Energy Distribution of Sputtered Cu Atoms

Energy distributions have been obtained for atoms sputtered from Cu (100), (110), (111), and polycrystalline surfaces bombarded by 80- to 1200-eV Hg and noble gas ions. Energies of sputtered atoms are found to depend markedly on the angle of ejection. For a (110) surface bombarded by 1000-eV Kr ions, average energies of ejected atoms are 9.5 eV in the [110] direction (normal to the surface) and 14.2 eV in the [011] direction (60° to the surface normal). Ejection energies decrease for lighter ions in the order Kr+, Ar+, Ne+, and He+. For a (110) surface bombarded by 600-eV He ions, the average energy of atoms ejected in the [110] direction is 5.5 eV. Dependence on bombarding ion energy is very weak above 1000 eV where average energies of sputtered atoms are found to be in the range 5–15 eV. Ejection energies decrease at lower bombarding ion energies and decrease rapidly below 200 eV. For atoms ejected in the [110] direction from a (110) surface under Kr ion bombardment, the average energy decreases from 5.5 eV at an ion energy of 200 eV to 2.6 eV at an ion energy of 80 eV.