Study on the Phase Transition from Amorphous Phases to Crystalline TiSi2

1995 ◽  
Vol 402 ◽  
Author(s):  
H. G. Nam ◽  
Nam-Ihn Cho
Keyword(s):  
Phase Transition ◽  
Distribution Functions ◽  
Titanium Silicide ◽  
Atomic Ordering ◽  
Amorphous Phases ◽  
Si Substrates ◽  
Transmission Electron ◽  
Short Range Ordering ◽  
Silicide Compounds ◽  
Deposition Conditions

AbstractTitanium silicides were prepared by coevaporation of Ti and Si on Si substrates at intermediate substrate temperatures followed by high temperature annealing. Depending on the deposition conditions, transmission electron diffraction analyses revealed two different halo patterns from the as-deposited samples. Variations in the deposition conditions included substrate temperature, deposition rate, and film thickness. Radial distribution functions were calculated to estimate the short range ordering of the amorphous phases. The interatomic distances of all the titanium silicide compounds were also calculated in order to compare them with the atomic ordering of amorphous phases. Phase transition from these amorphous phases to the first crystalline silicide is discussed in terms of kinetic variations as well as the atomic ordering.

Growth Behavior of Au on Semiconductor and Insulating Substrates

1985 ◽  
Vol 47 ◽  
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh ◽  
R. B. Laibowltz ◽  
J. A. Lacey
Keyword(s):  
Single Crystal ◽  
Substrate Surface ◽  
Electron Beam Evaporation ◽  
Growth Behavior ◽  
Tem Analysis ◽  
Si Substrates ◽  
Transmission Electron ◽  
Substrate Surface Roughness ◽  
Amorphous Si ◽  
Deposition Conditions

ABSTRACTThere is a great deal of interest in forming Au grains on semiconductor and insulating substratcs for device application. Reduction in density of grain boundaries is known to cause improvement of clectromigration in thin films. Transmission electron microscopy and diffraction have been used to study the growth behavior and morphology of vapor deposited Au on these substrates. Electron beam evaporation techniques were used to evaporate Au at high rates (50Å/sec or higher) on substrates held at low temperature (Rm. Temp. to 250°C). Large Au grains laave been found to form on both amorphous (Si3N4 and SiO2) and single crystal Si substrates. The grain size of Au was also found to be dependent on substrate surface roughness; rough surfaces tended to retard the formation of large grains. Grains as large as 1/2 μ in a matrix of smaller ones were observed in films as thin as 350Å Annealing up to 350°C, subsequent to deposition, did not appreciably increase the size of the larger grains, although the smaller ones grew by about 10%. The TEM analysis together with RBS and AES data showed no significant interaction between Au and Si (that is to say no atomic intermixing or silicide formation) under all deposition conditions as well as annealing heat treatments. The significance of this in relation to the growth behavior of Au on the insulating and single crystal Si substrates will be shown.

Phase Transition and Formation of TiSi2 Codeposited on Atomically Clean Si(111).

1993 ◽  
Vol 311 ◽  
Author(s):  
Hyeongtag Jeon ◽  
Y. S. Cho ◽  
E. Y. Kang ◽  
J. W. Park ◽  
R.R. Nemanich
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
High Temperature ◽  
Rough Surface ◽  
Smooth Surface ◽  
Elevated Temperatures ◽  
Titanium Silicide ◽  
Surface And Interface ◽  
Si Substrates ◽  
Si Films

ABSTRACTIn this study, the phase transformation and the surface and interface morphologies of TiSi2 formed on atomically clean Si substrates are investigated. 200Å Ti and 400A Si films on Si(111) have been co-deposited at elevated temperatures (400°C - 800°C) in ultrahigh vacuum. The phase transition of TiSi2 is characterized with using XRD. The results distinguish the formation of the C49 and C54 crystalline titanium silicides. The surface and interface morphologies of titanium silicides have been examined with SEM and TEM. A relatively smooth surface is observed for the C49 phase while a rough surface and interface are observed for the C54 phase. The islanding of the C54 phase becomes severe at high temperature (800°C). Islands of TiSi2 have been observed at temperatures above 700°C but no islands are observed at temperatures below 600°C. For films deposited at 400TC and 500°C, weak XRD peaks corresponding to TiSi were observed and TEM micrographs exhibited small crystalline regions of titanium silicide at the interface.

Electron Energy Analysis of Germanium and Silica Layers on Silicon Substrates

1975 ◽  
Vol 33 ◽  
pp. 96-97
Author(s):  
R. W. Ditchfield ◽  
A. G. Cullis
Keyword(s):  
Epitaxial Growth ◽  
Electron Energy ◽  
Silicon Substrates ◽  
Secondary Phases ◽  
Si Substrates ◽  
Transmission Electron ◽  
Layer Structures ◽  
Si Films ◽  
Electron Energy Loss ◽  
Growth Centres

An energy analyzing transmission electron microscope of the Möllenstedt type was used to measure the electron energy loss spectra given by various layer structures to a spatial resolution of 100Å. The technique is an important, method of microanalysis and has been used to identify secondary phases in alloys and impurity particles incorporated into epitaxial Si films.Layers Formed by the Epitaxial Growth of Ge on Si Substrates Following studies of the epitaxial growth of Ge on (111) Si substrates by vacuum evaporation, it was important to investigate the possible mixing of these two elements in the grown layers. These layers consisted of separate growth centres which were often triangular and oriented in the same sense, as shown in Fig. 1.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Transmission Electron Microscopy characterization of epitaxial III-V semiconductor thin films grown on Si(100) by ion-assisted deposition

1990 ◽  
Vol 48 (4) ◽  
pp. 686-687
Author(s):  
L. Hultman ◽  
C.-H. Choi ◽  
R. Kaspi ◽  
R. Ai ◽  
S.A. Barnett
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Irradiation ◽  
High Energy ◽  
Nucleation Mechanism ◽  
Layer By Layer ◽  
Extended Defect ◽  
Island Formation ◽  
Si Substrates ◽  
Transmission Electron

III-V semiconductor films nucleate by the Stranski-Krastanov (SK) mechanism on Si substrates. Many of the extended defects present in the films are believed to result from the island formation and coalescence stage of SK growth. We have recently shown that low (-30 eV) energy, high flux (4 ions per deposited atom), Ar ion irradiation during nucleation of III-V semiconductors on Si substrates prolongs the 1ayer-by-layer stage of SK nucleation, leading to a decrease in extended defect densities. Furthermore, the epitaxial temperature was reduced by >100°C due to ion irradiation. The effect of ion bombardment on the nucleation mechanism was explained as being due to ion-induced dissociation of three-dimensional islands and ion-enhanced surface diffusion.For the case of InAs grown at 380°C on Si(100) (11% lattice mismatch), where island formation is expected after ≤ 1 monolayer (ML) during molecular beam epitaxy (MBE), in-situ reflection high-energy electron diffraction (RHEED) showed that 28 eV Ar ion irradiation prolonged the layer-by-layer stage of SK nucleation up to 10 ML. Otherion energies maintained layer-by-layer growth to lesser thicknesses. The ion-induced change in nucleation mechanism resulted in smoother surfaces and improved the crystalline perfection of thicker films as shown by transmission electron microscopy and X-ray rocking curve studies.

scholarly journals Direct TEM observation of the “acanthite α-Ag2S–argentite β-Ag2S” phase transition in a silver sulfide nanoparticle

2019 ◽  
Vol 1 (4) ◽  
pp. 1581-1588 ◽  
Author(s):  
S. I. Sadovnikov ◽  
E. Yu. Gerasimov
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Silver Sulfide ◽  
Transmission Electron ◽  
Silver Sulfide Nanoparticles ◽  
Microscopy Method ◽  
Electron Microscopy Method ◽  
First Time

For the first time, the α-Ag2S (acanthite)–β-Ag2S (argentite) phase transition in a single silver sulfide nanoparticles has been observed in situ using a high-resolution transmission electron microscopy method in real time.

Amorphous Phase Formation of Titanium Silicide on The 4° off-Axis and on-Axis Si(100) Substrates

1996 ◽  
Vol 427 ◽  
Author(s):  
Hyeongtag Jeon ◽  
Sukjae Lee ◽  
Hwackjoo Lee ◽  
Hyun Ruh
Keyword(s):  
Layer Thickness ◽  
Amorphous Layer ◽  
Film Deposition ◽  
Titanium Silicide ◽  
Atomic Scale ◽  
Phase Identification ◽  
Atomic Steps ◽  
Si Substrates ◽  
Annealing Temperatures ◽  
Scale Roughness

AbstractTwo different Si(100) substrates, the 4°off-axis and the on-axis Si(100), were prepared. Ti thin films were deposited in an e-beam evaporation system and the amorphous layers of Ti-silicide were formed at different annealing temperatures. The Si(100) substrates before Ti film deposition were examined with AFM to verify the atomic scale roughness of the initial Si substrates. The amorphous layer was observed by HRTEM and TEM. And the chemical analysis and phase identification were examined by AES and XRD. The Si(100) substrate after HF clean shows the atomic scale microroughness such as atomic steps and pits on the Si surface. The on-axis Si(100) substrate exhibits much rougher surface morphologies than those of the off-axis Si(100). These differences of atomic scale roughnesses of Si substrates result in the difference of the thicknesses of amorphous Ti-silicide layers. The amorphous layer thicknesses on the on-axis exhibit thicker than those of the off-axis Si(100) and these differences inamorphous layer thicknesses became decreased as annealing temperatures increased. These indicate that the role of the atomic scale roughness on the amorphous layer thickness is much significant at low temperatures. In this study, the correlation between the atomic scale roughness and the amorphous layer thickness is discussed in terms of the atomic steps and pits based on the observation with using analysis tools such as AFM, TEM and HRTEM.

Phase transition and piezoelectricity of sol–gel-processed Sm-doped BiFeO3 thin films on Pt(111)/Ti/SiO2/Si substrates

2015 ◽  
Vol 3 (9) ◽  
pp. 2115-2122 ◽  
Author(s):  
Wei Sun ◽  
Jing-Feng Li ◽  
Qi Yu ◽  
Li-Qian Cheng
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Sol Gel ◽  
Orthorhombic Phase ◽  
High Quality ◽  
Si Substrates ◽  
Bifeo3 Thin Films ◽  
Gel Processing

We prepared high-quality Bi1−xSmxFeO3 films on Pt(111)/Ti/SiO2/Si substrates by sol–gel processing and found rhombohedral–orthorhombic phase transition with enhanced piezoelectricity.

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