Additional Imaging Modes
5
Keysight 5500 SPM User’s Guide
5-29
Kelvin Force Microscopy (KFM)
Kelvin Force Microscopy (KFM) is similar to EFM. An additional
feedback loop applies a DC bias to the tip to counteract deflection due to
the surface electrostatic force. The output from this feedback loop
provides a
quantitative
analysis of changes in the applied or intrinsic
electrostatic field of the sample.
As in EFM Mode, KFM requires conductive tips, a sample plate with
electrode connection, an AC nose assembly, and a MAC III controller to
provide the drive signals. Lock-in 1 is used to drive the cantilever.
Lock-in 2 provides an AC bias. The MAC III internal servo drive
provides the DC bias to counteract tip deflection.
The procedure for imaging in KFM Mode is the same as that for EFM
Mode, with the additional step of setting up the DC bias servo. This
should be completed after approach:
1
Choose
Controls > Advanced > AC Mode
, then click the
Other
tab
).
Figure 7-15
Advanced AC Mode Controls Other tab
2
Set the
I
and
P
gains for the Servo to
1 %
.
3
In the Realtime Images window, choose to display images for
Topography
,
Phase
and
SP
(the output from the servo).
