PROCESSES IN LOW-ENERGY ION-SURFACE COLLISIONS - PREFERENTIAL SPUTTERING, DEFECT AND ADATOM FORMATION

Emphasizing impact energies in the low- and sub-keV range, current adv ances in elucidating the interaction of ions with solid surfaces are h ighlighted by means of selected examples. Specifically, the following topics are addressed: (i) The influence of mass differences on the mag nitude of preferential sputtering effects is investigated by monitorin g, via mass spectrometric techniques, the angle- and energy-differenti al fluxes of the isotopes of an element. (ii) The modification and gra dual amorphization of crystalline semiconductors under ion bombardment is studied for various impact conditions (energy, fluence and current density) by electron spectroscopy and electron diffraction. (iii) The formation of adatoms as observed in recent experiments and computer s imulations is discussed and the respective yields are related to those of ejected species.