Showing papers by "Tolek Tyliszczak published in 1992"

Thermal stability of the [(Si)m/(Ge)n]p superlattice interface

Abstract: The structure of [(Si) m /(Ge) n ] p superlattice interfaces and the onset of relaxation and interdiffusion initiated by annealing have been investigated with the use of extended x-ray-absorption fine structure and Raman scattering. For the as-grown material, the Ge-Ge bond length (0.2409 nm) was equal to that calculated for a fully strained Ge layer (0.2412 nm) while the Si-Ge bond length was significantly shorter. The results show conclusively that substantial intermixing along with partial relaxation of the Ge-Ge bonds occurs even for the shortest anneal at 700°C

Simultaneous analysis of multiple extended x-ray-absorption fine-structure spectra: Application to studies of buried Ge-Si interfaces

Abstract: Ge K-edge extended x-ray-absorption fine-structure (EXAFS) spectra of a series of strained-layer [(Si${)}_{\mathit{m}}$/(Ge${)}_{\mathit{n}}$${]}_{\mathit{p}}$ superlattices grown by molecular-beam epitaxy on the 〈100〉 face of single-crystal Si have provided a determination of the degree of intermixing and the extent of relaxation as a function of the thickness of the Ge layer. The results are obtained with use of constrained simultaneous nonlinear least-squares curve fits to multiple data files from different samples. This procedure, along with associated analysis of the fit surface, has improved the reliability of the analysis. We discuss the general applicability of simultaneous analysis procedures to EXAFS analysis of a series of related samples, such as those spanning compositional variation or thermal processing.