X-ray standing wave and high-resolution x-ray diffraction study of the GaAs/InAs/GaAs(100) heterointerface

The composition profile of a InAs monolayer buried in a GaAs matrix is studied by combining high-resolution x-ray diffraction and x-ray standing-wave experiments. This combination provides a comprehensive structural analysis in terms of strain status, layer thickness, and interfacial atomic configuration of this extremely thin layer. We found the InAs layer to be pseudomorphically matched to the GaAs host crystal. Moreover, we measure a total amount of In (6.739×{}10¹⁴ atoms/cm²) distributed, at the heterointerface, within 3 monolayers in the following percentages: 75% in the first monolayer and 20% and 5% in the second and third, respectively. The In atoms are not randomly distributed as they would be in a Gaₓ{In}_{1{{-}}x}$As alloy, but form InAs terraces. Finally, these results demonstrate the growth procedure employed to be very efficient in minimizing the impact of In segregation.