The atomic force microscope (AFM) was developed to overcome a basic drawback with STM – it can only image conducting or semiconducting surfaces. The AFM has the advantage of imaging almost any type of surface, including polymers, ceramics, composites, glass, and biological samples. Analogous to how an Scanning Tunneling Microscope works, a sharp tip is raster-scanned over a surface using a feedback loop to adjust parameters needed to image a surface. Unlike Scanning Tunneling Microscopes, the Atomic Force Microscope does not need a conducting sample. Instead of using the quantum mechanical effect of tunneling, atomic forces are used to map the tip-sample interaction.
Traditionally, most Atomic Force Microscopes use a laser beam deflection system where a laser is reflected from the back of the reflective AFM lever and onto a position-sensitive detector. AFM tips and cantilevers are typically micro-fabricated from Si or Si3N4. Typical tip radius is from a few to 10s of nm.