The reliability of revealing threading dislocations in epitaxial films by structure-sensitive etching

Correspondence between threading dislocations (TDs) in epitaxial films and the etch pits observed upon selective chemical etching of the samples was studied in Ge/Si(001) heterostructures. It is established that the density of TDs revealed in epitaxial films with thicknesses $h\le 1$ $\mu$m can be significantly understated because of insufficient resolution of optical microscopy. Recommendations are given that increase the reliability of PD density estimation by means of structure-sensitive etching.