Cross-sectional Transmission Electron Microscopy Samples Research Articles

Femtosecond-laser-induced modifications on the surface of a single-crystalline diamond

We investigated femtosecond-laser-induced modifications on the surface of a single-crystalline diamond and the changes that occur in them with annealing by observing the cross sections of laser-irradiated lines by transmission electron microscopy (TEM). Femtosecond laser pulses were irradiated on the (001) surface of a diamond by scanning along straight lines. An aluminum film was deposited on the (001) surface after the irradiation, and a TEM sample was prepared. Element mapping and electron diffraction analyses showed that the laser-modified regions were composed of single-crystalline diamond, graphite, and amorphous carbon. The existence of aluminum in the laser-modified regions suggested that the regions were porous when laser-irradiated. After the bulk sample was annealed, another cross-sectional TEM sample was prepared. The annealing induced the diffusion of aluminum from the film into the laser-modified regions where the extension of amorphous areas was observed.

Cross-Sectional Transmission Electron Microscopy Sample Preparation of Soldering Joint Using Ultramicrotomy

Many studies have reported the interfacial reaction of Sn-Ag/ electroless nickel immersion gold (ENIG). Various analysis techniques, such as scanning electron microscopy, electron probe microanalyzer, and transmission electron microscopy (TEM), have been used to examine interfacial reaction. Among them, TEM equipped with analytical attachments offers the most complete tool for characterizing the formation of intermetallic compounds (IMCs) at the interface. However, solders are typically soft and ductile, while IMCs tend to be quite hard and brittle, which has limited the level of success in preparing TEM samples. We utilized ultramicrotomy since it might offer a reasonable and relatively quick alternative in this case. Ultramicrotomy has been used for the preparation of TEM specimens from biological materials and extending a range of materials including polymers, coating layer, particles, and even metals (Becker & Bange, 1993; Glanvill, 1995; Howell et al., 1995). TEM sample making to section hard materials by ultramicrotomy are not new. Besides, it has been traditionally considered that the mechanical damage during sectioning by diamond knife might hinder unambiguous specimen characterization. However, this technique also has many advantages such as no ion beam irradiation damage, no chemical mixing, no differential thinning rate and the ease of preparation of many serial sections with large, thin areas of uniform thickness in a relatively short time (Quintana, 1997). The increasing acceptability of ultramicrotomy in materials science is evidenced by a number of recent paper giving results for different hard materials (Hwang & Suganuma, 2003).

Fabrication of high aspect ratio AFM probes with different materials inspired by TEM “lift-out” method

The most commonly used materials in all commercially available high-aspect-ratio (HAR) nanowire's (NW) tips are made of silicon and carbon nanotube which limit their applications in other types of atomic force microscopy (AFM), such as conducting AFM and magnetic force microscope. Therefore, a simple process inspired by cross-sectional transmission electron microscopy sample preparation method was used to demonstrate the feasibility of fabricating HAR AFM probes, which can easily define the tilt angle of the NW tip with respect to the direction that is normal to the axis of the cantilever to which it is attached by simply tilting the sample stage where the cantilever is placed. This is very important as it enables precise control of the inclination angle of the NW tip and allows the tip to be made perpendicular to the probed surface for scanning with different AFM mounts. Two different tips were fabricated, one attached parallel and the other attached at an angle of 13° with respect to the normal of the cantilever axis. These tips were used to profile the topography of a silicon nanopillar array. Only the probe attached at an angle of 13° allowed mapping of the topography between nanopillars. This is the first successful demonstration of an HAR AFM tip being used to map the topography of a nanopillar array. In addition, the authors also demonstrated that this method can be extended to fabricate HAR AFM tips of different materials such as copper with a slightly modified approach.

The Effect of Phosphorus Exposure on Diesel Oxidation Catalysts—Part II: Characterization of Structural Changes by Transmission Electron Microscopy

Phosphorus poisoning and its effect on the diesel oxidation catalysts morphology was studied by transmission electron microscopy (TEM). The studied catalyst samples were PtPd or Pt supported on the alumina-based washcoat including additives. The laboratory-scale phosphorus exposures were carried out with two different phosphorus concentrations. The cross-sectional TEM samples were prepared from the fresh and phosphorus-treated catalysts. After phosphorus exposures, significant structural changes were observed compared to the fresh catalysts. The shape of the noble metal particles had changed from irregular to more spherical-shaped particles. In addition, phosphorus was detected throughout the catalyst TEM samples but the amount varied depending on the local composition of the support. Phosphorus accumulated mainly in the alumina-containing areas of the support and indications of dense and amorphous aluminium phosphates were found. Based on the results gained, cross-sectional TEM characterization is essential to observe these kinds of morphological changes in the catalysts caused e.g. by phosphorus exposures. In addition, cross-sectional TEM samples are needed to study the effect of local variation in the support composition on the phosphorus accumulation.

Specimen Preparation Method to Dual-Axis TEM Analysis Technique

We usually do Physical Failure Analysis (PFA) to visualize the failure in the semiconductor process. First, we find the site-specific target (or failed cell). And then, we should do de-processing which contains lapping and chemical etch. As the semiconductor gets more complex and multi-layer, we should do multi-de-processing steps. If the failure has the oxide-material, we cannot know the cause of failure. Because the oxide can be removed by Hydrogen Fluoride (HF) chemical, which means the failure will be gone during de-processing step. We should use Focused Ion Beam (FIB) which can make a thin sample to exclude chemical step. High-resolution analytical tools such as Transmission Electron Microscopy (TEM) have become indispensable in PFA. We make a Dual-Axis TEM (DAT) method for PFA. We make a Plan-view TEM (PTEM) sample with FIB first, we can find an exact location of failure through the first step. And then, we make cross-sectional TEM (XTEM) sample with a site-specific target in PTEM sample. Below summarizes the four major steps and its precautions;1. Making a Planar lamella by FIB2. Observing a PTEM specimen with TEM(Precaution : zone axis should be adjusted exactly)3. Making a cross-section lamella by FIB(Precaution : Protection layer should be deposited on both sides)4. Observing a XTEM specimen with TEMWe propose DAT method to improve the problem of artifact in de-processing step. The TEM result with DAT method is shown in figure 4. We can know the exact location of failure with observing a PTEM sample. We can know the cause of failure with observing a XTEM sample. Moreover, we can analysis the chemical and physical information through DAT method. This method is very effective and has a high success rate in analysis. REFERENCE [1] A.E.M. De Veirman, “3-Dimensional’ TEM silicon-device analysis by combining plan-view and FIB sample preparation”, Materials Science and Engineering: B, 102(1-3), pp. 63-69, 2003. [2] Jon C. Lee, David Su, J.H. Chuang, “A Novel Application of the FIB Lift-out Technique for 3-D TEM Analysis”, Microelectronics Reliability Asset, 41(9-11), pp. 1551-1556, 2001. Figure 1

Cross-sectional analysis of W-cored Ni nanoparticle via focused ion beam milling with impregnation.

Tungsten and nickel bimetallic nanoparticle is synthesized by radio frequency thermal plasma process which belongs to the vapor phase condensation technology. The morphology and chemical composition of the synthesized particle were investigated using the conventional nanoparticle transmission electron microscopy (TEM) sample. A few part of them looked like core/shell structured particle, but ambiguities were caused by either TEM sample preparation or TEM analysis. In order to clarify whether a core/shell structure is developed for the particle, various methodologies were tried to prepare a cross-sectional TEM sample. Focused ion beam (FIB) milling was conducted for cold-compacted particles, dispersed particles on silicon wafer, and impregnated particles with epoxy which is compatible with electron beam. A sound cross-sectional sample was just obtained from cyanoacrylate impregnation and FIB milling procedure. A tungsten-cored nickel shell structure was precisely confirmed with aid of cross-sectional sample preparation method.

Thickness Measurements Using Photonic Modes in Monochromated Electron Energy-Loss Spectroscopy

Characteristic energies of photonic modes are a sensitive function of a nanostructures' geometrical parameters. In the case of translationally invariant planar waveguides, the eigen-energies reside in the infrared to ultraviolet parts of the optical spectrum and they sensitively depend on the thickness of the waveguide. Using swift electrons and the inherent Cherenkov radiation in dielectrics, the energies of such photonic states can be effectively probed via monochromated electron energy-loss spectroscopy (EELS). Here, by exploiting the strong photonic signals in EELS with 200 keV electrons, we correlate the energies of waveguide peaks in the 0.5-3.5 eV range with planar thicknesses of the samples. This procedure enables us to measure the thicknesses of cross-sectional transmission electron microscopy samples over a 1-500 nm range and with best-case accuracies below ± 2%. The measurements are absolute with the only requirement being the optical dielectric function of the material. Furthermore, we provide empirical formulation for rapid and direct thickness estimations for a 50-500 nm range. We demonstrate the methodology for two semiconducting materials, silicon and gallium arsenide, and discuss how it can be applied to other dielectrics that produce strong optical fingerprints in EELS. The asymptotic form of the loss function for two-dimensional materials is also discussed.

In situ TEM study of stability of TaRhx diffusion barriers using a novel sample preparation method

The atomic diffusion mechanisms associated with metallurgical failure of TaRhx diffusion barriers for Cu metallizations were studied by in situ transmission electron microscopy (TEM). The issues related to in situ heating of focused ion beam (FIB) prepared cross-sectional TEM samples that contain Cu thin films are discussed. The Cu layer in Si/(13nm)TaRhx/Cu stacks showed grain growth and formation of voids at temperatures exceeding 550°C. For Si/(43nm)TaRhx/Cu stacks, grain growth of Cu was delayed to higher temperatures, i.e., 700°C, and void formation was not observed. Extensive surface diffusion of Cu, however, preceded bulk diffusion. Therefore, a 10nm film of electron beam evaporated C was deposited on both sides of the TEM lamellae to limit surface diffusion. This processing technique allowed for direct observation of atomic diffusion and reaction mechanisms across the TaRhx interface. Failure occurred by nucleation of orthorhombic RhSi particles at the Si/TaRhx interface. Subsequently, the barrier at areas adjacent to RhSi particles was depleted in Rh. This created lower density areas in the barrier, which facilitated diffusion of Cu to the Si substrate to form Cu3Si. The morphology of an in situ annealed lamella was compared with an ex situ bulk annealed sample, which showed similar reaction morphology. The sample preparation method developed in this study successfully prevented surface diffusion/delamination of the Cu layer and can be employed to understand the metallurgical failure of other potential diffusion barriers.

Characterization of defect evolution in ultrathin SiO2 layers under applied electrical stress

The structural evolution of ultrathin dielectric SiO2 layers within a Co-silicide/poly-Si/SiO2/Si multilayer system was studied by in situ transmission electron microscopy (TEM). The interface structure represents a model system for field effect transistors with a SiO2 dielectric layer. Electrical bias was applied across the interfaces of cross sectional TEM samples using a scanning tunneling microscopy (STM) tip. Atomic structure modifications of the dielectric layer due to the applied electrical field were observed by this in situ STM-TEM technique. Constant bias (+5.0 V) and ramped bias (+3.0 to +10.5 V) stresses applied to the CoSi2 gate electrode resulted in a loss in capacitance of the dielectric layer consistent with descriptions of soft dielectric breakdown (SBD) and hard dielectric breakdown (HBD). It was found that SBD events are characterized by fluctuations within uniform current step increase of 21 nA and increased roughness of the SiO2 film due to oxygen vacancy percolation. HBD, however, was found to be preceded by multiple SBD events between +6.5 V and +10 V, cobalt atom migration into the dielectric layer, partial crystallization of the amorphous gate dielectric (dielectric breakdown induced epitaxy), and significant diffusion of oxygen from the SiO2 layer into the silicon substrate through a reduction-oxidation reaction of the Si/SiO2 interface. Experimental results demonstrate the feasibility of in situ STM-TEM experiments for studying time-dependent dielectric breakdown behaviors to obtain a direct correlation of individual defect structures and their corresponding electrical signatures. Experimental limitations of this new technique are critically discussed.

Optimized Ar+-ion milling procedure for TEM cross-section sample preparation

High-quality samples are indispensable for every reliable transmission electron microscopy (TEM) investigation. In order to predict optimized parameters for the final Ar(+)-ion milling preparation step, topographical changes of symmetrical cross-section samples by the sputtering process were modeled by two-dimensional Monte-Carlo simulations. Due to its well-known sputtering yield of Ar(+)-ions and its easiness in mechanical preparation Si was used as model system. The simulations are based on a modified parameterized description of the sputtering yield of Ar(+)-ions on Si summarized from literature. The formation of a wedge-shaped profile, as commonly observed during double-sector ion milling of cross-section samples, was reproduced by the simulations, independent of the sputtering angle. Moreover, the preparation of wide, plane parallel sample areas by alternating single-sector ion milling is predicted by the simulations. These findings were validated by a systematic ion-milling study (single-sector vs. double-sector milling at various sputtering angles) using Si cross-section samples as well as two other material-science examples. The presented systematic single-sector ion-milling procedure is applicable for most Ar(+)-ion mills, which allow simultaneous milling from both sides of a TEM sample (top and bottom) in an azimuthally restricted sector perpendicular to the central epoxy line of that cross-sectional TEM sample. The procedure is based on the alternating milling of the two halves of the TEM sample instead of double-sector milling of the whole sample. Furthermore, various other practical aspects are issued like the dependency of the topographical quality of the final sample on parameters like epoxy thickness and incident angle.

Cross-sectional transmission electron microscopy of thin graphite films grown by chemical vapor deposition

Graphene has been the subject of an extraordinary upsurge of interest due to its intriguing properties and potential applications. Recent work has shown that excellent electronic properties are exhibited by large-scale ultrathin graphite films, grown by chemical vapor deposition on a polycrystalline metal and transferred to a device-compatible surface. The properties of such multilayered graphene films could depend strongly on film thickness and uniformity. Unlike the other common methods for analysis in the literature, cross-sectional transmission electron microscopy (TEM) would provide direct, straightforward analysis of film thickness and quality, as well as provide a means to investigate specific defect structures (e.g. wrinkles). However, this approach has not often been pursued due to the sensitivity of graphite to the electron and ion beam damage in such a procedure. Here, an approach to creating cross-sectional TEM samples using a focused ion beam lift-out method is presented, along with the resulting TEM images of thin graphite films and several wrinkle defects. Samples removed from as-grown films on polycrystalline nickel and films removed from measured devices are presented. The benefits and limitations to this approach are discussed.

A high-throughput approach for cross-sectional transmission electron microscopy sample preparation of thin films

Cross-sectional transmission electron microscopy (XTEM) is a very useful technique to study the interfacial diffusion and reactions and the grain growth of thin films. However, the preparation of XTEM samples of thin films is tedious and challenging. Difficulties may include the delamination of films from the substrate, fracture of brittle substrates and differential milling rates of the substrate and the film. This paper describes an improved technique using a combination of tripod polishing and focused ion beam milling to prepare XTEM samples of thin films. The technique can be widely used for high-throughput production of samples having varying film and substrate properties. Two different geometries are introduced. The first one is suitable for XTEM sample preparation of most films at a high yield rate, but with a limited view area. The other geometry is able to give a larger view area and is more suitable for thicker films. The technique is illustrated by an example of the sample preparation of Fe/Pt multilayer films on SiO2/Si substrates.

Transmission Electron Microscopy Observations on the Interfacial Structures of the Pt/SrBi2Ta2O9/Pt Thin-Film Capacitors Prepared by Metallo-Organic Decomposition

Interfacial structures of the Pt/SBT/Pt capacitors prepared by metallo-organic decomposition were examined by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) as a function of the postannealed time at 750°C to investigate the interfacial evolution developed in the Pt/SBT/Pt capacitors. The results show that after postannealing at 750°C for a short time (e.g., 300 s), a thin amorphous layer was observed at the interfaces of the SBT/Pt-bottom and the SBT/Pt-top electrodes in the Pt/SBT/Pt capacitors, whereas after postannealing for a moderate time (e.g., 20 min), the interfaces of the SBT/Pt-bottom and the SBT/Pt-top electrodes became quite smooth and uniform, and almost free of the interfacial phase. However, after postannealing for a longer time (e.g., 60 min), an interfacial phase consisting of oval-shaped nanocrystallites was developed at both the SBT/Pt-bottom and the SBT/Pt-top electrode interfaces, which resulted in weakly bonded interfaces between the SBT films and Pt electrodes. This is the reason why a Pt electrode peeling phenomenon (similar to that reported in the Pt/SBT/Pt/capacitors annealed in the forming gas atmosphere) is frequently observed in the Pt/SBT/Pt capacitors postannealed for 60 min during the fabrication of cross-sectional TEM samples. Based on two-dimensional lattice fringes of the HRTEM images from the small nanocrystallites and the corresponding fast Fourier transform patterns, the oval-shaped nanocrystallites precipitated at both the SBT/Pt-bottom and the SBT/Pt-top electrode interfaces were determined to be a PtBi2 phase with a cubic structure. The formation of the Pt–Bi-based interfaces in the Pt/SBT/Pt capacitors is due to the reaction of bismuth (out-diffused from the SBT films) with Pt electrodes during the postannealing process. The elliptical morphology of the interfacial PtBi2 phase can be ascribed to its different growth rates in the parallel and vertical directions of the interface, and also the limited space for grain growth perpendicular to the interface.

Cross-sectional transmission electron microscopy method and studies of implant damage in single crystal diamond

Few transmission electron microscopy (TEM) studies of single crystal diamond have been reported, most likely due to the time and difficulty involved in sample preparation. A method is described for creating a TEM cross section of single crystal diamond using a focused ion beam and in situ lift-out. The method results in samples approximately 10μm long by 3μm deep with an average thickness of 100–300nm. The total time to prepare a cross-sectional TEM sample of diamond is less than 5h. The method also allows for additional thinning to facilitate high resolution TEM imaging, and can be applied to oddly shaped diamond samples. This sample preparation technique has been applied to the study of ion implantation damage in single crystal diamond and its evolution upon annealing. High-pressure–high-temperature diamonds were implanted with Si+ at an energy of 1MeV and a temperature of 30°C. One sample, with a (110) surface, was implanted with a dose of 1×1014Sicm−2 and annealed at 950°C for 10 and 40min. No significant defect formation or evolution was discernible by cross-sectional transmission electron microscopy. Another sample, with a (100) orientation, was implanted with 1MeV at 1×1015Sicm−2 and annealed at 1050°C for 10min. Prior to annealing, a heavily damaged but still crystalline region was observed. Upon annealing, the sample showed no signs of conversion either to an amorphous form of carbon or to graphite. This is unexpected as the energy and dose are above the previously reported graphitization threshold for diamond. Higher annealing temperatures and possibly a high vacuum will be required for future study of defect formation, evolution, and phase transformations in ion-implanted single crystal diamond.

Probing the electrostatic potential of charged dislocations inn−GaNandn−ZnOepilayers by transmission electron holography

Epitaxial layers frequently contain a high density of threading dislocations, which may exceed values of ${10}^{9}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$ for ZnO and GaN. To study the electrical activity of single dislocations off-axis electron holography in a transmission electron microscope was applied. The electrostatic potential in the vicinity of charged dislocations was determined from the reconstructed phase of the electron wave, which also provides access to the charge density at the dislocation. On the basis of the electrostatic potential for a screened line charge given by Read [Philos. Mag. 45, 775 (1954)] a refined model is proposed in which a charge density with a finite spatial distribution at the dislocation core is assumed. Comparing the measured and theoretically expected potential, charge densities between $5\ifmmode\times\else\texttimes\fi{}{10}^{19}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}\phantom{\rule{0.3em}{0ex}}\mathrm{and}\phantom{\rule{0.3em}{0ex}}5\ifmmode\times\else\texttimes\fi{}{10}^{20}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$ in cylinders with radii up to $5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ around the dislocation lines were found. An important aspect of our work is the analysis of dislocations in cross-section transmission electron microscopy samples where the dislocation lines are oriented perpendicular to the electron beam. The advantages and drawbacks of the cross-section geometry are discussed. Electrostatic potentials due to piezoelectric charges in the dislocation strain field are considered and found to be insignificant with respect to dislocation charges.

Analysis of Nanoscale Stress in Strained Silicon Materials and Microelectronics Devices by Energy-Filtered Convergent Beam Electron Diffraction

The convergent beam electron diffraction (CBED) technique of transmission electron microscopy (TEM) has excellent capabilities for strain detection at high spatial resolution. Here we report strain measurements in a bulk s-Si/SiGe/Si wafer and in a strained 35nm PMOS device in which SiGe acts as the source and drain. CBED measurements of the composition of the relaxed SiGe buffer are in quantitative agreement with Raman spectroscopy. For the PMOS device, CBED measured a uniaxial compressive stress of 1.12GPa in the channel. However, it was found that even in the cross-sectional TEM samples with thicknesses greater than 300nm, the intrinsic surface strain relaxation was often so severe that no recognizable high-order Laue zone lines in the CBED patterns could be collected. The amorphorization of both free surfaces of the TEM sample to a range of about 80nm is proposed to minimize the impact of surface strain relaxation for future study.

Limitations to low-voltage focused ion beam operation

While standard high energy (30 keV) focused ion beam (FIB) systems have reached a very high level of technological perfection, instrument manufacturers are only just beginning to also explore the possible performance of these systems at lower landing energies of the order of a few keV or even below. Such low-voltage ion beams might be beneficially used in the preparation of cross-sectional transmission electron microscopy samples or as ion probes for depth profiling in secondary ion mass spectroscopy. In the following some of the challenges to low-voltage FIB instrumentation will be addressed using the specific example of a novel ion beam column concept based on immersion optics. Both, limitations arising from practical or operational considerations as well as from the growing impact of Coulomb interaction effects at low landing energy will be discussed.

Influence of an in situ-deposited [formula omitted] intermediate layer inside GaN and AlGaN layers on SiC substrates

In this work we present a study on the influence of an in situ grown SiN x intermediate layer inside (Al)GaN epitaxial layers grown on SiC substrates on dislocation densities and material strain of the epitaxial films. A defect density of 6 × 10 8 cm - 2 was achieved by reducing the number of pure edge dislocations in the order of one magnitude. It was found that a reduction of the dislocation density is only successful by inserting the SiN x layer inside GaN films and no defect reduction takes place with SiN x inside AlGaN films. The presence of stacking faults at the close vicinity of the SiN x layer plays an important role for the mechanism of dislocation termination at the SiN x interface. To determine dislocation densities an etch pit density method was carried out combining transmission electron microscopy (TEM) investigations of plan-view samples with atomic force microscopy (AFM) scans. Structural properties were investigated by cross-sectional TEM samples. Composition of AlGaN at the SiN x interface was determined by energy dispersive X-ray analysis (EDX) and secondary ion mass spectroscopy (SIMS). Material strain was investigated by micro-photoluminescence measurements ( μ -PL).

Mesostructured MTES-Derived Silica Thin Film with Spherical Voids Investigated by TEM: 2. Dislocations and Strain Relaxation

A mesostructured silica thin film with nanosized voids arranged in a body-centered cubic (bcc) array with a slight distortion was studied by transmission electron microscopy (TEM) for line defects. This film was engineered by a preferential solvent evaporation-induced sol−gel and self-assembly process and subsequent pyrolysis to remove its structure-directing agent. Methyl triethoxysilane [MTES, Si(OCH2CH3)3CH3] was the silica precursor. Two types of dislocations were observed from a cross-sectional TEM sample of this non-free-standing film on a Si(001) substrate. One is an edge dislocation; the other is a dislocation dipole. The edge dislocation, with its Burgers vector b = a[010] and dislocation line direction ξ = [100], was formed by the reaction of two regular dislocations: b = b1 + b2, while b1 = (a/2)[1,1,−1] and b2 = (a/2)[−1,1,1]. The origin of this edge dislocation is related to the tensile strain developed in the film because of film shrinkage during the fabrication; its development is argued to arise from the partial relief of developed strain. A new concept, namely, critical mesostructure thickness for the occurrence of the stress relaxation, is proposed and computed using an elastic strain energy argument. The possible factors for the termination site of the edge dislocation are discussed briefly. The dislocation dipole has the Burgers vectors b = ±(a/2)[−1,1,1] on a (0,1,−1) plane.

Microstructural And Microchemical Analysis of Chalcopyrite Cu(In,Ga)Se2 Films

AbstractThe microstructure and microchemistry of Cu(In, Ga)Se2 (CIGS) films have been analyzed by means of transmission electron microscopy (TEM). Specimens were obtained from a number of groups producing high-performance solar cells from these materials. Both plan-view and cross-sectional TEM samples were prepared by mechanical grinding and ion milling. Twins can be found easily within the films while dislocations are present only in a few grains and with low density. No extended structural defects such as stacking faults were discovered. X-ray energy dispersive spectroscopy was used to study the chemical composition of grains and grain boundaries. Experimental results showed no difference between the composition in the grain interiors and the grain boundary. In addition, there is no obvious enhancement of oxygen and sodium at grain boundaries. Structural depth dependences were also not found.