Characterisation of Interfaces in SiGe Superlatrlces by Combined Grazing Incidence X-Ray Fluorescence and Reflectivity

X-Ray reflectivity enables the determination of interface and surface roughness along with the variations present in the electron density. Total reflection X-ray fluorescence allows surface analysis with high sensitivity and quantification. By use of grazing angle x-ray fluorescence taken simultaneously with the reflectivity measurements, over a range of angles near the critical angle, it is possible in principle to produce a depth profile of each element, with a composition sensitivity of 0.0002%. A silicon-germanium single layer was used to calibrate the instrument and a Si-Ge 5- period superlattice for a demonstration measurement.