Computer-simulated energy and angular distributions of sputtered Cu atoms

Abstract

The energy and angular distributions of copper atoms ejected by 5 keV incident Ar ions have been simulated using the multiple interaction molecular dynamics technique. Calculations carried out with two independently written computer codes yielded essentially identical results. As in previous simulation studies of low to medium energy sputtering, virtually all ejected atoms came from the first layer or second layer. Two different ion-atom potentials were used in the simulations. Absolute sputtering yields depended strongly on the choice of potential; relative yields and angular distributions were found to be insensitive to the choice of potential. For Ar ions normally incident on the (100), (110), and (111) faces of a fcc Cu crystallite, ejected atoms from the second layer of the crystallite exited preferentially in the forward direction compared to those sputtered from the first layer. The energy spectra of atoms ejected from the second layers were harder than those of the first layer atoms.