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ANALYSIS OPERATION
6-92
TMPM5200-2
6.11 MAPPING MENU (IMAGE PROCESSING FUNCTION)
The SPS mapping function performs SPS measurements at each point (128
×
128) in the
measurement area while scanning this area. It is possible to perform mapping
measurements for various SPS measurements such as I-V, S-V, I-S, force curve and
friction force curve.
We here explain the procedure of mapping for I-V measurements, as an example of the
SPS mapping function. The procedure of other mapping measurements is the same as
that of the mapping for I-V measurements, so when you carry out the other mapping
measurements, apply the following explanation to the measurements to be performed.
The SPS mapping measurement for I-V measurements are called the CITS (Current
Imaging Tunneling Spectroscopy) function measures I-V characteristics at each point of
scanning. That is, I-V data is obtained at each pixel.
Ｖ
I
V
Tip
Specimen
I
V
The top left image on the screen is a topographic image obtained under the parameters
specified in the SPM Parameters window. The next (right-hand side) image and all others
show tunneling current images obtained at various bias voltages without changing the tip
height at which the topography image was obtained.
—2.0 V —1.9 V —1.8 V
The var ying bias voltage at each
point (pixel) of scanning and
tunneling current at specific bias
voltage value are displayed on the
frame corresponding to the
specific bias voltage.
Topography image
Bias voltage
Tunnel current
Since I-V data and a topographic image are measured at the same time, there is a perfect
position correspondence between the topographic image and tunneling current. It is
possible to select, using the mouse, an arbitrary point on the specimen while watching its
topographic image and accurately display the I-V characteristics of the selected point.
