Sputtering simulations of organic overlayers on metal substrates by monoatomic and clusters projectiles

This paper reviews our recent work on computer simulations of monoatomic and cluster bombardment of metal and organic surfaces. The investigated surfaces are irradiated with keV monoatomic (C, Ar, Ga) and polyatomic (C-60) projectiles that are recognized as valuable sources for desorption of high mass particles in secondary ion and neutral mass spectrometry (SIMS/SNMS) experiments. The analysis of the results reveals that the C-60 ion beam enables to perform chemical imaging with higher sensitivity, better depth resolution, and lower contamination than monoatomic projectiles with similar kinetic energy. For monoatomic projectiles, the development of a linear collision cascade is the predominant mechanism responsible for the ejection of particles. In contrast, strongly nonlinear, collective processes occur during C60 bombardment. These nonlinear processes lead to the enhanced removal of material and the formation of a macroscopic crater. This paper presents theoretical insight into possible mechanisms responsible for the observed behavior with the emphasis on the phenomena important to the SIMS/SNMS community. (C) 2004 Elsevier B.V. All rights reserved.