Resputtering effects during ion beam assisted deposition and the sputter yield amplification effect

Sputter yield amplification (SYA) is an effect where the sputtering yield of a given material is significantly increased by the introduction of a small concentration of a heavy impurity at the surface. The basic ideas behind the SYA effect as well as its major physical mechanisms are presented and discussed in some detail. Exhaustive numerical simulation results are shown to support the models suggested. Experimental verification of key predictions, such as magnitude of sputter yield amplification as well as selective ion-assisted deposition, are also presented. More specifically, the paper first treats a number of cases in relation to sputtering of composite targets. Results are presented showing the conditions under which optimum amplification is achieved as well as cases exhibiting a peculiar transition to steady state. We also look at a series of ion-assisted deposition situations where sputter yield amplification during resputtering has a pronounced effect. Attention here is drawn to the peculiarities of sputtering of ultra-thin films and particularly to interface evolution during ion-assisted deposition with single and multiple deposition fluxes.