AFM Scanner for Atomic Force Microscopy

Piezo-Based Scanning Stages Play a Key Role

To give an example, modular designed microscopy systems can today allow equipping a confocal Raman microscope with atomic force microscopy or scanning near-field optical microscopy (SNOM). The basis for these extremely high-resolution methods is always the highly precise positioning of the specimen in all three axes of motion.

Positioning with Very High Position Resolution and Dynamics

The resolution of the specimen scanner must lie in the subnanometer range as the positioning system provides the spatial resolution. At the same time, high dynamics are required, the faster the topography can be moved in Z direction, the quicker the positioning on the X and Y axis. This reduces measurement times and also reduces possible temperature drift which increases with time.

Key Role of the Scanning Stage

The piezo-based scanning stage plays a key role in specimen positioning. It is designed for travel ranges of 100 or 200 µm along the axes of the scanning plane and 30 µm in direction of the Z axis and allows position resolution better than 2 nm.

In addition, active guiding using capacitive sensors increases path fidelity: The sensors measure any deviations in the perpendicular axis to the direction of motion.

Any undesired crosstalk of the motion can thus be detected and actively compensated in real time. The digital electronics performing the appropriate control also operate at a high cycle rate. This is crucial for the precise assignment of the scanner's position values and the recording camera.