Merlin vp sem

Scanning helium ion microscopy and lithography on single layer graphene was performed using a Zeiss ORION Nanofab He/Ne ion microscope, operating at an accelerating voltage of 30 kV and a beam current of 4.2 pA. All the graphene devices were fabricated using the ion microscope’s built-in patterning software and imported bitmaps. Each milled area was exposed to the He⁺/Ne⁺ beam at a field of view and pixel spacing that yielded a fluence of ~1 × 10¹⁹ ions/cm² for He⁺ beam and ~5 × 10¹⁷ ions/cm² for the Ne⁺ beam. Subsequent high-resolution images were acquired at the same field of view using a 50 μs dwell time.
Scanning electron microscopy secondary electron images of the exact same graphene devices were obtained using a Zeiss MERLIN VP SEM equipped with an in-lens detector operating at 3 kV.

SBF-SEM data was collected using a Merlin VP SEM (Zeiss) scanning electron microscope with 3view automated sectioning and image capture system (Gatan). Samples were trimmed to ~1 mm³ and mounted on 3view sample pins using an epoxy conductive adhesive from Circuitworks™. The block-face was imaged using a scanning electron beam with 3-5 kV accelerating voltage. Electron signal was detected using a back-scatter electron detector (OnPoint, Gatan) and nitrogen gas was injected to raise chamber pressure to 30pa. Pixel size was between 3-7 nanometer (nm) with a section thickness from 60-100 nm. Dwell time was approximately two seconds per pixel with a scan area of around 4,000 x 4,000 pixels. Completed SBF-SEM data sets contained anywhere from 50 – 500 sections.