New Cs sputter ion source with polyatomic ion beams for secondary ion mass spectrometry applications

Abstract

A simple design for a cesium sputter ion source compatible with vacuum and ion-optical systems as well as with electronics of the commercially available Cameca IMS-4f instrument is reported. This ion source has been tested with the cluster primary ions of Si n − and Cu n − . Our experiments with surface characterization and depth profiling conducted to date demonstrate improvements of the analytical capabilities of the secondary ion mass spectrometry instrument due to the nonadditive enhancement of secondary ion emission and shorter ion ranges of polyatomic projectiles compared to atomic ones with the same impact energy.

Ion Sources Used for Secondary Ion Mass Spectrometry

“…The ion beams produced with the source described by Gillen et al (via direct sputtering of the target with a Cs ion beam), were able to be focused into a spot of a few micrometers; however, sputtering of the target material in the source produced degradation of the beam intensity over the course of several hours, resulting in a daily replacement of the source target material. 36 A sputter-based primary ion source with a novel geometry was produced by Belykh et al 37 and used on a Cameca ims-4f to produce negative secondary ions. This source is shown in Figure 3.9.…”

Theoretical and Experimental Study of Negative LiF Clusters Produced by Fast Ion Impact on a Polycrystalline 7LiF Target

“…Nevertheless, the analysis of negative SIs is also important not only as a contribution to the understanding of the fundamental nature of the SI emission process but also because of their distinctive potential as generators of negative primary ion beams for practical applications. In particular, negative ion beams are suitable (i) for low-energy (electronvolts to kiloelectronvolts) charge−exchange experiments with surfaces, (ii) as a source to sputter ions for positive ion sources, and (iii) for injecting negative ion beams into electrostatic tandem accelerators . For cluster ion projectiles, it is well known that they are capable of inducing much higher desorption yields than atomic ions projectiles and are therefore suitable for surface analysis, erosion devices, and beam sources for secondary ion mass spectrometry (SIMS). − …”