UHV Helium Ion Microscopy - a new tool for surface science?

Full text: Helium Ion Microscopy (HIM) is a new tool that allows high resolution imaging of a wide range of materials. The fact that the technique is not limited to conductive materials and the many different contrast mechanisms make it a promising tool for nano structure research. HIM has demonstrated unprecedented resolution both on conductive and isolating materials. It is well known for its high surface sensitivity when using secondary electrons generated by the impinging ions. Chemical sensitivity is possible via the backscattered He. Both qualitative element contrast maps as well as quantitative localized Rutherford Backscattering are possible. In addition Ionoluminescence allows to obtain information on the band structure and defects, such as color centers, by analyzing the emitted photons. The extension of the method to UHV conditions and the high surface sensitivity allow to investigate surface and interface properties with a high spatial resolution. Investigated systems of interest to surface science include self assembled monolayers and thin films of conjugated molecules. However, I will also show results on the visualization of buried interfaces and demonstrate how crystallographic information can be obtained. In all cases the relevant contrast mechanisms will be discussed. (author)