Thickness Dependence of Epitaxial TiSi2 on Si(111).

1990 ◽  
Vol 202 ◽  
Author(s):  
Hyeongtag Jeon ◽  
J. W. Honeycutt ◽  
C. A. Sukow ◽  
G. A. Rozgonyi ◽  
R. J. Nemanich
Keyword(s):  
Three Dimensional ◽  
Titanium Silicide ◽  
Orientation Relationships ◽  
Island Growth ◽  
Si Substrates ◽  
Different Types ◽  
Disordered Layer ◽  
Temperature Deposition ◽  
Higher Temperature

ABSTRACTThe epitaxy and morphology of TiSi2 on Si(l 11) are studied as a function of Ti thickness. Titanium thicknesses of 1–2 monolayers and Ti films with thicknesses of 50Å; were examined. The titanium silicide films were formed on atomically clean Si substrates by ultrahigh vacuum (UHV) deposition of Ti followed by in situ annealing. In situ LEED and AES measurements characterized the reaction process. For room temperature deposition of less than two monolayers of Ti the LEED pattern associated with the reconstructed substrate disappeared, and the 1×1 bulk pattern also disappeared completely. Annealing at 200°C resulted in a decrease in the Ti AES signal indicating interdiffusion. For annealing up to 500°C, a series of changes in the LEED patterns were observed, which indicated that the disordered layer transformed to an ordered surface layer. Annealing to higher temperature resulted in the reappearance of the diffraction pattern associated with the 7×7 reconstructed Si(111) surface. This indicated three dimensional island growth. For the TiSi2 formed by in situ annealing of 50Å of Ti on Si(111), three different types of island morphologies were observed and identified as the C49 phase of TiSi2. The C49 TiSi2 was proven to be an epitaxial titanium silicideby HRTEM and SAD. Two different orientation relationships of the TiSi2 islands are found: 1) [3 1 1] C49 TiSi2 // [112]Si and (130) C49 TiSi2 //(11 1) Si, and 2) [1 1 2] C49 TiSi2 // [110] Si and (021) C49 TiSi2 //(1 11) Si. The C49 nucleation and island morphologies are discussed in terms of the character of the epitaxial interface.

Effect of growth temperature on the microstructure of the nucleation layers of GaN grown by MOCVD on (1120) sapphire

2002 ◽  
Vol 743 ◽  
Author(s):  
T. Wojtowicz ◽  
P. Ruterana ◽  
M. E. Twigg ◽  
R. L. Henry ◽  
D. D. Koleske ◽  
...  
Keyword(s):  
High Temperature ◽  
Structural Analysis ◽  
Growth Temperature ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Nucleation Mechanism ◽  
Structural Defects ◽  
Orientation Relationships ◽  
Island Growth ◽  
Work Done

AbstractMost of the work done on GaN has taken into account layers grown on the (0001) sapphire plane. However one would expect the growth on the (1120) plane to lead to different structural defects. As has been shown, in one direction, the mismatch is rather small. In this work, we have carried out structural analysis of nucleation layers grown at temperatures ranging from 600°C to 1100°C. It is shown that for many of the structural parameters, such as the orientation relationships, the layer morphology and the nucleation mechanism critically depend on the growth temperature. At the lowest temperatures, the growth is completely three dimensional with a mixture of the two traditional orientation relationships, but the coalescence thickness is small. In a next step, the A orientation relationship predominates and the layer roughness tends to slightly decrease. This orientation is never perfect, and there is always 1.5° misorientation to the same direction in sapphire, whereas the B orientation is always perfect. At an intermediate temperature, island growth is predominant, whereas towards the high temperature end the B orientation becomes predominant. For the highest growth temperatures, the nucleated layers are completely flat and with the B orientation, although they contain a quite large number of defects such as inversion domains.

scholarly journals Liquid phase epitaxy set-up designed for in situ X-ray study of SiGe island growth on (001) Si substrates

2008 ◽  
Vol 43 (12) ◽  
pp. 1278-1285 ◽  
Author(s):  
Th. Teubner ◽  
U. Jendritzki ◽  
K. Böttcher ◽  
G. Schadow ◽  
R. Heimburger ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Liquid Phase Epitaxy ◽  
Island Growth ◽  
X Ray ◽  
Si Substrates ◽  
Set Up

Impact of Local Texture on Recrystallization and Grain Growth via In Situ EBSD

2005 ◽  
Vol 495-497 ◽  
pp. 1121-1130 ◽  
Author(s):  
Stuart I. Wright ◽  
David P. Field ◽  
Matthew M. Nowell
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Three Dimensional ◽  
Orientation Imaging Microscopy ◽  
Boundary Mobility ◽  
Orientation Relationships ◽  
In Situ Techniques ◽  
Grain Boundary Mobility

While electron backscatter diffraction (EBSD) has become an established technique within materials characterization labs around the world, the technique is still relatively young and new applications are continuing to emerge. Automated EBSD or Orientation Imaging Microscopy (OIM) systems are being used in combination with other equipment within the scanning electron microscope (SEM) to perform in-situ measurements. This includes tensile stages for observing changes in local orientation during deformation and heating stages for studying orientation changes arising during recrystallization and grain growth as well as phase transformations. In addition to these temporally three-dimensional studies, spatially three-dimensional studies can be performed by in-situ serial sectioning in microscopes equipped with both electron and focused ion beams. These in-situ techniques are briefly reviewed. The review is followed by a detailed analysis of in-situ heating experiments on copper. The movement of grain boundaries during recrystallization and subsequent grain growth are tracked. The effect of orientation relationships on grain boundary mobility and nucleation are explored. No special relationship with grain boundary mobility was observed. However, twins appear to play a significant role in the nucleation process.

Edge-to-Edge Matching at Ti-TiH Interfaces: Kinetics of Hydride Growth and Clustering of Precipitates with Different Orientation Relationships

2011 ◽  
Vol 172-174 ◽  
pp. 242-247 ◽  
Author(s):  
Egle Conforto ◽  
Daniel Caillard
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Volume Expansion ◽  
Three Dimensional ◽  
Orientation Relationships ◽  
Edge Matching ◽  
Transmission Electron ◽  
Isotropic Distribution ◽  
Kinetics Of

The motion of steps during the growth of hydride precipitates has been observed by in situ transmission electron microscopy. Precipitates in different orientation relationships (OR) are shown to obey to the rules of three-dimensional edge-to-edge matching. They form clusters in order to realize a more isotropic distribution of the volume expansion, and to decrease their total elastic energy.

Effects of Annealing on Structural and Optical Properties of ZnO Nanowires

2014 ◽  
Vol 1675 ◽  
pp. 21-25
Author(s):  
Anas Mazady ◽  
Abdiel Rivera ◽  
Mehdi Anwar
Keyword(s):  
Annealing Temperature ◽  
Defect Density ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Optical Quality ◽  
Structural And Optical Properties ◽  
Si Substrates ◽  
Higher Temperature ◽  
First Time

ABSTRACTWe report, for the first time, effects of annealing of ZnO NWs grown on p-Si substrates. ZnO NWs are grown using metalorganic chemical vapor deposition (MOCVD) and thermal annealing was performed in situ under nitrogen ambient at different stages of the growth process. Increasing the annealing temperature of the ZnO seed epi-layer from 635 °C to 800 °C does not affect the morphology of the grown NWs. In contrast, annealing the NWs themselves at 800 °C results in a 48% decrease of the surface area to volume ratio of the grown NWs. The optical quality can be improved by annealing the seed layer at a higher temperature of 800 °C, although annealing the NWs themselves does not affect the defect density.

In Situ XPS Study of Interaction of Thin IVA, VA Metal Films with Native Oxide on Si Substrates

1999 ◽  
Vol 564 ◽  
Author(s):  
N. M. Sushkova ◽  
A. G. Akimov
Keyword(s):  
Metal Oxides ◽  
Room Temperature ◽  
Three Dimensional ◽  
Metal Films ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Si Substrates ◽  
In Situ Xps ◽  
Xps Study

AbstractPhase formation and change in morphology of Ti, V and Nb oxide films on (100)Si and (111)Si, with native oxide layer, have been studied by XPS in situ. The metal oxides were formed by the interaction at room temperature in UHV multistep deposited of Ti, V or Nb with native oxide. The formation of clean silicon regions during the growth of three-dimensional metal oxide islands is discussed. Differences observed in composition of Nb oxides on (100) Si and (111) Si are considered.

Using Growth Kinetics for Nanoengineering of Si-Ge Surfaces

1998 ◽  
Vol 533 ◽  
Author(s):  
I. Goldfarb ◽  
G. A. D. Briggs
Keyword(s):  
Three Dimensional ◽  
Self Assembling ◽  
Deposition Parameters ◽  
Temperature Ranges ◽  
Nucleation And Growth Mechanisms ◽  
Temperature Deposition ◽  
Higher Temperature ◽  
The Difference ◽  
Lower Temperature ◽  
Post Deposition

AbstractIn this work we explore how various growth characteristics of Ge on Si(001) can be used to fabricate structures for potential nanodevices. In the first example, the self-assembling tendency of germanium for three-dimensional islanding on Si(001) is considered, e.g. for application in devices based on quantum dots and wires. We aimed at achieving a detailed understanding of dot nucleation and growth mechanisms from germane. By controlling the deposition parameters, such as the germane pressure and substrate temperature, arrays of dots and antidots can be created on the grown surface, and further modified by post-deposition anneals. While lower temperature deposition leads to randomly distributed dots (i.e. small and coherent three-dimensional clusters with pyramidal shapes), a higher temperature deposition results in formation of antidots (i.e. pyramidal pits), which, in turn, are gradually replaced by the clusters, if the deposition is allowed to continue. The difference is caused by the different hydrogen behaviour at the respective temperature ranges. The germanium tendency to incorporate preferentially at the step and island edges is another beneficial property, which can be used to align the dots along step edges, creating wires rather than dots, or to fabricate ultrasmall Si-Ge heterojunctions, of a less than 10 nanometer size.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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