On the kinetic energies of sputtered excited particles. III. Recoil sputtering as a source of high-energy particles

Recent work on the sputtering of excited atoms and ions has included measurements of light-vs.-distance. These measurements were interpreted in terms of the kinetic energies of the excited particles and led to the conclusion that the kinetic energies had distributions with threshld values, E*, of 102-103 eV. The present work is concerned with developing a model, based on the theory of the recoil sputtering of both atoms and energy, which is capable of rationalizing such high energies. The calculations show, firstly, that, except for atoms with low E* such as Li, recoil-sputtering yields are much larger than the high-energy (i.e. E>E*) tails of cascade-sputtering yields. Secondly, recoil-sputtering yields are shown to be larger than the experimental excited-state yields of Tsong and Yusuf. Thirdly, and of most interest, the mean energy per recoil-sputtered atom is found consistently to be either larger than, or similar to, the experimental E*. © 1981.