2. Scanner Artifacts
2.2 Edge Overshoot
This artifact occurs when the scanner moves further than it should vertically, leading to a very "sharp" edge on the features in the image.
You can spot it in the topography profile as "bumps" on the edges of tall features. It's due to hysteresis in piezoelectric scanners.
How to avoid it.
If you scan more slowly, you will avoid this artifact. However, it is usually only noticable on samples that are very flat, with square features.