LabAdviser/314/Microscopy 314-307/SEM/Nova

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The FEI Nova nanoSEM 600

The Nova is, in it's normal configuration, a very versatile characterisation instrument. Capable of producing enlarged images of a variety of specimens and achieving magnifications of over 500.000 times with ultra high resolution imaging in both high and low vacuum. The Nova has become highly evolved in it’s life at DTU Nanolab and it is possible to carry out advanced processes including in-situ experiments using heat, gas injection and probing. At the time being this microscope is mainly designated for advanced microstructural characterisation and particle analysis techniques using electron backscatter diffraction (EBSD) ,Energy-dispersive X-ray spectroscopy (EDS) and forward scatter electron imaging by detectors recently bought from Bruker.

Who may operate the Nova

There are restrictions on who is given access to the Nova due to the development activities of the Bruker detectors fitted to the tool. Currently, Dr. Alice Bastos Fanta is co-ordinating the activities that take place on Nova. Alice is consulted about the planned activities beforehand in the bi-weekly meetings which are held at DTU Nanolab and coordinates the bookings in agreement with all the users. The rules of who may operate the Nova and to what extent they may operate it are:

  • Only users who have been trained and approved by DTU Nanolab personnel may operate the instrument. Irregardless of their prior experience any new user without official DTU Nanolab training or approval may not operate the instrument, not even under close supervision by experienced users.
  • Users may only use the instrument to the extent they have been trained. This means that one should not try to operate the following options/capabilities without explicit training:
    • Low vacuum
    • EBSD capability
    • EDX capability
    • Backscatter detectors
    • STEM

How to operate the Nova

To find the basic instructions for operating the instrument, the reader is referred to the labmanager manual.

Processing guidelines on the Nova

When one combines the 6 different detectors, 2 vacuum modes and 3 SEM modes with the traditional SEM parameters such as high voltage, working distance, spot sizes etc. it is clear that the FEI SEM has a huge number of different ways to be operated in. The number of ways that produce ultra high quality images is, however, limited. It is therefore crucial that the operators share their knowledge of how to obtain great images.

Steps to follow

There is no single general approach to taking good images on the FEI SEM. These points below are only guidelines.

What kind of images are needed

It is important to consider what kind of images are needed before you start. The different requirements/conditions could be some of the following:

High resolution at high magnification (above 10.000x) images are wanted
For conducting samples: Use TLD and mount the sample so that short WD's are possible.
For non-conducting samples: Mount the Helix detector and use short (app. 5 mm) WD.
Images of very thin (> 10 nm) metal films on low atom number materials
Use the backscatter detectors
Images with high resolution, large field of view and depth of focus are wanted
The TLD and Helix detectors do not provide large field of view and depth of focus when operated in SEM mode II.

Detectors on the Nova

The Nova has 8 electron detectors and 2 photon (X-ray) detectors.

Tag Name Vacuum mode Signal SEM modes
ETD Everhardt Thornley Detector HiVac SE, BSE (detector bias adjustable) 1 and 3
TLD Through Lens Detector HiVac SE, BSE (detector bias adjustable) 1, 2 and 3
BSED BackScatter Electron Detector HiVac BSE 1, 2 and 3
EBSD/TKD Electron Backscatter Diffraction HiVac+LowVac BSE 1 and 2
ARGUS ARGUS(TM) HiVac+LowVac BSE,FSE and STEM (BF and DF) 1 and 2
LVD Low Vacuum Detector LowVac SE + BSE 1 and 3
Helix High resolution Low Vacuum detector LowVac SE 1, 2 and 3
GAD Gaseous Analytical Detector HiVac and Lowvac BSE 1, 2 and 3
EDS Energy Dispersive X-ray detector HiVac and Lowvac X-ray photons 1,2 and 3
EDS Flat Quad X-ray detector HiVac ONLY X-ray photons 1,2 and 3

Equipment performance and process related parameters

Equipment "Nova" FEI Nova nanoSEM 600
Purpose Visualisation and Microanalysis
  • Visualisation of surfaces (topography and Z contrast)
  • Visualisation of projected image (BF STEM image)
  • Energy Dispersive X-ray analysis (EDS)
  • Microstructural characterisation (EBSD/TKD/STEM)
Performance Resolution The resolution of Nova depends on the sample and is in Mode II
  • High Vacuum operation in Mode II:
    • 1.0 nm at 15 kV (TLD detector and optimum working distance)
    • 1.8 nm at 1 kV (TLD detector and optimum working distance)
  • Low Vacuum operation in Mode II:
    • 1.5 nm at 10 kV (Helix detector and optimum working distance)
    • 1.8 nm at 3 kV (Helix detector and optimum working distance)1 nm at 15keV for Au on C sample with the TLD detector
Instrument specifics Detectors
  • ETD- Everhart-Thornley for secondary electrons
  • BSD- Solid state Back Scattered Detector
  • LFD- Large Field Detector for secondary electrons
  • GSED- Gaseous Secondary Electron Detector
  • GBSD- Gaseous Backscattered Electron Detector
  • GAD- Gaseous Analystical Detector
  • STEM- right field Scanning Tramission Electron detector
  • vCD- low voltage BSED
  • CCD camera
Electron source
  • Field Emission - Tungsten filament
Stage
  • X, Y: 75 × 75 mm (piezo)
  • Z 10mm (DC motor)
  • T: 0 to 70o (DC motor)
  • R: 360o (piezo)
FlatQuad EDS
  • Bruker FlatQuad (High Vacuum ONLY)
EBSD/TKD
  • Bruker eFlash
EDS
  • Bruker 50 mm2 silicon drift detector, MnKα resolution at 124 eV
Operating pressures
  • High vacuum (10-4 Pa), Low vacuum mode (up to 130Pa)
Samples Sample sizes
  • No actual limit (limitted by stage movment and detector position).
Allowed materials
  • Conductors, Semiconductors,Insulators,Wet Samples, Biological (not pathogents!)


Characterization Techniques