Use Of Transmission Electron Microscope Research Articles

Development of low-temperature bonding platform using ultra-thin area selective deposition for heterogeneous integration

The Cu-Cu bonding technology is an indispensable vehicle for achieving heterogeneous integration, providing architects and designers with a new solution to address the limitations of transistor miniaturization. In this study, a next-generation efficient-process passivation bonding technology has been developed and investigated. The area-selective passivation bonding platform enables chips to be bonded at ambient temperatures below 200 ℃, while mitigating potential patterning issues and simplifying the complex conventional passivation process. The surface exploration of the area-selective films and their bonding mechanism have been thoroughly investigated through the use of transmission electron microscope (TEM) analyses. The results demonstrate exceptional film quality and the bonded reliability of the area-selective films. Furthermore, devices bonded using an optimized process exhibit more reliable mechanical strength than those bonded using conventional passivation methods.

Deformation twinning during high temperature compression tests of the Ni-base superalloy ATI 718Plus®

This study discusses the deformation mechanisms active during high temperature compression tests of the Ni-base superalloy ATI 718Plus®. Deformation twins were observed in deformed grains across a range of temperatures and strain rates by use of transmission electron microscopes (TEM). Even at strain rates as low as 0.01 s−1 and temperatures up to 1025∘C the microstructure contained of grains which deformed by deformation twinning. It was concluded that the low stacking fault energy of the alloy, which was measured to be 15mJm−2 caused the formation of the deformation twins. In addition, several examples of the early stages of twin formation were captured. The twinning partials were in most cases emitted from grain boundaries. In a second instance cross-slip events from a Frank-Read source lead to the formation of partials which formed stacking faults.

MICROSCOPICAL AND SEROLOGICAL STUDIES WITH ULTRASTRUCTURE DESCRIPTION OF SARCOCYSTIS SPECIES IN SHEEP IN ASSIUT

This study was conducted to determine theinfection rate of Sarcocystis species in sheep in Assiut. A total of 100 slaughtered sheep examined for Sarcocystis, no macroscopic cysts were observed, 93% (93/100) were positive by microscopical examination and 28% (28/100) were positive by using Agar gel diffusion test.Theinfection rate of Sarcocystis had very high significant differences between microscopic examination and Agar gel diffusion test. High statistical significant effect was found on the infection rate of Sarcocystis in different examined muscles of sheep. The highest infection rate was recorded in oesophagus (71%), followed by diaphragm (65%), tongue (58%), skeletal muscles (53%) and heart muscles (43%). The infection rate of Sarcocystis in males was 95.2% (40/42) while in females were 91.4% (53/58) by microscopical examination. Higher infection rate of Sarcocystis were detected in sheep 6 months - 2 years age 95% (38/40) than that of sheep between 2-4 years old 92.7% (38/41) and those equal or older than 4 years 89.5% (17/19). No significant difference between infection and age groups or sex of animals was observed. The use of transmission electron microscope (TEM) allowed the identification of S. tenella and S. arieticanis in sheep in Assiut. Examination of S. tenella cyst wall with TEM showed palisade-like villar protrusions while, examination of S. arieticanis cyst wall showed hair-like villar protrusions parallel to cyst wall.

Adhesion of silver/polypyrrole nanocomposite coating to a fluoropolymer substrate

This paper describes the adhesive interface between a conducting polymer/metal composite and a polytetrafluoroethylene (PTFE) substrate. Strong adhesion was observed from using a Ag/polypyrrole (Ag/PPy) composite on a fluoropolymer substrate, which in most cases has a very low adhesion to different materials. To clarify the adhesion mechanism between the Ag/PPy composite and the PTFE substrate, the interfacial structure was studied by the use of transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Our results show that Ag/PPy composite is absorbed inside the nano-sized pores of PTFE and the composite mechanically interlocks after solidifying, which causes the nanocomposite to stick strongly to the substrate. The use of Ag/PPy coating could be a novel technique for developing electrodes, antennae or other high performance applications as this metal/conductive polymer composite has excellent adhesion properties on various plastics.

In situ conversion of nanostructures from solid to hollow in transmission electron microscopes using electron beam.

With the current development of electron beam sources, the use of transmission electron microscopes is no more limited to imaging or chemical analysis but has rather been extended to nanoengineering. This includes the e-beam induced growth, etching and structural transformation of nanomaterials. In this review we summarize recent progress on the e-beam induced morphological transformation of nanostructures from solid to hollow. We provide a detailed account of the processes reported so far in the literature with a special emphasis on the mechanistic understanding of the e-beam induced hollowing of nanomaterials. Through an important number of examples, we discuss how one can achieve a precise control of such hollowing processes by understanding the fundamental mechanisms occurring at the atomic scale during the irradiation of solid nanostructures. Finally, we conclude with remarks and our own view on the prospective future directions of this research field.

Effect of boron concentration on physicochemical properties of boron-doped carbon nanotubes

Boron-doped carbon nanotubes (B-CNTs) were synthesized using chemical vapour deposition (CVD) floating catalyst method. Toluene was used as the carbon source, triphenylborane as boron as well as the carbon source while ferrocene was used as the catalyst. The amount of triphenylborane used was varied in a solution of toluene and ferrocene. Ferrocene was kept constant at 2.5 wt.%. while a maximum temperature of 900 °C was used for the synthesis of the shaped carbon nanomaterial (SCNMs). SCNMs obtained were characterized by the use of transmission electron microscope (TEM), scanning electron microscope (SEM), high resolution-electron microscope, electron dispersive X-ay spectroscopy (EDX), Raman spectroscopy, inductively coupled plasma-optical emission spectroscopy (ICP-OES), vibrating sample magnetometer (VSM), nitrogen adsorption at 77 K, and inverse gas chromatography. TEM and SEM analysis confirmed SCNMs obtained were a mixture of B-CNTs and carbon nanofibres (B-CNF). EDX and ICP-OES results showed that boron was successively incorporated into the carbon hexagonal network of CNTs and its concentration was dependent on the amount of triphenylborane used. From the VSM results, the boron doping within the CNTs introduced ferromagnetic properties, and as the percentage of boron increased the magnetic coactivity and squareness changed. In addition, boron doping changed the conductivity and the surface energy among other physicochemical properties of B-CNTs.

Abstract 16789: Loss of Endothelial Barrier in Fibrillin-1-Deficient Marfan Mice (mgR/mgR) Results in Severe Inflammation After Adenoviral Gene Therapy

Introduction: Nowadays surgery still remains option of choice for therapy of aneurysm in Marfan syndrome. Aortic tissue of Marfan patients shows elastolysis enhanced by proteolytic activity of Matrix Metalloproteinases (MMPs). In this study we performed adenoviral gene transfer of Tissue Inhibitor of MMP-1 (TIMP-1) in aortic grafts of Fibrillin-1-deficient Marfan mice (mgR/mgR) in order to reduce aortic elastolysis. Methods: We performed heterotopic infrarenal transplantation of thoracic aorta in female mice (n=35, n=7/group). MgR/mgR and wild-type (WT) aorta (C57BL/6) was either incubated ex vivo with adenoviral vector coding for human TIMP-1 or ß-Galactosidase (5x10^9pfu/ml) or as control with culture medium. 30 days after surgery overexpression of transgene was assessed by immunohistochemistry (IHC) and collagen in situ zymography (ISZ). Histologic staining was performed to outline elastin breaks, signs of inflammation and Neointimal Index (NI). Endothelial barrier was evaluated with the use of transmission electron microscope (TEM) and perfusion of fluorescent albumin. Results: IHC and ISZ revealed sufficient expression of transgene. Severe intimal hyperplasia and distinctive signs of cellular inflammation were solely observed in mgR/mgR aorta after adenoviral transduction (NI: ß-Gal 0.23; TIMP-1 0.43), but not in WT aorta (NI: Native 0.01; TIMP-1 0.00). Compared to native mgR/mgR and TIMP-1 treated WT aorta, NI in TIMP-1 treated mgR/mgR aorta was highly significantly larger (p=0.001; p=0.001). Native mgR/mgR grafts presented with severe elastolysis compared to WT (p=0.001). Regardless of the vector transduced elastolysis in mgR/mgR aorta after adenoviral gene therapy was more pronounced compared to WT aorta (ß-Gal p=0.001; TIMP-1 p=0.001). Albumin diffusion through the endothelial barrier was increased in native mgR/mgR aorta compared to native WT aorta (p=0.037). TEM analysis of mgR/mgR aorta displayed reconstruction of the basement membrane and basolateral space. Conclusions: Murine Marfan aortic grafts developed severe inflammation after adenoviral exposure. Fibrillin-1-deficiency is associated with dysfunction of endothelial barrier which could be a target for alternative therapies in Marfan syndrome.

A Triple Beam <i>In</i>-<i>Situ</i> Facility at Xiamen University

The ion implantation is a powerful scientific and technological tool in material research. Multiple ion beam facilities have been used to simulate the irradiation effects of neutrons on relevant nuclear materials over 30 years. By the use of transmission electron microscope (TEM) link facility, the microstructure evolvement in material can be in-situ studied during the irradiation and following annealing processes. In this paper, a triple beam in-situ facility, composed of a 400kV heavy ion implanter, a 50kV hydrogen­helium coaxial ion implanter and a 300kV electron microscope, will be presented. This facility will also be the first in-situ facility with the capacity of delivering the triple ion beam including hydrogen, helium and heavy ion beam to the specimen in TEM simultaneously. The angle between the two beam lines and microscope axis is 30°, respectively. [doi:10.2320/matertrans.MD201301]

The fine structure of the midgut epithelium in a centipede, Scolopendra cingulata (Chilopoda, Scolopendridae), with the special emphasis on epithelial regeneration

Scolopendra cingulata has a tube-shaped digestive system that is divided into three distinct regions: fore-, mid- and hindgut. The midgut is lined with a pseudostratified columnar epithelium which is composed of digestive, secretory and regenerative cells. Hemocytes also appear between the digestive cells of the midgut epithelium. The ultrastructure of three types of epithelial cells and hemocytes of the midgut has been described with the special emphasis on the role of regenerative cells in the protection of midgut epithelium. The process of midgut epithelium regeneration proceeds due to the ability of regenerative cells to proliferate and differentiate according to a circadian rhythm. The regenerative cells serve as unipotent stem cells that divide in an asymmetric manner.Additionally, two types of hemocytes have been distinguished among midgut epithelial cells. They enter the midgut epithelium from the body cavity. Because of the fact that numerous microorganisms occur in the cytoplasm of midgut epithelial cells, we discuss the role of hemocytes in elimination of pathogens from the midgut epithelium. The studies were conducted with the use of transmission electron microscope and immunofluorescent methods.

Direct Growth of Au-Ga2O3 Core-Shell Nanowires and Their Field Emission Properties

A simple, direct synthesis method for the growth of Au-Ga2O3 core-shell nanowires was reported in the work. The uneven concentration of precursor in Au catalyst in the vapor-liquid-solid process was proposed to induce a different growth rate at the interface between substrate and catalyst. The as-synthesized nanostructures were investigated by the use of transmission electron microscope. The existence of ~10 nm Ga3O layer at the surface of Au tip was verified by high angle annular dark field images. The small electron affinity of the thin layer Ga3O results in a remarkably high field enhancement factor of ~1200, and a lower turn-on field of ~4.7 V um-1 in the field emission measurement. This simple approach and outstanding field emission performance promises future applications of core-shell nanowires in nanoelectronics and vacuum electronic.

Dislocation Configurations in Single-Crystal Superalloys during High-Temperature Low-Stress Creep

Dislocation configurations in two single-crystal superalloys during high-temperature low-stress creep (1100°C, 137 MP) were illustrated schematically with the use of transmission electron microscope (TEM). For an alloy with a small lattice misfit, the dislocations move in the combination of climbing and gliding processes. In the primary stage, the dislocations first move by slip in the g-matrix channels. When they reach the g¢ cuboids, they move by climb along the g¢ cuboid surfaces. In the secondary creep stage, dislocation reorientation in the (001) interfacial planes happens slowly, deviating from the deposition orientation of <110> to the misfit orientation of <100>. For an alloy with a large lattice misfit, the dislocations are able to move smoothly by cross slip in the horizontal g channels. The dislocation reorientation from the deposition orientation of <110> to the misfit orientation of <100> in the (001) interfacial planes can be completed in the primary creep stage.

Structural Characterization of Organics Using Manual and Automated Electron Diffraction

In the last decade the importance of transmission electron microscopic studies has become increasingly important with respect to the characterization of organic materials, ranging from small organic molecules to polymers and biological macromolecules. This review will focus on the use of transmission electron microscope to perform electron crystallography experiments, detailing the approaches in acquiring electron crystallographic data. The traditional selected area approach and the recently developed method of automated diffraction tomography (ADT) will be discussed with special attention paid to the handling of electron beam sensitive organic materials.

Structure and Properties of the Melt-Spun Fe<sub>41</sub>Ni<sub>39</sub>P<sub>10</sub>Si<sub>5</sub>B<sub>5</sub> Alloy Heat Treated at Elevated Temperatures

The aim of the work was to provide information on structure development and change of properties at elevated temperatures in Fe41Ni39P10Si5B5 amorphous alloy. The alloy was characterized by X-ray diffraction. The changes of properties were characterized with use of dynamic mechanical thermal analysis (DMTA) and the resistivity measurements at elevated temperatures. The microstructure of the melt spun ribbon was investigated with use of transmission electron microscope (TEM) at different stages of phase transformations after heating to different temperatures. The initially amorphous structure undergoes phase transformations due to glass transition and crystallization of the alloy. The appearance of glass transition region results in decrease of storage modulus and in a reversible change of temperature coefficient of resistivity (TCR). The phases are characterized with use of TEM. The crystallization was found to have the two stages. Formation of bcc crystals and Ni12P5 is followed by transformation of the products into fcc crystals and Ni3P. Temporary changes of the storage modulus and elongation of the sample suggest formation of hard phases during crystallization.

Characterisation and structure development of Ni 64Cu 9Fe 8P 19 glass forming alloy at elevated temperatures

Nickel–copper–iron–phosphorus Ni 64Cu 9Fe 8P 19 alloy was prepared using 99.95 wt.% Ni, 99.95 wt.% Cu, 99.95 wt.% Fe and the Ni–P master alloy. The precursors were melted in the arc furnace under argon gettered protective atmosphere. Then the alloy was induction melted in quartz tubes under vacuum (10 −2 bar) and quenched in water to obtain ingot of 10 mm diameter. The primary microstructure of the ingot was investigated by the use of light microscope. The Ni 64Cu 9Fe 8P 19 alloy was cast using melt spinning. The ribbon in the as cast state was characterised with use of transmission electron microscope (TEM) and X-ray diffraction (XRD). Differential thermal analysis (DTA) of the melt-spun ribbon was made to determine the thermal stability and glass forming ability of the alloy. The pieces of ribbon were heated to different temperatures and annealed during 1 h then characterised with use of the Mössbauer spectroscopy and the X-ray diffraction to see the change of the microstructure after heating to elevated temperatures. It has been found that the devitrification sequence consists of progressive formation of the (Ni, Fe, Cu) 3P phase and (Ni, Fe, Cu)-FCC phase. The temperature range of the sequence is determined under isochronal conditions.

Kinetics of phase transformations in Ni 87P 13 alloy upon heating

Ni 87P 13 amorphous electroless alloy was prepared. For the alloy the structural disorder parameter was calculated and the alloy was investigated by means of the temperature dependence of the resistivity. Kinetic parameters of spherulitic growth process were evaluated. The spherulitic structure was characterized by use of transmission electron microscope.

Comparison of ultra high resolution immersion lens CFESEM and TEM for imaging of semiconductor devices

The use of transmission electron microscopes (TEM) has proven to be very valuable in the observation of semiconductor devices. The need for high resolution imaging becomes more important as the devices become smaller and more complex. However, the sample preparation for TEM observation of semiconductor devices have generally proven to be complex and time consuming. The use of ion milling machines usually require a certain degree of expertise and allow a very limited viewing area. Recently, the use of an ultra high resolution "immersion lens" cold cathode field emission scanning electron microscope (CFESEM) has proven to be very useful in the observation of semiconductor devices. Particularly at low accelerating voltages where compositional contrast is increased. The Hitachi S-900 has provided comparable resolution to a 300kV TEM on semiconductor cross sections. Using the CFESEM to supplement work currently being done with high voltage TEMs provides many advantages: sample preparation time is greatly reduced and the observation area has also been increased to 7mm. The larger viewing area provides the operator a much greater area to search for a particular feature of interest. More samples can be imaged on the CFESEM, leaving the TEM for analyses requiring diffraction work and/or detecting the nature of the crystallinity.

Transmission electron microscopic observation of CFU-Mix culture in normal adults and leukemia patients

By use of transmission electron microscope we demonstrated that the limiting dilution assay is an important method for investigating differentiation of hemopoietic cells in vitro. If various growth factors were added into this culture system, the stem cells of normal adults could differentiate into erythrocyte, granulocyte, megakaryocyte and macrophage, while leukemic progenitor cells could not. The colony forming cell in leukemia still had the nature of leukemic cell.

Surface studies of single copper crystals by REM

In the last decade, the use of transmission electron microscopes for surface imaging in the reflection mode has been shown to have considerable potential as a means for studying surfaces. Many REM (Reflection Electron Microscopy) studies have been done as reviewed recently by Cowley and Yagi. However, due to the lack of success with clean and flat single-crystal surface preparation technique, the surface studies of less inert metals, such as copper single crystal, have not been reported. The normal method of forming spherical platinum or gold single crystal by simply melting the end of platinum or gold thin wire with an acetylene-oxygen flame in air for REM observation is difficult here. The formation of flat copper surfaces occurs during the well-controlled crystallization process and is sensitively influenced by its physical and chemical properties. This paper reports a new method of overcoming these difficulties in the copper single crystal preparation. Observations of the samples have been made by REM and RHEED (Reflection High Energy Elecrton Diffraction).

Use of scanning and transmission electron microscopes for fractographic analysis of steels

1. The selection of transmission or scanning electron microscopes depends on the goal of the investigation and the object investigated. 2. The use of the transmission electron microscope is expedient in studying the characteristics of the fine structure which are revealed at large magnifications and require a high resolving capacity. 3. It is expedient to use the scanning electron microscope to study the characteristics of the structure which can be revealed by the three-dimensional picture in a large range of magnifications. 4. It is possible to determine the character of fracture from the fine structure (ductile, brittle, intergranular, and fatigue fractures) with scanning and transmission electron microscopes, since the microfractographic patterns obtained with both instruments are identical. 5. It is of considerable interest to analyze the characteri of fracture with the scanning electron microscope with use of stereoscopic images, which permit the most complete analysis of the structure. The method of preparing and analyzing stereoscopic images is of great practical interest, since it opens up additional possibilities for quantitative analysis of fractures.