Morphology of Etch Pits on Germanium Studied by Optical and Scanning Electron Microscopy

A comparison is made between optical and scanning electron microscopy techniques on germanium surfaces that have been etched in several common chemical etchants. The morphology of the etch pits due to dislocations and different types of surface preparation are discussed. The high resolution and depth of field of the scanning electron microscope allowed resolution of the fine structure of the etch figures. Due to the manner in which the image is formed on the scanning electron microscope, the limit of resolution is much higher and light interference encountered using standard metallurgical microscopes is eliminated.