| AVS 63rd International Symposium & Exhibition | |
| Advanced Ion Microscopy Focus Topic | Wednesday Sessions |
| Session HI-WeA |
| Session: | 10 Years of GFIS Microscopy |
| Presenter: | David Dowsett, Luxembourg Institute of Science and Technology (LIST), Luxembourg |
| Authors: | D.M.F. Dowsett, Luxembourg Institute of Science and Technology (LIST), Luxembourg J.-N. Audinot, Luxembourg Institute of Science and Technology (LIST), Luxembourg F. Vollnhals, Luxembourg Institute of Science and Technology (LIST), Luxembourg T. Wirtz, Luxembourg Institute of Science and Technology (LIST), Luxembourg |
| Correspondent: | Click to Email |
The Helium Ion Microscope (HIM) has become an ideal tool for imaging and nano-patterning [1]. Imaging with helium ions leads to resolutions of 0.5 nm for secondary electron (SE) based imaging, while structures with sub 20 nm feature sizes may be rapidly patterned using Ne. Despite these advantages, the analysis capability of the instrument is currently limited. At beam energies of 35 keV helium or neon ions do not lead to the emission of characteristic X-rays from a sample. While some compositional information can be obtained from back scattered helium [2], identifying elemental information is more difficult. Secondary Ion Mass Spectrometry (SIMS) is a powerful ion beam based technique for analysing surfaces capable of high sensitivity and high mass resolution. SIMS is based on the generation and identification of characteristic secondary ions by irradiation with a primary ion beam (in this case helium or neon). The typical interaction volume for SIMS is around 10 nm in the lateral direction. As the probe size in the HIM is substantially smaller (both for He and Ne) the lateral resolution is limited only by fundamental considerations [3-4] and not, as is currently the case on commercial SIMS instruments, the probe size.
We have developed a prototype SIMS spectrometer specifically adapted to the Zeiss ORION NanoFab. Notably the instrument is capable of producing elemental SIMS maps with lateral resolution limited only by the fundamental interaction between the primary beam and the sample. All elements/isotopes and small clusters with masses up to 500 amu are detectable with a mass resolution M/ΔM greater than 400 and parallel detection of 4 mass channels (Figure 1).
The prospect of adding SIMS to the HIM yields not just a powerful analytical capability, but opens the way for in-situ correlative imaging combining high resolution SE images with elemental and isotopic ratio maps from SIMS [5]. This approach allows SE images of exactly the same zone analysed with SIMS to be acquired easily and rapidly. Figure 2 shows a combined SE-SIMS image of a lithium titanate and boron nitride nanoparticle mixture. The SE image has a resolution of a few nanometres, clearly showing the structure of individual nanoparticles, while the SIMS image has a resolution of a few tens of nanometres and allows unambiguous identification of individual nanoparticles.
We will present the performance characteristics of the spectrometer along with the latest results in the field of materials science.