Formation of Sn metal spheres by plasma treatment

Sn metal spheres were produced by treatment of Sn films in various atmospheres. Sn films of different thicknesses (100–1000 nm) were used, and the heat-treatment was carried out either in a vacuum, in a hydrogen plasma, or in an Ar plasma. The as-deposited Sn films were dewetted as a result of a morphology change from a film to metal particles during post-treatment. The metal particles produced by heat-treatment in a hydrogen plasma were more spherical than those produced using an Ar plasma or without any plasma. As a result of spinodal dewetting, the mean diameter of the particles was closely related to the thickness of the Sn film.