Determination of The State of Deformation in Epitaxial Layers Using High Resolution X-Ray Diffraction

1993 ◽  
Vol 319 ◽  
Author(s):  
P.J. Dugdale ◽  
R.C. Pond ◽  
S.J. Barnett

AbstractThe state of deformation in epitaxial layers of InGaAs grown by MBE on GaAs substrates has been determined using high resolution X-ray diffraction. This method enables the strains and rigid body rotations which occur in the layers to be measured and these are described by means of a tensor. Layers of different thicknesses have been grown on substrates whose dislocation densities differ by three orders of magnitude in order to assess the influence of this parameter on layer relaxation through the motion of misfit dislocations to the interface. Transmission electron microscopy has also been used to provide additional information on the relaxations.

1992 ◽  
Vol 280 ◽  
Author(s):  
M. S. Goorsky ◽  
S. T. Horng ◽  
S. R. Sriffler ◽  
C. S. Stanis

ABSTRACTComparison of high resolution x-ray diffraction and transmission electron microscopy measurements of Si-based heterostructures demonstrates that diffraction is much more sensitive to strain relaxation than previously reported. This study used as-grown and annealed Si1-x Gex structures grown on (001) Si by UHV/CVD. (004), (113), and (115) rocking curves were employed. Using the TEM measurements as a quantitative guide, relaxation was observed in rocking curves when the misfit dislocation line density was as low as 1 μ-1. Also, interference fringes strongly depend on the presence of interfacial defects. At higher dislocation densities, the diffraction peak from the epitaxial layer broadens considerably but does not shift to a position that represents complete relaxation. Broadening of the substrate diffraction peak also occurs, which is due to dislocations that loop into the substrate.


Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.


1990 ◽  
Vol 101 (1-4) ◽  
pp. 572-578 ◽  
Author(s):  
A.M. Keir ◽  
A. Graham ◽  
S.J. Barnett ◽  
J. Giess ◽  
M.G. Astles ◽  
...  

1995 ◽  
Vol 378 ◽  
Author(s):  
R. H. Thompson ◽  
V. Krishnamoorthy ◽  
J. Liu ◽  
K. S. Jones

AbstractP-type (100) silicon wafers were implanted with 28Si+ ions at an energy of 50 keV and to doses of 1 × 1015, 5 × 1015 and 1 × 1016 cm−2, respectively, and annealed in a N2 ambient at temperatures ranging from 700°C to 1000°C for times ranging from 15 minutes to 16 hours. The resulting microstructure consisted of varying distributions of Type II end of range dislocation loops. The size distribution of these loops was quantified using plan-view transmission electron microscopy and the strain arising from these loops was investigated using high resolution x-ray diffraction. The measured strain values were found to be constant in the loop coarsening regime wherein the number of atoms bound by the loops remained a constant. Therefore, an empirical constant of 7.7 × 10−12 interstitial/ppm of strain was evaluated to relate the number of interstitials bound by these dislocation loops and the strain. This value was used successfully in estimating the number of interstitials bound by loops at the various doses studied provided the annealing conditions were such that the loop microstructure was in the coarsening or dissolution regime.


1991 ◽  
Vol 35 (A) ◽  
pp. 593-599 ◽  
Author(s):  
M. Griffiths ◽  
J.E. Winegar ◽  
J.F. Mecke ◽  
R.A. Holt

AbstractX-ray diffraction (XRD) line-broadening analysis has been used to determine dislocation densities in zirconium alloys with hexagonal closepacked (hep) crystal structures and a complex distribution of dislocations reflecting the plastic, anisotropy of the material. The validity of the technique has been assessed by comparison with direct measurements of dislocation densities in deformed polycrystalline and neutron-irradiated single crystal material using transmission electron microscopy (TEM). The results show that-there is good agreement between the XRD and TEM for measurements on the deformed material whereas there is a large discrepancy for measurements on the irradiated single crystal; the XRD measurements significantly underestimating the TEM observations.


2003 ◽  
Vol 255 (1-2) ◽  
pp. 63-67 ◽  
Author(s):  
X.H. Zheng ◽  
H. Chen ◽  
Z.B. Yan ◽  
Y.J. Han ◽  
H.B. Yu ◽  
...  

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