Sputtering of chemisorbed nitrogen from single-crystal planes of tungsten and molybdenum

Abstract

The sputtering of chemisorbed nitrogen from W(100), W(111), W(110), and Mo(100) by bombardment with helium, argon, and xenon ions has been investigated in the energy range between 300 and 5000 eV. It is concluded that the physical sputtering of chemisorbed nitrogen is not influenced by lattice damage, mixing phenomena, or thermal spikes. The yield does, however, depend upon the type of adsorption site and the mass of the surrounding atoms. It is shown that direct collisions between the ion and adsorbed nitrogen make a significant contribution to the sputter cross section for all ions and at all energies investigated. These direct-collision sputter events strongly influence the energy dependence of the sputter yield so that its behavior is significantly different from single-element materials. The implication of these results for the sputtering of multicomponent materials is discussed. © 1987 The American Physical Society.