
Force Imaging
Force Calibration (Contact Mode AFM)
220 Dimension 3100 Manual Rev. D
Motor
The Motor menu allows you to withdraw or manually control the tip position using the stepper
motor. Selecting Step Motor opens a dialog box containing the following buttons:
• Tip Up: This command moves the tip up by the SPM step size displayed inside the
window.
• Tip Down: This command moves the tip down by the SPM step size displayed inside
the window.
13.4 Force Calibration (Contact Mode AFM)
13.4.1 Obtaining a Good Force Curve
Figure 13.4a Typical Force Calibration Curve
Figure 13.4b Piezo Positions for Typical Force Curve
To minimize or calculate the contact force between the tip and sample, obtain a good force curve
which shows the typical features displayed in the example curve in Figure 13.4b. However, the
force curve rarely looks “typical” right after invoking Force Calibration mode. This section
(Z Scan start -Ramp size)
Setpoint
Slope = Volts of Deflection/nanometers (or volts) of piezo travel
+
Cantilever Off Surface
(Z Scan start) Z Piezo Voltage
12
3
4
5
6
V
csmin
Cantilever Deflection
Voltage
Piezo travel
direction
Position
number
Up
1
Up
2
At
Bottom
3
Down
5
6
Down
4
Up Up
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