
TappingMode AFM
Preparation Prior to Imaging
Rev. B MultiMode SPM Instruction Manual 109
7.2.5 Additional preparations
In TappingMode, the RMS amplitude representing AC voltage signal is used to provide the
dynamic feedback signal for surface height tracking. The vertical deflection signal (displayed on
the “Vertical or Horizontal Difference” meter) should be close to zero (± 1.0V) prior to running
Cantilever Tune and/or attempting engagement. If you are uncertain how to set parameters for the
Channel 1 panel, try the following settings:
7.2.6 Tune the Cantilever
This section describes steps required to find the resonance peak of the cantilever and adjust the
oscillation voltage so the cantilever will vibrate at an appropriate amplitude. A range of vibration
frequencies will be applied to the cantilever to determine the frequency which produces the largest
response (the resonance frequency). In most instances, the resonance peak will have a sharp
Gaussian distribution but sometimes the peak can be somewhat asymmetric. The system will
tolerate some deviation in the shape of the peak.
• Click View > Sweep > Cantilever Tune, or use the Cantilever Tune icon. Several
panels will appear (see Figure 7.2e).
Panel Parameter Setting
Channel 1 Data type Height
Z range
0-4.50µm
a
a. A Z range value of 4.50µm is the maximum for most “J” scanners.
Always start with a low Z range value if feature height is
unknown, then increase until the image is optimized. On the
200nm step height calibration sample, a reasonable Z range setting
would be 300nm initially
Line direction Trace
Scan line Main
Realtime Planefit Line
Offline planefit Full
High-pass filter Off
Low-pass filter Off
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