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

From LabAdviser
Revision as of 07:35, 25 March 2020 by Afull (talk | contribs)

The FEI Nova 600 NanoSEM

The FEI Nova 600 NanoSEM Scanning Electron Microscope is a very versatile characterization instrument that produces enlarged images of a variety of specimens, achieving magnifications of over 500.000 times providing ultra high resolution imaging. At the time being this microscope is mainly designated for microstructural characterization 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 FEI SEM

Currently, Dr. Alice Bastos Fanta is co-ordinating all the activities that take place on FEI Nova 600 NanoSEM. So she must be informed about the planned activities before hand in the bi-weekly meetings which are held at DTU Nanolab. Alice makes the bookings in agreement with all the users. The rules of who may operate the FEI SEM 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 with no official DTU Nanolab training or approval cannot 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

How to operate the FEI Nova 600 NanoSEM

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

Processing guidelines on the FEI SEM

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 FEI SEM

The FEI SEM has 6 electron detectors and 1 photon (X-ray) detector.

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 Electron Backscatter Diffraction HiVac BSE 1 and 3
ARGUS ARGUS(TM) HiVac BSE 1 and 3
LVD Low Vacuum Detector LoVac SE + BSE 1 and 3
Helix High resolution Low Vacuum detector LoVac SE 1, 2 and 3
GAD Gaseous Analytical Detector HiVac and Lovac SE + BSE 1, 2 and 3
EDX Energy Dispersive X-ray detector HiVac and Lovac X-ray photons 2 and 3

Equipment performance and process related parameters

Equipment QFEG Cryo SEM FEI Quanta FEG 200
Purpose Vizualization and Microanalysis
  • Vizualization of surfaces (topography and Z contrast)
  • Vizualization of projected image (BF STEM image)
  • Energy Dispersive X-ray analysis (EDS)
Performance Resolution The resolution of QFEG dependends on the sample and the operation mode!
  • 2 nm at 30 keV for Au on C sample with the ETD 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 (room temperature)
  • X, Y: 25 × 25 mm
  • T: 0 to 60o (Full tilt require removment of cryo cold trap.)
  • R: 360o
Peltier stage
  • FEI Peltier stage -10o to 22o
Cryo stage
  • Quorum PP2000 Cryo System
EDS
  • Oxford Instruments 80 mm2 X-Max silicon drift detector, MnKα resolution at 124 eV
Operating pressures
  • High vacuum (10-4 Pa), Low vacuum and Enviromental mode (up to 2700Pa)
Substrates Sample sizes
  • No actual limit (limitted by stage movment and detector position).
Allowed materials
  • Conductors, Semiconductors,Insulators,Wet Samples, Biological (not pathogents!)


Feedback to this page: click here


Characterization Techniques


Feedback to this page: click here