADED THIN-FILM CAUSED BY EVAPORATION

A theoretical description of the shift of the boundary of beaded thin films is given supposing that the boundary motion is initiated by evaporation. In our treatment the role of the surface reaction control (at the perimeters of beads) is also taken into account. It is shown that the shift can be controlled by surface diffusion or by surface reaction: analytical expressions for both cases are derived. It is pointed out that from simultaneous measurements of the time dependence of the effective thickness and the shift of the boundary all characteristic parameters of the surface mass transport can be determined. This is experimentally illustrated for the case of a copper film on the (110) surface of molybdenum, where a surface reaction control was observed.