Comparative analysis of synchrotron X-ray transmission and reflection topography techniques applied to epitaxial laterally overgrown GaAs layers

Article type: Research Article

Authors: Rantamäki, R. | Tuomi, T. | Zytkiewicz, Z.R. | McNally, P.J. | Danilewsky, A.N.

Affiliations: Optoelectronics Laboratory, Helsinki University of Technology, P.O. Box 3000, FIN-02015 HUT, Finland. | Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warszawa, Poland. | Microelectronics Research Laboratory, School of Electronic Engineering, Dublin City University, Dublin 9, Ireland. | D-79108 Freiburg, Germany.

Abstract: Synchrotron X-ray topographs of epitaxial laterally overgrown GaAs (ELO) samples are made in both transmission and reflection geometries. Samples grown on GaAs substrates with separated and merged ELO layers are studied. Transmission, transmission section, back-reflection, back reflection section and grazing incidence X-ray topographs are compared. The topographs, complementary to each other, show that the bending of the ELO layers is visible in all geometries, though ELO images are seen in different ways in different geometries. The observed contrast of the ELO layers is explained using a model based on orientational image contrast. A pair of back-reflection section and back-reflection topographs taken subsequently from the same position is required for successful and unambigious interpretation of topographs.

Journal: Journal of X-Ray Science and Technology, vol. 8, no. 4, pp. 277-288, 1998