ABSTRACT
This chapter deals with some essential aspects of quantitative analysis by Secondary Ion Mass Spectrometry (SIMS) and Sputtered Neutral Mass Spectrometry (SNMS). With electron-impact SNMS, the achievable ionisation efficiencies are relatively low compared with SIMS, but the absence of matrix effects makes this a useful technique in many applications. In contrast to SIMS, SNMS makes use exclusively of positively charged ions. As a result of primary ion impact atoms and molecules from the topmost layers of the sample are sputter ejected into the vacuum outside the sample surface. Since all elements of the periodic table can be removed from a solid sample by sputtering, a mass analysis of the sputtered flux provides a direct measure of the composition of the eroded volume of the sample. The most common methods for determining the sputtering yield are based upon a post-bombardment measurement either of the change in mass of the sample or of the volume of the crater produced in the sample.
