Are major instrumental developments in TEM still to be Expected?

1988 ◽  
Vol 46 ◽  
pp. 646-647
Author(s):  
K.D. van der Mast ◽  
A.J. Koster
Keyword(s):  
Surface Science ◽  
New Technologies ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Analytical Instrument ◽  
Electron Efficiency ◽  
In Situ Experiments ◽  
New Ideas

In general instrumental developments are caused either by new application demands or by the availability of new technologies. If we investigate the trends in application demands, some predictions can be made safely: More and more the TEM will be used as an analytical instrument. The number of desired signals (detectors) will increase and the quality of the signals must be improved in terms of noise and electron efficiency. Examples are parallel collection EELS and Auger detectors (Kruit and Venables, 1988).The first experiments on coincidence techniques are also promising (Kruit et al, 1984) and exciting new ideas are investigated today. Besides this, another area of applications will probably become more important: surface science in situ experiments. Especially for this type of experiments it is difficult to transfer the specimen to another system without spoiling the experiment. So these applications will lead to an ultra high vacuum specimen environment - constructed in a way that many accessories necessary for surface experiments can be added: Ion guns, preparation chamber, knudsen cells etc.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

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.

Using a Moderate Vacuum, Hot/Cryo-Stage Equipped AFM for In-Situ Observation of α-Phase Growth In 60SN40PB Hypoeutectic Solder

1998 ◽  
Vol 4 (S2) ◽  
pp. 316-317
Author(s):  
D. N. Leonard ◽  
P.E. Russell
Keyword(s):  
Surface Science ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
In Situ Observation ◽  
Atmospheric Conditions ◽  
Tunneling Microscopy ◽  
Wide Range ◽  
Gas Environment

Atomic force microscopy (AFM) was introduced in 1984, and proved to be more versatile than scanning tunneling microscopy (STM) due to the AFM's capabilities to scan non-conductive samples under atmospheric conditions and achieve atomic resolution. Ultra high vacuum (UHV) AFM has been used in surface science applications when control of oxidation and corrosion of a sample's surface are required. Expensive equipment and time consuming sample exchanges are two drawbacks of the UHV AFM system that limit its use. Until recently, no hot/cryo-stage, moderate vacuum, controlled gas environment AFM was commonly available.We have demonstrated that phase transformations are easily observable in metal alloys and polymers with the use of a moderate vacuum AFM that has in-situ heating/cooling capabilities and quick (within minutes) sample exchange times. This talk will describe the results of experiments involving a wide range of samples designed to make use of the full capabilities of a hot/cryo-stage, controlled gas environment AFM.

Initial Oxidation Kinetics of Copper (110) Thin Films As Investigated By IN SITU UHV-TEM

2001 ◽  
Vol 7 (S2) ◽  
pp. 1274-1275
Author(s):  
Guang-Wen Zhou ◽  
Mridula D.Bharadwaj ◽  
Judith C.Yang
Keyword(s):  
Surface Science ◽  
Room Temperature ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Science Methods ◽  
Metal Oxidation ◽  
Initial Oxidation ◽  
Transmission Electron ◽  
Kinetics Of

In the study of metal oxidation, there is a wide gap between information provided by surface science methods and that provided by bulk oxidation studies. The former have mostly examined the adsorption of up to ∽1 monolayer (ML) of oxygen on the metal surface, where as both low and high temperature bulk oxidation studies have mainly focused on the growth of an oxide layer at the later stages of oxidation. Hence, we are visualizing the initial oxidation stages of a model metal system by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM), where the surfaces are atomically clean, in order to gain new understanding of these ambiguous stages of oxidation. We have previously studied the growth of Cu2O islands during initial oxidation of Cu(100) film. We are presently investigating the initial stages of Cu(110) oxidation, from 10−4 Torr O2 to atmospheric pressures and temperature range from room temperature to 700 °C.

In Situ Uhv-Tem Oxidation And Reduction Of Metals

1999 ◽  
Vol 5 (S2) ◽  
pp. 132-133
Author(s):  
J. C. Yang ◽  
M Yeadon ◽  
B. Kolasa ◽  
J. M. Gibson
Keyword(s):  
Surface Science ◽  
Materials Science ◽  
Film Growth ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Science Methods ◽  
Copper Oxidation ◽  
Transmission Electron ◽  
Partial Pressures

In this proceedings, we present a review of our experimental results of our investigations of the mechanisms of the initial stages of copper oxidation. We examined the initial stages of Cu(001) oxidation and reduction by in situ ultra-high vacuum (UHV) transmission, electron microscopy (TEM). We observed surface reconstruction and nucleation and growth of copper oxide islands. We have examined the oxidation processes from oxygen partial pressures of 10-5 torr to atmospheric pressures and temperatures from 25°C to 600°C, in order to gain fundamental insights into this important gas-metal reaction.Fundamental knowledge of gas-metal reactions, in particular oxidation, is important for a wide variety of materials science fields, such as dry corrosion, catalysis, as well as some thin film growth, such as ferroelectrics. However, there is a wide gap between information provided by surface science methods and that provided by bulk oxidation studies. The former have mostly examined the adsorption of up to ˜1ML of oxygen on the metal surface.

Initial Kinetics of Copper Oxidation in Different Oxidizing Atmospheres as Studied by In Situ UHV-TEM

2000 ◽  
Vol 6 (S2) ◽  
pp. 42-43
Author(s):  
Mridula D. Bharadwaj ◽  
Lori Tropia ◽  
Murray Gibson ◽  
Judith C. Yang
Keyword(s):  
Surface Science ◽  
High Vacuum ◽  
Practical Interest ◽  
Ultra High Vacuum ◽  
Copper Oxidation ◽  
Initial Oxidation ◽  
Kinetics Of Oxidation ◽  
Transmission Electron ◽  
Kinetics Of

It is of fundamental and practical interest to understand the oxidation process since a desirable property for metals is resistance to corrosion. But there is a wide gap between information provided by surface science methods and that provided by bulk oxidation studies. The former have mainly examined the adsorption of ∼ 1 ML of oxygen on the metal surface, where as both low and high temperature bulk oxidation studies have mainly focused on the growth of an oxide layer at the later stages of oxidation.We are probing the initial oxidation stage of a model metal system by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM) in order to gain insights into the initial kinetics of oxidation. We have previously shown that the growth mechanism of the cuprous oxide is initially dominated by oxygen surface diffision.

In-Situ Tem Observations of Electron Beam-Stimulated Reactions in NiO Under Oxidizing and Reducing Atmospheres

1991 ◽  
Vol 235 ◽  
Author(s):  
M. I. Buckett ◽  
L. D. Marks
Keyword(s):  
Radiation Damage ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
In Situ Tem ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Damage Process ◽  
Electron Stimulated Desorption ◽  
Surface Environment

ABSTRACT:L: NiO surfaces have been the subject of numerous investigations using a wide variety of techniques, including transmission electron microscopy (TEM). The findings, however, remain inconclusive regarding the relative contributions of irradiation effects such as ballistic erosion, electron-stimulated desorption (ESD) and electron-stimulated reaction (ESR), especially at incident electron energies exceeding 100 keV. In earlier studies it was suggested that the surface environment played a significant role in the radiation damage process. In this study, the effect of the surface environment is further illustrated by in-situ experiments in controlled sample environments. NiO surfaces were irradiated with electrons, ranging in energy from 3 keV to 300 keV, and examined in-situ under ultra-high vacuum (UHV) conditions (10−10 Torr), as well as in controlled oxidizing (oxygen) and reducing (CO) atmospheres. The nature of the surface reactions and their contribution to the overall radiation damage process in the various energy regimes is examined.

Methods and Applications of UV Photoelectron Microscopy in Surface Science

1990 ◽  
Vol 48 (1) ◽  
pp. 564-565
Author(s):  
M. Mundschau ◽  
E. Bauer ◽  
W. ᔒwięch
Keyword(s):  
Surface Science ◽  
Semiconductor Industry ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Significant Advance ◽  
Crystalline Substance ◽  
Order Of Magnitude ◽  
Molecular Layers ◽  
Proper Interpretation

Photoelectron microscopy is sensitive to single atomic or molecular layers on surfaces at submonolayer coverages. A significant advance for fundamental studies in surface science has been the construction of ultra-high vacuum versions of classical photoelectron microscopes and the combination with other techniques of surface analysis - most notably low-energy electron diffraction and microscopy. This is essential for the proper interpretation of the micrographs. The technique is well suited for in situ studies of large flat samples such as silicon wafers, single crystals and polished metallurgical samples.One of the most promising fields for application of the photoelectron microscope is in the area of epitaxial growth.In epitaxy a crystalline substance grows as an oriented overgrowth atop a substrate. It has widespread use in the semiconductor industry and in the field of quantum electronics, in which epitaxially grown structures have the dimensions of the same order of magnitude as the wavelengths of the conducting electrons.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Hetero-Epitaxy of Group Va Metals on Sapphire

1972 ◽  
Vol 30 ◽  
pp. 492-493
Author(s):  
J. E. O'Neal ◽  
J. J. Bellina ◽  
B. B. Rath
Keyword(s):  
Thermal Contact ◽  
High Vacuum ◽  
Electron Beam Evaporation ◽  
Ultra High Vacuum ◽  
Backing Plate ◽  
Sapphire Substrates ◽  
Deposition Parameters ◽  
Polishing Damage ◽  
Reflection Electron Diffraction

Thin films of the bcc metals vanadium, niobium and tantalum were epitaxially grown on (0001) and sapphire substrates. Prior to deposition, the mechanical polishing damage on the substrates was removed by an in-situ etch. The metal films were deposited by electron-beam evaporation in ultra-high vacuum. The substrates were heated by thermal contact with an electron-bombarded backing plate. The deposition parameters are summarized in Table 1.The films were replicated and examined by electron microscopy and their crystallographic orientation and texture were determined by reflection electron diffraction. Verneuil-grown and Czochralskigrown sapphire substrates of both orientations were employed for each evaporation. The orientation of the metal deposit was not affected by either increasing the density of sub-grain boundaries by about a factor of ten or decreasing the deposition rate by a factor of two. The results on growth epitaxy are summarized in Tables 2 and 3.

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