Transmission Electron Microscopy of Epitaxial silicides grown by ultra high vacuum deposition

1989 ◽  
Vol 47 ◽  
pp. 462-463
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Transmission Electron

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.

Modifications of a JEOL 2000EX TEM for insSitu surface studies

1993 ◽  
Vol 51 ◽  
pp. 640-641
Author(s):  
Michael T. Marshall ◽  
Xianghong Tong ◽  
J. Murray Gibson
Keyword(s):  
Electron Diffraction ◽  
Surface Science ◽  
Film Growth ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Transmission Electron ◽  
Fundamental Insight

We have modified a JEOL 2000EX Transmission Electron Microscope (TEM) to allow in-situ ultra-high vacuum (UHV) surface science experiments as well as transmission electron diffraction and imaging. Our goal is to support research in the areas of in-situ film growth, oxidation, and etching on semiconducter surfaces and, hence, gain fundamental insight of the structural components involved with these processes. The large volume chamber needed for such experiments limits the resolution to about 30 Å, primarily due to electron optics. Figure 1 shows the standard JEOL 2000EX TEM. The UHV chamber in figure 2 replaces the specimen area of the TEM, as shown in figure 3. The chamber is outfitted with Low Energy Electron Diffraction (LEED), Auger Electron Spectroscopy (AES), Residual Gas Analyzer (RGA), gas dosing, and evaporation sources. Reflection Electron Microscopy (REM) is also possible. This instrument is referred to as SHEBA (Surface High-energy Electron Beam Apparatus).The UHV chamber measures 800 mm in diameter and 400 mm in height. JEOL provided adapter flanges for the column.

Growth and Structure of Al/MgO Interfaces

1994 ◽  
Vol 357 ◽  
Author(s):  
T. Wagner ◽  
M. Ruhle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Ultra High Vacuum ◽  
Structural Defects ◽  
Cross Sectional ◽  
Aluminum Films ◽  
Transmission Electron

AbstractThe A1/MgO system has been used as a model system to study growth processes and structure at metal/ceramic interfaces. Aluminum films were grown on air-cleaved MgO (100) substrates in ultra high vacuum (UHV) by molecular beam epitaxy (MBE). The substrates and films were characterized by reflection high energy electron diffraction (RHEED), x-ray diffraction (XRD), conventional transmission electron microscopy (CTEM), and high resolution transmission electron microscopy (HREM). XRD measurements exhibited a pronounced {100} texture. Employing electron diffraction in the TEM on cross sectional samples, we observed the following orientation relationship between Al and MgO: (100)A1 II (100)MgO; [010]A1 II [010]MgO. The atomistic structure of the interface was investigated by HREM. Regions of structural defects can be identified clearly at the interface.

scholarly journals Surface Kinetics of Copper Oxidation Investigated by In Situ Ultra-high Vacuum Transmission Electron Microscopy

2001 ◽  
Vol 7 (6) ◽  
pp. 486-493 ◽  
Author(s):  
Judith C. Yang ◽  
Mridula D. Bharadwaj ◽  
Guangwen Zhou ◽  
Lori Tropia
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Water Vapor ◽  
High Vacuum ◽  
Quantitative Model ◽  
Ultra High Vacuum ◽  
Copper Oxidation ◽  
Initial Oxidation ◽  
Transmission Electron

AbstractWe review our studies of the initial oxidation stages of Cu(001) thin films as investigated by in situ ultra-high vacuum transmission electron microscopy. We present our observations of surface reconstruction and the nucleation to coalescence of copper oxide during in situ oxidation in O2. We have proposed a semi-quantitative model, where oxygen surface diffusion is the dominant mechanism of the initial oxidation stages of Cu. We have also investigated the effect of water vapor on copper oxidation. We have observed that the presence of water vapor in the oxidizing atmosphere retards the rate of Cu oxidation and Cu2O is reduced when exposed directly to steam.

Initial Oxidation Kinetics of Cu(100), (110), and (111) Thin Films Investigated by in Situ Ultra-high-vacuum Transmission Electron Microscopy

2005 ◽  
Vol 20 (7) ◽  
pp. 1684-1694 ◽  
Author(s):  
Guangwen Zhou ◽  
Judith C. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Diffusion ◽  
High Vacuum ◽  
Nucleation And Growth ◽  
Ultra High Vacuum ◽  
Initial Oxidation ◽  
Transmission Electron ◽  
Oxygen Surface

The initial oxidation stages of Cu(100), (110), and (111) surfaces have been investigated by using in situ ultra-high-vacuum transmission electron microscopy (TEM) techniques to visualize the nucleation and growth of oxide islands. The kinetic data on the nucleation and growth of oxide islands shows a highly enhanced initial oxidation rate on the Cu(110) surface as compared with Cu(100), and it is found that the dominant mechanism for the nucleation and growth is oxygen surface diffusion in the oxidation of Cu(100) and (110). The oxidation of Cu(111) shows a dramatically different behavior from that of the other two orientations, and the in situ TEM observation reveals that the initial stages of Cu(111) oxidation are dominated by the nucleation of oxide islands at temperatures lower than 550 °C, and are dominated by two-dimensional oxide growth at temperatures higher than 550 °C. This dependence of the oxidation behavior on the crystal orientation and temperature is attributed to the structures of the oxygen-chemisorbed layer, oxygen surface diffusion, surface energy, and the interfacial strain energy.

The Low-temperature Initial Oxidation Stages of Cu(100) Investigated by in situ Ultra-high-vacuum Transmission Electron Microscopy

2005 ◽  
Vol 20 (7) ◽  
pp. 1910-1917 ◽  
Author(s):  
L. Sun ◽  
J.C. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Vacuum ◽  
Three Dimensional ◽  
Nucleation And Growth ◽  
Ultra High Vacuum ◽  
Initial Oxidation ◽  
Triangular Shape ◽  
Transmission Electron

The nucleation and growth of Cu2O islands due to Cu(100) oxidation at temperatures from 200 to 350 °C have been observed by in situ ultra-high-vacuum transmission electron microscopy. For this temperature range, epitaxial Cu2O islands form a triangular shape with rounded edges when Cu(100) is exposed to dry oxygen at 5 × 10−4 Torr in situ. Our initial analysis on the nucleation and growth of these three-dimensional Cu2O islands agrees well with the heteroepitaxial model of surface diffusion of oxygen.

Si NWs Conversion to Si-SiC Core-Shell NWs by MBE

2015 ◽  
Vol 821-823 ◽  
pp. 965-969
Author(s):  
Fernando Lloret ◽  
D. Araujo ◽  
M.P. Villar ◽  
L. Liu ◽  
Konstantinos Zekentes
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Vacuum ◽  
High Energy ◽  
Ultra High Vacuum ◽  
Si Nanowires ◽  
Transmission Electron ◽  
Set Up

Si nanowires (NWs) samples have been converted to silicon carbide (SiC) NWs at different conditions of substrate temperature in an ultra-high vacuum using a molecular beam epitaxy (MBE) set-up. Auger electron spectroscopy (AES) and reflection high-energy electron diffraction (RHEED) have been in-situ carried out to control the growth process. Scanning electron microscopy (SEM) and conventional transmission electron microscopy (CTEM) have been used to characterize the resulting nanostructures. In addition, the samples have been prepared by focused ion beam (FIB) in order to have electron-transparently lamellas for TEM with the interface nanowire-substrate. SiC/Si shell/core NWs free of planar defects have been obtained for conversion tmpratures lower than 800oC.

Silicon Homoepitaxy at 300°C Using ArF Excimer Laser Photolysis of Disilane

1990 ◽  
Vol 201 ◽  
Author(s):  
B. Fowler ◽  
T. Lian ◽  
D. Bullock ◽  
S. Banerjee
Keyword(s):  
Electron Diffraction ◽  
Excimer Laser ◽  
Growth Rates ◽  
Defect Density ◽  
High Vacuum ◽  
High Energy ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Arf Excimer Laser

AbstractPhotolysis of Si2H6 by an ArF excimer laser has been used to deposit Si homoepitaxial layers at temperatures as low as 300°C. The chemical vapor deposition process at growth rates from 0.5-4 Å/minute is performed in an ultra-high vacuum chamber which, along with an ex situ HF dip and a novel in situ hydrogen clean using laser excitation, results in minimization of oxygen and carbon contamination which inhibits Si epitaxy. The growth involves photolytic decomposition of Si2H6 and the generation and adsorption of SiH2 precursors on the hydrogenated Si surface, which is the rate limiting step. Growth rates are observed to vary proportionally with laser power. Very low defect density films in terms of stacking faults and dislocation loops (less than 105 cm−2), and excellent crystallinity have been deposited as confirmed by Schimmel etching and Nomarski microscopy, transmission electron microscopy, electron diffraction and in situ reflection high energy electron diffraction.

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