Epitaxial layers, grown onto InP (001) substrates, were characterized by means of etch-pit density measurements, using an HBr and acetic acid solution; with a 1:7 concentration by volume. Atomic force microscopy was used to characterize the morphology of the etched surfaces. The latter results showed that the etch-pit depth became constant below a depth which corresponded roughly to the II-VI layer thickness. The accuracy of the etch-pit density method for revealing stacking faults and dislocations was verified by means of plan-view transmission electron microscopy. Both stacking faults and threading dislocations which originated from misfit dislocations were revealed by this etchant. The transmission electron and atomic force microscopic results showed that the etching was very selective. The present ZnCdMgSe layers had an etch-pit density of 106/cm2.

L.Zeng, B.X.Yang, B.Shewareged, M.C.Tamargo, J.Z.Wan, F.H.Pollak, E.Snoeks, L.Zhao: Journal of Applied Physics, 1997, 82[7], 3306-9