Fluid Operation
TappingMode in Fluids
Rev. B
MultiMode SPM Instruction Manual
135
Figure 8.3a
A 100µm, Narrow-legged, Si
3
N
4
Cantilever Fluid Tune Curve
•
Manually adjust the
Zoom in
and
Offset
functions above the Cantilever Tune display.
Note:
If the expected peak does not appear in the spectrum, choose another peak,
engage on the surface and disengage immediately. With the tip closer to the
surface, the peak at 8 to 9 kHz appears.
Adjust the
Drive Amplitude
until a desired probe RMS amplitude is obtained.
•
An RMS amplitude of
0.5V
is appropriate for soft samples and typically results from a
Drive Amplitude
of
250-500mV
. A
Drive Amplitude
>
1.0V
generally works poorly
with soft samples.
•
For rougher samples, target
1-2V
RMS amplitude. Experiment to
fi
nd what level of
probe oscillation gives best results for speci
fi
c applications.
a. Set
the
Scan Rate
to
1Hz
.
b. Set the
Integral gain
to
0.5
.
c. Set the
Proportional gain
to
0.7
.
d. Set the
Z range
to
50nm
.
e. Select the Channel 1
Data type
as
Height
.
f.
Select the Channel 2
Data type
as
Amplitude
.
g. Optional: Select the Channel 3
Data type
as
Phase
.
•
The RMS amplitude must be adjusted when the AFM tip is near the sample surface
(<50µm).
•
Verify that the tip is very close to the sample surface when tuning the probe under
fl
uid.
