Tomographic Mapping Analysis in the Depth Direction of High-Ge-Content SiGe Layers with Compositionally Graded Buffers Using Nanobeam X-ray Diffraction

A high-Ge-content Si1–yGey/compositionally graded Si1–xGex-stacked structure grown on Si(001) is now considered to be an important platform for the realization of advanced nanometer-scale complementary metal oxide semiconductor devices with high-mobility channel materials, such as III–V materials and Ge, and monolithically integrated photonic modules. The performance of such advanced devices is critically influenced by crystalline inhomogeneity in the stacked structure; therefore, precise characterization of the crystallinity is important. In particular, the development of a characterization method not only for in-plane crystallinity but also for in-depth crystallinity is strongly required. This is because the crystalline quality of the constant composition Si1–yGey is sensitively dependent on that of the compositionally graded Si1–xGex layers underneath. Here, we have demonstrated in-depth tomographic mapping of a high-Ge-content Si1–yGey/compositionally graded Si1–xGex-stacked structure using position-d...