Propagation of Dislocations Through GeSi/Si Strained Layers and Superlattices

1988 ◽  
Vol 116 ◽  
Author(s):  
R. Hull ◽  
J.C. Bean ◽  
R.E. Leibenguth
Keyword(s):  
Single Layer ◽  
Dislocation Nucleation ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Strained Layers ◽  
Activation Barriers ◽  
Strained Layer ◽  
Growth Activation ◽  
Si Epitaxy ◽  
Strained Layer Superlattices

AbstractWe describe in-situ transmission electron microscope observations of the relaxation of strained layer GeSi/Si epitaxy. Dynamic observations of misfit dislocations in these structures reveal that dislocation nucleation and growth activation barriers, as well as interactions, limit the rate at which strain is relieved. The equivalence of threading and misfit dislocations in this system is demonstrated. Extension of the principles learnt from these single layer experiments to threading dislocation propagation through multilayer structures, enables us to understand the relative inefficiency of GeSi/Si strained layer superlattices in blocking threading dislocations.

scholarly journals The Structure of GaAs/Si(211) Heteroepitaxial Layers

1987 ◽  
Vol 91 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
E.R. Weber ◽  
J. Washburn ◽  
T.Y. Liu ◽  
H. Kroemer
Keyword(s):  
Buffer Layer ◽  
Surface Preparation ◽  
Gaas Layer ◽  
Misfit Dislocations ◽  
Strained Layer ◽  
Si Substrates ◽  
Density Of Dislocations ◽  
Gaas Buffer Layer ◽  
Graded Layers ◽  
Strained Layer Superlattices

ABSTRACTGallium arsenide films grown on (211)Si by molecular-beam epitaxy have been investigated using transmission electron microscopy. The main defects observed in the alloy were of misfit dislocations, stacking faults, and microtwin lamellas. Silicon surface preparation was found to play an important role on the density of defects formed at the Si/GaAs interface.Two different types of strained-layer superlattices, InGaAs/InGaP and InGaAs/GaAs, were applied either directly to the Si substrate, to a graded layer (GaP-InGaP), or to a GaAs buffer layer to stop the defect propagation into the GaAs films. Applying InGaAs/GaAs instead of InGaAs/InGaP was found to be more effective in blocking defect propagation. In all cases of strained-layer superlattices investigated, dislocation propagation was stopped primarily at the top interface between the superlattice package and GaAs. Graded layers and unstrained AlGaAs/GaAs superlattices did not significantly block dislocations propagating from the interface with Si. Growing of a 50 nm GaAs buffer layer at 505°C followed by 10 strained-layer superlattices of InGaAs/GaAs (5 nm each) resulted in the lowest dislocation density in the GaAs layer (∼;5×l07/cm2) among the structures investigated. This value is comparable to the recently reported density of dislocations in the GaAs layers grown on (100)Si substrates [8]. Applying three sets of the same strained layersdecreased the density of dislocations an additional ∼2/3 times.

Rapid Thermal Processing of Buried Sil−xGex Strained Layers; Photoluminescence Decay and Misfit Dislocation Generation.

1990 ◽  
Vol 198 ◽  
Author(s):  
D.C. Houghton ◽  
N.L. Rowell
Keyword(s):  
Quantum Wells ◽  
Misfit Dislocation ◽  
Thermal Processing ◽  
Internal Quantum Efficiency ◽  
Dislocation Nucleation ◽  
Multiple Quantum ◽  
Misfit Dislocations ◽  
Dislocation Generation ◽  
Strained Layers ◽  
Wide Range

ABSTRACTThe thermal constraints for device processing imposed by strain relaxation have been determined for a wide range of Si-Ge strained heterostructures. Misfit dislocation densities and glide velocities in uncapped Sil-xGex alloy layers, Sil-xGex single and multiple quantum wells have been measured using defect etching and TEM for a range of anneal temperatures (450°C-1000°C) and anneal times (5s-2000s). The decay of an intense photoluminescence peak (∼ 10% internal quantum efficiency ) from buried Si1-xGex strained layers has been correlated with the generation of misfit dislocations in adjacent Sil-xGex /Si interfaces. The misfit dislocation nucleation rate and glide velocity for all geometries and alloy compositions (0<x<0.25) were found to be thermally activated processes with activation energies of (2.5±0.2)eV and (2.3-0.65x)eV, respectively. The time-temperature regime available for thermal processing is mapped out as a function of dislocation density using a new kinetic model.

The Stability of Si-Si1-xGex Strained Layer Heterostructures.

1988 ◽  
Vol 130 ◽  
Author(s):  
D. C. Houghton ◽  
J-M. Baribeau ◽  
K. Song ◽  
D. D. Perovic
Keyword(s):  
Interference Microscopy ◽  
Layer System ◽  
Strained Layers ◽  
Strained Layer ◽  
Transmission Electron ◽  
Metastable Structures ◽  
Abrupt Changes ◽  
The Stability ◽  
Strained Layer Superlattices ◽  
Stability Limits

AbstractThe structural stability of strained layer superlattices (SLS's) is addressed using an equilibrium model and then compared to the stability of single strained layers. Relaxation mechanisms are described for various superlattice geometries. The application of a critical thickness/strain criterion to define stability limits was found to be very useful in predicting the detailed relaxation process. The competition between relaxation by misfit accommodation at the base of the SLS and at individual strained interfaces is considered for the initial condition of full coherency and after partial relaxation. Experimental data for the Si-Ge strained layer system are presented; as-grown by MBE and after annealing in the temperature range 500°C – 900°C. The extent of relaxation and the detailed dislocation structure within the SLS's were determined by X-ray rocking curve analysis, Nomarski interference microscopy and transmission electron microscopy. The abrupt changes in relaxation behaviour indicate that rigid boundaries between stable and metastable structures do exist, as predicted by the equilibrium models.

Threading Dislocation Dynamics in ZnSSe Strained-Layer Superlattices

2020 ◽  
Vol 97 (4) ◽  
pp. 79-88
Author(s):  
Johanna Raphael ◽  
Tedi Kujofsa ◽  
John E Ayers
Keyword(s):  
Dislocation Dynamics ◽  
Threading Dislocation ◽  
Strained Layer ◽  
Strained Layer Superlattices

The Role of an Interface Misfit Dislocation in Blocking the Glide of a Threading Dislocation in a Strained Epitaxial Layer

1989 ◽  
Vol 160 ◽  
Author(s):  
L. B. Freund ◽  
J. C. Ramirez ◽  
A. F. Bower
Keyword(s):  
Epitaxial Layer ◽  
Misfit Dislocation ◽  
Driving Force ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Dislocation Theory ◽  
Strained Layer

AbstractThe glide of a threading dislocation in a strained layer may be impeded as it encounters interface misfit dislocations on intersecting glide planes. An estimate of the change in driving force on the threading dislocation during this interaction is discussed within the framework of elastic dislocation theory.

Confinement of Threading Dislocations in Simox with a GeSi Strained Layer

1990 ◽  
Vol 198 ◽  
Author(s):  
F. Namavar ◽  
E. Cortesi ◽  
D.L. Perry ◽  
E.A. Johnson ◽  
N.M. Kalkhoran ◽  
...  
Keyword(s):  
Alloy Layer ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Epitaxial Silicon ◽  
Strained Layers ◽  
Strained Layer ◽  
Si Substrates ◽  
Plane View ◽  
Gesi Layer

ABSTRACTWe have investigated improving the crystalline quality of epitaxial silicon grown on SIMOX by confining threading dislocations in the original Si top layer using a GeSi strained layer. Epitaxial Si/GeSi/Si structures were grown by CVD on SIMOX and Si substrates with a GeSi alloy layer about 1000 − 1500 angstroms thick with Ge concentrations of about 0−20%. A Ge concentration in the alloy layer of about 5.5% or higher appears to be necessary in order to bend any of the threading dislocations from the original SIMOX top layer. For a higher Ge concentration of about 16%, most of the threading dislocations appear to be bent and confined by the GeSi layer. In addition, the GeSi strained layers grown by CVD (at about 1000°C) appear to be high quality and no misfit dislocations were observed in the regions studied by XTEM and plane view TEM.

Threading Dislocation Dynamics in ZnSSe Strained-Layer Superlattices

2020 ◽  
Vol MA2020-01 (23) ◽  
pp. 1363-1363
Author(s):  
Johanna Raphael ◽  
Tedi Kujofsa ◽  
John E Ayers
Keyword(s):  
Dislocation Dynamics ◽  
Threading Dislocation ◽  
Strained Layer ◽  
Strained Layer Superlattices

Dislocation Density Reduction in GaAs Epilayers on Si Using Strained Layer Superlattices

1989 ◽  
Vol 160 ◽  
Author(s):  
S. Sharan ◽  
J. Narayan ◽  
J. C. C. Fan
Keyword(s):  
Dislocation Density ◽  
Defect Density ◽  
Full Potential ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Strained Layer ◽  
Density Reduction ◽  
Threading Dislocation Density ◽  
Superlattice Structures ◽  
Strained Layer Superlattices

AbstractDefects such as dislocations and interfaces play a crucial role in the performance of heterostracture devices. The full potential of GaAs on Si heterostructures can only be realized by controlling the defect density. The reduction of threading dislocations by the use of strained layer superlattices has been studied in these heterostructures. Several superlattice structures have been used to reduce the density of threading dislocations in the GaAs epilayer. The use of strained layer superlattices in conjunction with rapid thermal annealing was most effective in reducing threading dislocation density. Transmission electron microscopy has been used to study the dislocation density reduction and the interaction of threading dislocations with the strained layers. A model has been developed based on energy considerations to determine the critical thickness required for the bending of threading dislocations.

Asymmetric Mosaic Spread During Relaxation in SiGe/ Si Strained Layer Superlattices Grown on Miscut Substrates

1995 ◽  
Vol 379 ◽  
Author(s):  
S. Nam ◽  
M. S. Goorsky
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Critical Thickness ◽  
Chemical Vapor ◽  
Misfit Dislocations ◽  
Satellite Peak ◽  
Strained Layer ◽  
Mosaic Spread ◽  
Peak Intensity ◽  
Strained Layer Superlattices

ABSTRACTThe evolution of defects in SiGe/Si strained layer superlattices (SLS)-with thickness and composition near the critical thickness -was investigated. The structures were grown on 2° miscut (001) substrates by ultrahigh vacuum chemical vapor deposition. The samples were then annealed between 700 °C and 900 °C. After annealing, the satellite peak intensity from double axis diffraction decreased and triple axis diffraction showed that this decreased intensity was due to increased mosaic structure. Interestingly, for some of the annealed samples, the (004) reciprocal space maps showed an asymmetric mosaic spread, indicating a preferential tilt. This result stems from a preferential propagation of certain types of misfit dislocations due to the substrate miscut.

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