Laser Reflectogram Method for the Study of Crystal Surfaces and Epitaxial Deposits

When a collimated beam of light is reflected from an etched crystal surface or an epitaxial deposit, the pattern formed by this reflection provides information on the microscopic morphology of the reflecting surface. Using a He/Ne laser as a source of high-intensity collimated light, both SiC etched in ClF(3) and cubic CdS grown epitaxially on GaP have been examined. Certain regions of the SiC were found to give rise to diffraction effects in the resulting reflectrogram. The epitaxial layer of CdS was found to show a threefold symmetry indicative of a {111} deposit and a negligible diffraction effect.