AFM University Introduction to Atomic Force Microscopy by Paul West

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6.1 Probe Artifacts
6.1.1 Features on a Surface Appear Too Large
6.1.2 Features in an Image Appear Too Small
6.1.3 Strangely Shaped Objects
6.1.4 Repeating Strange Patterns in an Image
6.2 Scanner Artifacts
6.2.1 Probe / Sample Angle
6.2.2 X-Y Calibration / Linearity
6.2.3 Z Calibration / Linearity
6.2.4 Background Bow / Tilt
6.2.5 Z Edge Overshoot
6.2.6 Scanner Drift
6.2.7 X-Y Angle Measurements
6.2.8 Z Angle Measurements
6.3 Image Processing
6.3.1 Leveling
6.3.2 Low Pass Filter
6.3.3 Matrix Filter / Smoothing
6.3.4 Fourier Filtering
6.3.5 Image Looks Too Good
6.4 Vibrations
6.4.1 Floor Vibrations
6.4.2 Acoustic Vibrations
6.5 Other Sources
6.5.1 Surface Contamination
6.5.2 Electronics
6.5.3 Vacuum Leaks
6.5.4 PID Settings / Scan Rate
6.5.5 Laser Interference Patterns
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Chapter 6
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FIGURE 6-25 This high resolution image of a test grid shows the effect of acoustic noise on an image. A: Image and line profiles measured while acoustic noise was present in the room. B: Image that was measured without the acoustic noise.
6.5 Other Sources
6.5.1 Surface Contamination
Substantial contamination at the surface of a sample such as a fi ngerprint or oil film can cause AFM image artifacts. Such artifacts appear as streaks on the image especially in locations where there are "sharp" features and edges on the sample's surface. Often the streaking can be reduced or even eliminated by cleaning the sample with a high purity solvent.
FIGURE 6-26 A: SEM image of a test pattern that is contaminated. B: AFM image of the same test pattern that is covered with contamination. The contamination is identified by the streak marks at the top of the scan.
6.5.2 Electronics
Image artifacts can appear in AFM scans because of faulty electronics.

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