STUDY OF THE INFLUENCE OF NATIVE-OXIDE LAYERS ON ATOMIC-FORCE MICROSCOPY IMAGING OF SEMICONDUCTOR SURFACES

We have investigated the influence of the native oxide layer on semico nductor surfaces on the imaging properties of the atomic force microsc ope operated under ambient conditions by using epitaxial In1-xGaxAs la yers grown by Metal-Organic Chemical Vapour Deposition (MOCVD) on (001 ) oriented InP substrates which have been kept under ambient condition s for two years. The thickness and composition of the native oxide lay ers were studied with ellipsometry and X-ray photoelectron spectroscop y, respectively. Subsequently, the sample surfaces were imaged by mean s of atomic force microscopy operated in air which revealed terrace st ructures separated by monoatomic steps. The obtained data were compare d with the surface morphology which can be expected from the MOCVD gro wth process. The results suggest that an accurate study of semiconduct or layer growth by atomic force microscopy in air is possible.