New Imaging Modalities in Helium Ion Microscopy

Standard Helium Ion Microscopy (HIM) is providing best resolution gas field ion source based imaging and nanofabrication capabilities[1], but is lacking analytical capabilities. Elemental information in the HIM can be obtained using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Here, the primary beam hits the sample in pulses as short as 20 ns. Ionized sputtered particles from the sample are than analyzed with respect to their TOF. A lateral resolution of 8 nm has been achieved [2]. I will present details of the implementation and show results obtained on materials for Li batteries [3] and Zn coated steel samples. In a different approach we developed scanning transmission ion microscopy (STIM) to reveal buried and structural information of the investigated samples. The implementation is based on a new detector based on a combination of MCP stack and a solid state delay line detector. This moveable ≈4 Mpx detector has a spatially and time resolved count rate of 5 Mcps. It allows to record the scattering angle (<33°) and the energy of all transmitted particles [4]. In addition to mass-thickness contrast in bright and dark field also transmission channeling patterns can be obtained revealing the crystal structure of the sample. This work has been supported by BMWi grant 03ET7016, BMBF grant 03THW12F01, H2020 grant 720964, and FNR project C16/MS/11354626.