| AVS 55th International Symposium & Exhibition | |
| Applied Surface Science | Tuesday Sessions |
| Session AS-TuA |
| Session: | Practical Surface Analysis |
| Presenter: | F. Kollmer, ION-TOF GmbH, Germany |
| Authors: | F. Kollmer, ION-TOF GmbH, Germany F.M. Green, National Physical Laboratory, UK E. Niehuis, ION-TOF GmbH, Germany I.S. Gilmore, National Physical Laboratory, UK M.P. Seah, National Physical Laboratory, UK |
| Correspondent: | Click to Email |
Static SIMS is a well-established, powerful technique for the analysis of complex molecules on the outermost surface of a solid. However, the complexity of static SIMS spectra and the difficulties in the interpretation thereof have been significant barriers to the wider uptake of the technique. G-SIMS has been demonstrated to be a useful approach for simplifying complex static SIMS spectra of organics at surfaces leading to a direct identification of different substance classes.1 G-SIMS uses two ion beams that generate high and low fragmentation conditions at the surface. This allows an extrapolation to equivalent experimental conditions with very low fragmentation. The resulting spectra are less complex, contain more structural information and are easier to interpret. A barrier for the wider uptake of G-SIMS into the community are the requirements for two ion beams producing suitably different fragmentation conditions and the need for their registration at the surface, which is especially important for heterogeneous samples. The most popular source is the liquid metal ion source, which is now sold with almost every new ToF-SIMS instrument. These produce a high brightness source of atomic and cluster ions such as Bin+, Aun+. Unfortunately, a preliminary study shows that the cluster primary ions are less suitable for G-SIMS. We have developed a novel emitter consisting of a mixture of bismuth and manganese that produces selectable beams of Bi+ and Mn+ for high and low fragmentation conditions respectively. The beams are automatically aligned at the surface. This combines the cluster beam capabilities of a Bin+ cluster source with the ability to give excellent G-SIMS imaging and spectroscopy, without significantly comprising the cluster ion performance. We investigated the fundamental fragmentation conditions of Bi+ and Mn+, their ability to provide clear G-SIMS spectra and compared them to previously applied species as Ar+ and Cs+. Moreover, we investigated the beam performance of the BiMn source and the possibility of high resolution imaging in combination with G-SIMS analysis.
1I. S. Gilmore, M. P. Seah, Appl. Surf. Sci. 161 (2000) 465.