Influence of Reactive Gases on Sputtering and Secondary Ion Emission. Pt. 2. Oxidation of Titanium and Vanadium During Energetic Particle Irradiation

摘要

As a continuation of earlier sputtering yield measurements in an ion microprobe, the influence of oxygen and nitrogen on sputtering yield, ionization efficiency and depth resolution has been studied. For inert gas bombardment the yield of Ti and V falls sharply at a certain oxygen exposure. While this decrease in yield can be correlated with an increase in surface binding energy in the case of titanium, cone formation causes the yield to drop for oxygen-exposed vanadium. In contrast, during nitrogen bombardment the only effect of oxygen exposure is a drastic increase of the ionization efficiency; the sputtering yield or the depth resolution delta z/z is hardly influenced by oxygen coverage. As was observed earlier in the case of Cu-Ni layers, delta z is essentially constant for erosion depths z >= 800 A, thus yielding better resolution at large depths than is to be expected from a sequential layer removal model. The extent of the transition zone, delta z, is determined by surface topography and thus depends on the target composition as well as its structure. (Atomindex citation 09:390162)