A. Nagarajan, S. Mukherjee, et al.
Journal of Applied Mechanics, Transactions ASME
The lattice parameters and Ge-to-Si nearest-neighbor and next-nearest-neighbor distances were measured using x-ray rocking curves and extended x-ray-absorption fine-structure spectroscopy for four different Si-rich Si1-xGex/Si(100) epitaxial films. The Si-Ge films, two prepared by molecular-beam epitaxy and two by chemical-vapor deposition, had thicknesses of 500-900 and Ge concentrations of xGe=0.060.18. Lattice parameters of the films, corrected for coherency strain, agreed with values reported for bulk Si-Ge alloys. Ge-to-Si distances were 2.375±0.02 and 3.85±0.06 for nearest and next-nearest neighbors, respectively, and were independent of Ge concentration within these experimental uncertainties. A simple, random-solid-solution model using composition-independent values for nearest-neighbor distances rSi-Si, rGe-Ge, and rGe-Si reproduced the average nearest-neighbor distance r(xGe) deduced from observed lattice parameters a(xGe) for our range of Ge concentrations. Composition variations of interatomic distances expected from various theoretical models [Martins and Zunger, Phys. Rev. B 30, 6217 (1984); Shih et al., B 31, 1139 (1985); Thorpe and Garboczi, Bull. Am. Phys. Soc. 35, 781 (1990)] all fell within our experimental uncertainty of ±0.02. © 1991 The American Physical Society.
A. Nagarajan, S. Mukherjee, et al.
Journal of Applied Mechanics, Transactions ASME
S.F. Fan, W.B. Yun, et al.
Proceedings of SPIE 1989
L.K. Wang, A. Acovic, et al.
MRS Spring Meeting 1993
H.D. Dulman, R.H. Pantell, et al.
Physical Review B