Surface Sputtering of Ag{100} by KeV Particle Bombardment

Abstract

AbstractThe atoms emitted from the single-crystal surface due to keV particle bombardment have been characterized using molecular dynamics to simulate the energy dissipation process. The model system in the calculation utilizes a Ag(100) microcrystallite of about 2000 atoms which is bombarded by as many as 1600 incident Ar atoms of 2-keV energy. The surface order is found to be preserved to a certain extent during the bombardment of static particle beams. A preferred direction of ejection is observed for the lower-kinetic-energy atoms (< I eV) sputtered from the second surface layer. Most of these atoms which take off late in the collision cascade originate from positions on the surface within three to four lattice spacings from the point of impact. The ejecting atoms are confined by the top layer atoms which are still located close to their lattice points when the collision cascade subsides. In addition, the angular pattern of ejection changes slightly as the emission energy of detection is varied. We found that the angular pattern of ejection did not vary with the emission energy in the low energy regime, in which the surface structure may be better determined.