Sputter Yield Dependence on Substrate

Z2 Sputter Yield Dependence on Substrate As with Section 3.2.2.1, this section will concentrate on the general trends noted under the more routinely used conditions applied in SIMS, i.e. those noted under primary ion impact within the 0.1-50 keV energy range with incidence angles ranging from 0 to 80° relative to the surface normal. 

As also indicated, all dependencies tend to be substrate specific. But what should be noted is the fact that ion beam impact under sufficiently energetic conditions will induce modifications of their own to the substrate surface. These tend to scale with dose, at least until steady-state sputtering conditions prevail. The subsequent two sections will thus cover substrate-specific variations (those typically noted following steady-state sputtering conditions) and those resulting from the ion bean-induced modifications. The former are covered in Section 3.2.2.2.1, whereas the latter are covered in Section 3.2.2.22. 

For the sake of clarity, single-component substrates of amorphous or polycrystalline structure are only discussed unless otherwise specified. Multicomponent systems introduce additional effects as will be discussed in Section 3.2.3.4. Lastly, the bulk of the discussion is centered on the use of atomic and/or snnaU molecular ion impact, since there are too numerous a number of molecular ion-substrate combinations, many which still lack a full understanding of the trends exhibited. For specific cases, the reader is advised to access the latest literature. 

In its simplest form, such sputter yields can be shown to vary primarily as a function of  

The dependence on the collisional cross section is impact energy dependent (see Relation 3.1). At a specific energy, the cross section also varies according to the atomic numbers of the collision partners. This dependence takes the form of a larger collisional cross section for heavier elements, which is the reason why heavier ions are used in sputtering (the small cross section of He+ allows this ion to travel a 

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