SIMS analysis with neutral cesium deposition: Negative secondary ion sensitivity increase and quantification aspects

Abstract

To overcome the SIMS matrix effect in the negative secondary ion mode, analyses can be performed on the Cation Mass Spectrometer using neutral cesium deposition with simultaneous primary ion bombardment. This paper discusses the advantages of this technique by applying it on several samples. The useful yields of various elements detected as negative secondary ions are calculated and discussed in terms of work function and electron affinity. The additional Cs deposition allows a significant increase of the useful yields of negative secondary ions and thus of the analysis sensitivity compared to traditional Cs + primary ion bombardment. At maximal cesium surface concentrations, quantitative analyses become possible for elements with high electron affinities. For other elements a significant increase of the analysis sensitivity is achieved.