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C-AFM Software Selection

  1. Click the Select Experiment icon in the NanoScope toolbar. This opens the Select Experiment window, shown in Figure 1.

Figure 1: The Select Experiment, C-AFM mode, window.

  1. Select Electrical & Magnetic in the Experiment Category panel.
 
  1. Select Application Modules in the Experiment Group panel.
  2. Select Conductive AFM (C-AFM) in the Select Experiment panel.
  3. Click the Load Experiment button.
  4. The Feedback and C-AFMpanels, shown in Figure 2, in the Scan Parameter list display the C-AFM control parameters.

Figure 2: C-AFM control parameters in the Scan Parameter list

 
NOTE: If you have Torsional Resonance and C-AFM, there is an additional mode. Refer to TUNA and TR Mode for details.

Bruker recommends performing C-AFM measurements in open loop mode only. In open loop mode, the user selects a DC bias and measures the current passing through the sample. The Scan Parameters relevant to C-AFM are shown in Table 1.
Parameter Use with C-AFM
Feedback Mode Disabled: open loop. Enabled: closed loop. For C-AFM, select Disabled.
Current Sensitivity

Selects the gain of the C-AFM sensor:

  • 1nA/V = gain of 109
  • 100nA/V = gain of 107
DC Test Bias Provides an additional bias for the purpose of testing the C-AFM sensor.
DC Sample Bias Selectable bias to chuck/sample.
Bias Upper Limit Limits the maximum bias.
Bias Lower Limit Limits the minimum bias applied to the chuck/ sample in closed loop mode.
Feedback Igain Integral gain used for closed-loop mode.
Feedback Setpoint Not used in open loop mode. Selects the current setpoint in closed loop mode.

Table 1: C-AFM Control parameters

NOTE: Due to inherent mechanical characteristics of the specialized probe holder necessary for this imaging mode, reduced closed loop X IGain and Y IGain parameters are necessary.
  1. Select Calibrate > Scanner > X-Y... from the main menu. The OptoXY Closed Loop Calibration dialog will open.
  2. Set X IGain and Y IGain to 8.
  3. Click OK to close the window and continue with your experiment.

Ensure that you reset the parameters to their default values (12) when using the standard air tapping or TR holder.

 

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