Real-time structural analysis of compositionally graded InxGa1−xAs/GaAs(001) layers

Summary form only given. In situ three dimensional X-ray reciprocal space mapping during compositionally graded In_xGa_1-xAs/GaAs(001) molecular beam epitaxial (MBE) growth is performed for real-time structural analysis. The symmetrical 004 and asymmetrical 022 reflections are measured during layer growth to investigate lattice relaxation and lattice tilting, respectively, at synchrotron facility, SPring-8 in Japan. It was found that lattice relaxation of 1^st layer was classified to three thickness ranges with different processes after 2^nd layer growth. Furthermore, degrees and directions of lattice tilting could be directly observed during 1^st and 2^nd layers growth. We demonstrated that 3D-RSM is a powerful characterization technique for real-time structural analysis of compositionally graded layers, and believe that the fundamental knowledge obtained in this study will be useful to design the metamorphic III-V solar cells with high crystal quality.