The Effect of The Initial Nucleation Temperature on The Misfit Dislocation Structure of InP-on-GaAs Heterostructures

1992 ◽  
Vol 263 ◽  
Author(s):  
Ferenc Riesz ◽  
G. Radnoczi ◽  
B. Pecz ◽  
K. Rakennus ◽  
T. Hakkarainen ◽  
...  
Keyword(s):  
Dislocation Structure ◽  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Initial Growth ◽  
Misfit Stress ◽  
X Ray ◽  
Transmission Electron ◽  
Initial Nucleation ◽  
Island Type ◽  
Indirect Information

ABSTRACTThe misfit dislocation structure of vicinal InP-on-GaAs heterostructures is studied by transmission electron microscopy (TEM). An island type growth is identified. The misfit stress is not fully relaxed at the interface. X-ray measurements on strain relaxation and epilayer misorientation are also reported, and the latter results are explained with the asymmetric introduction of 6Ø° dislocations at island edges. Comparing the results, it is concluded that x-ray data supply additional, although indirect, information on initial growth which is hardly detectable by TEM.

Characterization of the Defect Evolution in Thick Heavily Al-Doped 4H-SiC Epilayers

2014 ◽  
Vol 778-780 ◽  
pp. 151-154 ◽  
Author(s):  
Shi Yang Ji ◽  
Kazutoshi Kojima ◽  
Yuuki Ishida ◽  
Hirotaka Yamaguchi ◽  
Shingo Saito ◽  
...  
Keyword(s):  
Misfit Dislocation ◽  
Doping Level ◽  
Growth Stage ◽  
Initial Growth ◽  
Al Doping ◽  
X Ray ◽  
Defect Evolution ◽  
Koh Etching

The defect evolution on 90 μm-thick heavily Al-doped 4H-SiC epilayers with Al doping level higher than 1020 cm-3 was studied by tracing back to initial growth stage to monitor major dislocations and their propagations in each growth stage. Results from X-ray topography and KOH etching demonstrate that all existing dislocations on the surface of 90 μm-thick epilayer can be identified as the defects originating from substrate. In other words, there seems no new dislocation generated after a long-term growth. Nevertheless, a high density of misfit dislocation was found appearing near the substrate/epilayer interface for epilayer with Al doping level of 3.5×1020 cm-3, while misfit dislocation cannot be seen on epilayer with Al doping level of 1.5×1020 cm-3.

Structural Studies Of Epitaxial CdF2 Layers on Si(111)

1996 ◽  
Vol 441 ◽  
Author(s):  
A. Yu. Khilko ◽  
R. N. Kyutt ◽  
G. N. Mosina ◽  
N. S. Sokolov ◽  
Yu. V. Shusterman ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Optimal Growth ◽  
Misfit Strain ◽  
X Ray Diffraction ◽  
Optimal Growth Temperature ◽  
Light Emitting ◽  
X Ray ◽  
Light Emitting Devices ◽  
Transmission Electron

AbstractEpitaxial CdF2 layers, which may be used in light-emitting devices integrated with silicon, were grown by Molecular Beam Epitaxy (MBE). Characterization of the layers by Rutherford Backscattering Spectroscopy (RBS), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) showed that optimal growth temperature lies in the range 60–80°C. The sticking coefficient of CdF2 molecules was found to decrease at temperatures above 100°C. Different modes of misfit strain relaxation were observed above and below that temperature.

Characterization of ultrathin Ge epilayers on (100) Si

1991 ◽  
Vol 69 (3-4) ◽  
pp. 246-254 ◽  
Author(s):  
J. -M. Baribeau ◽  
D. J. Lockwood ◽  
T. E. Jackman ◽  
P. Aebi ◽  
T. Tyliszczak ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Three Dimensional ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Short Period Superlattices ◽  
Direct Band ◽  
X Ray Absorption

The understanding of the epitaxy of pure Ge layers on Si is an important step towards the synthesis of SimGen (m, n < 10 monolayers) short-period superlattices. The possibility of a direct band-gap character makes these structures extremely attractive. We have grown thin buried Gen ([Formula: see text] monolayers) films on (100) Si by molecular beam epitaxy and studied their structural properties by a variety of techniques including Raman scattering spectroscopy, glancing incidence X-ray reflection, Rutherford backscattering, transmission electron microscopy, and extended X-ray absorption fine structure analysis. All these techniques allowed detection of the thin Ge layers and provided information about the thickness, morphology, strain distribution, and interface sharpness of these heterostructures. The Ge„ films with [Formula: see text] had a two-dimensional nature and showed no sign of strain relaxation. Intermixing at the Si–Ge interfaces was present in all these films and estimated to be not more than two monolayers. This smearing at the interfaces may have contributed to the maintenance of that pseudomorphicity. A thicker Ge layer (n = 12) showed evidence of strain relaxation and clustering in three-dimensional islands.

A Study on the Strain and Microstructure in SiGe Film Grown on Si(001) Substrate by MBE

1994 ◽  
Vol 356 ◽  
Author(s):  
Kyoung-Ik Cho ◽  
Sahn Nahm ◽  
Sang-Gi Kim ◽  
Seung-Chang Lee ◽  
Kyung-Soo Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Large Strain ◽  
Strain Relaxation ◽  
Stacking Faults ◽  
Double Crystal ◽  
Crystalline Layer ◽  
X Ray ◽  
Transmission Electron ◽  
Plain Strain

AbstractSi/Si0.8Ge0.2/Si(001) structures were grown at various growth temperatures (250 ∼ 760 °C) using molecular beam epitaxy, and the variation of strain and microstructure of the film was investigated using double crystal X-ray diffractometry and transmission electron microscopy. SiGe films with good single crystallinity were obtained at the growth temperatures of 440 ∼ 600 °C. For the samples grown below 350 °C, an amorphous SiGe film was developed over the SiGe single crystalline layer with a jagged amorphous/crystalline (a/c) interface, and many defects such as stacking faults and microtwins were formed below the a/c interface. Dislocations were developed through out the films for the samples grown above 680 °C. In addition, for the samples grown below 680 °C, the amount of in-plane strain of the SiGe film was found to be about − 8×l0−3 without strain relaxation. However, the SiGe films grown at 760 °C have small in-plain strain of − 4×l0−3 and large strain relaxation of 50%.

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.

scholarly journals Initial Growth Stages of Epitaxial BaTiO3 Films on Vicinal SrTiO3:Nb (001) Substrates

2001 ◽  
Vol 688 ◽  
Author(s):  
A. Visinoiu ◽  
M. Alexe ◽  
H. N. Lee ◽  
D. N. Zakharov ◽  
A. Pignolet ◽  
...  
Keyword(s):  
Growth Mechanism ◽  
Laser Deposition ◽  
Growth Stages ◽  
Initial Growth ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Transmission Electron ◽  
Film Substrate ◽  
Substrate Surfaces

AbstractThe growth mechanism of epitaxial BaTiO3 films on vicinal Nb-doped SrTiO3 (SrTiO3:Nb) (001) substrate surfaces was studied in terms of surface morphology, crystalline orientation, microstructure, and film/substrate interface. Well-oriented BaTiO3 thin films were grown on SrTiO3 substrates with well-defined terraces by pulsed laser deposition. The regularly terraced TiO2-terminated surfaces of vicinal SrTiO3:Nb (001) substrates were prepared by a definite chemical and thermal treatment. Under our conditions, BaTiO3 seems to grow with a layer-then-island (Stranski-Krastanov) growth mechanism. In order to investigate the orientation and crystallinity of the BaTiO3 films, x-ray diffraction and high-resolution transmission electron microscopy were performed. Ferroelectricity of the BaTiO3 films was proved by electrical measurements performed on Pt/BaTiO3/SrTiO3:Nb heterostructures.

Strain Relaxation in Epitaxial Heterostructures: Sensitivity of High Resolution X-Ray Diffraction

1992 ◽  
Vol 280 ◽  
Author(s):  
M. S. Goorsky ◽  
S. T. Horng ◽  
S. R. Sriffler ◽  
C. S. Stanis
Keyword(s):  
High Resolution ◽  
Strain Relaxation ◽  
Dislocation Line ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Complete Relaxation ◽  
Dislocation Densities ◽  
Interfacial Defects

ABSTRACTComparison of high resolution x-ray diffraction and transmission electron microscopy measurements of Si-based heterostructures demonstrates that diffraction is much more sensitive to strain relaxation than previously reported. This study used as-grown and annealed Si1-x Gex structures grown on (001) Si by UHV/CVD. (004), (113), and (115) rocking curves were employed. Using the TEM measurements as a quantitative guide, relaxation was observed in rocking curves when the misfit dislocation line density was as low as 1 μ-1. Also, interference fringes strongly depend on the presence of interfacial defects. At higher dislocation densities, the diffraction peak from the epitaxial layer broadens considerably but does not shift to a position that represents complete relaxation. Broadening of the substrate diffraction peak also occurs, which is due to dislocations that loop into the substrate.

Nucleation of CVD-TiN on tungsten

1993 ◽  
Vol 8 (9) ◽  
pp. 2239-2244 ◽  
Author(s):  
K. Glejb⊘l ◽  
N.H. Pryds ◽  
A.R. Thölén
Keyword(s):  
Vapor Deposition ◽  
Catalytic Properties ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Titanium Nitrides ◽  
Initial Growth ◽  
Surface Material ◽  
Tin Coating ◽  
X Ray ◽  
Transmission Electron

Using Chemical Vapor Deposition (CVD), TiN was deposited on sharp tungsten needles. The reactant gases were TiCl4, N2, and H2. A Transmission Electron Microscopy (TEM) investigation revealed that the first nuclei of the CVD–TiN coating on tungsten did not consist of δ–TiN, but were a mixture of α–TiN and δ–TiN. These results were also verified with x-ray measurements. From these experimental results a possible mechanism for the initial growth of TiN on tungsten is suggested. It may be that the change in relative concentrations of the different titanium nitrides suggested as mechanism of the initial growth of CVD–TiN can be applied in general for all TiCl4/H2/N2/metal systems where the original substrate surface material partly or completely consists of a metal with catalytic properties.

Epitaxial CoSi2/Porous-Si Strained Layer Structres Grown by Mbe

1987 ◽  
Vol 91 ◽  
Author(s):  
Y. C. Kao ◽  
D. Jamieson ◽  
G. Bai ◽  
C. W. Nieh ◽  
T. L. Lin ◽  
...  
Keyword(s):  
Strain Measurement ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Porous Si ◽  
Interface Quality ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron ◽  
Stress Energy ◽  
Measurement Results

ABSTRACTCoSi2 epitaxial layers with thickness ranging from 24 nm to 170 nm have been grown onto porous Si substrates by molecular beam epitaxy. The X-ray rocking curves and transmission electron microscopy (TEM) are used to examine the strain relaxation and interface quality. Backscattering with channeling is used to characterize the crystallinity of the epilayers. The results show that it is necessary to grow a thin buffer Si layer in order to improve the interfacial sharpness and crystallinity of the epilayers; near perfect crystallinity is then obtained as the thickness of the CoSi2 films exceed 50 nm. TEM results reveal that both CoSi2/Si and CoSi2/porous-Si interfaces are flat and layer thickness is uniform. It is found by TEM that the dislocation density of CoSi2 grown on porous Si is much lower than that on single-crystal Si. For thin CoSi2 grown on porous Si, the TEM and strain measurement results imply that part of the film is pseudomorphic where no dislocations are observed. Average strains of CoSi2 films grown on porous Si substrates with thicknesses greater than 30 nm show a lower strains comparing to that on crystalline Si. This suggests that by using porous Si as substrates the stress energy in the epilayer can be accommodated by the Si buffer layer that bridged over the trenches of porous Si.

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