A Practical Guide to SPM

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In TappingMode, when operating on the high-frequency side of the
resonance peak (Figure 10-6), rings may appear around raised
features that make them look like they are “surrounded by water,” as
in the image of Ti grains on the left. Decreasing the drive frequency
during imaging can eliminate this artifact, as shown in the image on
the right. (When reducing the drive frequency, the setpoint voltage
may need to be reduced, too.)
Figure 10-6. Rings during high-frequency operation.
The arch-shaped bow in the scanner becomes visible at large scan
sizes (Figure 10-7, left). The bow in this image can be removed by
performing a second order planefit in X and Y (Figure 10-7, right).
At large scan sizes, the bow in the scanner may take on an S-shaped
appearance (Figure 10-8, left). The bow in this image can be removed
by performing a third order planefit in X and Y (Figure 10-8, right).
Figure 10-7. Large scan size, second order bow.
Data scale = 30nm.
Figure 10-8. Large scan size, third order bow.
Data scale = 324nm.