Managing specimen contamination while performing TEM
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- เผยแพร่เมื่อ 13 ต.ค. 2024
- Have you ever tried showering with an electron beam? Specimen contamination when performing TEM can be extremely detrimental to your images/data, especially when performing any type of high-resolution imaging (such as atomic-resolution HAADF-STEM). In this video, I discuss the origins of contamination build up while performing TEM, why this negatively impacts the quality of your images/data, and (most importantly) how to effectively manage it.
Thank you for watching; if you found this video useful, please like, share, and subscribe; if you have questions, comments, or a suggestion for a topic for a future, video, please let me know.
Original video covering atomic-resolution STEM where I encountered a contamination problem (and thus gave me the idea for this video):
• FEI Tecnai F20 S/TEM: ...
Video covering plasma cleaner operation:
• Fischione Instruments ...
Great videos! Your videos help me a lot in studying TEM, could you make a video about how to image samples that are easily damaged by electron beams?
Thank you! Imaging samples that are easily damaged really comes down to a combination of two things: using a lower beam voltage (mostly) and/or using a lower beam current. It would be a good video to discuss the challenges associated with imaging while doing these things, so thanks for the suggestion.
@@NicholasRudawski I feel very honor to receive your positive reply. Looking forwards to learning new videos from you. Great job.
Hello Nicholas. Thanks for your videos. They are really helpful! I have a question about beam shower. The mechanism of beam shower is to deposit hydrocarbons in larger area. After this, the remaining contamination in chamber runs low so we would not build thick layer of contamination in the areas at which we perform high resolution (S)TEM afterwards. If my understanding is right, could I do this?
After I load the sample into TEM, I first deposit the contamination in the unimportant areas on purpose by beam shower method, for example, showering the connection point of lamella and the FIB grid post. This will decrease the amount/concentration of contamination in chamber. Then in my real characterization sessions, since the contamination level is low, the chance to build contamination is reduced.
Hi Yao: you want to beam shower the places where you plan to image. The way the beam shower works is that it fixes the contamination in place over a large area with fine thickness rather than allowing it to accumulate much thicker in a small area. If you perform a beam shower in a place you don't intent to image, that won't really help you when go you to image the areas of interest, you need to beam shower where you plan to image.
@@NicholasRudawski Thanks for the further explanation.
Please make a video on complete STEM alignment. It would be so great. Thank you so much in advance.
Please see these videos on my channel covering STEM:
th-cam.com/video/JtVmDOa--gg/w-d-xo.html
th-cam.com/video/oZ45seme5cA/w-d-xo.html