AFM University Introduction to Atomic Force Microscopy by Paul West

« Cover
« Foreward
« Chapter 1
 « Chapter 2
 « Chapter 3
 
3.1 Sample Preparation
3.2 Probe Alignment
3.3 Probe Approach
3.4 Optimizing Scan Conditions
3.5. Scan Image / Zoom
3.6 AFM Scanning Suggestions
 « Chapter 4
 « Chapter 5
 « Chapter 6
 « Chapter 7
« Appendix A
« Appendix B
« Appendix C
« Appendix D
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Chapter 3
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is to initiate a probe approach. Probe approach moves the probe from approximately 1 mm from the surface to a condition of "feedback". If tip approach is not implemented correctly, there is a great risk that the tip will crash into the surface and break.
Typically, the woodpecker method is used for doing tip approach. In the woodpecker method, the probe is moved in steps in the Z direction towards the surface until the force sensor detects forces associated with the surface. Section 2.3.4 describes the woodpecker method for probe approach. Figure 3-3 illustrates an SEM image of a probe that was damaged in tip approach.
Probes crash into the surface if the probe approach is made too rapidly or if the feedback electronics are not switched on rapidly enough after the surface is detected by the force sensor.
FIGURE 3-3 An operator must know how to operate the AFM such that probes are not damaged. Left: SEM image of sharp probe and an AFM image measured with the sharp probe. Right: SEM image of damaged probe and an AFM image measured with the damaged probe.
3.4 Optimizing Scan Conditions
Assuming that probe approach is completed, the AFM probe can be scanned

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