Defect Characterization of InAs Films Grown by Two-Step MOCVD on (100) InP Substrates

1992 ◽  
Vol 280 ◽  
Author(s):  
A. K. Ballal ◽  
L. Salamanca-Riba ◽  
D. L. Partin
Keyword(s):  
Electron Microscopy ◽  
Lattice Mismatch ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
Plan View ◽  
Inp Substrates

ABSTRACTIn this paper we investigate the defect morphology and misfit strain in InAs films grown on (100) InP substrates using two-step metal organic chemical vapor deposition (MOCVD). High quality InAs films were obtained despite the 3.2% lattice-mismatch between the InAs film and the InP substrate. Cross-sectional and plan-view transmission electron microscopy has been used to characterize the ∼3μm thick InAs films. Almost all the lattice mismatch is accomodated by an orthogonal array of pure edge Lomer dislocations which are favored over the 60° type since they are more efficient in relieving misfit strain. In addition to misfit dislocations, threading dislocations were observed propagating through the film. Most of the threading dislocations were 60° type dislocations along the < 211 > and < 110 > directions on inclined {111} planes. The threading dislocations originate from island coalescence during film growth. High resolution electron microscopy shows the epitaxial relationship between the film and the substrate and reveals an abrupt and sharp interface with periodic dislocation cores.

Defect Structures in Epitaxially Grown InAs Films on InP Substrates

1991 ◽  
Vol 238 ◽  
Author(s):  
A. K. Ballal ◽  
L. Salamanca-Riba ◽  
D. L. Partin ◽  
J. Heremans ◽  
L. Green ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Organic Chemical ◽  
Misfit Dislocations ◽  
Defect Structures ◽  
Substrate Interface ◽  
Film Substrate ◽  
Inp Substrates

ABSTRACTIn this paper we study the lattice-mismatch induced defect structures of InAs films grown on semi-insulating InP substrates using metal organic chemical vapor deposition. The defect structure studies were carried out on films of equal total thicknesses but for different duration for nucleation of a layer of InAs deposited at low temperature on the substrate. Misfit strain is caused by the inherent lattice mismatch of approximately three percent and this is partially relieved by the generation of misfit dislocations at the film/substrate interface. Transmission electron microscopy studies show the presence of an intrinsic strain and the generation of thermal etchpits at the heteroepitaxial interface. Our studies show that there is a direct correlation between the density of dislocations generated at the film/substrate interface and the duration of nucleation of the film on the substrate. Dislocation densities at the surface of the InAs films and at the heteroepitaxial interface differed by almost two orders of magnitude. High resolution electron microscopy reveals abrupt and sharp interfaces in films with thick nucleation layers and also confirms that the lattice mismatch is partially accommodated by the generation of misfit dislocations at the film/substrate interface.

Ordered Structures of Zn1−xFexSe Epilayers Grown on InP and GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
K. Park ◽  
H.- Y. Wei ◽  
L. Salamanca-Riba ◽  
B. T. Jonker
Keyword(s):  
Lattice Mismatch ◽  
Misfit Strain ◽  
Growth Direction ◽  
Ordered Structure ◽  
Cross Sectional ◽  
Ordered Structures ◽  
Gaas Substrates ◽  
Lattice Images ◽  
Diffraction Patterns ◽  
Inp Substrates

AbstractWe present evidence for two types of ordered structures, CuAu-I and CuPt, in Zn1−xFexSe (x≈ 0.4) epilayers grown by molecular beam epitaxy. These ordered structures are observed in both electron diffraction patterns and cross-sectional high-resolution lattice images. The CuAu-I ordered structure occurs in Zn1−xFexSe epilayers grown on (001) InP substrates, while the CuPt-type occurs in epilayers grown on (001) GaAs substrates. The ordered structure of Zn1−xFexSe grown on InP substrates consists of alternating ZnSe and FeSe layers along the [001] growth direction and the [110] direction. In contrast, the ordered structure of Zn1−xFexSe grown on GaAs substrates consists of alternating ZnSe and FeSe layers along the < 111 > directions. We have also investigated the role of the misfit strain associated with the lattice mismatch between the epilayers and the substrates on the type of ordered structure.

Growth of a-plane ZnO Thin Films on r-plane Sapphire by Plasma-assisted MBE

2005 ◽  
Vol 891 ◽  
Author(s):  
Junqing Q. Xie ◽  
J. W. Dong ◽  
A. Osinsky ◽  
P. P. Chow ◽  
Y. W. Heo ◽  
...  
Keyword(s):  
Thin Films ◽  
Lattice Mismatch ◽  
Defect Density ◽  
Zno Thin Films ◽  
Rf Plasma ◽  
Misfit Dislocations ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Small Lattice

ABSTRACTZnO thin films have been epitaxially grown on r-plane sapphire by RF-plasma-assisted molecular beam epitaxy. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies indicate that the epitaxial relationship between ZnO and r-plane sapphire is (1120)ZnO // (1102)sapphire and [0001]ZnO // [1101]sapphire. Atomic force microscopy measurements reveal islands extended along the sapphire [1101] direction. XRD omega rocking curves for the ZnO (1120) reflection measured either parallel or perpendicular to the island direction suggest the defect density anisotropy along these directions. Due to the small lattice mismatch along the ZnO [0001] direction, few misfit dislocations were observed at the ZnO/Al2O3 interface in the high-resolution cross-sectional TEM image with the zone axis along the ZnO [1100] direction.

Dislocations in SrTiO3 thin films grown on LaAlO3 substrates

2002 ◽  
Vol 17 (12) ◽  
pp. 3117-3126 ◽  
Author(s):  
Y. L. Qin ◽  
C. L. Jia ◽  
K. Urban ◽  
J. H. Hao ◽  
X. X. Xi
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Lattice Mismatch ◽  
Orthogonal Arrays ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Burgers Vector ◽  
Transmission Electron

The dislocation configurations in SrTiO3 thin films grown epitaxially on LaAlO3 (100) substrates were studied by conventional and high-resolution transmission electron microscopy. Misfit dislocations had, in most cases, a Burgers vector a〈100〉 and line directions of 〈100〉 These dislocations constitute orthogonal arrays of parallel dislocations at the interface, relieving the lattice mismatch between SrTiO3 and LaAlO3. Threading dislocations were found to be the major defects in the films. Two types of threading dislocations with the Burgers vectors a〈100〉?and a〈100〉?were identified. The relations of these threading dislocations with the misfit dislocations were investigated and are discussed in this paper.

Two-step Defect Reduction of GaAs/Si Epitaxy by Selective Aspect Ratio Trapping

2007 ◽  
Vol 1030 ◽  
Author(s):  
Jizhong Li ◽  
J. Bai ◽  
C. Major ◽  
M. Carroll ◽  
A. Lochtefeld ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Defect Formation ◽  
Lattice Mismatch ◽  
Defect Density ◽  
Layer Growth ◽  
Threading Dislocations ◽  
Cross Sectional ◽  
Defect Reduction ◽  
Plan View ◽  
Step Defect

AbstractWe report on the MOCVD growth of GaAs on patterned Si utilizing the Aspect Ratio Trapping (ART) method to reduce threading dislocations resulting from lattice mismatch. Defect-free GaAs was obtained from growth in sub-micron trenches formed in SiO2 on Si (001) substrates. Material quality has been characterized by cross-sectional and plan-view TEM and XRD. It was found that when growing GaAs above the trenched region, coalescence-induced threading dislocations (TDs) and planar defects were introduced at the coalescence junction interfaces. These defects were found to be unrelated to the misfit defects (MDs) on GaAs/Si interface that originated during initial epitaxial growth. Causes of coalescence defect formation were experimentally investigated by employing a two-step defect reduction scheme. It is concluded that by further optimizing growth conditions during coalesce layer growth, low defect-density GaAs material can be obtained on Si substrate.

Electron Microscopy Investigation of the Role of Surface Steps in the Generation of Dislocations during MOCVD Growth of GaN on 4H-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 1509-1512 ◽  
Author(s):  
N.D. Bassim ◽  
Mark E. Twigg ◽  
Michael A. Mastro ◽  
Philip G. Neudeck ◽  
Charles R. Eddy ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Substrate Surface ◽  
Atomic Scale ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Nucleation Layer ◽  
Plan View ◽  
Surface Steps

Through the use of specially-prepared on-axis SiC substrates with patterned mesa tops completely free of atomic-scale surface steps, we have previously reported the growth of highquality GaN heteroepitaxial films with greatly reduced threading dislocation densities on the order of 107/cm2. In these films, we reported a defect substructure in which lateral a-type dislocations are present in the nucleation layer but do not bow into threading dislocations during the subsequent GaN growth. This study focuses further on the role of SiC substrate surface steps in the generation of misfit, a-type, and threading dislocations at the heteroepitaxial interface. By using weak-beam imaging (both to eliminate Moiré effects and to observe narrow dislocation images) from plan-view transmission electron microscopy (TEM), we identify dislocations generated on stepped and unstepped mesas and compare their geometries. We observe that misfit dislocations nucleated on an unstepped SiC mesa are confined to one set of a-type Burgers vectors of the form g=1/3 [2110] _ _ , straight and well-ordered so that they are less likely to interact with each other. On the other hand, misfit dislocation structures on a stepped SiC mesa surface are not nearly as well-ordered, having bowed structure with threading dislocations that appear to nucleate at SiC surface steps.

Transmission electron microscopy observation of the interfacial reaction between a metal-organic chemical vapor deposition BaTiO3 thin film and a (100) MgO substrate

1995 ◽  
Vol 10 (11) ◽  
pp. 2885-2891 ◽  
Author(s):  
Cheol Seong Hwang ◽  
Mark D. Vaudin ◽  
Gregory T. Stauf
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Organic Chemical ◽  
Single Crystal Substrate ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Cross Sectional ◽  
Plan View ◽  
Transmission Electron

Cross-sectional and plan-view transmission electron microscopy were used to characterize a BaTiO3 thin film deposited on a (100) MgO single-crystal substrate at 1000 °C. The major observations were as follows: interdiffusion between the film and substrate; a large number of antiphase boundaries in the BaTiO3; a two-phase microstructure in the film composed of perovskite BaTiO3 and a second nonperovskite phase, Ba2MgTi5O13 (2:1:5); and a well-defined orientation relationship between the 2 : 1 : 5 and BaTiO3 phases. We propose a mechanism for the formation of the 2 : 1 : 5 phase based on the similarities between the crystal structure of this phase and the structure of (210) antiphase boundaries in BaTiO3.

Microstructural study of GaAs epitaxial layers on Ge(100) substrates

1995 ◽  
Vol 10 (4) ◽  
pp. 843-852 ◽  
Author(s):  
N. Guelton ◽  
R.G. Saint-Jacques ◽  
G. Lalande ◽  
J-P. Dodelet
Keyword(s):  
Electron Microscopy ◽  
Surface Preparation ◽  
Growth Conditions ◽  
Vapor Transport ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Antiphase Boundaries ◽  
Microstructural Study ◽  
Mismatch Strain ◽  
Transmission Electron

GaAs layers grown by close-spaced vapor transport on (100) Ge substrates have been investigated as a function of the experimental growth conditions. The effects on the microstructure of the surface preparation, substrate misorientation, and annealing were studied using optical microscopy and transmission electron microscopy. Microtwins and threading dislocations are suppressed by oxide desorption before deposition. Single domain GaAs layers have been obtained using a 50 nm thick double domain buffer layer on an annealed Ge substrate misoriented 3°toward [011]. The mismatch strain is mainly accommodated by dissociated 60°dislocations. These misfit dislocations extend along the interface by the glide of the threading dislocations inherited from the substrate, but strong interaction with antiphase boundaries (APB's) prevents them from reaching the interface. These results are discussed and compared with previous reports of GaAs growth on Ge(100).

HIGH RESOLUTION ELECTRON MICROSCOPE STUDY OF CdTe-Cd0.6Mn0.4 Te SUPERLATTICES

1985 ◽  
Vol 56 ◽  
Author(s):  
C. CHOI ◽  
N. OTSUKA ◽  
L. A. KOLODZIEJSKI ◽  
R. L. GUNSHOR-a
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Phase Contrast ◽  
Electron Microscope Study ◽  
Lattice Mismatch ◽  
Thick Layer ◽  
High Resolution Electron Microscopy ◽  
Misfit Dislocations ◽  
Resolution Electron ◽  
High Resolution Electron Microscope

AbstractStructures of CdTe-Cd0.6Mn0.4Te superlattices which are caused by the lattice mismatch between suterlattice layers have been studied by high resolution electron microscopy (HREM). In thin-layer superlattices, the crystal lattice in each layeris elastically distorted, resulting in the change of the crystal symmetry from cubic to rhombohedral. The presence of the small rhombohedral distrotion has been confirmed through a phase contrast effect in HREM images. In a thick-layer superlattice, the lattice mismatch is accommodated by dissociated misfit dislocations. Burgers vectors of partial misfit dislocations have been identified from the shift of lattice fringes in HREM images.

Direct Deposition Reactions Between Nickel and Silicon Substrates

1993 ◽  
Vol 311 ◽  
Author(s):  
Lin Zhang ◽  
Douglas G. Ivey
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Substrates ◽  
Silicide Formation ◽  
Cross Sectional ◽  
Deposition Rates ◽  
Plan View ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTSilicide formation through deposition of Ni onto hot Si substrates has been investigated. Ni was deposited onto <100> oriented Si wafers, which were heated up to 300°C, by e-beam evaporation under a vacuum of <2x10-6 Torr. The deposition rates were varied from 0.1 nm/s to 6 nm/s. The samples were then examined by both cross sectional and plan view transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy and electron diffraction. The experimental results are discussed in terms of a new kinetic model.

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