A Multiplication Mechanism for Misfit Dislocations

1992 ◽  
Vol 263 ◽  
Author(s):  
Michael A. Capano
Keyword(s):  
Dislocation Loop ◽  
Misfit Dislocation ◽  
Epitaxial Layers ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Sequential Process ◽  
Single Dislocation ◽  
Dislocation Arrays ◽  
Half Loop ◽  
Dislocation Sources

ABSTRACTA new mechanism which describes how misfit dislocations in epitaxial layers multiply is presented. This work demonstrates how a single threading dislocation can give rise to an array of dislocation sources, where each source generates a single dislocation loop perpendicular to the primary misfit dislocation. As a threading dislocation with pure screw character glides through an epilayer, certain processes occur which lead to the production of a single dislocation half-loop, and the regeneration of the original threading dislocation. The regenerated threading dislocation continues to propagate on its primary glide plane, which allows the process to repeat itself at some later time. The result of this sequential process is an array of half-loops perpendicular to the primary misfit dislocation. The shape and symmetry of the arrays also contains information regarding how the mechanism operates. The proposed mechanism is related to misfit dislocation arrays in a single Si0.87Ge0.13 layer on Si(001).

scholarly journals Investigation of Misfit Dislocation Sources in GaAs Epitaxial Layers

1996 ◽  
Vol 89 (3) ◽  
pp. 341-346 ◽  
Author(s):  
W. Wierzchowski ◽  
K. Mazur ◽  
Wł. Strupiński ◽  
K. Wieteska ◽  
W. Graeff
Keyword(s):  
Misfit Dislocation ◽  
Epitaxial Layers ◽  
Dislocation Sources

The Role of Misfit Dislocation During Epitaxial Growth

1987 ◽  
Vol 94 ◽  
Author(s):  
D. Cherns
Keyword(s):  
Misfit Dislocation ◽  
Lattice Spacing ◽  
Minimum Energy ◽  
Energy Criterion ◽  
Misfit Dislocations ◽  
Metal Metal ◽  
Correct Account ◽  
Pseudomorphic Growth ◽  
Dislocation Sources

ABSTRACTThe theory of Frank and van der Merwe (FM) in 1949 showed that a minimum energy criterion could explain the pseudomorphic growth of a deposit on a substrate of different lattice spacing and the subsequent relief of strain by misfit dislocations as the deposit thickness increases. Although the “equilibrium” theory is qualitatively correct, account must be taken of actual dislocation sources, which may be complex, and which may be more or less efficient for misfit relief than predicted by the FM model. Moreover, misfit dislocation sources may determine the morphology of the growing film, the interface topology and even the atomic structure of the deposit/substrate interface. These various roles of misfit dislocations are reviewed here with examples from work on metal/metal, semiconductor/semiconductor and metal/semiconductor systems.

Structure and Electronic Properties of Misfit Dislocations in ZnSe/GaAs(001) Heterojunctions

1994 ◽  
Vol 340 ◽  
Author(s):  
Y. Chen ◽  
X. Liu ◽  
E. Weber ◽  
E. D. Bourret ◽  
D. J. Olego ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electrical Properties ◽  
Electronic Properties ◽  
Misfit Dislocation ◽  
Orthogonal Array ◽  
High Density ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Dislocation Arrays

ABSTRACTStudies of the structure and electrical properties of regular and irregular misfit dislocations in undoped and N-doped ZnSe epilayers grown on GaAs(001) substrates by transmission electron microscopy (TEM), cathodoluminescence (CL) are reported. In undoped ZnSe epilayers, two sets of misfit dislocation arrays were observed: a straight orthogonal array along [110] and, and an irregular array roughly along [100] and [010] directions. The CL observations suggest that the irregular dislocations trap carriers more efficiently than the dislocations along <110>, possibly due to the high density of kinks existing along the zig-zag irregular dislocations. These irregular dislocations can be eliminated by doping nitrogen in the ZnSe epilayer with [N]≥l×1018 cm−3.

Interaction Length for Dislocations in Compositionally-Graded Heterostructures

2018 ◽  
Vol 27 (03n04) ◽  
pp. 1840022 ◽  
Author(s):  
Minglei Cai ◽  
Tedi Kujofsa ◽  
Xinkang Chen ◽  
Md Tanvirul Islam ◽  
John E. Ayers
Keyword(s):  
Misfit Dislocation ◽  
Practical Importance ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Multilayered Structures ◽  
Interaction Length ◽  
Dislocation Interaction ◽  
First Case ◽  
Future Work

Several simple models have been developed for the threading dislocation behavior in heteroepitaxial semiconductor materials. Tachikawa and Yamaguchi [Appl. Phys. Lett., 56, 484 (1990)] and Romanov et al. [Appl. Phys. Lett., 69, 3342 (1996)] described models for the annihilation and coalescence of threading dislocations in uniform-composition layers, and Kujofsa et al. [J. Electron. Mater., 41, 2993 (2013)] extended the annihilation and coalescence model to compositionally-graded and multilayered structures by including the misfit dislocation-threading dislocation interactions. However, an important limitation of these previous models is that they involve empirical parameters. The goal of this work is to develop a predictive model for annihilation and coalescence of threading dislocations which is based on the dislocation interaction length Lint. In the first case if only in-plane glide is considered the interaction length is equal to the length of misfit dislocation segments while in the second case glide and climb are considered and the interaction length is a function of the distance from the interface, the length of misfit dislocations, and the density of the misfit dislocations. In either case the interaction length may be calculated using a model for dislocation flow. Knowledge of the dislocation interaction length allows predictive calculations of the threading dislocation densities in metamorphic device structures and is of great practical importance. Here we demonstrate the latter model based on glide and climb. Future work should compare the two models to determine which is more relevant to typical device heterostructures.

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.

scholarly journals Misfit Dislocations in Epitaxial Ni/Cu Bilayer and Cu/Ni/Cu Trilayer Thin Films

2001 ◽  
Vol 673 ◽  
Author(s):  
Tadashi Yamamoto ◽  
Amit Misra ◽  
Richard G. Hoagland ◽  
Mike Nastasi ◽  
Harriet Kung ◽  
...  
Keyword(s):  
Thin Films ◽  
Layer Thickness ◽  
Misfit Dislocation ◽  
Interface Plane ◽  
Misfit Dislocations ◽  
Strain Fields ◽  
Plan View ◽  
Transmission Electron ◽  
Dislocation Arrays ◽  
20 Nm

ABSTRACTMisfit dislocations at the interfaces of bilayer (Ni/Cu) and trilayer (Cu/Ni/Cu) thin films were examined by plan-view transmission electron microscopy (TEM). In the bilayers, the spacing of misfit dislocations was measured as a function of Ni layer thickness. The critical thickness, at which misfit dislocations start to appear with the loss of coherency, was found to be between 2 and 5 nm. The spacing of the misfit dislocations decreased with increasing Ni layer thickness and reached a plateau at the thickness of 30 nm. The minimum spacing is observed to be about 20 nm. A g·b analysis of the cross-grid of misfit dislocations revealed 90° Lomer dislocations of the <110>{001} type lying in the (001) interface plane at a relatively large thickness of the Ni layer, but 60° glide dislocations of the <110>{111} type at a relatively small thickness of the Ni layer. In the trilayers, misfit dislocations formed at both interfaces. The spacing of the misfit dislocation is in agreement with that of the bilayers with a similar Ni layer thickness. The misfit dislocation arrays at the two interfaces, having the same line directions, are 60° dislocations with edge components with opposite signs but are displaced with respect to each other in the two different interface planes. This suggests that interactions of the strain fields of the dislocations have a strong influence on their positions at the interface.

Mechanisms and Kinetics of Misfit Dislocation Formation in Heteroepitaxial Thin Films

1990 ◽  
Vol 188 ◽  
Author(s):  
W. D. Nix ◽  
D. B. Noble ◽  
J. F. Turlo
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Dislocation Motion ◽  
Dislocation Nucleation ◽  
Dislocation Segment ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Film Substrate ◽  
Kinetics Of ◽  
Dislocation Formation

ABSTRACTThe mechanisms and kinetics of forming misfit dislocations in heteroepitaxial films are studied. The critical thickness for misfit dislocation formation can be found by considering the incremental extension of a misfit dislocation by the movement of a “threading” dislocation segment that extends from the film/substrate interface to the free surface of the film. This same mechanism allows one to examine the kinetics of dislocation motion and to illuminate the importance of dislocation nucleation and multiplication in strain relaxation. The effects of unstrained epitaxial capping layers on these processes are also considered. The major effects of such capping layers are to inhibit dislocation nucleation and multiplication. The effect of the capping layer on the velocity of the “threading” dislocation is shown to be small by comparison.A new substrate curvature technique for measuring the strain and studying the kinetics of strain relaxation in heteroepitaxial films is also briefly described.

Lattice Engineering Using Lateral Oxidation of Alas: an Approach to Generate Substrates With New Lattice Constants

1998 ◽  
Vol 535 ◽  
Author(s):  
P.M. Chavarkar ◽  
L. Zhao ◽  
S. Keller ◽  
K.A. Black ◽  
E. Hu ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Local Strain ◽  
Epitaxial Layers ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Reactive Material ◽  
New Approach ◽  
Lattice Constants ◽  
Lateral Oxidation ◽  
Threading Dislocation Density

AbstractWe demonstrate a new approach to the growth of dislocation free lattice-mismatched materials on GaAs substrates using Al2O3 interlayers obtained by lateral oxidation of AlAs. This is achieved by generating relaxed low threading dislocation density InGaAs templates which are mechanically supported but epitaxially decoupled from the host GaAs substrate. This process uses the phenomena of relaxation of strained coherent hypercritical thickness (h > hcritical,) layer in direct contact with an oxidizing Al-containing semiconductor (i.e. AlAs or AlGaAs). 5000 Å In0.11Ga0.89As layers were then grown on the In0.2 Ga0.8As/Al2O3/GaAs template which acts as a pseudo-substrate (lattice-engineered substrate). The epitaxial layers are partially relaxed and have extremely smooth surface morphology. Further TEM micrographs of these epitaxial layers show no misfit dislocations or related localized strain fields at the In0.2Ga0.8As/Al2O3 interface. The absence of misfit dislocations or local strain contrast at the In0.2Ga0.8As/Al2O3 interface is attributed to both reactive material removal during the oxidation process and the porous nature of the oxide itself. We propose that the strain relaxation in In0.3Ga0.7As is enhanced due to the absence of misfit dislocations at the In0.2Ga0.8As/A12O3 interface.

A Misfit Dislocation Blocking Mechanism in Continuous InGaAs Layers Grown on Patterned GaAs

1993 ◽  
Vol 308 ◽  
Author(s):  
G. Patrick Watson ◽  
Dieter G. Ast ◽  
Timothy J. Anderson ◽  
Balu Pathangey
Keyword(s):  
Misfit Dislocation ◽  
Energy Cost ◽  
Dislocation Segment ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Strained Layers ◽  
Blocking Mechanism

ABSTRACTPrevious work showed that misfit dislocations were blocked at trench walls in a unique way in InGaAs strained layers grown on GaAs that was patterned and etched to form a series of mesas separated by trenches. A model is developed to explain the behavior of misfit dislocations in this material. The energy cost of extending the threading dislocation segment, which accompanies a misfit dislocation during glide, can impede the motion of these defects if the trench walls are steep enough.

Initial Strain Relaxation in S0.91Ge0.09/Si Superlattice Structures via Misfit-Dislocations

1999 ◽  
Vol 570 ◽  
Author(s):  
J. Leininger ◽  
G. D. U'ren ◽  
M. S. Goorsky
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
High Vacuum ◽  
Average Density ◽  
Dislocation Nucleation ◽  
Ultra High Vacuum ◽  
Initial Strain ◽  
Homogeneous Distribution ◽  
Misfit Dislocations ◽  
Dislocation Sources

ABSTRACTWe addressed the initial strain relaxation of symmetric 95 Å period Si0.91Ge0.09/Si heterostructures grown by ultra-high vacuum chemical vapor deposition on vicinal substrates miscut 2.04° from (001) in a direction 36° from a [110]. Double-axis x-ray topography revealed misfit-dislocation sources in the as-grown samples with an average density of about 60 cm−2, although the distribution of these sites was not homogeneous. The progression of dislocation nucleation and growth was observed during subsequent rapid thermal annealing (800°C, 20s-320s). Physical heterogeneities were identified as dislocation sources, and they gave rise to orthogonal misfit dislocation bundles, which on a macroscopic scale resemble crosses. Upon longer annealing, a more homogeneous distribution of defects was observed without measurable relaxation. These original defects did propagate; however, they did not spur a cross-slip multiplication sequence.

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