What is the Flattest Material?
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In the very first AFM video, I showed a "precision" gage block and everyone was surprised how rough it looked. So today we are scanning a variety of surfaces (gage block, mirrors, silicon, mica) to see how they compare in flattness and roughness. The flattest surface is considered "atomically flat", meaning the surface is a single, continuous layer of atoms in the crystal all at the same height. Wild!
I mention in the video, but it should be noted that flatness and smoothness/roughness are not quite the same. Flatness is a global property of how planar the surface is, while smoothness/roughness is a measure of smaller deviations from the average or median surface. I freely interchange the terms, partially on accident, but also because at the scan size it becomes a bit meaningless. At 10 microns flat and smooth are pretty similar concepts.
==== References ====
- Ostendorf, F., Schmitz, C., Hirth, S., Kühnle, A., Kolodziej, J. J., & Reichling, M. (2008). How flat is an air-cleaved mica surface? Nanotechnology, 19(30), 305705. doi:10.1088/0957-4484/19/30/305705
==== Equipment and techniques ====
- nGauge AFM from ICSPI: https://www.icspicorp.com/
- Scans are post processed in Gwyddion (http://gwyddion.net/) and 3D images rendered in Blender
- Mica is from Ted Pella
==== Timeline ====
0:00 Intro
0:51 #6 - Gage Block
1:18 #5 - First surface mirror
1:52 #4 - λ/20 quartz mirror blank
3:05 #3 - Glass slide
4:13 Interlude - Flat vs Smooth/Rough
5:22 #2 - Silicon Wafer
6:41 #1 - Mica
9:03 Scan compilation comparison
9:39 Uses for mica
Тэги:
#atomic_force_microscope #afm #atomic_force_microscopy #icspi #mica #silicon #wafer #gage_block #flat #smooth #roughness #mirror #quartz #atomically_smooth #silicon_wafer #atomic_force_microscopy_images #atomic_force_microscopy_tapping_modeКомментарии:
Addendum
- Flat != Smooth, please don't fill the comments with hate. <3 At this scale it's mostly moot anyway, and it's hard to watch what you say 100% of the time when filming 😇
- I am bad at colors! 631nm is red, not green. 🤦
- I'm not super familiar with surface roughness measurements, so hopefully I didn't misinterpret the results too badly!
- When I say "RMS" I'm referring to "RMS roughness (Sq)"
- As annotated in the video, some of the scans had "depressions" in the corners. This was due to poor flat-fielding of the raw data on my part (raw AFM data often has a tilt or slope which needs to be corrected) and I didn't notice it until after editing the video :) After the video I re-processed the data, and while the numbers changed some, the overall results were basically the same so I didn't go back and re-edit the video. So just FYI, the glass samples in particular got a bit smoother but maintained their ordering.
you should see the wafers after we chemically-mechanically planarize them in the fab, nowadays our tolerances are down to singular atoms (in sub-nanometer research nodes), in volume manufacturing nodes ~4nm (at time of writing) i believe tolerances are on the order of only a few atoms. VERY FLAT!
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I"ll just say this: you've got my sub after one video. Achievement unlocked... by you :)
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I was disappointed that it wasnt the earth... 😔
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sakura >>>>>>>>>>>>>>>>>telescope mirror
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nice shirt bro
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How about the smoothness of inside of optic fibre cable where the total internal reflection of light occurs. How smooth is that?
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@breaking taps - Where did you get that shirt? I absolutely want one!
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Now just Draw the continents on it and the flat earthers got something to argue about
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My guess. I pat myself on the head and go and get a cookie!
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WTFlat !!!
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How about "Not Populist Sciencey American Advertising
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True level Morty
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Good to try a cleaved silicon facet and yttrium iron garnet monocrystall as it grows huge and pure. Those are easy to get and interesting to test.
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Dude I love that shirt I cant stop laughing
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Water
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ok and if you make it one atom thick, how flexible would it exactly be?
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Excellent video, thanks. Okay let's put up a satellite with chunks of mica and a means for cleaving them, so that a telescope can be constructed in space. Move over James Webb.
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Why don't they like apply pressure to cooling glass on metal plate instead of grinding? Or heat it better or purify it better.
For the high precision stuff
At small scale, floatglass is evened out by surface tension, not gravity.
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Was pretty sure I knew where this was headed from the beginning but it still blows my mind every time. The natural world is so dang cool if you know where to look
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