The Nanoscale World

SSRM mode on the ICON

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Top 75 Contributor
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Andres posted on Tue, Aug 14 2012 8:36 AM

Dear all,

I recently got involved in doing some SSRM measurements and I have some questions as how the ICON goes around doing the measurment:

  1. When doing scans I only choose trace (or retrace) is the voltage bias maintained during the retrace (trace?)
  2. when setting up a false engage with the resistor attached I have, in the software, a setting for the test bias and another for the sample bias. This to me seems to imply that when using the resistor instead of the tip the voltage is not the same source. Could I have an explanation (a little block diagram would suffice) of how they relate?
  3. Using the calibrated resistor provided we measured the resistance values using an external high resistance meter and got 8.2Gohms for the 10Gohm setting (as labeled by the box), 99MOhm for the 100Mohm setting and 0.92Mohm for the 1Mohm setting. Seeing the slight disprepancy on that end, where could we get a more detailed transfer curve of the logarithmic current amplifier? Would it be very different from the 24AB-LMC60-82A1M chip?
  4. we recently got a software update and the units for resistivity are now Log(ohm) does this mean that I just need to 10^x the values of the scan to get my resistance value? in the past it was 10^(6+x).

Thank you for your time!

 

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Top 25 Contributor
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Bruker Employee

Here are my answers to  your questions:

  1. The same bias voltage is maintained for both trace and retrace, so you can select data on either trace or retrace.
  2. When using false engage, you must set both sample bias and test bias to the same value that's better to be bigger than 500 mV, this is essential to get a proper calibration.
  3. There is usus. a bigger discrpancy on the 10 GOhm resistor. I will have to get back to to see which chip is used.
  4. Yes. In the new software, you just  just need to 10^x the values .

Regards

Chunzeng

Applications Scientist
Nano Surfaces Division, Bruker

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Top 75 Contributor
12 Posts
Points 147

Thank you very much Chunzeng! I have some followup questions/comments:

Chunzeng Li:

Here are my answers to  your questions:

  1. The same bias voltage is maintained for both trace and retrace, so you can select data on either trace or retrace.
Thanks!
Chunzeng Li:
  • When using false engage, you must set both sample bias and test bias to the same value that's better to be bigger than 500 mV, this is essential to get a proper calibration.
  • I have made sure of that, thank you, but I wanted to be able to compare it with the actual tip in contact with the stage: it seems that the circuit follows a very different path when testing and it is not comparible: Could I see a simplified circuit diagram showing the relation between test bias and sample bias?
    Chunzeng Li:
  • There is usus. a bigger discrpancy on the 10 GOhm resistor. I will have to get back to to see which chip is used.
  • Yes please, thank you!
    Chunzeng Li:
  • Yes. In the new software, you just  just need to 10^x the values .
  • Is there a way to get the value in Amps directly? I mean, before it is converted to Log(ohm). It is nice to have R-V curves for example but sometimes it is easier to relate if we have I-V curves.

     

     

     

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