Sputtering Experiments in the Rutherford Collision Region

Sputtering experiments have been conducted by bombarding the (110) plane and the (100) plane of single crystals of copper by deuterons incident normally with energies from 0.8 to 2.5 Mev from a Van de Graaff accelerator. Electron micrographs showed that surface etch pits were formed by bombardment, even at these high energies. Measurements of optical transmission of the sputtered film collected on a quartz tube indicated a deviation from a cosine distribution in the energy range investigated. For 800-kev deuterons bombarding a (100) plane in Cu, the absolute value of the sputtering ratio was $S=1.1\mathrm{}\times {10}^{-3\mathrm{}}$ atom/ion at 25° with respect to the surface normal and 5.8×${10}^{-4\mathrm{}}$ at angles larger than 40°; and $S<\mathrm{}0.9\mathrm{}\times {10}^{-3\mathrm{}}$ atom/ion at 25° for 1.5-Mev deuterons. For 0.80- and 2.5-Mev deuterons bombarding a (110) plane, $S<\mathrm{}5\mathrm{}\times {10}^{-2\mathrm{}}$ atom/ion. These data agree with the calculations of Goldman and Simon and of Pease within a factor of 2, but disagree with those reported by Pleshivtsev by 2 to 4 orders of magnitude. The sputtering ratio was found to decrease with increasing ion energy, in qualitative agreement with the theoretical predictions but contrary to the findings of Pleshivtsev.