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.

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).

Role of stacking faults as misfit dislocation sources and nonradiative recombination centers in II‐VI heterostructures and devices

1993 ◽  
Vol 63 (22) ◽  
pp. 3023-3025 ◽  
Author(s):  
S. Guha ◽  
J. M. DePuydt ◽  
J. Qiu ◽  
G. E. Hofler ◽  
M. A. Haase ◽  
...  
Keyword(s):  
Misfit Dislocation ◽  
Stacking Faults ◽  
Nonradiative Recombination ◽  
Recombination Centers ◽  
Dislocation Sources

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.

Misfit Dislocations in SiGe/Si Heterostructures: Nucleation - Propagation - Multiplication

2005 ◽  
Vol 108-109 ◽  
pp. 483-488 ◽  
Author(s):  
V.I. Vdovin ◽  
M.G. Mil'vidskii ◽  
M.M. Rzaev ◽  
Friedrich Schäffler
Keyword(s):  
Experimental Data ◽  
Low Temperature ◽  
Point Defects ◽  
Misfit Dislocation ◽  
Alloy Composition ◽  
Dislocation Nucleation ◽  
Buffer Layers ◽  
Misfit Dislocations ◽  
Intrinsic Point Defects

We present experimental data on the effect of low-temperature buffer layers on the dislocation structure formation in SiGe/Si strained-layer heterostructures under thermal annealing. Specific subjects include mechanisms of misfit dislocation nucleation, propagation and multiplication as well as the role of intrinsic point defects in these processes. Samples with lowtemperature Si (400°C) and SiGe (250°C) buffer layers were grown by MBE. In general, the processes of MD generation occur similarly in the heterostructures studied independently of the alloy composition (Ge content: 0.15, 0.30) and kind of buffer layer. Intrinsic point defects related to the low-temperature epitaxial growth influence mainly the rate of misfit dislocation nucleation.

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.

Quasiperiodic interfaces: HREM observations of grain and phase boundaries

1990 ◽  
Vol 48 (4) ◽  
pp. 332-333
Author(s):  
K. L. Merkle
Keyword(s):  
Atomic Structure ◽  
Direct Determination ◽  
Lattice Parameter ◽  
Atomic Scale ◽  
Misfit Dislocations ◽  
Oxide Systems ◽  
Atomic Structures ◽  
Periodic Arrays ◽  
Parameter Ratio ◽  
Metal Metal

The atomic structures of internal interfaces have recently received considerable attention, not only because of their importance in determining many materials properties, but also because the atomic structure of many interfaces has become accessible to direct atomic-scale observation by modem HREM instruments. In this communication, several interface structures are examined by HREM in terms of their structural periodicities along the interface.It is well known that heterophase boundaries are generally formed by two low-index planes. Often, as is the case in many fcc metal/metal and metal/metal-oxide systems, low energy boundaries form in the cube-on-cube orientation on (111). Since the lattice parameter ratio between the two materials generally is not a rational number, such boundaries are incommensurate. Therefore, even though periodic arrays of misfit dislocations have been observed by TEM techniques for numerous heterophase systems, such interfaces are quasiperiodic on an atomic scale. Interfaces with misfit dislocations are semicoherent, where atomically well-matched regions alternate with regions of misfit. When the misfit is large, misfit localization is often difficult to detect, and direct determination of the atomic structure of the interface from HREM alone, may not be possible.

Misfit Dislocations in the Ilmenite (FeTiO3)-Hematite (Fe2O3) System

1980 ◽  
Vol 38 ◽  
pp. 212-213 ◽  
Author(s):  
K.P.D. Lagerlöf ◽  
A.H. Heuer ◽  
T.E. Mitchell
Keyword(s):  
Misfit Dislocation ◽  
Lattice Parameters ◽  
Dislocation Network ◽  
Misfit Dislocations ◽  
Space Group ◽  
Two Phases ◽  
Hematite Fe2o3

It has been reported by Lally et. al. [1] that precipitates of hematite (Fe2O3, space group R3c) in a matrix of ilmenite (FeTiO3, space group R3) are lens shaped and flattened along the [0001]-direction. The coherency across the interface is lost by the introduction of a misfit dislocation network, which minimizes the strain due to the deviation in lattice parameters between the two phases [2]. The purpose of this paper is to present a new analysis of this network.

Metal-Metal Cooperative Bond Activation by Heterobimetallic Alkyl, Aryl, and Acetylide PtII/CuI Complexes

2020 ◽  
Author(s):  
Shubham Deolka ◽  
Orestes Rivada Wheelaghan ◽  
Sandra Aristizábal ◽  
Robert Fayzullin ◽  
Shrinwantu Pal ◽  
...  
Keyword(s):  
Alkyl Group ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Terminal Alkyne ◽  
Alkyl Aryl ◽  
Metal Metal ◽  
The Stability ◽  
Selective Formation ◽  
Organoplatinum Compounds

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

Stars and stripes. Nanoscale misfit dislocation patterns on surfaces

2002 ◽  
Vol 74 (9) ◽  
pp. 1663-1671 ◽  
Author(s):  
Raghani Pushpa ◽  
Shobhana Narasimhan
Keyword(s):  
Surface Structure ◽  
Misfit Dislocation ◽  
Domain Walls ◽  
Chemical Potential ◽  
Model System ◽  
Misfit Dislocations ◽  
Face Centered Cubic ◽  
Hexagonal Close Packed ◽  
Structure Changes ◽  
Face Centered

Close-packed metal surfaces and heteroepitaxial systems frequently display a structure consisting of regularly spaced misfit dislocations, with a network of domain walls separating face-centered cubic (fcc) and hexagonal close-packed (hcp) domains. These structures can serve as templates for growing regularly spaced arrays of nanoislands. We present a theoretical investigation of the factors controlling the size and shape of the domains, using Pt(111) as a model system. Upon varying the chemical potential, the surface structure changes from being unreconstructed to the honeycomb, wavy triangles, "bright stars", or Moiré patterns observed experimentally on Pt(111) and other systems. For the particular case of Pt(111), isotropically contracted star-like patterns are favored over uniaxially contracted stripes.

Role of a Metal–Metal Bonded Dimer Dication in the One-Electron Oxidation of Rh(η5-C5H5)(CO)(PPh3) and Related Compounds

2012 ◽  
Vol 31 (17) ◽  
pp. 6063-6070 ◽  
Author(s):  
Sabrina Trupia ◽  
Thomas E. Bitterwolf ◽  
William E. Geiger
Keyword(s):  
Metal Metal ◽  
The One ◽  
Related Compounds
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