Realtime Operation
40
Scanning Probe Microscope Training Notebook
Rev. F
Z-Center Position
: The Z-center voltage scale is located to the right side of the image on the
display monitor. It represents the current extension or retraction of the Z piezo electrode of the
scanner during operation.
•
It is displayed from -220V to +220V (440V full range) which represents the entire
vertical travel of the scanner (i.e. 5 to 6µm for a Dimension scanner or J MultiMode
scanner).
•
It is recommended that the Z-Center Position be kept as close to 0V as possible when
making height measurements. The Z-Center Position is adjusted by using Step Motor in
the Motor menu.
•
Images which are saved in Offline and are being acquired in Realtime are all referenced
to a Z-Center Position of 0V, which is the middle of the overall vertical movement. In
other words, when the system shows you an image, it centers the data at a Z-Center
Voltage value of 0V. Therefore, if the data is captured at an average value of 100V, a Z
offset of 100V will have to be removed from the image in order to observe the data.
This can be offset in Realtime and Offline by the
Realtime Planefit
and
Offline
Planefit
parameters, respectively.
Realtime Planefit
: The setting of this parameter only effects how the image is viewed in Realtime.
It has no effect on how the data is saved.
•
Line
: Removes tilt by applying a first-order planefit and removes the Z offset from
every line scan individually in the fast scan direction (X direction at 0°) during
scanning. This is essentially the same as performing a first-order Flatten (see Offline
Analysis). This setting is commonly used for everyday imaging.
•
Offset
: Does not remove the tilt from the scan lines, but does calculate and remove the
Z offset from each scan line individually. This setting is useful if you need to view the
tilt in the sample in Realtime
•
None
: Does not remove the tilt or the Z offset from the image. This setting is not
generally recommended.
Offline Planefit
: Controls whether the images are saved with or without tilt correction. There are
two primary choices:
•
Full
: Applies a first order planefit (explained in Offline Analysis) to the image in X and
Y and removes the Z offset before the image is saved.
•
Offset
: Saves the image without removing the tilt with a first order planefit, but does
remove the Z offset.
•
None
: Saves the image without removing the tilt or the Z offset.