Nanometer scale elemental analysis in the helium ion microscope using time of flight spectrometry

Abstract

Time of flight backscattering spectrometry (ToF-BS) was successfully implemented in a helium ion microscope (HIM). Its integration introduces the ability to perform laterally resolved elemental analysis as well as elemental depth profiling on the nm scale. A lateral resolution of ≤54nm and a time resolution of Δt≤17ns(Δt/t≤5.4%) are achieved. By using the energy of the backscattered particles for contrast generation, we introduce a new imaging method to the HIM allowing direct elemental mapping as well as local spectrometry. In addition laterally resolved time of flight secondary ion mass spectrometry (ToF-SIMS) can be performed with the same setup. Time of flight is implemented by pulsing the primary ion beam. This is achieved in a cost effective and minimal invasive way that does not influence the high resolution capabilities of the microscope when operating in standard secondary electron (SE) imaging mode. This technique can thus be easily adapted to existing devices. The particular implementation of ToF-BS and ToF-SIMS techniques are described, results are presented and advantages, difficulties and limitations of this new techniques are discussed.

Recent advances in MEIS

“…Additionally, the uncertainty due to neutralization of scattered ions can be eliminated for more quantitative analysis. Recently, TOF‐MEIS has been combined with He ion microscopy (HIM) that provides a He ion beam with 0.5‐nm diameter . In practice, the spatial resolution of TOF‐MEIS combined with HIM was <54 nm and the energy resolution △E/E in the range of 10 −2 , which is 10 times worse than the energy resolution △E/E of typical MEIS, which is in the range of 10 −3 .…”

Ibc - Ion Beam Center

“…In a di erent project semiconductor surfaces are patterned locally with the help of heavy poly-atomic focused ion beams. Recently, we also developed the rst time-of-ight backscatter spectrometer for the gas eld ion source (GFIS) based Orion NanoFab (Klingner et al, 2016). With an energy resolution of 2.5% and an unprecedented lateral resolution of 50 nm it can be used for spatially resolved, damage free materials analysis at the ion microscope.…”

Time of Flight Backscatter and Secondary Ion Spectrometry in a Helium Ion Microscope

“…While the technologyHIM technology is relatively young several efforts have been made to add such an analytic capability to the technique. So far, ionoluminescence [1,3], backscattering spectrometry (BS) [1,4,5], and secondary ion mass spectrometry (SIMS) using a magnetic sector [6] or time of flight (TOF) setup have been demonstrated [4].After a brief introduction to HIM itself and a summary of the existing approaches I will focus on our own time of flight based analytic approaches. TOF-HIM is enabled by using a fast blanking electronics to chop the primary beam into pulses with a minimal length of only 20 ns.…”

“…While the technologyHIM technology is relatively young several efforts have been made to add such an analytic capability to the technique. So far, ionoluminescence [1,3], backscattering spectrometry (BS) [1,4,5], and secondary ion mass spectrometry (SIMS) using a magnetic sector [6] or time of flight (TOF) setup have been demonstrated [4].…”