TappingMode AFM
Beyond Basics with Resonating Techniques
Rev. B
MultiMode SPM Instruction Manual
117
Figure 7.5c
Scope trace with Correct Scan Rate
7.5.2 Tuning the Cantilever Drive Frequency
The
Drive frequency
selected to oscillate the cantilever plays an important role in the performance
of the microscope while in TappingMode. As a
fi
rst step it is important to determine the resonance
frequency of the cantilever, but the Drive frequency should be further tuned to improve scanning
performance.
It has been determined that the microscope produces better data in TappingMode when the Drive
frequency is set lower than the resonance peak of the cantilever. The Drive frequency should be set
such that it coincides with a 10% decrease in the vibration amplitude.
shows the
suggested operating region. It should be noted that this is a suggestion based on our observations;
users are certainly encouraged to experiment with the microscope and decide what produces the
best results.
Figure 7.5d
Suggested Range for Drive Frequency
Z Range
50.00 nm/div
Scan Size - 2.50 µm/div
Trace
Retrace
Cantilever
Response
12.54 nm/div
Center Frequency - 338.8723 KHz
5.0 KHz/div
Setpoint
Drive Frequency
should
be within this range.
