| AVS 63rd International Symposium & Exhibition | |
| Advanced Ion Microscopy Focus Topic | Thursday Sessions |
| Session HI+NS-ThM |
| Session: | Fundamentals of Ion Beam Microscopy |
| Presenter: | Anders Barlow, Newcastle University, UK |
| Authors: | A.J. Barlow, Newcastle University, UK N. Sano, Newcastle University, UK J.F. Portoles, Newcastle University, UK P.J. Cumpson, Newcastle University, UK |
| Correspondent: | Click to Email |
The applications of ion beams in surface analysis are large and clear in the recent literature. In our multi-user facility most projects benefit from the use of an ion beam processing step, whether for cleaning or oxide removal prior to chemical analysis, or for sputter depth profiling through an interface or layer. In our facility we have access to a number of different ion beams: argon monoatomic and gas cluster ion beams (GCIB), C60 ion beams, and on our ORION NanoFab, helium/neon ion beams and a gallium focussed ion beam (FIB). These beams serve numerous purposes, from cleaning of surfaces prior to chemical analysis in X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS), to depth profiling in these techniques, to imaging and FIB milling. In all cases however, the ion beam is interacting with the surface under analysis, and this interaction needs to be studied and well-understood. In chemical analysis such as XPS and ToF-SIMS, this requires knowledge of damage mechanisms that impact the reported chemistry from the technique [1]. Understanding how the ion beam can generate nanoscale topography that directly affects the measurements is paramount [2,3].
We are applying helium ion microscopy (HIM) to studying how the ion beams on our instruments change the surfaces we are analysing. The ultra-high resolution of the HIM allows us to see nanoscale topography on surfaces with new-found sharpness at very high magnification, elucidating the mechanisms behind topography formation during treatment. We have investigated the GCIB etching of indium phosphide (InP) using 8keV Ar300 clusters (i.e. 300 Ar atoms per cluster). InP is known to generate significant topography following ion beam irradiation. We observe with a spectacular level of clarity the mechanisms behind topography formation, surpassing other commonly used imaging techniques such as scanning probe and scanning electron microscopy. We can also relate the stages of nanotopography growth with total ion beam dose, from a single GCIB etch crater. With this new technique we can more confidently relate the results we obtain from XPS and ToF-SIMS with the topography we observe in the HIM.
[1] Barlow A.J et al., J. Appl. Phys.116, 054908 (2014)
[2] Radny, T. and Gnaser, H., Nanoscale Research Letters9, 403 (2014)
[3] Seah, M.P. et al., Applied surface science144, 151-155 (1999)
[4] Cumpson, P.J. and Seah, M.P., Measurement Science and Technology1, 544 (1990)
[5] Cumpson, P.J. et al., J. Appl. Phys.114, 124313 (2013)