TEM Investigation of Si/βFeSi2/Si (100) and (111) Heterostructures Formed by Fe Implantation

1992 ◽  
Vol 283 ◽  
Author(s):  
C. W. T. Bulle-Lieuwma ◽  
D. J. Oostra ◽  
D. E. W. Vandenhoudt
Keyword(s):  
Three Dimensional ◽  
Si Substrate ◽  
Structural Examination ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dimensional Growth ◽  
Buried Layer ◽  
High Degree ◽  
Dimensional Surface ◽  
Fe Implantation

ABSTRACTSi/βFeSi2/Si (100) and (111) structures were obtained by implantation of 450 keV Fe+ ions with a dose of 6×1017 Fe+ ions/ cm2 into Si substrates. A continuous buried βFeSi2 layer with thickness of 250 nm was formed during subsequent annealing. By transmission electron microscopy it has been found that for (100) Si the layer consists of βFeSi2 grains with lateral dimensions of approximately O.5 μm and for (111) Si of grains of 5 μm in size. The βFeSi2 films exhibit a high degree of epitaxy with the Si substrate. A detailed structural examination shows the occurrence of several epitaxial relationships of βFeSi2 with the Si substrate. In contrast to two-dimensional surface growth techniques, the formation of a buried layer by implantation occurs by a three-dimensional growth process by the coalescence of βFeSi2 precipitates. The different orientations of the βFeSi2 grains in the buried layer are already established by the orientation of the precipitates formed during implantation.

Electrophoretic Deposition of Metal Nanoparticle Monolayers from Nonpolar Solvents for Hydrogen Sensing

2015 ◽  
Vol 654 ◽  
pp. 213-217 ◽  
Author(s):  
Jan Grym ◽  
Roman Yatskiv ◽  
Ondřej Černohorský ◽  
María Verde ◽  
Jan Lorinčík ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Reverse Micelles ◽  
Three Dimensional ◽  
Fast Response ◽  
Metal Nanoparticle ◽  
Hydrogen Sensors ◽  
Hydrogen Sensing ◽  
Nonpolar Solvents ◽  
Dimensional Growth ◽  
High Degree

We report on the electrophoretic deposition (EPD) of metal nanoparticles (NPs) prepared in reverse micelles on semiconductor substrates with the aim to fabricate sensitive Schottky-based hydrogen sensors with fast response and high degree of selectivity. We discuss the mechanism of NP monolayer formation and show which parameters are essential for the transition from three-dimensional to two-dimensional growth.

scholarly journals Characterization of Gaas/Si/GaAs Heterointerfaces

1989 ◽  
Vol 148 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
Raymond P. Mariella
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Defect Density ◽  
Si Substrate ◽  
Reverse Polarity ◽  
Si Substrates ◽  
Transmission Electron ◽  
Metal Semiconductor Metal

ABSTRACTTransmission electron microscopy of GaAs grown on Si for metal-semiconductor-metal photodetectors is presented in this paper. Two kinds of samples are compared: GaAs grown on a 15 Å Si epilayer grown on GaAs, and GaAs grown at low temperature (300°C) on Si substrates. It is shown that the GaAs epitaxial layer grown on thin Si layer has reverse polarity to the substrate (antiphase relation). Higher defect density is observed for GaAs grown on Si substrate. This higher defect density correlates with an increased device speed, but with reduced sensitivity.

scholarly journals O-Band Emitting InAs Quantum Dots Grown by MOCVD on a 300 mm Ge-Buffered Si (001) Substrate

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2450
Author(s):  
Oumaima Abouzaid ◽  
Hussein Mehdi ◽  
Mickael Martin ◽  
Jérémy Moeyaert ◽  
Bassem Salem ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Chemical Vapor ◽  
Lattice Parameter ◽  
Organic Chemical ◽  
Silicon Substrates ◽  
Wafer Level ◽  
Si Substrate ◽  
Si Substrates ◽  
Transmission Electron ◽  
Metal Organic

The epitaxy of III-V semiconductors on silicon substrates remains challenging because of lattice parameter and material polarity differences. In this work, we report on the Metal Organic Chemical Vapor Deposition (MOCVD) and characterization of InAs/GaAs Quantum Dots (QDs) epitaxially grown on quasi-nominal 300 mm Ge/Si(001) and GaAs(001) substrates. QD properties were studied by Atomic Force Microscopy (AFM) and Photoluminescence (PL) spectroscopy. A wafer level µPL mapping of the entire 300 mm Ge/Si substrate shows the homogeneity of the three-stacked InAs QDs emitting at 1.30 ± 0.04 µm at room temperature. The correlation between PL spectroscopy and numerical modeling revealed, in accordance with transmission electron microscopy images, that buried QDs had a truncated pyramidal shape with base sides and heights around 29 and 4 nm, respectively. InAs QDs on Ge/Si substrate had the same shape as QDs on GaAs substrates, with a slightly increased size and reduced luminescence intensity. Our results suggest that 1.3 μm emitting InAs QDs quantum dots can be successfully grown on CMOS compatible Ge/Si substrates.

Synthesis and Characterization of High Quality InN Nanowires and Nano-networks

2007 ◽  
Vol 1058 ◽  
Author(s):  
Zhihua Cai ◽  
Samir Garzon ◽  
Richard A. Webb ◽  
Goutam Koley
Keyword(s):  
Fast Rate ◽  
Three Dimensional ◽  
Catalyst Layer ◽  
Direct Reaction ◽  
Si Substrate ◽  
Large Area ◽  
High Quality ◽  
Dimensional Growth ◽  
Quartz Tube Furnace

ABSTRACTHigh quality InN nanowires have been synthesized in a horizontal quartz-tube furnace through direct reaction between metallic Indium and Ammonia using Nitrogen as the carrier gas. Thin film of Au on SiO2/Si substrate has been used as the catalyst layer, facilitating vapor-liquid-solid growth of the nanostructures. The nanowires were grown at a very fast rate of up to 30 μm/hr. Smooth and horizontal nanowire growth was achieved only with nanoscale catalyst patterns, while large area catalyst coverage resulted in uncontrolled and three-dimensional growth. The InN nanowires, which were usually covered with a thin shell layer of In2O3, grew along [110] direction, with overall diameters 20 - 60 nm and lengths 5 - 15 μm. The synthesized nanowires bent spontaneously or got deflected from other nanowires at multiples of 30 degrees forming nano-networks. The catalyst particles for the NWs were found mostly at the sides of the NW apex which helped them to bend spontaneously or get deflected from other NWs at angles which were multiples of 30 degrees. The NW based FETs with a back-gated configuration have already been investigated. The gate-bias dependent mobility of the NWs ranged from 55 cm2/Vs to 220 cm2/Vs, and their carrier concentration was ∼1018 cm−3.

New Approach to Growth of High-Quality GaAs Layers on Si Substrates

1988 ◽  
Vol 116 ◽  
Author(s):  
Jukka Varrio ◽  
Arto Salokatve ◽  
Harry Asonen ◽  
Minna Hovinen ◽  
Markus Pessa ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Layer Growth ◽  
Rutherford Backscattering ◽  
X Ray Diffraction ◽  
New Approach ◽  
Si Substrates ◽  
Surface Steps ◽  
Transmission Electron ◽  
Migration Enhanced Epitaxy ◽  
And Migration

AbstractGaAs layers were grown on Si (001) substrates by molecular beam epitaxy (MBE) and migration enhanced epitaxy (MEE). They were examined by transmission electron microscopy, doublecrystal X-ray diffraction and Rutherford backscattering/channeling technique. Initial layer growth in both MEE and MBE was governed by three-dimensional nucleation but a stronger tendency for GaAs islands to align along the surface steps of Si was observed in the case of MEE. There was no measurable tilt between the (001) planes of GaAs and Si if growth was initiated by MEE at low temperature, prior to further growth by MBE at higher temperatures. On the contrary, the tilt angle was 0.34• when the entire structure was prepared by conventional two-step MBE. Rutherford backscattering measurements indicated a significant reduction in the density of defects throughout MEE/MBE GaAs in comparison with MBE GaAs.

Morphology of Foliar Trichomes of the Chinese Cork OakQuercus variabilisby Electron Microscopy and Three-Dimensional Surface Profiling

2011 ◽  
Vol 17 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Ki Woo Kim ◽  
Do-Hyun Cho ◽  
Pan-Gi Kim
Keyword(s):  
Electron Microscopy ◽  
Three Dimensional ◽  
Abaxial Surface ◽  
Single Row ◽  
Adaxial Surface ◽  
Surface Profiling ◽  
Transmission Electron ◽  
Ultrastructural Characterization ◽  
Disturbance Factor ◽  
Dimensional Surface

AbstractMorphology of foliar trichomes was analyzed inQuercus variabilisby electron microscopy and three-dimensional surface profiling. Leaves from suppressed or dominant sprouts of the oak species were collected after a forest fire to unravel the effects of the disturbance factor on sprouting of the oak species. Scanning electron microscopy revealed two types of trichomes depending on the leaf surface. The trichomes on the adaxial surface were branched and constricted, and possessed a single row of thin-walled cells with a collapsed morphology (glandular branched uniseriate trichomes). Meanwhile, the trichomes on the abaxial surface were star-shaped, unfused with each other, and had 6 to 10 rays (nonglandular simple stellate trichomes). An apparent proliferation of trichomes was evident on the adaxial surface of the dominant sprouts. Uniseriate trichomes could be discernable as an elevation from the surface by white light scanning interferometry. By transmission electron microscopy, thin and convoluted cell wall, degenerated cytoplasm, and a single row of cells were characteristic of the trichomes on the adaxial surface. The thick cell walls of the mature trichomes on the abaxial surface represented the nonglandular nature. This is the first report on the morphological and ultrastructural characterization of foliar trichomes of the oak species.

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.

SURFACE MORPHOLOGY OF CHALKBOARD TIPS CAPTURES THE UNIQUENESS OF THE USER'S HAND STROKES

2010 ◽  
Vol 21 (04) ◽  
pp. 535-548
Author(s):  
CHRISTOPHER MONTEROLA ◽  
IRENE CRISOLOGO ◽  
JERIC TUGAFF ◽  
RENE BATAC ◽  
ANTHONY LONGJAS
Keyword(s):  
Three Dimensional ◽  
Principal Component ◽  
Photometric Stereo ◽  
Linear Discriminant ◽  
Average Classification Accuracy ◽  
Test Sets ◽  
Classification And Regression ◽  
High Degree ◽  
Dimensional Surface ◽  
Better Than

Penmanship has a high degree of uniqueness as exemplified by the standard use of hand signature as identifier in contract validations and property ownerships. In this work, we demonstrate that the distinctiveness of one's writing patterns is possibly embedded in the molding of chalk tips. Using conventional photometric stereo method, the three-dimensional surface features of blackboard chalk tips used in Math and Physics lectures are microscopically resolved. Principal component analysis (PCA) and neural networks (NN) are then combined in identifying the chalk user based on the extracted topography. We show that NN approach applied to eight lecturers allow average classification accuracy (Φ NN ) equal to 100% and 71.5 ± 2.7% for the training and test sets, respectively. Test sets are chalks not seen previously by the trained NN and represent 25% or 93 of the 368 chalk samples used. We note that the NN test set prediction is more than five-fold higher than the proportional chance criterion (PCC, Φ PCC = 12.9%), strongly hinting to a high degree of unique correlation between the user's hand strokes and the chalk tip features. The result of NN is also about three-fold better than the standard methods of linear discriminant analysis (LDA, Φ LDA = 27.0 ± 4.2%) or classification and regression trees (CART, Φ CART = 17.3 ± 3.7%). While the procedure discussed is far from becoming a practical biometric tool, our work offers a fundamental perspective to the extent on which the uniqueness of hand strokes of humans can be exhibited.

Formation of Heterogeneous Thickness Modulations During Epitaxial Growth of LPCVD-Si1−xGex/Si Quantum Well Structures

1992 ◽  
Vol 263 ◽  
Author(s):  
L. Vescan ◽  
W. Jäger ◽  
C. Dieker ◽  
K. Schmidt ◽  
A. Hartmann ◽  
...  
Keyword(s):  
Quantum Well ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Misfit Dislocations ◽  
Preferential Growth ◽  
Quantum Well Structures ◽  
Transmission Electron ◽  
Pressure Chemical ◽  
Dimensional Growth ◽  
Photoluminescence Studies

ABSTRACTTransmission electron microscopy and photoluminescence studies were performed to determine the critical thickness for generation of misfit dislocations in Sil-xGex layers grown by low pressure chemical vapor deposition. Above a certain Ge content the transition from two dimensional to three-dimensional growth occurs before generation of misfit dislocations. For instance, for x ∼0.3 and a substrate temperature around 700°C island formation was observed to start at 1.8 nm. The formation of islands is attributed to the preferential growth of SiGe in areas with less lattice strain. Islands were observed to broaden the exciton photoluminescence of the quantum well structures.

MoirÉ Pattern Studies of Thin Layers Deposited on (001)Si Substrates: Cases of Tisi2 and GaAs.

1989 ◽  
Vol 148 ◽  
Author(s):  
A. Rocher ◽  
X. Wallart ◽  
M.N. Charasse
Keyword(s):  
Three Dimensional ◽  
Thin Layers ◽  
Dislocation Network ◽  
Threading Dislocations ◽  
Si Substrates ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Dimensional Growth ◽  
Residual Strains

ABSTRACTMoiré pattern images have been used to investigate the crystalline quality of thin films deposited on (100)Si substrates. Observations performed on TiSi2 show a three-dimensional growth process and two different epitaxial modes. In the case of GaAs epilayers, it is shown that the residual strains are not uniformly distributed in the layer. Residual strain and threading dislocations are related to imperfections of the misfit dislocation network.

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