Partial strain relaxation via misfit dislocation generation at heterointerfaces in (Al,In)GaN epitaxial layers grown on semipolar (112¯2) GaN free standing substrates

2009 ◽  
Vol 95 (25) ◽  
pp. 251905 ◽  
Author(s):  
Anurag Tyagi ◽  
Feng Wu ◽  
Erin C. Young ◽  
Arpan Chakraborty ◽  
Hiroaki Ohta ◽  
...  
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Epitaxial Layers ◽  
Free Standing ◽  
Dislocation Generation

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.

Strain Relaxation at Low Misfits: Dislocation Injection vs. Surface Roughening

1995 ◽  
Vol 399 ◽  
Author(s):  
D.D. Perovic ◽  
B. Bahierathan ◽  
D.C. Houghton ◽  
H. Lafontaine ◽  
J.-M. Baribeau
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
Theoretical Description ◽  
Dislocation Nucleation ◽  
Surface Roughening ◽  
X Ray Diffraction ◽  
Dislocation Generation ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTTwo competing strain relaxation mechanisms, namely misfit dislocation generation and surface roughening, have been extensively studied using the GexSi1-x/Si (x< 0.5) system as an example. A predictive model has been developed which accurately describes the nature of misfit dislocation nucleation and growth under non-equilibrium conditions. Using optical and electron microscopy, coupled with a refined theoretical description of dislocation nucleation, it is shown that strain relieving dislocations are readily generated at low misfits with a characteristic activation energy barrier regardless of the growth technique employed (i.e. MBE, RTCVD and UHVCVD). Secondly we have studied the alternative elastic strain relaxation mechanism involving surface undulation; x-ray diffraction, electron and atomic force microscopy have been used to characterize GexSi1-x/Si (x<0.5) structures grown by UHVCVD and MBE at relatively higher temperatures. A theoretical model has been used to model the critical thickness for surface wave generation. The conditions governing the interplay between dislocation formation and surface buckling are described in terms of a "morphological instability diagram".

Misfit Dislocation Generation in InGaN Epilayers on Free-Standing GaN

2006 ◽  
Vol 45 (No. 22) ◽  
pp. L549-L551 ◽  
Author(s):  
Rong Liu ◽  
Jin Mei ◽  
Sridhar Srinivasan ◽  
Hiromasa Omiya ◽  
Fernando A. Ponce ◽  
...  
Keyword(s):  
Misfit Dislocation ◽  
Free Standing ◽  
Dislocation Generation

Misfit Dislocation Nucleation and Interactions at GexSi1-x/Si Interfaces

1989 ◽  
Vol 160 ◽  
Author(s):  
D.D. Perovic ◽  
G.C. Weatherly ◽  
D.C. Houghton
Keyword(s):  
Misfit Dislocation ◽  
Dominant Role ◽  
Strain Relaxation ◽  
Dislocation Nucleation ◽  
Interfacial Dislocation ◽  
Dislocation Generation ◽  
Transmission Electron ◽  
Metastable Structures ◽  
Nucleation Mechanisms ◽  
Generation Mechanisms

AbstractIn the study of elastic strain relaxation in semiconductor heterostructures, a number of misfit dislocation generation mechanisms have been suggested to account for the high interfacial dislocation density observed in these almost defect-free crystals. Several MBE-grown GexSi1-x/Si heterostructures, both in the as-grown and annealed condition have been studied using transmission electron microscopy. The results indicate that some of the popular theories of dislocation generation are less important or not applicable based on both theoretical and experimental considerations. Specifically, it will be shown that: (i) heterogeneous sources play a dominant role in the nucleation mechanisms, (ii) the strain relaxation behaviour during MBE growth may be different from that observed in metastable structures annealed after growth and (iii) the Hagen-S trunk multiplication mechanism is inoperative under most conditions in this system.

Influence of Interfacial Oxygen and Carbon on Misfit Dislocation Generation in SiGe Epitaxial Layers

2019 ◽  
Vol 19 (1) ◽  
pp. 213-221
Author(s):  
Masahiro Fukuda ◽  
Yosuke Shimamune ◽  
Katsuto Tanahashi ◽  
Keiji Ikeda ◽  
Masatoshi Nishikawa ◽  
...  
Keyword(s):  
Misfit Dislocation ◽  
Epitaxial Layers ◽  
Dislocation Generation ◽  
Interfacial Oxygen

Sublimation Sandwich Growth of Free Standing GaN Crystals

1997 ◽  
Vol 482 ◽  
Author(s):  
Yu. A. Vodakov ◽  
E. N. Mokhov ◽  
M. G. Ramm ◽  
M. S. Ramm ◽  
A. D. Roenkov ◽  
...  
Keyword(s):  
Growth Rates ◽  
Epitaxial Layers ◽  
Free Standing ◽  
Sandwich Method

AbstractThick epitaxial layers of GaN on SiC and sapphire are grown by using the sublimation sandwich method. It is shown that growth of good quality GaN crystals with the growth rates up to 0.5 mm/hour is possible using this technique. The grown layers have been separated from the seed and free standing GaN crystals up to 15 mm size were obtained.

Stress Relaxation in Uniquely Oriented SiGe/Si Epitaxial Layers

1999 ◽  
Vol 594 ◽  
Author(s):  
M. E. Ware ◽  
R. J. Nemanich
Keyword(s):  
Stress Relaxation ◽  
Surface Morphology ◽  
Strain Relaxation ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Strained Layers ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Deposited Films

AbstractThis study explores stress relaxation of epitaxial SiGe layers grown on Si substrates with unique orientations. The crystallographic orientations of the Si substrates used were off-axis from the (001) plane towards the (111) plane by angles, θ = 0, 10, and 22 degrees. We have grown 100nm thick Si(1−x) Ge(x) epitaxial layers with x=0.3 on the Si substrates to examine the relaxation process. The as-deposited films are metastable to the formation of strain relaxing misfit dislocations, and thermal annealing is used to obtain highly relaxed films for comparison. Raman spectroscopy has been used to measure the strain relaxation, and atomic force microscopy has been used to explore the development of surface morphology. The Raman scattering indicated that the strain in the as-deposited films is dependent on the substrate orientation with strained layers grown on Si with 0 and 22 degree orientations while highly relaxed films were grown on the 10 degree substrate. The surface morphology also differed for the substrate orientations. The 10 degree surface is relatively smooth with hut shaped structures oriented at predicted angles relative to the step edges.

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