Chapter 2
OBD vs active AFM
Classical AFM relies on optical beam deflection across all four core mechanisms. nano analytik's active cantilever replaces each with a purely electrical equivalent — simpler, more scalable, and alignment-free.
01
Cantilever Readout Principle
Optical Beam Deflection
- A laser focused on the cantilever.
- The reflected laser is aimed at a four quadrant photodetector.
- Bending of the cantilever changes the position of the illuminated spot on the detector.
- This change can be measured and used to determine the deflection of the cantilever.
Piezoresistive readout
Direct deflection readout via two dimensional electron gas based read-out in a full bridge Wheatstone configuration.
02
Cantilever Drive Principle
- External piezo shaker is used to excite the cantilevers at their resonant frequency.
- Alternatively a modulated secondary laser and cantilevers with integrated photothermal bimorph actuators can be used.
Integrated active thermomechanical bimorph actuator driven AFM-Controller.
03
Measurement Modes
- Contact
- Tapping
- Non-Contact
- Current-AFM
- Peak-Force Tapping mode
- Lateral force mode
- Magnetic/electrostatic/functionalized modes (Depends on tip)
- Contact
- Tapping
- Current-AFM
- Field-Emission-Scanning-Probe-Lithography
- Magnetic/electrostatic/functionalized modes (Depends on tip)
04
Scalability and Throughput
- Difficult and highly complex to parallelize for high-throughput, large-area imaging and metrology.
- Miniaturization limited by optical diffraction limit.
- Can be integrated in into multi-probe arrays.
- Cantilever downscaling is completely free from optical diffraction constraints.