X-Ray Study of Non-Periodic Si/SiGe Multilayers

X-ray diffraction is applied for the assessment of structural data such as lattice mismatch and layer thickness of MBE grown Si/Si1−xGex heterobipolar transistor and double-barrier resonant-tunneling structures. Rocking curves from the former structure show distinct features which are obviously correlated to the individual layer parameters. The diffraction profile of the resonant tunneling structure is not only more complicated because of the larger number of parameters but also due to the strong interference effects resulting from the layer set-up. For a determination of the structural parameters a comparison of the experimental diffraction pattern with simulated rocking curves is performed.