Bond lengths inGe1−xSixcrystalline alloys grown by the Czochralski method

Abstract

We measured the effect of alloy composition on the atomic bonding in bulk Ge 1Ϫx Si x alloys grown by the Czochralski method across the whole composition range 0ϽxϽ1. Extended x-ray-absorption fine-structure measurements performed at the Ge K edge at 20 K found that the Ge-Ge and Ge-Si bond lengths maintain distinctly different lengths and vary linearly with alloy composition. The topological rigidity parameter, estimated from the measured bond lengths, is around 0.6, which indicates that the bond lengths and bond angles are distorted with alloy composition.

X-ray Fluorescence Holography Study on Si<SUB>1&minus;</SUB><i><SUB>x</SUB></i>Ge<i><SUB>x</SUB></i> Single Crystal

“…While, the FWHM of the Si 0:999 Ge 0:001 is lower than those of above three samples, revealing that Ge-Si-Si bond is dominant. This result is reasonable taking into account the nature of the random substitution in SiGe system 3) and the Ge content of this sample.…”

“…The compositional dependence of the first shell homoatomic and heteroatomic bondings in SiGe alloys has been found to be mostly Pauling type. 2,3) Local lattice distortion characterized by the bond-length and angle is a key factor for understanding the electro and optical properties of SiGe system. The analysis of the second-or third-shell by the EXAFS is however a difficult task because the second-shell signal is overlapped with the third-shell signal and heavily contaminated by a triangular multiple scattering path.…”

Growth and fundamental properties of SiGe bulk crystals

“…Such an Si-O-Si quasi-molecule causes the anti-symmetric stretching vibration around 1106 cm À1 at room temperature. The 1106 cm À1 peak shifts to low frequency side with an increase in Ge, possibly due to the expansion of Si-Si bonds as revealed by the XAFS study described in a previous section [24,25].…”

“…Extended X-ray-absorption fine-structure (XFAS) spectroscopy on the grown Si x Ge 1Àx alloys in the whole composition range 0oxo1 were performed to clarify the effect of alloy composition on the atomic bonding of the nearest-neighbor in the local atomic structure [24,25]. XAFS spectra of Ge K-edge and Si Kedge were observed using transmission mode at the BL-10B and BL-11B station, respectively, of KEK-PF.…”

Elastic properties of indium nitrides grown on sapphire substrates determined by nano-indentation: In comparison with other nitrides

“…38 The strains may be accommodated mainly or partly by a change of bond angles instead of that of bond lengths in the narrowly spaced (0001) interatomic planes, similar to the situation of Pauling-type structure alloys such as InGaAs 39 and SiGe. 40 Probably, determination of the Poisson's ratio of AlN, assumed to be 0.255 at present, 41 is a task for future investigation. Here, it should be noted that E c is within the error shown in Table II, even if ν=0.272, the most common value cited as reliable, 9,41 is adopted for evaluation.…”