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.

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 Reduction and Its Mechanism of Selective Ge Epitaxy in Trenches on Si(001) Substrates Using Aspect Ratio Trapping

2007 ◽  
Vol 994 ◽  
Author(s):  
Ji-Soo Park ◽  
J. Bai ◽  
M. Curtin ◽  
B. Adekore ◽  
Z. Cheng ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Growth Process ◽  
Lattice Mismatch ◽  
Dominant Role ◽  
Great Promise ◽  
Silicon Substrates ◽  
Threading Dislocations ◽  
Defect Reduction ◽  
Device Applications ◽  
Conventional Photolithography

AbstractDefect-free germanium has been demonstrated in SiO2 trenches on silicon via aspect ratio trapping, whereby defects arising from lattice mismatch are trapped by laterally confining sidewalls. Results were achieved through a combination of conventional photolithography, reactive ion etching of SiO2, and selective growth of Ge as thin as 450 nm. It was revealed that facets, when formed early on in the growth process, play a dominant role in determining the configurations of threading dislocations in the films. This approach shows great promise for the integration of Ge and/or III-V materials, sufficiently large for key device applications, onto silicon substrates.

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.

TEM and SEM Studies of MOCVD-Grown GaP on Si

1985 ◽  
Vol 62 ◽  
Author(s):  
M. M. Ai-Jassim ◽  
J. M. Olson ◽  
K. M. Jones
Keyword(s):  
Defect Density ◽  
Growth Parameters ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Structural Defects ◽  
Organic Chemical ◽  
Cross Sectional ◽  
Plan View ◽  
Si Substrates ◽  
Antiphase Domains

ABSTRACTGaP and GaP/GaAsP epitaxial layers have been grown on Si substrates by metal-organic chemical vapor deposition (MOCVD). These layers were characterized by SEM and TEM plan-view and cross-sectional examination. At growth temperatures ranging from 600° C to 800° C, the initial stages of growth were dominated by three-dimensional nucleation. TEM studies showed that at high temperatures the nuclei were generally misoriented with respect to each other yielding, upon coalescence, polycrystalline layers. The growth of single-crystal layers was achieved by nucleating a 30–50 nm layer of GaP at 500° C, followed by annealing and continued growth at 750 ° C. The defect density in these structures was investigated as a function of various growth parameters and substrate conditions. A high density of structural defects was generated at the Si/GaP interface. The use of 2° off (100) Si substrates resulted in GaP layers free of antiphase domains. These results and their implications are discussed.

Characterization of Chemically Vapor Deposited GaN on Sic on a Simox Substrate

1997 ◽  
Vol 3 (S2) ◽  
pp. 487-488
Author(s):  
W.L. Zhou ◽  
P. Pirouz
Keyword(s):  
Lattice Mismatch ◽  
Defect Density ◽  
Silicon Layer ◽  
Large Defect ◽  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Transmission Electron ◽  
Potential Applications ◽  
Gan Film

GaN has been intensively studied because of its potential applications for the fabrication of blue- or ultraviolet-light emitting devices. Sapphire (α-Al2O3) is generally used as the substrate for growth of GaN film. However, the large lattice mismatch between GaN and Al2O3is a possible cause of the large defect density in the GaN films. Consequently, alternative substrates are being studied with the aim of growing films of lesser defect densities and improved opto-electronic properties. In this paper, we report a transmission electron microscopy (TEM) study of a GaN film grown on cubic SiC which has been obtained by carbonization of the top silicon layer of a SIMOX substrate, i.e. the system GaN/SiC/Si/SiO2/Si.Cross-sectional TEM specimens were prepared by the conventional sandwich technique with the foil surface normal to the Si[l10] direction. The composite sample was ground and dimpled to a thickness of ∼ 10μm, and subsequently ion thinned to electron transparency.

Plan-View and Cross-Sectional Photoluminescence Imaging Analyses of Threading Dislocations in 4H-SiC Epilayers

2013 ◽  
Vol 52 (4S) ◽  
pp. 04CP09 ◽  
Author(s):  
Masahiro Nagano ◽  
Isaho Kamata ◽  
Hidekazu Tsuchida
Keyword(s):  
Threading Dislocations ◽  
Cross Sectional ◽  
Plan View

Stress Controlled MBE-growth of GaN:Mg and GaN:Si

1997 ◽  
Vol 482 ◽  
Author(s):  
Y. Kim ◽  
R. Klockenbrink ◽  
C. Kisielowski ◽  
J. Krueger ◽  
D. Corlatan ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Defect Formation ◽  
Lattice Mismatch ◽  
Flux Ratio ◽  
Layer Growth ◽  
Mbe Growth ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Stress Changes ◽  
Formation Energies

AbstractThe stress in GaN thin films grown on sapphire is shown to be determined by lattice mismatch, by differences in thermal-expansion-coefficients and by the incorporation of point defects. It can be controlled by the buffer layer thickness, the buffer layer growth temperature, the V/III flux ratio, and by doping. It is argued that a Fermi-level dependence of defect formation energies affects the material stoichiometry and thereby lattice constants and stresses. We observed that stress relaxation occurred if the stresses exceeded a critical compressive or tensile stress value. The stress changes materials properties. As an example, it is demonstrated that the electron Hall mobility in GaN:Si can be increased with constant electron carrier concentration if large compressive stress is present.

scholarly journals Metamorphic Integration of GaInAsSb Material on GaAs Substrates for Light Emitting Device Applications

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1743
Author(s):  
Qi Lu ◽  
Andrew Marshall ◽  
Anthony Krier
Keyword(s):  
Quantum Wells ◽  
Buffer Layer ◽  
Lattice Mismatch ◽  
Cost Effective ◽  
Threading Dislocations ◽  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Gaas Substrates ◽  
Device Applications

The GaInAsSb material has been conventionally grown on lattice-matched GaSb substrates. In this work, we transplanted this material onto the GaAs substrates in molecular beam epitaxy (MBE). The threading dislocations (TDs) originating from the large lattice mismatch were efficiently suppressed by a novel metamorphic buffer layer design, which included the interfacial misfit (IMF) arrays at the GaSb/GaAs interface and strained GaInSb/GaSb multi-quantum wells (MQWs) acting as dislocation filtering layers (DFLs). Cross-sectional transmission electron microscopy (TEM) images revealed that a large part of the dislocations was bonded on the GaAs/GaSb interface due to the IMF arrays, and the four repetitions of the DFL regions can block most of the remaining threading dislocations. Etch pit density (EPD) measurements indicated that the dislocation density in the GaInAsSb material on top of the buffer layer was reduced to the order of 106 /cm2, which was among the lowest for this compound material grown on GaAs. The light emitting diodes (LEDs) based on the GaInAsSb P-N structures on GaAs exhibited strong electro-luminescence (EL) in the 2.0–2.5 µm range. The successful metamorphic growth of GaInAsSb on GaAs with low dislocation densities paved the way for the integration of various GaInAsSb based light emitting devices on the more cost-effective GaAs platform.

HRTEM and CTEM study of differently lattice-mismatched InxGa1-xAs/InP heterostructures grown by VPE

1990 ◽  
Vol 48 (4) ◽  
pp. 590-591
Author(s):  
C. Frigeri ◽  
G. Attolini ◽  
C. Pelosi ◽  
F. Corticelli
Keyword(s):  
Communication Systems ◽  
Lattice Mismatch ◽  
Growth Conditions ◽  
Hydride Vapor Phase Epitaxy ◽  
Structural Defects ◽  
Cross Sectional ◽  
Plan View ◽  
Deposition Zone ◽  
Point To Point ◽  
Matched Layers

InxGa1-xAs/InP heterostructures are used for optical communication systems. In order to establish the dependence of the structural defects on the growth conditions, differently lattice- mismatched samples have been characterized by both CTEM and HRTEM. The InGaAs layers were grown by hydride Vapor Phase Epitaxy on (001) oriented sustrates. Different layer mismatch (composition) was obtained by changing the GaCl flow in the deposition zone whereas the AsH3 and InCl flows were kept constant. A JEOL 2000 FX TEM with a point-to-point resolution of 0.31 nm at the Scherzer defocus of - 110 nm was employed. Both plan-view and cross-sectional specimens were investigated.The lattice-matched layers (x=0.53) were nearly defect-free even at the interface to the substrate as shown by the axial illumination HRTEM image given in Fig. 1. Different type of defects were observed in the lattice-mismatched layers depending on whether the mismatch ε was negative or positive. For negative lattice-mismatch the defects were mostly pyramidal stacking faults in a quite high density even for small mismatch as shown in Fig. 2 for a layer with ε= - 0.16% (x=0.51).

Progress in Large-Area 4H-SiC Epitaxial Layer Growth in a Warm-Wall Planetary Reactor

2014 ◽  
Vol 778-780 ◽  
pp. 103-108 ◽  
Author(s):  
Bernd Thomas ◽  
Darren M. Hansen ◽  
Jie Zhang ◽  
Mark J. Loboda ◽  
Junichi Uchiyama ◽  
...  
Keyword(s):  
Epitaxial Layer ◽  
Defect Density ◽  
Layer Growth ◽  
Power Devices ◽  
Large Area ◽  
Defect Reduction ◽  
Mean Values ◽  
Bipolar Devices ◽  
Thickness Measurements

Results are presented for epitaxial SiC layers grown on 100 mm and 150 mm wafers suitable for power devices by CVD using a VP2800WW multi-wafer reactor with 10×100mm and 6×150mm configurations. We have demonstrated continuous improvement in uniformity for thickness and doping, as well as in defect reduction in standard epitaxy on 100 mm wafers. Thickness and doping sigma/mean values of <1.5% and <8%, respectively, could be routinely achieved. Doping and thickness measurements of 30 μm layer growth show results similar to standard epilayer growth. The averaged projected site yields of 80% for 5x5 mm2 and of 96% for 2x2 mm2 correspond to a low epitaxial defect density of <1 cm="" sup="">-2 in 30μm thick epilayers. Epilayer structures for bipolar devices like PiN diodes and BJTs are shown. The interface regions between nitrogen doped and aluminum doped layers show an abrupt transition of dopant concentration. Wafer quality of 100 mm and 150 mm material is presented as an important base factor for excellent epitaxial layer quality. It is shown that 150 mm substrates exhibit TSD and BPD densities very similar to the 100 mm materials. Site counts for TSDs and BPDs on sample wafers show dislocations densities of 500 cm-2 and 300 cm-2, respectively. After CVD process optimization, a thickness uniformity (sigma/mean) of <1.5% and a doping uniformity of <13% was achieved on epitaxial layers on 150mm.

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