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

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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-Cen. She 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-Cen personnel may operate the instrument. Irregardless of their prior experience any new user with no official DTU-Cen 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

Characterization Techniques

• Electron Backscatter diffraction
• Transmission Kikuchi diffraction
• Micro 4-point probe

Kleindiek micromanipulator

The Kleindiek Nanotechnik MM3A-EM is a plug and play micromanipulator for SEM/FIB applications, with a versatile range of modular plug-ins. The MM3A-EM can be used in most SEM/FIB instruments and offers fast setup and removal. The system consists of a base over which the micromanipulator arm is mounted (Figure 1). The base can be attached to the SEM front door by two exagonal head screws (Figure 2).The arm is connected to the external power supply through two plug-ins on a PCB board mounted on the SEM door.

Front Image - - - Figure 1: the base with the micromanipulator mounted on it. Figure 2: the micromanipulator mounted on the Nova NanoSEM door. Controlling the MM3A The MM3A can be controlled in two ways: using the Joypad or the Nanocontroller. The possible micromanipulator movements are shown in figure 3. The two controllers can control in either fine or coarse mode depending on the speed selection. There are six speeds available, three in coarse mode and three in fine mode. Figure 3: the possible movements of the micromanipulator. Capres M4PP SEM Module The Capres M4PP SEM Module expands the capabilities of standard Scanning Electron Microscopes (SEM) with in-situ Microscopic Four Point Probing (M4PP). The M4PP SEM Module consists of a probe holder that attaches to a micro manipulator inside the SEM chamber, a stand-alone instrumentation unit, and software for control and data acquisition. The range of applications can vary from surface layer transport measurement to interconnect probing, to sheet resistance characterization, to characterization of inhomogeneous or microstructured advanced materials e.g. ultra-thin films and nanowires. Module schematic Figure 4: module schematics of the SEM Module system with all its components.