Metrology of semiconductor device structures by cross-sectional AFM

Atomic force microscopy (AFM) in air has been used to study various III–V semiconductor heterostructures. Topography of the (110) cleaved cross-sections has been examined where oxidation processes modify the surface and allow the structures to be investigated. It is shown that surface height differences of as little as 0.4 Å are sufficient to distinguish between layers, and that quantum wells of as little as 7 nm width are detectable.