Strain Relaxation in GaAs on Si by Two Groups of Misfit Dislocations

1995 ◽  
Vol 399 ◽  
Author(s):  
M. Tamura ◽  
T. Saitoh ◽  
T. Yodo
Keyword(s):  
Strain Relaxation ◽  
Lattice Misfit ◽  
Misfit Dislocations ◽  
Cross Sectional ◽  
Plan View ◽  
Partial Dislocations ◽  
Group I ◽  
Transmission Electron ◽  
Before And After ◽  
Gaas Films

ABSTRACTHigh-resolution cross-sectional and conventional plan-view transmission electron microscope observations have been carried out for molecular beam epitaxially grown GaAs films on vicinal Si (001) as a function of film thicknesses and observation directions between two orthogonal <110> directions before and after annealing. Two groups of misfit dislocations are characterized by analyzing whether their extra half planes exist in the film and the substrate side. The group I misfit dislocations due to a stress caused by a lattice misfit between GaAs and Si consist of partial and, 60° and 90° complete dislocations in an as-grown state. After annealing partial dislocations almost disappear and 90° perfect dislocations are predominantly observed. The group II misfit dislocations due to a thermal-expansion misfit-induced stress are all of the 60° type complete dislocations, independent of film thickness and annealing.

Transition From Inclined to In-Plane 60° Misfit Dislocations in a Diffuse Interface

1993 ◽  
Vol 319 ◽  
Author(s):  
X. J. Ning ◽  
P. Pirouz
Keyword(s):  
Strain Relaxation ◽  
Classical Model ◽  
Diffuse Interface ◽  
Misfit Dislocations ◽  
Dislocation Loops ◽  
Boron Diffusion ◽  
Plan View ◽  
Transmission Electron ◽  
Mechanisms Of Formation ◽  
Film Substrate

AbstractDespite tremendous activity during the last few decades in the study of strain relaxation in thin films grown on substrates of a dissimilar material, there are still a number of problems which are unresolved. One of these is the nature of misfit dislocations forming at the film/substrate interface: depending on the misfit, the dislocations constituting the interfacial network have predominantly either in-plane or inclined Burgers vectors. While, the mechanisms of formation of misfit dislocations with inclined Burgers vectors are reasonably well understood, this is not the case for in-plane misfit dislocations whose formation mechanism is still controversial. In this paper, misfit dislocations generated to relax the strains caused by diffusion of boron into silicon have been investigated by plan-view and crosssectional transmission electron microscopy. The study of different stages of boron diffusion shows that, as in the classical model of Matthews, dislocation loops are initially generated at the epilayer surface. Subsequently the threading segments expand laterally and lay down a segment of misfit dislocation at the diffuse interface. The Burgers vector of the dislocation loop is inclined with respect to the interface and thus the initial misfit dislocations are not very efficient. However, as the diffusion proceeds, non-parallel dislocations interact and give rise to product segments that have parallel Burgers vectors. Based on the observations, a model is presented to elucidate the details of these interactions and the formation of more efficient misfit dislocations from the less-efficient inclined ones.

Mechanisms of misfit strain relaxation in epitaxially grown BLT (Bi4-xLaxTi3O12, x = 0.75) thin films

2003 ◽  
Vol 779 ◽  
Author(s):  
Hyung Seok Kim ◽  
Sang Ho Oh ◽  
Ju Hyung Suh ◽  
Chan Gyung Park
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Strain Relaxation ◽  
Lattice Misfit ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
20 Nm

AbstractMechanisms of misfit strain relaxation in epitaxially grown Bi4-xLaxTi3O12 (BLT) thin films deposited on SrTiO3 (STO) and LaAlO3 (LAO) substrates have been investigated by means of transmission electron microscopy (TEM). The misfit strain of 20 nm thick BLT films grown on STO substrate was relaxed by forming misfit dislocations at the interface. However, cracks were observed in 100 nm thick BLT films grown on the same STO. It was confirmed that cracks were formed because of high misfit strain accumulated with increasing the thickness of BLT, that was not sufficiently relaxed by misfit dislocations. In the case of the BLT film grown on LAO substrate, the magnitude of lattice misfit between BLT and LAO was very small (~1/10) in comparison with the case of the BLT grown on STO. The relatively small misfit strain formed in layered structure of the BLT films on LAO, therefore, was easily relaxed by distorting the film, rather than forming misfit dislocations or cracks, resulting in misorientation regions in the BLT film.

Comparison of Growth and Strain Relaxation of Si/Ge Superlattices Under Compressive and Tensile Strain Field

1991 ◽  
Vol 220 ◽  
Author(s):  
Werner Wegscheider ◽  
Karl Eberl ◽  
Gerhard Abstreiter ◽  
Hans Cerva ◽  
Helmut Oppolzer
Keyword(s):  
Growth Parameters ◽  
Strain Relaxation ◽  
Dislocation Nucleation ◽  
Misfit Dislocations ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Short Period ◽  
Low Energy Electron ◽  
Superlattice Period

ABSTRACTOptimization of growth parameters of short period Si/Ge superlattices (SLs) has been achieved via in situ low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES) measurements during homo- and heteroepitaxy on Si (001) and Ge (001) substrates. Transmission electron microscopy (TEM) reveals that pseudomorphic SimGe12-m (m = 9 and 3 for growth on Si and Ge, respectively) SLs with extended planar layering can be prepared almost defect-free by a modified molecular beam epitaxy (MBE) technique. Whereas the SLs on Ge can be deposited at a constant substrate temperature, high-quality growth on Si demands for temperature variations of more than 100°C within one superlattice period. Strain relaxation of these SLs with increasing number of periods has been directly compared by means of TEM. For the compressively strained structures grown on Si we found misfit dislocations of the type 60° (a/2)<110>. Under opposite strain conditions i.e. for growth on Ge, strain relief occurs only by microtwin formation through successive glide of 90° (a/6)<211> Shockley partial dislocations. This is consistent with a calculation of the activation energy for both cases based on a homogeneous dislocation nucleation model.

High Quality in.Ga1−xas Heterostructures Grown on GaAs With Movpe

1998 ◽  
Vol 510 ◽  
Author(s):  
M.T. Bulsara ◽  
E.A. Fitzgerald
Keyword(s):  
Surface Roughness ◽  
Phase Separation ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Cross Sectional ◽  
Plan View ◽  
Force Microscopy ◽  
Optimum Growth Temperature ◽  
Transmission Electron ◽  
Metal Organic

AbstractInxGa1−xAs structures with compositionally graded buffers were grown by metal-organic vapor phase epitaxy (MOVPE) on GaAs substrates and characterized with plan-view and cross-sectional transmission electron microscopy (PV-TEM and X-TEM), atomic force microscopy (AFM), and x-ray diffraction (XRD). The results show that surface roughness experiences a maximum at growth temperatures where phase separation occurs in InxGa1−xAs. The strain energy due misfit dislocations in the graded buffer indirectly influences phase separation. At growth temperatures above and below this temperature, the surface roughness is decreased significantly; however, only growth temperatures above this regime ensure nearly complete relaxed graded buffers with the most uniform composition caps. With the optimum growth temperature for grading InxGa1−xAs determined to be 700°C, it was possible to produce In0.33Ga0.67As diode structures on GaAs with threading dislocation densities < 8.5 × 106/cm2

scholarly journals Investigation of III–V Nanowires by Plan-View Transmission Electron Microscopy: InN Case Study

2014 ◽  
Vol 20 (5) ◽  
pp. 1471-1478 ◽  
Author(s):  
Esperanza Luna ◽  
Javier Grandal ◽  
Eva Gallardo ◽  
José M. Calleja ◽  
Miguel Á. Sánchez-García ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Strain Relaxation ◽  
Milling Process ◽  
Specimen Preparation ◽  
Shell Layer ◽  
Ion Milling ◽  
Cross Sectional ◽  
Plan View ◽  
Transmission Electron

AbstractWe discuss observations of InN nanowires (NWs) by plan-view high-resolution transmission electron microscopy (TEM). The main difficulties arise from suitable methods available for plan-view specimen preparation. We explore different approaches and find that the best results are obtained using a refined preparation method based on the conventional procedure for plan-view TEM of thin films, specifically modified for the NW morphology. The fundamental aspects of such a preparation are the initial mechanical stabilization of the NWs and the minimization of the ion-milling process after dimpling the samples until perforation. The combined analysis by plan-view and cross-sectional TEM of the NWs allows determination of the degree of strain relaxation and reveals the formation of an unintentional shell layer (2–3-nm thick) around the InN NWs. The shell layer is composed of bcc In2O3 nanocrystals with a preferred orientation with respect to the wurtzite InN: In2O3 [111] || InN [0001] and In2O3 <110> || InN< $$ 11\bar 20 $$ >.

Strain Relaxation Via Interface Nucleation of Misfit Dislocations in Intermixing Layers

1992 ◽  
Vol 263 ◽  
Author(s):  
Hyo-Hoon Park ◽  
Jung Kee Lee ◽  
El-Hang Lee ◽  
Jeong Yong Lee ◽  
Soon-Ku Hong
Keyword(s):  
Electron Microscopy ◽  
Homogeneous Nucleation ◽  
Critical Thickness ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
Semiconductor Heterostructures ◽  
Misfit Dislocations ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Lattice Matched

ABSTRACTThe strain relaxation mechanism via the homogeneous nucleation of misfit dislocations from interface during interdiffusion in lattice-matched semiconductor heterostructures has been investigated. Transmission electron microscopy studies in intermixed GaInAsP/InP heterostructures revealed that the critical interdiffusion depth for the nucleation of 90° 1/6<112> partial dislocations from a tensile interface is much shallower than that of 60° 1/2<110> perfect dislocations from a compressive interface. A critical thickness model for the interface nucleation of these dislocations is developed as a modification of the classical surface nucleation'model.

A New Method of Wafer Level Plan View TEM Sample Preparation by DualBeam

2008 ◽  
Author(s):  
Hyoung H. Kang ◽  
Michael A. Gribelyuk ◽  
Oliver D. Patterson ◽  
Steven B. Herschbein ◽  
Corey Senowitz
Keyword(s):  
Sample Preparation ◽  
Ex Situ ◽  
Wafer Level ◽  
Cross Sectional ◽  
Plan View ◽  
Manufacturing Line ◽  
Transmission Electron ◽  
Thin Lamella ◽  
Preparation Techniques

Abstract Cross-sectional style transmission electron microscopy (TEM) sample preparation techniques by DualBeam (SEM/FIB) systems are widely used in both laboratory and manufacturing lines with either in-situ or ex-situ lift out methods. By contrast, however, the plan view TEM sample has only been prepared in the laboratory environment, and only after breaking the wafer. This paper introduces a novel methodology for in-line, plan view TEM sample preparation at the 300mm wafer level that does not require breaking the wafer. It also presents the benefit of the technique on electrically short defects. The methodology of thin lamella TEM sample preparation for plan view work in two different tool configurations is also presented. The detailed procedure of thin lamella sample preparation is also described. In-line, full wafer plan view (S)TEM provides a quick turn around solution for defect analysis in the manufacturing line.

Growth and Characterizations of Gaas on Inp with Different Buffer Structures by Molecular Beam Epitaxy

1989 ◽  
Vol 148 ◽  
Author(s):  
Xiaoming Liu ◽  
Henry P. Lee ◽  
Shyh Wang ◽  
Thomas George ◽  
Eicke R. Weber ◽  
...  
Keyword(s):  
Low Temperature ◽  
Buffer Layer ◽  
Gaas Layer ◽  
Optical Quality ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Layer Structures ◽  
Gaas Films ◽  
Initial Deposition ◽  
Strained Layer Superlattices

ABSTRACTWe report the growth and characterizations of 31μm thick GaAs films grown on (100) InP substrates by MBE employing different buffer layer structures during the initial deposition. The buffer layer structures under study are: 1) GaAs layer grown at low temperature; 2) GaAs layer grown at low temperature plus two sets of In0.08Ga0.92As/GaAs strained layer superlattices (SLS) and 3) a transitional compositionally graded InxGal-xAs layer between the InP substrate and the GaAs film. After the buffer layer deposition, the growth was continued by conventionalMBE to a total thickness of 3μm for all samples. From the 77K photoluminescence (PL) measurement, it was found that the sample with SLS layers has the highest PL intensity and the narrowest PL linewidth. Cross-sectional transmission electron microscopy (TEM) studies showed that the SLS is effective in reducing the propagation of threading dislocations and explains the observed superior optical quality from the PL measurement.

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.

Transmission electron microscopy of misfit dislocation and strain relaxation in lattice mismatched III-V heterostructures versus substrate surface treatment

2011 ◽  
Vol 1324 ◽  
Author(s):  
Y. Wang ◽  
P. Ruterana ◽  
L. Desplanque ◽  
S. El Kazzi ◽  
X. Wallart
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Treatment ◽  
Substrate Surface ◽  
Strain Relaxation ◽  
Dislocation Core ◽  
Misfit Dislocations ◽  
Heteroepitaxial Growth ◽  
Transmission Electron ◽  
Growth Initiation

ABSTRACTHigh resolution transmission electron microscopy in combination with geometric phase analysis is used to investigate the interface misfit dislocations, strain relaxation, and dislocation core behavior versus the surface treatment of the GaAs for the heteroepitaxial growth of GaSb. It is pointed out that Sb-rich growth initiation promotes the formation of a high quality network of Lomer misfit dislocations that are more efficient for strain relaxation.

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