Analytic approaches for Helium Ion Microscopy

Helium Ion Microscopy (HIM) utilizes a Gas Field Ion Source (GFIS) to create a Helium or Neon
ion beam with a diameter better than 0.5 nm and 1.8 nm, respectively. The method is well known
for its high resolution imaging and nano-fabrication capabilities which it is able to provide not only for
conducting but also insulating samples without the need for a conductive coating. However, the existing
GFIS based focused ion beam (FIB) tools suffer from the lack of a well integrated analytic method that
can enrich the highly detailed morphological images with material properties contrast. While HIM
technology is relatively young several efforts have been made to add such an analytic capability to
the technique. So far, ionoluminescence, secondary electron spectroscopy, backscattering spectrometry
(BS), and secondary ion mass spectrometry (SIMS) using a magnetic sector or time of flight (TOF)
setup have been demonstrated. In addition in-situ experiments can be performed that allow to directly
and in real time investigate the effect of the focused ion beam on the materials under various conditions.
I will present our efforts to perform in-situ experiments in the Helium Ion Microscope and enhance its
analytic capabilities. In the first part of my presentation I will give an overview of the in-situ characteri-
zation capabilities of the HZDR Orion NanoFab including in-situ heating and electrical characterization.
In the second part of the talk I will focus on different analytic approaches tested in the past. I will
briefly give an overview on ionoluminescence in the HIM and than present our newly developed TOF-BS
and TOF-SIMS setup which allow to obtain information on the composition of the sample. They both
utilize the same cost efficient and minimal invasive pulsing scheme for the primary ion beam. The lateral
resolution reached for TOF-BS is approximately 50 nm while for TOF-SIMS a value of 8 nm could be
reached. First images will be presented and the performance of the TOF-SIMS spectrometer will be
discussed.