Atomic Force Acoustic Microscopy
2. Performing Measurements
The user is supposed to have detailed knowledge of the contact and semicontact mode
AFM (see
Performing Measurements, chapter
3
) before conducting the AFAM
measurements.
In AFAM method the phase, the amplitude or the frequency of the cantilever bending
oscillations is measured near the contact resonance frequency simultaneously with
recording the topography map by the contact technique.
To obtain the AFAM image the follow the procedure below:
1. Select
Contact
in the menu for choosing the electrical configuration of the instrument
(Fig. 2-1).
Fig. 2-1
2. Perform the approach the same way as in the standard contact technique:
a. Switch to
Approach
tab;
b. Activate
Auto SetPoint
option;
c. Click on
Landing
button.
3. Make a trial measurement of the sample topography map and choose an area for
scanning.
4. Switch to
Resonance
tab.
5. Determine resonance frequencies for the cantilever bending oscillations in a free state
(i.e. when the feedback is turned off and the probe is far enough from the surface):
f
0
,
f
1
,
f
2
. For that:
a. Turn off the feedback (
button is not pressed in).
b. Energize the piezodrive in the probe holder with voltage from the generator. To this
purpose, open the instrument block scheme and commute the key as shown on
Fig. 2-2.
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