Pacific Nanotechnology Inc.

A Guide to AFM Image Artifacts

Vibrations

Environmental vibrations in the room where the AFM is located can cause the probe in the microscope to vibrate and make artifacts in an image. Typically, the artifacts appear as oscillations in the image. Both acoustic and floor vibrations can excite vibrational modes in an AFM and cause artifacts.

Floor Vibrations
Often, the floor in a building can vibrate up and down several microns at frequencies below 5 Hz. The floor vibrations, if not properly filtered, can cause periodic structure in an image. This type of artifact is most often noticed when imaging very flat samples. Sometimes the vibrations can be started by an external event such as an elevator in motion, a train going by, or even people walking in a hallway.

Acoustic Vibrations
Sound waves can cause artifacts in AFM images. The source of the sound can be from an airplane going over a building or from the tones in a person's voice. Below is an image that shows the noise derived from a person talking in the same room as the microscope.

Figure 25A-B: 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.