Surface processing by gas cluster ion beams

Surface processing with gas cluster ion beams which contain hundreds or even many thousands of atoms or molecules has been studied. The sputtering yields of various materials with Ar cluster ions are about one order of magnitude higher than those produced by Ar monomer ions with the same energy. Also, the sputtering yields of Si and W are chemically enhanced with SF₆ cluster ion beams. The surface roughness of Cu dramatically decreased when bombarded with Ar cluster ion beams compared with Ar monomer ion beams, and there is no roughening mechanism. This smoothing effect of gas cluster ion beams is applicable for very hard materials, such as CVD diamond films