VISUALIZATION OF INHOMOGENEITIES OF CRYSTAL-GROWTH BY OPTICAL OBSERVATIONS

Optical diffraction is used to map the distances of striations over macroscopic regions. The diffraction is due to striation-induced changes in transmission, refractive indices or surface shape after etching. In different modes of the experiment one obtains a survey of the dominant striation distances, areas of stationary growth, areas of striations with a certain distance and the distribution of distances. Examples for mixed oxide crystals and InP as well as requirements and limitations are discussed.