Low-Energy Ar+ Sputtering Yields of Solid and Liquid Tin

Abstract

Low-energy Ar+ sputtering yields have been obtained for solid and liquid tin from threshold to 1200 eV. The solid yield at 200 eV is twice that for the liquid but a crossover occurs at 375 eV above which liquid yields are 15% higher. The liquid-yield curve exhibits a linear dependence up to E=475 eV and breaks sharply to a lower dependence on ion energy. Yields of remelted solid were intermediate between the curves for liquid and solid, demonstrating the effect of surface roughness on the yield for polycrystalline targets. This work confirms experimentally the theory of Sigmund for yield of amorphous targets particularly in the low-energy range near threshold where surface effects predominate.