Contrast Differences Between Nitrogen and Helium Ion Induced Secondary Electron Images Beyond Instrument Effects

MRS Advances ◽  
2018 ◽  
Vol 3 (10) ◽  
pp. 505-510 ◽  
Author(s):  
Marek E. Schmidt ◽  
Shinichi Ogawa ◽  
Hiroshi Mizuta
Keyword(s):  
Secondary Electron ◽  
Bubble Formation ◽  
Ion Source ◽  
Limiting Factors ◽  
Helium Ions ◽  
Gas Field ◽  
Helium Ion ◽  
Ion Microscopy ◽  
Nitrogen Ion ◽  
Ion Species

ABSTRACTThe gas field ion source (GFIS) is able to generate tightly focused ion beams, which can be used to image or modify a specimen. Among the beam species, helium offers extremely high resolution, however, low sputter yield and sub-surface bubble formation are limiting factors in some applications. Therefore, heavier ions such as neon or nitrogen are used as well. In addition to being a suitable choice for lithographic mask editing, secondary electron (SE) generation by nitrogen beams has been recently shown to be affected by certain types of samples, providing additional contrast compared to helium ions. Here, we report our progress on the study of SE imaging differences between the nitrogen ion microscopy (N2IM) and helium ion microscopy (HIM). SE images of two nano-patterned samples comprising insulator, metal and carbon regions have been imaged by nitrogen and helium ions in two fundamentally different GFIS microscopes. The results corroborate previous reports of significant contrast differences in certain samples caused by the different ion species.

scholarly journals Imaging and milling resolution of light ion beams from helium ion microscopy and FIBs driven by liquid metal alloy ion sources

2020 ◽  
Vol 11 ◽  
pp. 1742-1749
Author(s):  
Nico Klingner ◽  
Gregor Hlawacek ◽  
Paul Mazarov ◽  
Wolfgang Pilz ◽  
Fabian Meyer ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Ion Beams ◽  
Ion Source ◽  
Metal Alloy ◽  
Gas Field ◽  
Helium Ion ◽  
Liquid Metal Alloy ◽  
Ion Species

While the application of focused ion beam (FIB) techniques has become a well-established technique in research and development for patterning and prototyping on the nanometer scale, there is still a large underused potential with respect to the usage of ion species other than gallium. Light ions in the range of m = 1–28 u (hydrogen to silicon) are of increasing interest due to the available high beam resolution in the nanometer range and their special chemical and physical behavior in the substrate. In this work, helium and neon ion beams from a helium ion microscope are compared with ion beams such as lithium, beryllium, boron, and silicon, obtained from a mass-separated FIB using a liquid metal alloy ion source (LMAIS) with respect to the imaging and milling resolution, as well as the current stability. Simulations were carried out to investigate whether the experimentally smallest ion-milled trenches are limited by the size of the collision cascade. While He+ offers, experimentally and in simulations, the smallest minimum trench width, light ion species such as Li+ or Be+ from a LMAIS offer higher milling rates and ion currents while outperforming the milling resolution of Ne+ from a gas field ion source. The comparison allows one to select the best possible ion species for the specific demands in terms of resolution, beam current, and volume to be drilled.

scholarly journals Scanning Helium Ion Microscopy-Induced Secondary Electron Yields of Composite Materials

2015 ◽  
Vol 21 (S3) ◽  
pp. 1691-1692
Author(s):  
Vighter Iberi ◽  
Uk Huh ◽  
Yueying Wu ◽  
Philip D. Rack ◽  
Adam J. Rondinone ◽  
...  
Keyword(s):  
Composite Materials ◽  
Secondary Electron ◽  
Helium Ion ◽  
Ion Microscopy

scholarly journals Direct Write of 3D Nanoscale Mesh Objects with Platinum Precursor via Focused Helium Ion Beam Induced Deposition

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 527
Author(s):  
Alex Belianinov ◽  
Matthew J. Burch ◽  
Anton Ievlev ◽  
Songkil Kim ◽  
Michael G. Stanford ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Source ◽  
Direct Write ◽  
Gas Field ◽  
Critical Dimensions ◽  
3D Mesh ◽  
Nanoscale Structures ◽  
Helium Ion

The next generation optical, electronic, biological, and sensing devices as well as platforms will inevitably extend their architecture into the 3rd dimension to enhance functionality. In focused ion beam induced deposition (FIBID), a helium gas field ion source can be used with an organometallic precursor gas to fabricate nanoscale structures in 3D with high-precision and smaller critical dimensions than focused electron beam induced deposition (FEBID), traditional liquid metal source FIBID, or other additive manufacturing technology. In this work, we report the effect of beam current, dwell time, and pixel pitch on the resultant segment and angle growth for nanoscale 3D mesh objects. We note subtle beam heating effects, which impact the segment angle and the feature size. Additionally, we investigate the competition of material deposition and sputtering during the 3D FIBID process, with helium ion microscopy experiments and Monte Carlo simulations. Our results show complex 3D mesh structures measuring ~300 nm in the largest dimension, with individual features as small as 16 nm at full width half maximum (FWHM). These assemblies can be completed in minutes, with the underlying fabrication technology compatible with existing lithographic techniques, suggesting a higher-throughput pathway to integrating FIBID with established nanofabrication techniques.

scholarly journals Channeling in helium ion microscopy: Mapping of crystal orientation

2012 ◽  
Vol 3 ◽  
pp. 501-506 ◽  
Author(s):  
Vasilisa Veligura ◽  
Gregor Hlawacek ◽  
Raoul van Gastel ◽  
Harold J W Zandvliet ◽  
Bene Poelsema
Keyword(s):  
Secondary Electron ◽  
Geometric Model ◽  
Particle Beam ◽  
Surface Layers ◽  
Charged Particle Beam ◽  
Surface Information ◽  
Surface Sensitivity ◽  
Helium Ion ◽  
Ion Microscopy ◽  
Unique Surface

Background: The unique surface sensitivity and the high resolution that can be achieved with helium ion microscopy make it a competitive technique for modern materials characterization. As in other techniques that make use of a charged particle beam, channeling through the crystal structure of the bulk of the material can occur. Results: Here, we demonstrate how this bulk phenomenon affects secondary electron images that predominantly contain surface information. In addition, we will show how it can be used to obtain crystallographic information. We will discuss the origin of channeling contrast in secondary electron images, illustrate this with experiments, and develop a simple geometric model to predict channeling maxima. Conclusion: Channeling plays an important role in helium ion microscopy and has to be taken into account when trying to achieve maximum image quality in backscattered helium images as well as secondary electron images. Secondary electron images can be used to extract crystallographic information from bulk samples as well as from thin surface layers, in a straightforward manner.

The Gas Field Ion Source for Finely Focused Ion Beam Systems

1995 ◽  
Vol 396 ◽  
Author(s):  
W. Thompson ◽  
A. Armstrong ◽  
S. Etchin ◽  
R. Percival ◽  
A. Saxonis
Keyword(s):  
Metal Ion ◽  
Focused Ion Beam ◽  
Vacuum Chamber ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Source ◽  
Max Planck ◽  
Gas Field ◽  
Ion Optics ◽  
Ion Species

AbstractThe Gas Field Ion Source, GFIS, promises a 109A/(cm2 str) brightness, small beam sizes, and inert gas ion species. If this performance could be demonstrated on a commercial system, the GFIS might replace the liquid metal ion source as the standard source for FIB applications. Recent work at the Max-Planck-Institut für Kernphysik (MPI-K) in Heidelberg, Germany has shown that a GFIS with a ‘Super Tipped’ emitter can be reliably fabricated and can be run with stable helium beam current for more than 200 hours. However, this GFIS source must operate in a bakable UHV chamber, at cryogenic temperatures, and at high voltages with low vibration. A GFIS is now being integrated with high resolution ion optics and a vacuum chamber designed for studying GFIS image quality and ion induced chemistry.

scholarly journals Pulsed Laser-Assisted Helium Ion Nanomachining of Monolayer Graphene—Direct-Write Kirigami Patterns

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1394 ◽  
Author(s):  
Cheng Zhang ◽  
Ondrej Dyck ◽  
David A. Garfinkel ◽  
Michael G. Stanford ◽  
Alex A. Belianinov ◽  
...  
Keyword(s):  
Ion Beam ◽  
Pulsed Laser ◽  
Ion Source ◽  
Ion Sources ◽  
Monolayer Graphene ◽  
Liquid Gallium ◽  
Direct Write ◽  
Gas Field ◽  
Helium Ion ◽  
Helium Gas

A helium gas field ion source has been demonstrated to be capable of realizing higher milling resolution relative to liquid gallium ion sources. One drawback, however, is that the helium ion mass is prohibitively low for reasonable sputtering rates of bulk materials, requiring a dosage that may lead to significant subsurface damage. Manipulation of suspended graphene is, therefore, a logical application for He+ milling. We demonstrate that competitive ion beam-induced deposition from residual carbonaceous contamination can be thermally mitigated via a pulsed laser-assisted He+ milling. By optimizing pulsed laser power density, frequency, and pulse width, we reduce the carbonaceous byproducts and mill graphene gaps down to sub 10 nm in highly complex kiragami patterns.

Comparison of He+ and Ga+ Voltage Contrast in N-wells

2019 ◽  
Author(s):  
Gregory M. Johnson ◽  
David Ferranti ◽  
John Notte ◽  
Brett Lewis ◽  
Chris H. Park ◽  
...  
Keyword(s):  
Process Monitoring ◽  
Secondary Electron ◽  
Marked Change ◽  
Quantitative Model ◽  
Ion Source ◽  
Field Of View ◽  
Gas Field ◽  
Voltage Contrast ◽  
Ga Doping

Abstract The examination of partially deprocessed ICs for well imaging has been investigated. First it has been shown [1] that Ga+ FIB imaging can readily and strongly highlight the N-well / P-well boundary in an IC as shown again here. Second, a model which only considers secondary electron creation and scattering [2] is confirmed to be sufficient for understanding these imaging effects. Heavy Ga doping provides no marked change in PVC (passive voltage contrast). Then comparisons in the same field of view between optimized He+ and Ga+ imaging, has shown that He+ provides much greater PVC contrast when looking through deep oxide, and much better resolution on shallow surfaces. The quantitative model Stopping and Range of Ions in Matter (SRIM) [3] was consulted and confirmed these expectations for resolution and depth superiority of the He+ beam. According to the SRIM, there may even be less damage from the He+ beam. Yet these known effects of Ga+ damage has not prevented its widespread use in semiconductor FA and process monitoring. Thus, the use of GFIS (Gas field ion source) He+ beam for voltage contrast and junction imaging warrants further exploration.

scholarly journals An Introduction to the Helium Ion Microscope

2006 ◽  
Vol 14 (4) ◽  
pp. 24-31 ◽  
Author(s):  
John Morgan ◽  
John Notte ◽  
Raymond Hill ◽  
Bill Ward
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Ion Source ◽  
Gas Field ◽  
Interaction Volume ◽  
Small Probe ◽  
Helium Ion ◽  
High Resolution Images ◽  
Scanning Electron

In order to get high resolution images from any scanning beam microscope one must be able to produce a sufficiently small probe, have a small interaction volume in the substrate and have an abundance of information-rich particles to collect to create the image. A typical scanning electron microscope is able to meet all of these requirements to some degree. However, a helium ion microscope based on a Gas Field Ion Source (GFIS) has significant advantages over the SEM in all three categories.

Contrast Mechanisms and Image Formation in Helium Ion Microscopy

2009 ◽  
Vol 15 (2) ◽  
pp. 147-153 ◽  
Author(s):  
David C. Bell
Keyword(s):  
Imaging System ◽  
Ion Source ◽  
Ion Imaging ◽  
Small Surface ◽  
Surface Sensitivity ◽  
Helium Ion ◽  
Contrast Mechanisms ◽  
Ion Microscopy ◽  
Imaging Instrument ◽  
Enhanced Surface

AbstractThe helium ion microscope is a unique imaging instrument. Based on an atomic level imaging system using the principle of field ion microscopy, the helium ion source has been shown to be incredibly stable and reliable, itself a remarkable engineering feat. Here we show that the image contrast is fundamentally different to other microscopes such as the scanning electron microscope (SEM), although showing many operational similarities due to the physical ion interaction mechanisms with the sample. Secondary electron images show enhanced surface contrast due the small surface interaction volume as well as elemental contrast differences, such as for nanowires imaged on a substrate. We present images of nanowires and nanoparticles for comparison with SEM imaging. Applications of Rutherford backscattered ion imaging as a unique and novel imaging mechanism are described. The advantages of the contrast mechanisms offered by this instrument for imaging nanomaterials are clearly apparent due to the high resolution and surface sensitivity afforded in the images. Future developments of the helium ion microscope should yield yet further improvements in imaging and provide a platform for continued advances in microscope science and nanoscale research.

HIMaging the kidney: High resolution helium ion microscopy

2014 ◽  
pp. 32-35
Author(s):  
Teodor Paunescu ◽  
Sylvie Breton ◽  
Dennis Brown
Keyword(s):  
High Resolution ◽  
Helium Ion ◽  
Ion Microscopy
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