Angulardependence of the sputteringyield from acylindricaltrack

E.M. BRINGA; R.E. JOHNSON

NUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH B - BEAM INTERACTIONS WITH MATERIALS AND ATOMS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2001 vol. 180 p. 99 - 104

0168-583X

The dependence of the sputteringyield on the incident angle, ¥È, is determined using molecular dynamics (MD) simulations for acylindricaltrack produced by a fast ion. For a `small' spike radius and for the mean energy in the track, Eexc, smaller than the binding energy, U, a (cos¥È)−1.7dependence is found, close to the linear collision cascade (LCC) result and to some thermal spike models. On the other hand, when Eexc>U, the incident angle dependence is (cos¥È)−1. For a larger spike radius we obtain a ¡­(cos¥È)−1.6dependence for both high and low energy densities. Analytic spike models based on diffusive transport are shown not to give satisfactory results. In addition, at low energy densities we see correlated atom ejection ignored in analytic models. Applying the MD results to the experimental data for electronic sputtering of solid O2 at large excitation densities suggests that the effective spike radius is larger than the initial Bohr adiabatic radius indicating that energy is rapidly transported from the initially narrow track.