Breakerspace SEM Tutorial

Overview

The Breakerspace has two scanning electron microscopes (SEM), a ThermoFisher Phenom XL and Phenom Pure.

SEMs use a focused beam of electrons to image materials at much higher magnification than can be achieved with an optical microscope, with our instruments able to resolve features as small as 100 nm in optimum conditions.

Our Phenom XL has a large 100x100 mm sample stage, a low vacuum mode for non-conducting samples, can perform energy dispersive spectroscopy (EDS), and also has a tensile stage for in-situ observation of mechanical experiments. The Phenom Pure can observe a single sample on an 18 mm or smaller stub, under either low or high vacuum, and has a cold-stage for observation of frozen samples. Both instruments have backscatter (BSD) and secondary electron (SED) detectors.

Index:

Standard operating protocol - (startup, operation, shutdown)
Materials and sample prep
Detailed operating instructions
Data processing and analysis
Common failure modes
Manufacturer manuals
Links
Exercises

Standard operating protocol:

Instrument startup:

Log on to instrument workstation using your MIT Kerberos
Start the Phenom User Interface software
Wake the instrument up if needed
- The first time you log on, and occasionally thereafter, you may need to connect to the instrument in Settings/Phenom/Status

Operation:

Wear nitrile gloves when handling your sample, sample stages, and other sample preparation components
Prepare samples externally at the sample prep table* Load your sample(s) into the instrument
Remove your gloves while using the computer
Perform characterization relevant to your sample (image capture, measurement/annotation, EDS)
Wear nitrile gloves
Unload samples
Repeat as needed

Instrument shut down:

Close the software - press F11 to switch out of fullscreen view
Log off Windows
The instrument will put itself in standby

Compatible materials and sample prep:

Samples should be non-hazardous and safe to handle in the Breakerspace
Samples should be free of volatiles (dry), excepting samples to be frozen on the Phenom Pure cold stage
Samples must be free of loose particles (“flush” with compressed air)
Samples must be well secured to a sample stub
Non-conductive samples can be viewed in low vacuuum mode, or sputter coated
Phenom XL maximum sample size is 100mm x 100mm x 35mm
Phenom Pure maximum sample size is a cylinder about 18mm diameter and 12mm tall

If you have any questions about whether a material is appropriate to characterize in the Breakerspace, please ask before bringing it to the lab.

Sample prep basics:

Prepare samples externally at the sample prep table
Firmly attach samples to stub
Remove loose debris with compressed air

Solid sample prep (basic)

Place a bare sample stub in a sample tray ADD IMAGES
Attach a double-sided carbon pad to the stub
Attach the sample to the pad
For an expanded discussion of sample prep techniques, see page 15 of the manual

Detailed operating instructions:

Sample loading:

Remove sample stage from the microscope (or drawer for Phenom Pure)
Phenom XL: sample compartment is opened by pressing eject button in the software
Phenom Pure: sample compartment is manually opened and closed, but must be unlocked with the eject button in the software
Using stub tweezers, push pin on stub into a hole in the sample stage
Phenom Pure: black stage sets instrument in high vacuum mode, gray stage sets instrument in low vacuum mode for charge reduction on non-conducting samples
Set proper sample height
Phenom XL: set the tallest part of your tallest sample level with the opening of the sample stage, then lower by 6 notches on the dial
Phenom Pure: the tallest part of the sample should be just lower than the top edge of the sample stage
Load the sample stage into the instrument
Close the door and your sample should be visible in the NavCam

Characterization:

Customize: When your sample is loading, this is a good time to visit Settings/Customize and change the Label and Location fields to a name and folder that are relevant to your project

NavCam: When you first load a sample into the SEM you see your sample(s) on the NavCam. This is an optical image of the sample stage that can be used for navigation once you are in SEM observation mode. If you will rely on the NavCam image for navigating your sample(s), it is helpful at this stage to make sure the brightness, contrast, and focus are all acceptable in key areas of your sample. If you wish, you can click the camera icon in the NavCam to save the NavCam image to a file.

LiveSEM view: Once you click “Move to SEM” add image you will be in the LiveSEM view. Here you can adjust brightness, contrast, and focus, as well as changing magnification. The recommended UI setup is to leave the scroll wheel set to change magnfication, hold down the right mouse button and move the mouse cursor horizontally to change focus, and to use auto brightness/contrast. A full set of keyboard and mouse shortcuts can be found in Settings/Phenom/Help. Detailed operating instructions and a full UI overview can be found starting on page 20 of either the XL or Pure manual.

Gallery: The gallery will show you all images in the active folder. In addition to reviewing the images, you can add dimensions and notes. If you annotate the images the annotated versions need to be saved as new files.

Acquisition: Press the camera icon on the left side of the screen to acquire an image. Images will be saved in the resolution and with the averaging specified in the Operational Settings/Acquisition menu. Pay attention to acquisition times, and take some test images first. Higher averaging settings swill increase signal to noise, and result in cleaner images, but longer acquisition times. If there are issues related to charging, such as drift, they will be more visible in longer acquisitions, so higher averaging is not always better or needed.

EDS: Energy dispersive spectroscopy (EDS), available on the Phenom XL, allows you to perform elemental analysis and save out full reports, included map images, images and data of captured spectrum, and a CSV files with raw data. Recommended settings for EDS are 15kV acceleration voltage and map beam intensity. Click the square to stop data collection before navigating to a different section.

Live EDS: Live EDS mode, (Phenom XL only) lets you perform quick elemental analysis on a spot on your sample, without generating any files or documentation. It is useful for quick spot checks. Recommended settings for EDS are 15kV acceleration voltage and map beam intensity. Click the square to stop data collection before navigating to a different section.

For a more complete description and instructions on how to use any of these features, please see the XL or Pure manuals.

Sample unloading:

Open the sample compartment
Remove sample(s)
Phenom XL: return sample stage to sample compartment, close door
Phenom Pure: close door, place sample stage in drawer

Common failure modes:

Phenom XL: If the SEM fails to start press the eject button to open and close the door and reinitialize the sample loading process
Phenom XL: In either live EDS or EDS, if you do not press the stop button, and attempt to return to observation mode, you will get an error message, and need to return to where you were and press stop add image/gif
Sensitive samples may experience [degredation]](https://www.thermofisher.com/us/en/home/materials-science/learning-center/applications/sample-degradation-scanning-electron-microscope-sem.html), often in the form of cracks on the surface, or the sample may appear to be melting or boiling. Lowering acceleration voltage, beam intensity, and magnification will all help slow the rate of degredation.
EDS low or no counts: check working distance is between 4 mm and 7 mm, and if not, adjust stage height to correct working distance into this range. Also verify acceleration voltage is 15kV and beam intensity is set to map

Manufacturer’s manuals:

Exercises:

coming soon