Fraunhofer Institute for Surface Engineering and Thin Films IST
3D image of a polycrystalline diamond layer.
Very-high resolution 3-dimensional surface imaging: AFM
Atomic Force Microscopy (AFM)
The atomic force microscope and the scanning tunneling microscope (AFM/STM) are suitable for images with particularly high resolution. The surface is scanned by means of an ultra-fine tip, with minimal force, generating a 3D image of the surface. Lateral resolutions of 1-10 nm and vertical resolutions of less than 1 nm are achieved. Monolayer samples can be resolved. The atomic force microscope (AFM) is particularly suitable for characterizing extremely smooth surfaces. Friction microscopy or modulation techniques can also be used to show material contrasts.
Quantitative evaluation
The advantage of Atomic Force Microscopy (AFM) is that it provides not only a "photo" of the surface, but a complete three-dimensional data set of the surface topography. A great deal of quantitative information can be obtained from this:
- Roughness
- Step heights and widths
- Pitch angle
- Grain sizes
- Skewness and kurtosis
- Power spectral density and more
The data can also be made available as a 3D data set to the customer for their own evaluations.
STM image of a metal DLC layer
The figure shows nanocrystalline platinum particles in an amorphous carbon matrix. The platinum particles have a diameter of just a few nanometers, but appear somewhat enlarged in the image due to folding with the geometry of the scanning tip.
Polymer surface
AFM-tapping-mode-image of a polymer surface. Tapping mode is a very low-impact scanning method, with which even soft materials such as polymers can be imaged without damage.
Microchip surface
3D image of the surface of an electronic microchip.
3D images of the surface of an electronic microchip and measurement of the structure sizes.
Glass
Pitting in corroded glass surface.