scholarly journals Strain Relaxation via Misfit Dislocation in Step-Graded In GaN Heteroepitaxial Layers Grown on Semipolar (1122) and (1101) GaN

2012 ◽  
pp. 049-053 ◽  
Author(s):  
Md. Arafat Hossain ◽  
Md. Mahbub Hasan ◽  
Md. Rafiqul Islam
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Heteroepitaxial Layers

Control of threading dislocations in lattice-mismatched heteroepitaxy

1992 ◽  
Vol 263 ◽  
Author(s):  
L.J. Schowalter ◽  
A.P. Taylor ◽  
J. Petruzzello ◽  
J. Gaines ◽  
D. Olego
Keyword(s):  
Misfit Dislocation ◽  
Gaas Substrate ◽  
Strain Relaxation ◽  
Threading Dislocations ◽  
Practical Applications ◽  
Gaas Substrates ◽  
Mismatched Heteroepitaxy ◽  
Matched Layers ◽  
Heteroepitaxial Layers ◽  
Lattice Matched

ABSTRACTIt is generally observed that strain relaxation, which occurs by misfit dislocation formation, in lattice-mismatched heteroepitaxial layers is accompanied by the formation of threading dislocations. However, our group and others have observed that strain-relaxed epitaxial layers of In1−xGaxAs on GaAs substrates can be grown without the formation of threading dislocations in the epitaxial layer. We have been able to grow strain-relaxed layers up to 13% In concentration without observable densities of threading dislocations in the epilayer but do observe a large number of dislocations pushed into the GaAs substrate. The ability to grow strain-relaxed, lattice-mismatched heteroepitaxial layers has important practical applications. We have succeeded in growing dislocation-free layers of ZnSe on appropriately lattice-matched layers of In1−xGaxAs.

Development of Cross-Hatch Morphology During Growth of Lattice Mismatched Layers

2001 ◽  
Vol 673 ◽  
Author(s):  
A. Maxwell Andrews ◽  
J.S. Speck ◽  
A.E. Romanov ◽  
M. Bobeth ◽  
W. Pompe
Keyword(s):  
Misfit Dislocation ◽  
Film Growth ◽  
Strain Relaxation ◽  
Dislocation Generation ◽  
Force Microscopy ◽  
Step Flow ◽  
Atomic Force ◽  
Subsequent Step ◽  
Step Flow Growth ◽  
Lateral Scale

ABSTRACTAn approach is developed for understanding the cross-hatch morphology in lattice mismatched heteroepitaxial film growth. It is demonstrated that both strain relaxation associated with misfit dislocation formation and subsequent step elimination (e.g. by step-flow growth) are responsible for the appearance of nanoscopic surface height undulations (0.1-10 nm) on a mesoscopic (∼100 nm) lateral scale. The results of Monte Carlo simulations for dislocation- assisted strain relaxation and subsequent film growth predict the development of cross-hatch patterns with a characteristic surface undulation magnitude ∼50 Å in an approximately 70% strain relaxed In0.25Ga0.75As layers. The model is supported by atomic force microscopy (AFM) observations of cross-hatch morphology in the same composition samples grown well beyond the critical thickness for misfit dislocation generation.

Heteroepitaxial Layer Morphology and Misfit Defect Formation

1995 ◽  
Vol 399 ◽  
Author(s):  
A.G. Cullis
Keyword(s):  
Free Energy ◽  
Misfit Dislocation ◽  
Defect Formation ◽  
Elastic Stress ◽  
Stress Relief ◽  
Misfit Strain ◽  
Theoretical Modelling ◽  
Initial Growth ◽  
Dislocation Source ◽  
Heteroepitaxial Layers

ABSTRACTThe manner in which misfit strain can influence the morphology of heteroepitaxial layers is reviewed. Following a brief consideration of theoretical modelling, examples of experimental observations for two important materials systems, SiGe/Si and InGaAs/GaAs, are given. It is demonstrated that the formation of undulations of specific types is driven by partial elastic stress-relief and a lowering of the system free energy. Under these conditions, islands of deposit can be formed during initial growth and ripples can be produced upon continuous layers. Furthermore, the presence of surface morphological distortions and the accompanying strain fluctuations also can have a significant impact upon misfit dislocation introduction. Relationships between these fluctuations and dislocation source behaviour are described.

The Roles of Stress, Geometry and Orientation on Misfit Dislocations Kinetics and Energetics in Epitaxial Strained Layers.

1991 ◽  
Vol 239 ◽  
Author(s):  
R. Hull ◽  
J. C. Bean ◽  
F. Ross ◽  
D. Bahnck ◽  
L. J. Pencolas
Keyword(s):  
Misfit Dislocation ◽  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Misfit Dislocations ◽  
Slip Systems ◽  
Strained Layers ◽  
Burgers Vector ◽  
Partial Dislocations ◽  
Strain Stress ◽  
Kinetics Of

ABSTRACTThe geometries, microstructures, energetics and kinetics of misfit dislocations as functions of surface orientation and the magnitude of strain/stress are investigated experimentally and theoretically. Examples are drawn from (100), (110) and (111) surfaces and from the GexSi1–x/Si and InxGa1–x/GaAs systems. It is shown that the misfit dislocation geometries and microstructures at lattice mismatch stresses < - 1GPa may in general be predicted by operation of the minimum magnitude Burgers vector slipping on the widest spaced planes. At stresses of the order several GPa, however, new dislocation systems may become operative with either modified Burgers vectors or slip systems. Dissociation of totál misfit dislocations into partial dislocations is found to play a crucial role in strain relaxation, on surfaces other than (100) under compressive stress.

Misfit dislocation formation at heterointerfaces in (Al,In)GaN heteroepitaxial layers grown on semipolar free-standing GaN substrates

2011 ◽  
Vol 109 (3) ◽  
pp. 033505 ◽  
Author(s):  
F. Wu ◽  
A. Tyagi ◽  
E. C. Young ◽  
A. E. Romanov ◽  
K. Fujito ◽  
...  
Keyword(s):  
Misfit Dislocation ◽  
Free Standing ◽  
Heteroepitaxial Layers ◽  
Dislocation Formation

Control of misfit dislocation glide plane distribution during strain relaxation of CuPt-ordered GaInAs and GaInP

2012 ◽  
Vol 112 (2) ◽  
pp. 023520 ◽  
Author(s):  
R. M. France ◽  
W. E. McMahon ◽  
A. G. Norman ◽  
J. F. Geisz ◽  
M. J. Romero
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Dislocation Glide ◽  
Plane Distribution

Strain relaxation in ultrathin films: A modified theory of misfit-dislocation energetics

1993 ◽  
Vol 47 (20) ◽  
pp. 13730-13736 ◽  
Author(s):  
A. P. Payne ◽  
B. M. Lairson ◽  
B. M. Clemens
Keyword(s):  
Misfit Dislocation ◽  
Ultrathin Films ◽  
Strain Relaxation ◽  
Modified Theory

Strain Relaxation Mechanisms in He+-Implanted and Annealed Si1−xGex Layers on Si(001) Substrates

2001 ◽  
Vol 686 ◽  
Author(s):  
S.H. Christiansen ◽  
P.M. Mooney ◽  
J.O. Chu ◽  
A. Grill
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Three Dimensional ◽  
Dislocation Network ◽  
Misfit Dislocations ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Transmission Electron ◽  
Microscopy Techniques

AbstractStrain relaxation in He+-implanted and annealed Si(001)/Si1−xGex heterostructures was investigated using transmission electron microscopy techniques and x-ray diffraction. Depending on the implant conditions, bubbles and/or platelets form below the Si/Si1−xGex interface upon annealing and act as nucleation sources for dislocation loops. The dislocation loops extend to the interface and form a misfit dislocation network there, resulting in relaxation of 30-80% of the strain in layers as thin as 100-300 nm. When bubbles form close to the interface, dislocations nucleate by a climb loop mechanism. When smaller bubbles form deeper in the Si substrate an irregular three-dimensional dislocation network forms below the interface resulting in an irregular misfit dislocation network at the interface. When platelets form deeper in the Si substrate, prismatic punching of dislocation loops is observed and dislocation reactions of misfit dislocations at the interface result in Lomer dislocation formation.

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