Focused particle beam-induced processing

• Michael Huth and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2015, 6, 1883–1885, doi:10.3762/bjnano.6.191

• alleviate the resolution-limiting issues in FEBID on solid substrates is the employment of helium ion microscopy (HIM). In its current development stage, HIM is mainly used for imaging applications, providing enhanced contrast for surface features as compared to scanning electron microscopy. Along this

• direction, Yuri Petrov and Oleg Vyvenko have exploited reflected helium ions for high-resolution imaging with “chemical contrast” [11]. Hongzhou Zhang and coworkers have utilized a focused helium ion beam to modify and mill thin silicon foils [12], which constitutes pioneering work in HIM towards

• the gold surface. A novel route towards focused particle beam-induced processing (FPBIP) with HIM is paved by Xianghui Zhang and coworkers [16]. They used focused helium ions to perform the controlled modification of materials in monomolecular organic films. Here, ion exposure induced 2D

Imaging of carbon nanomembranes with helium ion microscopy

• André Beyer,
• Henning Vieker,
• Robin Klett,
• Hanno Meyer zu Theenhausen,
• Polina Angelova and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2015, 6, 1712–1720, doi:10.3762/bjnano.6.175

• can visualize them. However, CNMs are electrically insulating, which makes them sensitive to charging. We demonstrate that the helium ion microscope (HIM) is a good candidate for imaging freestanding CNMs due to its efficient charge compensation tool. Scanning with a beam of helium ions while

• recording the emitted secondary electrons generates the HIM images. The advantages of HIM are high resolution, high surface sensitivity and large depth of field. The effects of sample charging, imaging of multilayer CNMs as well as imaging artefacts are discussed. Keywords: 2D materials; carbon

• particle microscopy techniques such as scanning electron microscopy (SEM) or helium ion microscopy (HIM). As illustrated in Supporting Information File 1, Figure S1, SEM shows a low signal-to-noise-ratio for freestanding CNMs, especially at higher magnifications, due to charging issues [4][16]. This tends

Scanning reflection ion microscopy in a helium ion microscope

• Yuri V. Petrov and
• Oleg F. Vyvenko

Beilstein J. Nanotechnol. 2015, 6, 1125–1137, doi:10.3762/bjnano.6.114

• microscope (HIM). The reflected ions were detected by their “conversion” to secondary electrons on a platinum surface. An angle of incidence in the range 5–10° was used in the experimental setup. It was shown that the RIM image contrast was determined mostly by surface morphology but not by the atomic

• narrow beam divergence angle of about 0.5 mrad [15][16], which is ten times less than the best beam divergence angle possible in SEM. The large depth of focus makes helium ion microscopy (HIM) a very promising tool for scanning reflection microscopy. During the last decade the imaging capabilities of HIM

• -SE conversion was used for the detection of backscattered electrons in SEM [36] and for scanning transmission mode in HIM [37]. A schematic of the originally developed RI detection system is shown in Figure 1. The sample (1) was mounted on a stage at a grazing angle relative to the focused helium ion

Fabrication of carbon nanomembranes by helium ion beam lithography

• Xianghui Zhang,
• Henning Vieker,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2014, 5, 188–194, doi:10.3762/bjnano.5.20

• , which allowed for an ex situ observation of the cross-linking process by helium ion microscopy (HIM). In this way, three growth regimes of cross-linked areas were identified: formation of nuclei, one-dimensional (1D) and two-dimensional (2D) growth. The evaluation of the corresponding HIM images

• of these films, too. This is related to changes in the chemical structures of the polymers [16][17]. Recently, the helium ion microscope (HIM) has been employed as an imaging and measurement tool for nanotechnology, for which the sub-nanometer sized ion probe and its resulting high brightness lead to

• , the low proximity effect that arises from the finite excited volume, in which the ion–material interaction takes place, extending deeply into the material, and the confinement of ion scattering to the secondary electron escape depth promise an outstanding performance of HIM [20]. So far, various

Digging gold: keV He⁺ ion interaction with Au

• Vasilisa Veligura,
• Gregor Hlawacek,
• Robin P. Berkelaar,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2013, 4, 453–460, doi:10.3762/bjnano.4.53

• microscopy (HIM) was used to investigate the interaction of a focused He+ ion beam with energies of several tens of kiloelectronvolts with metals. HIM is usually applied for the visualization of materials with extreme surface sensitivity and resolution. However, the use of high ion fluences can lead to

• crystals; helium ion microscopy; ion beam/solid interactions; vacancies in crystals; Introduction The helium ion microscope allows the projection of a He+ beam of several tens of kiloelectronvolts with a diameter of 0.4 nm [1] onto a sample. This makes HIM an attractive tool for surface patterning and

• nanofabrication [2][3][4][5][6]. In addition to ultrahigh-resolution imaging, HIM can be utilized for the compositional analysis and crystallographic characterization of samples [7][8]. Since it is a relatively new technique, many questions concerning the interaction of the focused He+ beam with matter remain

Nano-structuring, surface and bulk modification with a focused helium ion beam

• Daniel Fox,
• Yanhui Chen,
• Colm C. Faulkner and
• Hongzhou Zhang

Beilstein J. Nanotechnol. 2012, 3, 579–585, doi:10.3762/bjnano.3.67

• microscope (HIM) is a new type of focused ion beam microscope. The HIM uses helium ions instead of gallium ions. Helium ions have a lower mass and therefore are less destructive than gallium ions. Helium ions are effectively non-contaminating. The source is a gas field ion source which does not suffer the

• energy spread and subsequent chromatic aberration which limits the resolution of the FIB [10]. Our HIM is capable of sub-nm resolution imaging with its <0.75 nm probe size. This makes it ideally suited to both high resolution imaging and also modification of materials with a higher level of control and

• precision than can be offered by other ion beam tools. The HIM has the unique ability to directly mill arbitrary patterns with sub 10 nm feature sizes. To date most of this work has been done on graphene [11][12][13]. The HIM can also directly write sub 10 nm features via precursor gas decomposition [14][15

Imaging ultra thin layers with helium ion microscopy: Utilizing the channeling contrast mechanism

• Gregor Hlawacek,
• Vasilisa Veligura,
• Stefan Lorbek,
• Tijs F. Mocking,
• Antony George,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2012, 3, 507–512, doi:10.3762/bjnano.3.58

• geometric calculations of the opaque crystal fraction, the contrast that is observed in the images can be interpreted in terms of changes in the channeling probability. Conclusion: The suppression of ion channeling into crystalline matter by adsorbed thin films provides a new contrast mechanism for HIM

• ion microscopy; ion scattering; thin layers; Introduction The helium ion microscope (HIM) has established itself as a high-performance alternative to the classic scanning electron microscope (SEM). The superior resolution and the outstanding performance on insulating samples are well-known facts [1

• crystal orientation. Channeling along low index directions affects SE as well as BSHe images [3][4]. Here, we discuss how channeling can be utilized to gain unexpected contrast in BSHe images on ultrathin surface layers. HIM already provides superior surface sensitivity in SE-based images. The described

Channeling in helium ion microscopy: Mapping of crystal orientation

• Vasilisa Veligura,
• Gregor Hlawacek,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2012, 3, 501–506, doi:10.3762/bjnano.3.57

• microscope (HIM) and its outstanding performance on insulating samples [1][2] make it an interesting tool for materials research. Whilst images based on secondary electrons (SE) can yield an edge resolution down to 0.29 nm [2], backscattered helium (BSHe) images reveal the elemental composition of the

• developed to obtain texture data or crystallographic information systematically in HIM. Especially the latter is an important issue in materials characterization. An important phenomenon that can be exploited in HIM for this purpose is channeling. This well-known process has been studied extensively in the

• past in the context of ion scattering methods, such as Rutherford backscattering (RBS) and medium- and low-energy ion scattering. Many ion scattering phenomena are well understood for the very high energies of several hundred keV up to MeV that are used in RBS. Although energies in HIM are different

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5