In-Situ Observation Of Aln Formation During Nitridation Of Sapphire By Ultrahigh Vacuum Transmission Electron Microscopy

1997 ◽  
Vol 482 ◽  
Author(s):  
M. Yeadon ◽  
M. T. Marshall ◽  
F. Hamdani ◽  
S. Pekin ◽  
H. Morkoc ◽  
...  
Keyword(s):  
Ultrahigh Vacuum ◽  
Ex Situ ◽  
In Situ Observation ◽  
Island Growth ◽  
Kinetic Measurements ◽  
Transmission Electron ◽  
Before And After ◽  
Subsequent Exposure ◽  
Diffraction Patterns

AbstractUsing a novel ultrahigh vacuum transmission electron microscope (UHV TEM) with insitu molecular beam epitaxy capability we have studied the nitridation of (0001) sapphire upon exposure to ammonia. Atomically flat sapphire surfaces for the experiments were obtained by high temperature annealing. Subsequent exposure to ammonia flow at 950°C led to the successful synthesis of epitaxial AIN; the films were characterized in-situ using TEM. Complimentary ex-situ atomic force microscopy (AFM) was also performed in order to characterize the surface morphology before and after nitridation.The experiments indicate that AIN grows by a 3D island growth mechanism. Electron diffraction patterns suggest an abrupt AIN/sapphire interface with no evidence of the formation of Al–O–N compounds. The rate limiting step in the nitridation reaction appears to be the diffusion of nitrogen and oxygen species between the free surface of the growing AIN film and the reaction interface. It is inferred from kinetic measurements that diffusion of these species occurs along the boundaries between coalescing AIN islands.

Studies of Material Reactions by In Situ High-Resolution Electron Microscopy

MRS Bulletin ◽  
1994 ◽  
Vol 19 (6) ◽  
pp. 26-31 ◽  
Author(s):  
Robert Sinclair
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Atomic Scale ◽  
Ex Situ ◽  
New Materials ◽  
Kinetic Measurements ◽  
Transmission Electron ◽  
Resolution Electron

Processing has always been a key component in the development of new materials. Basic scientific understanding of the reactions and transformations that occur has obvious importance in guiding progress. Invaluable insight can be provided by observing the changes during processing, especially at high magnification by in situ microscopy. Now that this can be achieved at the atomic level by using high-resolution electron microscopy (HREM), atomic behavior can be seen directly. Accordingly, many deductions concerning reactions in materials at the atomic scale are possible.The purpose of this article is to illustrate the level reached by in situ HREM. The essential procedure is to form a high-resolution image of a standard transmission electron microscope (TEM) sample and then to alter the structure by some means in a controlled manner, such as by heating. Continual recording on videotape allows subsequent detailed analysis of the behavior, even on a frame-by-frame (1/30 second) basis. The most obvious advantage is to follow the atomic rearrangements directly in real time. However, in addition, by continuous recording no stages in a reaction are missed, which can often occur in a series of conventional ex situ annealed samples because of the limited number of samples that can realistically be examined by HREM. One can be sure that the same reaction, in the same area, is being studied. Furthermore, by changing the temperature systematically, extremely precise kinetic measurements can be made (e.g., for activation energies and kinetic laws) and the whole extent of a material transformation can be investigated in one sample, something that would take months of work if studied conventionally. The information provided by in situ HREM is often unique and so it can become an important technique for fundamental materials investigations.

In-situ TEM Observation for Reaction Mechanism in MgH2 Hydrogen Storage Material

2009 ◽  
Vol 1216 ◽  
Author(s):  
Akifumi Ono ◽  
Shigehito Isobe ◽  
Yongming Wang ◽  
Naoyuki Hashimoto ◽  
Somei Ohnuki
Keyword(s):  
Hydrogen Diffusion ◽  
In Situ Tem ◽  
In Situ Observation ◽  
Desorption Process ◽  
Voltage Electron ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Diffraction Patterns ◽  
Nano Size

AbstractIn-situ observation on the catalytic effect of Nb2O5 in MgH2 was carried out by using transmission electron microscopy (TEM). We prepared two kinds of samples, because we tried to observe the reaction from two kinds of viewpoints. MgH2 catalyzed with 1 mol% of Nb2O5 was prepared for an overall viewpoint on the desorption process of MgH2 with catalyst by conventional TEM. The dehydrogenation of the 1 mol% sample started at 150 °C and Mg nano-size particles were formed. However, Nb2O5 was not confirmed in diffraction patterns and images, because it was highly dispersed by ball-milled. So MgH2 catalyzed with 10 mol% of Nb2O5 was prepared for local viewpoint to focus the boundary between the catalyst and the Mg phase by high voltage electron micro scope (HVEM). The sample mixed in mortar was prepared for this, because it was difficult to find the boundary in the sample ball-milled. The high resolution images of the 10 mol% sample revealed that the dehydrogenation started from the interface of MgH2 and Nb2O5. The result suggested that the dehydrogenation could proceed with hydrogen diffusion from MgH2 phase to the interface between Mg and Nb2O5.

A Jeolco 200A Cartridge with Specimen Heating, Tilting, and Power Provisions

1975 ◽  
Vol 33 ◽  
pp. 152-153
Author(s):  
R. M. Anderson ◽  
J. K. Howard ◽  
P. Fullam
Keyword(s):  
Integrated Circuits ◽  
Thin Metal Film ◽  
Ex Situ ◽  
In Situ Observation ◽  
Electron Microscopic ◽  
Transmission Electron Microscopic Study ◽  
Transmission Electron ◽  
Heat Treated ◽  
Gradient Effects

The transmission electron microscopic study of thin metal film interconnections on electronic integrated circuits requires a sophisticated in-situ capability. Electromigration, particularly, cannot be investigated solely by viewing static heat-treated or electrically stressed specimens ex-situ. The key to the early electromigration studies by Blech, and others, was the in-situ observation of material movement in anelectrical-powering-stage equipped TEM. Blech's approach was insensitive to structure effects because of an absence of heating capability; he therefore relied on joule heating and temperature gradient effects.

Development of UHVTEM with UHV compatible goniometer and specimen-treatment chamber for surface studies

1994 ◽  
Vol 52 ◽  
pp. 496-497
Author(s):  
Y. Kondo ◽  
H. Kobayashi ◽  
Y. Ishibashi ◽  
T. Kasai ◽  
H. Nunome ◽  
...  
Keyword(s):  
Ultrahigh Vacuum ◽  
The Other ◽  
In Situ Observation ◽  
Surface Studies ◽  
Transmission Electron ◽  
New Type ◽  
Pre Treatment ◽  
Electron Microscopes ◽  
And Performance

JEOL has previously been involved in the development of various ultrahigh vacuum transmission electron microscopes (UHVTEM). Interest in UHVTEM is increasing, and for higher vacuum, higher resolution and specimen treatment capability, we have developed a new type of UHVTEM, the JEM- 2000FXVII. This paper reports the construction and performance of this new UHVTEM including a newly developed UHV compatible goniometer, specimen treatment chamber and various types of specimen heating holders.Figure 1 shows the overview of the JEM-2000FXVII with a specimen pre-treatment chamber (PTC) and UHV compatible goniometer. The PTC consists of two chambers: one for specimen treatment and the other for pre-evacuation. Specimen treatment is accomplished by using any of 7 attachment ports (six 70ϕ ICFs and a 152ϕ ICFs) in the PTC (Fig. 2). The PTC is attached directly to the TEM column and quick exchange of the specimen from PTC to column is thus possible. In-situ observation is also possible using the three attachment ports (70ϕ ICFs) in the column.

scholarly journals In Situ Observation of Liquid Solder Alloys and Solid Substrate Reactions Using High-Voltage Transmission Electron Microscopy

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 510
Author(s):  
Xin F. Tan ◽  
Flora Somidin ◽  
Stuart D. McDonald ◽  
Michael J. Bermingham ◽  
Hiroshi Maeno ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Voltage ◽  
Ex Situ ◽  
In Situ Observation ◽  
Liquid Solder ◽  
Solder Alloys ◽  
Transmission Electron ◽  
High Voltage Transmission

The complex reaction between liquid solder alloys and solid substrates has been studied ex-situ in a few studies, utilizing creative setups to “freeze” the reactions at different stages during the reflow soldering process. However, full understanding of the dynamics of the process is difficult due to the lack of direct observation at micro- and nano-meter resolutions. In this study, high voltage transmission electron microscopy (HV-TEM) is employed to observe the morphological changes that occur in Cu6Sn5 between a Sn-3.0 wt%Ag-0.5 wt%Cu (SAC305) solder alloy and a Cu substrate in situ at temperatures above the solidus of the alloy. This enables the continuous surveillance of rapid grain boundary movements of Cu6Sn5 during soldering and increases the fundamental understanding of reaction mechanisms in solder solid/liquid interfaces.

In situ Transmission Electron Microscopy Investigation of Radiation Effects

2005 ◽  
Vol 20 (7) ◽  
pp. 1654-1683 ◽  
Author(s):  
R.C. Birtcher ◽  
M.A. Kirk ◽  
K. Furuya ◽  
G.R. Lumpkin ◽  
M-O. Ruault
Keyword(s):  
Radiation Effects ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Ex Situ ◽  
In Situ Observation ◽  
Dislocation Loops ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Ion Impact

In situ observation is of great value in the study of radiation damage utilizing electron or ion irradiation. We summarize the facilities and give examples of work found around the world. In situ observations of irradiation behavior have fallen into two broad classes. One class consists of long-term irradiation, with observations of microstructural evolution as a function of the radiation dose in which the advantage of in situ observation has been the maintenance of specimen position, orientation, and temperature. A second class has involved the recording of individual damage events in situations in which subsequent evolution would render the correct interpretation of ex situ observations impossible. In this review, examples of the first class of observation include ion-beam amorphization, damage accumulation, plastic flow, implant precipitation, precipitate evolution under irradiation, and damage recovery by thermal annealing. Examples of the second class of observation include single isolated ion impacts that produce defects in the form of dislocation loops, amorphous zones, or surface craters, and single ion impact-sputtering events. Experiments in both classes of observations attempt to reveal the kinetics underlying damage production, accumulation, and evolution.

Crystallization of Glass Films on Single-Crystal MgO Substrates

1993 ◽  
Vol 321 ◽  
Author(s):  
Sundar Ramamurthy ◽  
Michael P. Mallamaci ◽  
C. Barry Carter
Keyword(s):  
Single Crystal ◽  
Magnesium Silicate ◽  
Heat Treatments ◽  
Ex Situ ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Before And After ◽  
Calcium Magnesium ◽  
Glass Films

ABSTRACTThin, calcium magnesium silicate glass films have been deposited onto (001) -oriented single-crystal MgO substrates by pulsed-laser deposition (PLD). The substrates were thinned to electron transparency and characterized in the transmission electron Microscope (TEM) before and after the deposition and following different heat treatments. Energy Dispersive X-ray Spectroscopy (EDS) was used in the TEM to characterize the chemistry of the films. The heat treatments were performed both in situ and ex situ. Direct evidence for crystallization was obtained by in-situ experiments at 950°C. Subsequent heat treatments were performed for longer times in air between 950°C and 1100°C. The crystallized phase was found to be Monticellite (CaMgSiO4) and the crystallites show moderate epitaxy with the underlying substrate. Films contaminated with aluminum resulted in the growth of magnesium aluminate spinel (MgAl2O4) epitaxially from the substrate. These observations of epitaxy indicated that crystallization initiated at the surface of MgO.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

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