[Spm] Missing indents in array

[Don Chernoff at ASM]

 Linda Kenoyer wrote that some indents in a large array (10 rows x 10 columns) are missing.  I think the following should be checked:
-is the surface really level?  Scan it with offline planefit = offset.   If it is not level, then what you experienced is expected and I have seen it myself.  The reason is that all of the indent Z scans start at the same absolute height and this height is set for the position at the middle of the array.  On surfaces that are tilted too much, you can even see scratches made by the tip when it translated from the end of 1 row to the beginning of the next.
-is the trigger level set to a relative value?  If not, then drift in the signal level could cause some of the difficulties you experienced.

regards,
Don
=============================================
Don Chernoff, Ph.D., President
Advanced Surface Microscopy, Inc.    E-Mail:  donc at asmicro.com
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[business activities:  analytical services in AFM, AFM probes, consulting, training,
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original message:
We have a Veeco Dimension 3100 microscope with Nanoscope IV controller.  We 
have been doing arrays of nanoindentations using a VeecoProbes diamond 
indenter tip.  When we do a 10 x 10 array with a low trigger voltage 
(anything lower than .8 V), about half of the columns do not show indents.  
The columns that do indent all have about the same deflection curve, but the 
failed indents show a flat deflection curve (the tip never reaches the 
surface).  The columns and rows are about 1um apart.  Sometimes there are a 
few indents in the last column before the failed columns that show a 
deflection curve with the approach and retract curves nowhere near each 
other. The surface we are indenting on seems pretty flat from the scans we 
have done of the area.

Have any of you seen this behavior before?  What can we do to fix it?

Linda Kenoyer
Knowlton Research Lab
Boise State University
1920 University Drive
Boise, ID 83725
(208) 426-5716
lindakenoyer at boisestate.edu

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