Installed in 2014, the FIB (Thermo/FEI Scios located in WH172B) is primarily for making cross-section samples for study using SEM imaging and X-ray analysis. This process may possibly be followed by in-situ lift-out, thinning and polishing site-specific samples that are ready for TEM or STEM.
The FIB added new electron back-scattered diffraction (EBSD) and upgraded energy dispersive spectroscopy (EDS) facilities in 2016; it is capable of high speed X-ray analysis in part because it has a bright field-emission electron source (delivering up to 400 nA) and because the silicon-drift EDS electronics (EDAX Ametek) has a high throughput (it can analyze hundreds of thousands of X-rays per second). Rapid X-ray mapping is therefore a major strength of this system.
The instrument boasts an excellent SEM column (ultimate resolution of about 1.5 nm) with both in-lens secondary and in-lens back-scattered electron (BSE) detectors. Other detectors include an Everhard-Thorley (ET) electron detector and a versatile detector capable of collecting ions or electrons (ICE).
The gallium ion column efficiently cuts through materials to reveal sub-surface structure, makes patterns in a surface for optical device applications and facilitates the deposition of an highly localized protective platinum coating or marker. The maximum ion beam current is 65 nA with typical beam energies ranging between 2 keV and 30 keV.
The EBSD system produces accurate crystal orientation measurements and can combine with the EDS system to simultaneously map samples. The sample stage can handle up to 6″ wafers or a large number of standard SEM stubs, it can tilt to 90 degrees; and automated stage control adds the facility to montage large (mm-scale) areas.
- High vacuum operation, option to add liquid nitrogen trapping
- Micromanipulator with integrated motion control
- The FIB is compatible with an Hysitron picoindenter system PI-85
- Built-in plasma cleaner to clean sample and/or chamber
- Navigation camera integrated to facilitate rapid sample movement
- Automated “Slice and View” software to provide 3D dataset
- Beam deceleration technology to optimize low energy SEM
- Transmission Kikuchi Diffraction (TKD) is an available technique.
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The SEM is capable of good resolution, an example of in-situ deposited platinum (with nanoscale particle size) is shown in the 3 kV BSE image below. The deposit turns out to be about 80% carbon (though it is still 80% Pt by weight) and there is some evidence that particles as small as 5 nm in diameter are visible. The beam current is a reliable 13 pA and the detector is clearly able to collect enough signal to provide a remarkably clean image.
Short video (14 secs) of Platinum deposition process (often used as a first step in TEM sample preparation as well as in SEM cross-section imaging).
An example of SEM cross-sectioning is shown below where a gold nanoparticle (bright dot) was found a few microns below a fracture surface in the core of an optical fiber.
