Microfocussed Ion Beams for Surface Analysis and Depth Profiling
Secondary Ion Mass Spectrometry (SIMS) microprobe analysis can now be readily achieved using a Liquid Metal Ion Source (LMIS) to produce the primary ion probe. These sources have high brightness and small source size and permit the formation of high intensity sub-micron ion probes with energies from a few keV up to 30 keV. The use of such ion probes to extend the imaging capability SIMS of well into the submicron range has recently been demonstrated1,2. Ease of operation and full UHV compatibility of a gallium microprobe (VG Scientific MIG100) have allowed it to be included in both dedicated SIMS and multi-technique surface analysis instruments, e.g. in combination with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Applications of SIMS microanalysis have been demonstrated on a wide variety of samples including superconductors, steels, alloys, optical fibres, integrated circuits, catalysts, polymers and biological specimens. SIMS has proved to be especially useful when AES analysis is difficult for reasons such as surface charging, electron induced sputtering or migration, low sensitivity and excessive analysis time. Particular advantages of SIMS are its good to excellent sensitivity for all elements and the short time required to acquire an image, typically only a minute. In this paper we report on four further developments on the VG Scientific “SIMSLAB” which have significantly enhanced its imaging capabilities and its ability to give surface chemical analysis of insulators.
KeywordsImaging Capability Auger Electron Spectroscopy Analysis Probe Current Density Characteristic Fragmentation Pattern Neutralize Surface Charge
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