The Nanoscale World

Scanner artefact?

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Answered (Not Verified) This post has 0 verified answers | 5 Replies | 3 Followers

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glopec posted on Sun, Feb 20 2011 12:01 PM


I noticed that often happens when I do imaging that left vertical or right vertical part of image look a bit distorted.   When I do trace and retrace I notice the same artefact but on the other sides of image.

This sometimes happens and sometimes not. It is more pronounced on smaller scales where often almost 30 % image is distorted. When I changed the scanner this artefact dissapeared. Can this be due to the non linearity od scanner?

Should a new calibration help ?

Tnx

 

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Bruker Employee

Hi,

Can you post an image or line trace of the problem you are having? I am not completely clear of the issue from your post.

Also, what system and scanner you are using?

Thanks,
Steve

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Answered (Not Verified) replied on Tue, Feb 22 2011 3:45 PM

It sounds like your "overscan" settings should be increased a bit. Overscan is an area that is not used for sampling image data to allow the scanner to settle into a constant motion on the left and right (and top/bottom). If that area is too small you may see effects from the scanner chaning directions. Depending on your AFM system used these settings can be found in a variety of places. I'd check the user manual first for it.

 

Stefan

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glopec replied on Wed, Feb 23 2011 2:47 PM

Thx for answers. I'm using J scan, mounted on MM. How can I change these overscan settings?

I upload image with artefacts  with distorted left and right side;

http://img14.imageshack.us/i/aretfacts.png/

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replied on Wed, Feb 23 2011 5:30 PM

In Nanoscope you have to change the "rounding" value. It can be found under Scanner->Calibration->XY. If it is 0.0 right now you may try 0.1 or so. Be advised though that this may reduce you maximum scan range a little bit.

If the above does not help, please contact Bruker customer service directly.

Best regards,

Stefan

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Bruker Employee

this issue could be many things.  Rounding (as suggested by Stefan K) may work.  To truly know the behavor of your scanner it is best to get an image of the calibration grid.  Please scan full scan size with 0 deg scan angle on the calibration grid that is 10um pitch and 200nm depth (tapping or contact mode will work fine) and send me an image (john.tedesco@bruker-nano.com).  I need the actual nanoscope image file to truly help.  It is really hard to truly determine the issue based on the images you've provided only because it is not a known sample for me though it definitely appears to have some distortion in different areas of the scan.

Some simple possilbe problems are:

1. sample tilt  causing poor tracking in certain areas - this changes with the position of the sample where you've engaged as the multimode scanners tend to have somewhat of a parabolic scan

2. thermal drift - the slow scan axis is usually affected more

3. non-linear scan due to faulty scanner or damage

4. poor calibration or the wrong calibration file

With your image of the grid I will most likely be able to tell you which of the above is an issue. Sometimes it is a combination of 1 and 2 as well.

thanks,

John Tedesco

Bruker Support

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