５
MEASUREMENT OPERATION
TMPM5200-2
5-223
Therefore, if you input a numerical value in the Bias Offset input box so that
box will be:
Bias voltage – Bias offset voltage.
Bias Offset is used only as a marker. The voltage output from the SPM
CONTROL unit is the same as the Forward voltage displayed when the Bias
Offset voltage is 0 V.
This function is in effect when heating the specimen using a current. You can-
not use it when indirectly heating the specimen by using the optional Indirect
Heating Holder.
•
High Bias
The HV-AMP with 20 times greater gains is installed in the bias voltage source line.
The usual bias voltage is
±
10 V. However, by using the HV-AMP, the bias voltage
can be made 20 times greater.
When the Off radio button is selected, if you click on the On radio button, a warn-
ing message will appear. If you have no problem, click on the Yes button. To return
the output bias voltage to normal, click on the On radio button.
Whenever you change the output bias voltage, the probe is automatically
retracted.
In the SPM instrument that applies the bias voltage to the probe, you cannot use
High Bias to prevent damaging or shorting the probe due to the concentration
of the electric field at the probe tip by applying high voltage on the probe.
If you click on the On radio button, the displayed maximum value of the bias
voltage will be changed to
±
200 V. However, since the power voltage is
±
150 V
in some SPM instruments, the actual output voltage is limited to
±
150 V.
•
External Offset
Using External Offset electrically gives the offset voltage to the Friction Force.
the optional Vacuum Evacuation System is installed, External Offset can
annot correct the Friction Force value, use
External Offset for adjustment.
First, correct the Force value using th photodiode Y-axis adjusting knob. Then
e value is
larger than
±
10 V even after the Force value is corrected, you could not probably
ain any correct data even if you could correct the value. In such a case, vent the
strument, you can change the destination to which the bias
voltage is applied between sample and tip. Select either Sample or Tip in the radio
buttons to apply the bias voltage.
When you select Tip for the destination to which the bias voltage is applied, the
radio button of the High Bias automatically turns Off.
you do not mistake the bias voltage actually applied, the bias voltage displayed
in the Forward
When
correct the bending of the cantilever that occurs in evacuation. Though in
JSPM
−
5200, you can correct the Force value from the outside using the photodiode
Y-axis adjusting knob, since you c
e
correct the Friction Force value. However, if the shift of the Friction Forc
obt
vacuum and adjust the Friction Force value again.
•
Bias Select
Depending on the SPM in
