The Dektak 150 is a profilometer. It measures step heights, surface roughness, etc by means of a stylus in contact with the measured surface.
Relatively large surfaces like e.g. a silicon wafer can be scanned. The result can be presented as a curve for one scan. Several parallel scans can be presented as a 2-D topographic picture or as a 3-D picture.
Stylus with different radii is available.
It is also possible to do stress measurements.