Deep Luminescence from ‘Relaxed’ Si1−xGex Epitaxial Layers

1991 ◽  
Vol 220 ◽  
Author(s):  
Gordon Davies ◽  
Victor Higgs ◽  
Richard Kubiak ◽  
Adrian Powell ◽  
Terry Whall ◽  
...  
Keyword(s):  
Diagnostic Tool ◽  
Critical Thickness ◽  
Epitaxial Layers ◽  
X Rays ◽  
Dislocation Related Luminescence

ABSTRACTIn MBE Si1−xGex which is grown to thicknesses greater than the critical thickness hc, the dislocation-related luminescence peaks Dl and D2 have energies which are independent of x up to x ≈ 0.3, and then decrease, as observed in LPE Si1−xGex. In MBE Si1−xGex layers grown to thicknesses less than hc, post-growth annealing produces dramatic changes in the luminescence, giving spectra as from relaxed alloy, even though the relaxation determined by X-rays is negligible. These results establish photoluminescence as a sensitive diagnostic tool for detecting dislocations in Si1−xGe*.

Bond length variation in In0.25Ga0.75As/InP epitaxial layers thicker than the critical thickness

1999 ◽  
Vol 86 (5) ◽  
pp. 2533-2539 ◽  
Author(s):  
M. Tormen ◽  
D. De Salvador ◽  
M. Natali ◽  
A. Drigo ◽  
F. Romanato ◽  
...  
Keyword(s):  
Bond Length ◽  
Critical Thickness ◽  
Epitaxial Layers ◽  
Length Variation

The Critical Thickness of Layers Subject to Anisotropic Misfit.

1991 ◽  
Vol 239 ◽  
Author(s):  
Richard Beanland
Keyword(s):  
Dislocation Density ◽  
Layer Thickness ◽  
Critical Thickness ◽  
Theoretical Calculations ◽  
Critical Layer ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Critical Layer Thickness ◽  
New Formulation

ABSTRACTIt is well known that it becomes energetically favourable for misfit dislocations to be introduced into strained epitaxial layers above a certain ‘critical’ layer thickness, hc. To date, theoretical calculations of hc have only been made for cases of isotropie misfit - i.e. cases where the misfit is the same for every direction in the interface. Using a new formulation of the Frank-Bilby equation and the concept of coherency dislocations, it is now possible to treat cases of anisotropie misfit, such as silicon on sapphire (SOS). The method used to obtain the critical thickness is described, and values of hc and equilibrium dislocation density are given for various materials systems.

The GEMpix detector as new soft X-rays diagnostic tool for laser produced plasmas

2016 ◽  
Vol 87 (10) ◽  
pp. 103505 ◽  
Author(s):  
G. Claps ◽  
D. Pacella ◽  
F. Murtas ◽  
K. Jakubowska ◽  
G. Boutoux ◽  
...  
Keyword(s):  
Diagnostic Tool ◽  
X Rays

Synchrotron X-Ray Topographic Studies of Recombination Activated Shockley Partial Dislocations in 4H-Silicon Carbide Epitaxial Layers

2008 ◽  
Vol 600-603 ◽  
pp. 357-360 ◽  
Author(s):  
Yi Chen ◽  
Xian Rong Huang ◽  
Ning Zhang ◽  
Michael Dudley ◽  
Joshua D. Caldwell ◽  
...  
Keyword(s):  
Stacking Faults ◽  
Epitaxial Layers ◽  
Threading Dislocations ◽  
X Rays ◽  
Electron Hole ◽  
X Ray ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Edge Component ◽  
Hole Recombination

Electron-hole recombination activated Shockley partial dislocations bounding expanding stacking faults and their interactions with threading dislocations have been studied in 4H-SiC epitaxial layers using synchrotron x-ray topography. The bounding partials appear as white stripes or narrow dark lines in back-reflection X-ray topographs recorded using the basal plane reflections. Such contrast variations are attributable to the defocusing/focusing of the diffracted X-rays due to the edge component of the partial dislocations, which creates a convex/concave distortion of the basal planes. Simulation results based on the ray-tracing principle confirm our argument. The sign of the partial dislocations can be subsequently determined.

Strained Layer Epitaxy on Rough Si Surfaces

1995 ◽  
Vol 379 ◽  
Author(s):  
T.D. Lowes ◽  
M. Zinke-Allmang
Keyword(s):  
Epitaxial Layer ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Rough Surfaces ◽  
Misfit Strain ◽  
Surface Roughening ◽  
Epitaxial Layers ◽  
Dislocation Generation ◽  
Surface Features ◽  
Initial Substrate

ABSTRACTLattice mismatch associated with heteroepitaxy imposes a significant limitation on the epitaxial compatibility between overlayer and substrate. In lattice mismatched systems the misfit may be accommodated to some extent by strain. However, in order to maintain misfit strain and avoid dislocation generation the epitaxial layer must not exceed a critical thickness. Some success has been reported in avoiding damaged epitaxial layers with thicknesses greater than the critical thickness by overgrowing on patterned or rough surfaces. For the case of Si, surface roughening by energetic Ar+ bombardment as a pre-growth roughening treatment is discussed and assessed. Evolution of surface features as a function of initial substrate treatment, ion accelerating potential, and the duration of bombardment are presented. Stability of the surface features generated by bombardment for typical overgrowth conditions was tested to assess feasibility of this technique for Si heteroepitaxy.

scholarly journals X-ray Diffraction Investigation of Epitaxial Layers of CdTe on Sapphire

1990 ◽  
Vol 43 (6) ◽  
pp. 793 ◽  
Author(s):  
Andrew W Stevenson ◽  
Geoff N Pain
Keyword(s):  
The Other ◽  
Epitaxial Layers ◽  
Anomalous Scattering ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Two Samples ◽  
Species Being

The anomalous scattering of X-rays has been used to determine the polarity of CdTe epitaxial layers on sapphire. The results for two samples are presented, one of (111) orientation ('A face'), the other of (III) orientation (,B face'). The (III) layer is twinned, the two twin species being related by a 180� rotation about the [1111 axis. The twin fraction shows considerable variation for different positions on this sample, and must be taken into account when analysing the integrated X-ray intensities, in order to get meaningful Bijvoet ratios. The polarities of the two twin species are found to be the same.

scholarly journals Theoretical research on critical thickness of HgCdTe epitaxial layers

2005 ◽  
Vol 54 (12) ◽  
pp. 5814
Author(s):  
Wang Qing-Xue ◽  
Yang Jian-Rong ◽  
Wei Yan-Feng
Keyword(s):  
Critical Thickness ◽  
Theoretical Research ◽  
Epitaxial Layers

The Morphological Stability of Strained Epitaxial Layers

1996 ◽  
Vol 440 ◽  
Author(s):  
B. W. Wessels
Keyword(s):  
Thin Films ◽  
Critical Thickness ◽  
Strain Relaxation ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Epitaxial Layers ◽  
Two Dimensional ◽  
Morphological Stability

AbstractThe morphological stability of strained-layer thin films is analyzed using classical nucleation theory. For the case where strain relaxation occurs by formation of coherent islands, the model predicts that the critical thickness for transition from two-dimensional (2D) to three dimensional (3D) growth depends inversely on the square of the misfit. The predicted dependence of critical thickness on misfit is in agreement with recent experimental studies on the heteropitaxy of III-V compounds.

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