Specimen Preparation For Electron Microscopy Research Articles

Post-thinning technique for a lifted-out membrane

A novel technique for post-thinning of lifted-out membranes already mounted on a mesh was developed using a Ga(+) ion beam at an accelerating voltage of 5 kV. It was applied to the preparation of transmission electron microscopy specimens from a selected cell of a silicon dynamic random-access memory.

Focused ion beam and transmission electron microscopy method for root cause analysis of InP ridge laser devices

To remain competitive in industry, the continual assessment of product reliability is critical. This article discusses the focused ion beam preparation of transmission electron microscopy (TEM) specimens from InP ridge laser devices for observation and analysis of a wide range of microstructural and chemical phenomena (root cause) in reliability-tested lasers. A method is described that enables routine sectioning of ridge lasers mounted ridge up or down and/or beneath solder. The laser devices provided for reliability studies were fully wire bonded on ceramic carriers. Given the geometry, several specimens could be acquired from a single device. Here, it was imperative to thin the metal, dielectric and semiconductor layers in one specimen where the active region of the device was 1 to 3 μm below the metal contact. The structure and morphology of the devices were studied using analytical TEM with energy dispersive x-ray spectroscopy.

Freeze Fracture Direct Imaging: A New Freeze Fracture Method for Specimen Preparation in Cryo-Transmission Electron Microscopy

In this paper, we present a new freeze fracture method for specimen preparation for transmission electron microscopy frozen samples. We call it freeze fracture direct imaging (FFDI) because it is a hybrid of conventional freeze fracture electron microscopy (FFEM) and cryo-transmission electron microscopy (cryo-TEM), combining elements of the fracture technique with direct imaging. Like in FFEM, the sandwich method is used to prepare the sample in a protected fashion. However, after the sample is vitrified and fractured, it is not shadowed but directly imaged. The new technique avoids some experimental artifacts produced by the blotting procedure in conventional cryo-TEM. It relies, though, on occasional fractures transparent to the electrons. The advantageous features are demonstrated by a comparison between conventional cryo-TEM and FFDI micrographs of vesicular solutions. The second outstanding advantage over conventional cryo-TEM is the fact that it is now possible for the very first time to directly image oil-rich mixtures films which normally would dissolve in the cryo-medium ethane. Micrographs of pure oil and of oil-rich microemulsions clearly prove the reliability of the FFDI technique as well as its enormous potential.

Phase transformations of thermally grown oxide on (Ni,Pt)Al bondcoat during electron beam physical vapor deposition and subsequent oxidation

Phase constituents, morphology and microstructure of thermally grown oxide (TGO) as a function of electron beam physical vapor deposition (EP-PVD) time, (Ni,Pt)Al bondcoat surface treatment and subsequent oxidation in air were examined for a series of thermal barrier coatings (TBCs). Photostimulated luminescence spectroscopy (PSLS) and focused ion beam (FIB) in-situ lift-out (INLO) specimen preparation for (scanning) transmission electron microscopy were employed to characterize the TBCs. Photostimulated luminescence only from α-Al 2O 3 was observed on grit-blasted bondcoat for all YSZ deposition times, while that from metastable Al 2O 3 phases including α-Al 2O 3 was observed for the TGO on as-coated (i.e. not grit blasted) bondcoat. Relative to the luminescence intensity of the α-Al 2O 3, the luminescence intensity from the metastable Al 2O 3 phases decreased with an increase in deposition time and corresponding thickness of ZrO 2–Y 2O 3 (YSZ). On subsequent oxidation in air at 1000, 1050 and 1100 °C for 0.5, 10 and 50 h, the luminescence intensity from the metastable Al 2O 3 phases decreased while that of α-Al 2O 3 increased. These observations regarding the phase constituents of TGO were confirmed by diffraction analysis using high resolution TEM (HR-TEM) via FIB INLO. The initial development of the TGO during EB-PVD deposition consisted of a mixed-oxide zone. The relative thickness of the mixed-oxide zone for TGO formed on the as-coated bondcoat surface was greater than that of TGO formed on grit-blasted bondcoat surface. The variation in the presence of metastable Al 2O 3 in the TGO for as-processed TBCs was observed to influence the overall growth of TGO during short-term isothermal oxidation, particularly as the temperature decreased

Phase transformations of thermally grown oxide on (Ni,Pt)Al bondcoat during electron beam physical vapor deposition and subsequent oxidation

Phase constituents, morphology and microstructure of thermally grown oxide (TGO) as a function of electron beam physical vapor deposition (EP-PVD) time, (Ni,Pt)Al bondcoat surface treatment and subsequent oxidation in air were examined for a series of thermal barrier coatings (TBCs). Photostimulated luminescence spectroscopy (PSLS) and focused ion beam (FIB) in-situ lift-out (INLO) specimen preparation for (scanning) transmission electron microscopy were employed to characterize the TBCs. Photostimulated luminescence only from α-Al2O3 was observed on grit-blasted bondcoat for all YSZ deposition times, while that from metastable Al2O3 phases including α-Al2O3 was observed for the TGO on as-coated (i.e. not grit blasted) bondcoat. Relative to the luminescence intensity of the α-Al2O3, the luminescence intensity from the metastable Al2O3 phases decreased with an increase in deposition time and corresponding thickness of ZrO2–Y2O3 (YSZ). On subsequent oxidation in air at 1000, 1050 and 1100 °C for 0.5, 10 and 50 h, the luminescence intensity from the metastable Al2O3 phases decreased while that of α-Al2O3 increased. These observations regarding the phase constituents of TGO were confirmed by diffraction analysis using high resolution TEM (HR-TEM) via FIB INLO. The initial development of the TGO during EB-PVD deposition consisted of a mixed-oxide zone. The relative thickness of the mixed-oxide zone for TGO formed on the as-coated bondcoat surface was greater than that of TGO formed on grit-blasted bondcoat surface. The variation in the presence of metastable Al2O3 in the TGO for as-processed TBCs was observed to influence the overall growth of TGO during short-term isothermal oxidation, particularly as the temperature decreased

Preparation of Transmission Electron Microscope Specimens from Ultra-Fine Fibers by a FIB Technique

Journal Article Preparation of Transmission Electron Microscope Specimens from Ultra-Fine Fibers by a FIB Technique Get access Jian Li, Jian Li Materials Technology Laboratory, CANMET, 568 Booth St. Ottawa, Ontario, Canada, K1A 0G1 Search for other works by this author on: Oxford Academic Google Scholar V Y Gertsman, V Y Gertsman Materials Technology Laboratory, CANMET, 568 Booth St. Ottawa, Ontario, Canada, K1A 0G1 Search for other works by this author on: Oxford Academic Google Scholar J Lo J Lo Materials Technology Laboratory, CANMET, 568 Booth St. Ottawa, Ontario, Canada, K1A 0G1 Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 9, Issue S02, 1 August 2003, Pages 888–889, https://doi.org/10.1017/S1431927603444449 Published: 24 July 2003

Rapid Cross-Section TEM Specimen Preparation of III-V Materials

Abstract Cross-section transmission electron microscope (TEM) specimen preparation of Ill-V materials using conventional methods can be a painful and time-consuming activity, with a day or more from receipt of a sample to examination in the TEM being the norm. This article describes the cross-section TEM specimen preparation technique used at Bookham Caswell. The usual time from start to finish is <1 hour. Up to 10 samples can be prepared at once, depending upon sample type. Most of the tools used are widely available and inexpensive, making the technique ideal for use in institutions with limited resources.

Veratti and beyond: Structural contributions to the study of muscle activation

Veratti’s work provided a key background element in our understanding of how muscle fibers are activated to contract. The black reaction of Golgi, as applied by Veratti and as beautifully illustrated in his illustrations, highlights a pervasive system of tubules that penetrates across the entire fiber cross section at periodical intervals. Continuity of the system with the fiber periphery is clearly demonstrated in Veratti’s drawings and was later confirmed by electron microscopy. Veratti’s technique, applied to specimen preparation for electron microscopy, has further shown that the sarcoplasmic reticulum is also highlighted by the potassium dichromate-osmium-silver nitrate infiltration. Images from infiltrated muscles, examined in the electron microscope have provided extensive details of the precise matching between the properties of the membrane systems responsible for delivering calcium and those of the contractile material resulting in harmonious muscle operation.

The use of the focused ion beam technique to prepare cross-sectional transmission electron microscopy specimen of polymer solar cells deposited on glass

The use of the focused ion beam (FIB) technique for cross-sectional transmission electron microscopy (TEM) specimen preparation of polymer solar cells deposited on glass substrates is described. Ultra-thin sections were prepared using the ‘lift-out’ technique. Electron microscopy investigations of these specimen resulted in detailed morphological information of the devices (e.g. thickness and interface roughness of the layers). In comparison with standard sample preparation routes for TEM investigations the used technique is well suited for precise sectioning of hybrid structures.

The effect of the gold sputter-coated films in minimising damage in FIB-produced TEM specimens

A sputter-coated gold film, of variable thickness, was used to protect the near surface region structure of an AlAs–InAs superlattice from damage during transmission electron microscope (TEM) specimen preparation using a focused ion beam (FIB) miller. This coating was applied before the deposition of any platinum protective film in the FIB. The extent of any damage in this specimen was investigated by TEM. Where the gold film was either locally absent or of low thickness (<15 nm), ion beam damage of this near surface region was evident. It was concluded that the deposition of platinum in the FIB may lead to surface modification of TEM specimens and that the application of a gold layer at least 60 nm in thickness should be made prior to any FIB processing.

Micromechanical Testing of Polyisobutylene—Polystyrene Block-Type Thermoplastic Elastomers

Abstract The mechanical properties of a variety of linear triblock copolymers (polysytrene-polyisobutylene-polystyrene, PS-PIB-PS) have been measured. The molecules were synthesized using living carbocationic polymerization of isobutylene, followed by the sequential addition of the second monomer, styrene. The microstructure of the resulting materials was examined as a function of mass fraction of PS using transmission electron microscopy of stained thin films. At small mass fractions, the reinforcing phase (PS) was distributed within the rubbery PIB phase, and the composite could be considered micromechanically using the Bard and Chung model. The comparison of experiment to theory revealed a strong mechanical dependence on Langley-Graessley intermolecular entanglement in the PIB phase. At higher mass fractions the microstructure was seen to consist of interpenetrating networks similar to the double gyroid morphology reported for block copolymers. The experimental approach involved the preparation of solution cast transmission electron microscopy specimens from which the undistorted size, distribution and arrangement of phases could be measured, and the similar preparation of thicker tensile specimens from which the accurate mechanical response could be measured. In this way the correlation between the microstructure and deformation was made accurately. The unique mechanical testing methods and instrumentation to measure tensile properties of thin samples were described.

The Effect of Implanted Gallium on the Recrystallization of Amorphous Layers formed during FIB Milling of Silicon

The focused ion beam (FIB) miller allows preparation of site-specific transmission electron microscopy (TEM) specimens from a wide range of materials in both cross-sectional and planar configurations [1,2]. However, radiation damage during exposure to the high-energy gallium beam may result in the formation of amorphous regions on thin film specimens. The thickness of such damage layers, on both sides of a TEM specimen, is comparable with the thickness required for lattice imaging. For example, the thickness of an amorphous layer in Si after 30 kV Ga+FIB processing has been reported in the range from 15 [3] to 28 nm [4]. This problem limits the capabilities of FIB sample fabrication.The aim of this study was to investigate, in detail, the structure, composition and the thickness of the damage layers in Si specimens after milling with a gallium ion beam. Using a FEI xP200 FIB system, with 30 kV Ga+ions, a row of trenches on a silicon sample was milled under different beam currents ranging from 150 to 6600 pA. The average size of such trenches was 15×10 μm wide and 1 μm deep. The trenches were then removed from the FIB and sputter coated with a thick Au film to preserve the trench surfaces from further damage during subsequent TEM specimen preparation steps. Cross-sectional TEM specimens of the trench walls were then prepared using standard FIB procedures [5]. Observations were made using a Philips CM 200 Field Emission Gun TEM operating at an accelerating voltage of 200 kV.

Preparation of cross-sectional transmission electron microscopy specimens of obliquely deposited magnetic thin films on a flexible tape

In this article a method is described for preparing cross sections of obliquely deposited metal thin films on polymer substrates for transmission electron microscopy (TEM) observation. The layers of interest are brittle in nature and therefore it is difficult to obtain suitable TEM samples with conventional methods. Apart from the sample preparation method some details of the deposition technique will be elucidated.

Preparation of transmission electron microscope specimens from FeAl and WC powders using focused-ion beam milling

Specimens were prepared for transmission electron microscope (TEM) examination from both FeAl and WC powders using a focused-ion beam (FIB) miller. These powders are used in preparation of FeAl–WC metal matrix composites (MMCs), and TEM examination is desired for comparison with the consolidated product. Due to the geometry of the powders, specimen preparation difficulties have precluded high-resolution examination of these materials to date. Specimens were successfully prepared by imbedding powders in resin and thinning using a FIB. A large thin area was prepared (∼10×10 μm) in a relatively short period of time (∼2 h milling time). Chemical analysis revealed some evidence of redeposition, but negligible gallium implantation. Ion damage was observed in the metallic powder, but not in the ceramic powder. Both materials retained their crystallographic integrity.

Structural analysis of non-crystalline macromolecules: the ribosome.

Single-particle analysis using cryo-electron microscopy has emerged recently as a tool for elucidating the structure of biological macromolecules and their assemblies. A prerequisite for single-particle analysis is an ensemble of images of structurally identical particles in different orientations. There are a variety of techniques used for image processing of this type of object in electron microscopy. The paper gives an overview of the general philosophy of image analysis of single particles in electron microscopy. It has been shown that multivariate statistical analysis of large data sets in conjunction with angular reconstitution is capable of yielding a structural resolution approaching that of X-ray structural analysis of large macromolecules. Structure preservation during specimen preparation for electron microscopy is crucial for high-resolution studies. Nowadays, cryo-electron microscopy is a beneficial method for studying biological macromolecules in their natural environment, allowing their rapid freezing in a particular functional state. The processing of images of 50S Escherichia coli ribosomal subunits embedded in vitreous ice is used as an example of image analysis of single particles at 7.5 A resolution.

Biological Specimen Preparation for Transmission Electron Microscopy (Volume 17 of the Series on Practical Methods in Electron Microscopy) Audrey M. Glauert and Peter R. Lewis. 2000. Princeton University Press, Princeton, NJ. 316 pages. (hardback, $150; paperback, $65.50)

Journal Article Biological Specimen Preparation for Transmission Electron Microscopy (Volume 17 of the Series on Practical Methods in Electron Microscopy) Glauert Audrey M and Lewis Peter R. 2000. Princeton University Press, Princeton, NJ. 316 pages. (hardback, $150; paperback, $65.50) Get access José A Mascorro José A Mascorro Department of Anatomy, Tulane University School of Medicine, New Orleans, LA 70112 Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 6, Issue 5, 1 September 2000, Pages 478–479, https://doi.org/10.1007/S100050010046 Published: 07 August 2002

Microstructural Characterization of Automated Specimen Preparation for TEM Analysis

Abstract Automated specimen preparation for transmission electron microscopy has the obvious advantage of saving personnel time. While some people may perform labor intensive specimen preparation techniques quickly, automated specimen preparation performed in a timely and reproducible fashion can significantly improve the throughput of specimens in an industrial laboratory. The advent of focused ion beam workstations for the preparation of electron transparent membranes has revolutionized TEM specimen preparation. The FIB lift-out technique is a powerful specimen preparation method. However, there are instances where the “traditional” FIB method of specimen preparation may be more suitable. The traditional FIB method requires that specimens must be prepared so that the area of interest is as thin as possible (preferably less than 50 μm) prior to FIB milling. Automating the initial specimen preparation for brittle materials (e.g., Si wafers) may be performed using the combination of cleaving and sawing techniques as described below.

A Stress Relief Method to Control Warping of Focused Ion Beam Prepared Membranes for Transmission Electron Microscopy

Abstract The continued decrease in microelectronic feature dimensions has led to a reliance on the focused ion beam (FIB) for site-specific transmission electron microscopy (TEM) specimen preparation. To maximize the capabilities of the FIB, methods must be developed to consistently produce specimens thin enough to generate TEM lattice images. The limiting factor in producing quality TEM specimens by either the traditional or lift-out method is the final thickness of the specimen. The FIB is used to prepare TEM specimens by removing the bulk material that surrounds a desired feature by sputtering with a focused gallium ion beam. Successively lower beam currents are used to sputter away material until an electron transparent membrane (-0.2 μm) containing the desired feature remains. For a 300 keV TEM, lattice imaging of silicon requires additional membrane thinning to less than 0.05 μm. The loss of rigidity during the thinning process makes the membrane highly prone to deformation due to residual stresses, linear expansion, and ion beam interaction.

Site Specific TEM Specimen Preparation using an FIB/TEM System

Abstract The focused ion beam(FIB) technique, developed for the microelectronics industry has become a major method for site specific transmission electron microscopy(TEM) specimen preparation in a wide range of materials[l]. The FIB lift-out technique has improved the specimen preparation procedures by removing complicated initial fabrication required prior to the FIB milling[2]. However, conventional FIB techniques are still having increased difficulty in meeting failure analysis needs from high technology industries such as microelectronics. We have developed a site specific TEM specimen preparation method using a combination of an FIB instrument and an intermediate voltage TEM equipped with a scanning attachment [3]. In this method, the specimen is mounted on an FIB-TEM compatible specimen holder, so that localization of the specific site can be carried out in the FIB and TEM using the same holder. The scanning electron imaging mode may be used to observe surface structures of the milled area, and the scanning transmission electron microscopy(STEM) mode may be used to observe structures inside of the milled surface.

Focused Ion Beam Induced Copper Artifact Dose Study

Abstract Reduced feature dimensions in microelectronic devices has led to a growing reliance on the focused ion beam (FIB) for scanning electron microscopy (SEM) and transmission electron microscopy (TEM) specimen preparation. The introduction of copper for use in electrical interconnects will increase this reliance. Copper, much more so than aluminum, tends to smear when conventional polishing techniques are employed, rendering mechanical polishing unsuitable for quality specimen preparation. The sputtering characteristics of copper differ greatly from the aluminum based materials currently in use. Copper exhibits a grain orientation dependent sputtering rate that tends to produce uneven FIB polished surfaces. The sputtering rate for copper is also much higher than the silicon and dielectric materials that must be simultaneously removed. These differences in sputtering rates lead to the formation of curtains and ledges that also affect specimen quality. Another FIB induced artifact was observed when preparing SEM specimens (Figure 3).