Helium ion microscopy and dual-beam nanofabrication

The Zeiss ORION NanoFab is an advanced scanning ion microscope that utilises an interchangeable dual-ion beam (helium and neon) for nanofabrication and sub-nanometre imaging.

Imaging

The HIM excels at imaging surfaces with sub-nanometer resolution and high surface sensitivity. Imaging is achieved by detecting secondary electrons generated when the ions impact the sample surface. It offers new insight from materials with greater depth of field and can probe non-conductive samples without the need for coating. The NanoFab is thus well suited to imaging challenging samples such as polymers, nanoparticles and biological samples.

Milling / Deposition / Implantation

The HIM also offers unique nanofabrication capabilities. The Ne⁺ beam can be used for micro-nano milling, after which features can be refined using the He⁺ beam. Complex patterns can be generated using the Nanopatterning and Visualization Engine (NPVE) interface. A gas injection system (GIS) enables gas-assisted etching of silicon as well as ion-beam-induced deposition of tungsten and silicon dioxide. Nanoscale implantation studies using both beams can also be performed.

Specifications

He⁺ beam (GFIS): 10 to 30 kV, Ne⁺ beam (GFIS): 10 to 25 kV
Everhart-Thornley (ET) secondary electron detector
Stage travel: x=50mm, y=50mm, z=8 mm, rotation 0-360°, tilt 0-56°
Oxford Instruments OmniGIS II gas injection system: W, SiO₂, XeF₂
Patterning Software: NPVE, 16 bit scan generator, create a range of fully editable shapes (array builder), full control over dose variation, real time image visualization
Sample types: conductive, insulating, magnetic, hard and soft materials
Limitations: High vacuum atmosphere. Escape of trapped helium can present a challenge in a few materials (notably silicon and diamond). Damage is generally low, but needs to be monitored

Sample Preparation

As with all vacuum techniques cleanliness is key. Samples should be free from moisture and oils, adhered onto a substrate or to double-sided conductive adhesive tape. Mounting on SEM pin stubs is preferable, please discuss with the instrument manager if you are not sure.

Access

The NanoFab can be operated by researchers or on a fee for service basis by MCFP platform staff. Trained users can book through the MCFP iLab booking system. Please note that training will only be offered to researchers for whom the HIM will form a large part of their research program, or where the user already has EM expertise. Please contact Anders Barlow to arrange access or training.

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