Monte Carlo (MC) simulations for microbeam analysis, in which the author has been involved for 45 years, are retrospectively reviewed by tracing the development of simulations models for describing complicated scattering processes of incident projectiles (electron, ion, etc.) in matter. The simulation model is based on the uses of theoretical expressions which describe elastic and inelastic scattering, respectively, no matter whether incident projectile be electron or ion.
MC simulation modellings of different types are outlined by presenting applications to microbeam analysis with primary electrons and ions, respectively, drawing attention into the close correlation between a new modeling and a new micoanalytical instrumentation that was marketed at different times.
Finally, the author takes a liberty to propose an international cooperative joint work for database construction of secondary electron yield, by introducing the working group activities which the JSPS-141 committee (microbeam analysis) has supported since 2009.

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There is a growing recognition that nanoparticles and other nanostructured materials are sometimes inadequately characterized and that this may limit or even invalidate some of the conclusions regarding particle properties and behavior. A number of international organizations are working to establish the essential measurement requirements that enable adequate understanding of nanoparticle properties for both technological applications and for environmental health issues. Our research on the interaction of iron metal-core oxide-shell nanoparticles with environmental contaminants and studies of the behaviors of ceria nanoparticles, with a variety of medical, catalysis and energy applications, have highlighted a number of common nanoparticle characterization challenges that have not been fully recognized by parts of the research community. This short review outlines some of these characterization challenges based on our research observations and using other results reported in the literature. Issues highlighted include: 1) the importance of surfaces and surface characterization, 2) nanoparticles are often not created equal - subtle differences in synthesis and processing can have large impacts; 3) nanoparticles frequently change with time having lifetime implications for products and complicating understanding of health and safety impacts; 4) the high sensitivity of nanoparticles to their environment complicates characterization and applications in many ways; 5) nanoparticles are highly unstable and easily altered (damaged) during analysis.

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Four terms are commonly used as measures of the surface sensitivity of Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS): the inelastic mean free path (IMFP), the effective attenuation length (EAL), the mean escape depth (MED), and the information depth (ID). These terms have been defined by the International Organization for Standardization (ISO) and ASTM International, and are utilized in various ISO standards. The IMFP, EAL, MED, and ID are intended for different applications. We give information on sources of data for IMFPs, EALs, and MEDs, and present simple analytical expressions from which IMFPs, EALs, MEDs, and IDs can be determined.

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Recent activities on the quantification of alloy films and the thickness measurement of ultra-thin oxide films are reviewed in this paper. The quantification and in-depth analysis are the main applications of surface analysis methods. However, surface analyses require certified reference materials because the determinations of the film thickness and the quantities of constituent elements by surface analysis methods are not absolute. International standardization on surface chemical analysis is focused on the establishment of traceability and the reduction of the measurement uncertainty. Pilot studies and key comparisons were performed for the measurements of the thickness of nm SiO₂ films and the chemical composition of binary alloy films by the surface analysis working group of the consultative committee for amount of substance.

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To evaluate the present errors in the calibration of the mass scale of time-of-flight secondary ion mass spectrometry (ToF-SIMS) in the practical field of Japanese industries, ToF-SIMS Working Group (WG) of Surface Analysis Society of Japan (SASJ) conducted the inter-laboratory studies among 14 instruments in 2007, 2008 and 2009. There was significant scatter over 200 ppm in the relative mass accuracy at the first inter-laboratory test in 2007. Clearly, this is poor compared with the requirement for identification. However, the great deviation in the mass accuracy has been dramatically decreased at the second and third inter-laboratory tests by the accumulating knowledge through the discussion among the WG. Based on the results obtained, a practical guide to analysts for mass scale calibration will be provided in near future.

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In this paper, novel approaches to the study of the relationship between the chemical structures and the wear properties of lubricants on an ophthalmic lens by various analytical methods are described. The X-ray damage of lubricants by X-ray photoelectron spectroscopy (XPS) depends upon the lubricant structure. Further, the lubricant structure influences the wear properties. In particular, the experimentally observed X-ray damage and wear properties indicate that the straight linear chain structure with no side chain structure ((-CF₂-CF₂-O-)m-(CF₂-O-)n) is stronger than that with the side chain structure ((-CF (CF₃)-CF₂-O-)m). This result suggests that the investigation of X-ray damage by XPS is equivalent to an examination of the strength of the wear characteristic. The abovementioned methods are suitable for studying the durability of lubricants on ophthalmic lenses.

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We have studied the adsorption reaction of L-Cysteine on Cu nanoparticle by S K-edge NEXAFS measurement. The Cu nanoparticle used for the adsorption reaction is fabricated by the gas evaporation method. The results of the NEXAFS measurement are given as follows. The electron transfer between Cu nanoparticle and substrate changes the chemical state of Cu nanoparticle. The behavior of adsorbed L-Cysteine is influenced by the electron transfer between Cu nanoparticle and substrate. This result suggests the possibility that the catalytic activity of nanoparticle can be controlled by the electron transfer between nanoparticle and substrate.

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Based on Bohmian quantum trajectory theory, an investigation of electron scattering in a thin crystal has been performed. A time-independent interaction potential was employed to describe electron scattering from model crystal. Quantum trajectories were calculated by a numerical solution of the time-dependent Schrödinger equation. The probability density functions and quantum trajectories representing the electron diffraction in real space were obtained from the calculation. The quantum trajectories provide an intuitive dynamics of the interaction process during the electron diffraction.

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(ZrO2)_0.66(HfO₂)_0.34 dielectric films on p-Si (100) were grown by atomic layer deposition method, for which the conduction band offsets, valence band offsets and band gaps were obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence and conduction band offset values for (ZrO₂)_0.66(HfO₂)_0.34 dielectric thin film grown on Si substrate were about 5.34, 2.35 and 1.87 eV, respectively. The band alignment is similar to that of ZrO₂ thin film. In addition, The dielectric function ε(κ,ω), index of refraction n and the extinction coefficient k for the (ZrO₂)_0.66(HfO₂)_0.34 thin films were obtained from a quantitative analysis of REELS data by comparison to detailed dielectric response model calculations using the QUEELS-ε(κ,ω)-REELS software package. These optical properties for (ZrO₂)_0.66(HfO₂)_0.34 thin films are similar to that of ZrO₂ dielectric thin films.

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For detail analysis of fragmentation of organic molecules in TOF-SIMS spectra, fragmentation process of a polyethylene glycol (PEG) was simulated by using Quantum Molecular Dynamics method. In the simulation, fragmentation process of the PEG model was assumed as thermal decomposition. Initial thermal energies given to the model were 20 - 90 eV at every 10 eV step, and the energies were relaxed to 1.5 eV by using Brendsen method. Simulation results of the mass spectra for PEG model were in considerably good accordance with experimental ones of PEG in TOF-SIMS.

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There is currently renewed interest in the backscattering correction for Auger electron spectroscopy (AES). There are several reasons for this interest. First, the energy of the primary-beam energy reaches 25 keV in modern AES instruments and Shimizu's predictive formulae based on calculations for primary energies between 3 keV and 10 keV are of uncertain validity at higher energies. Second, it has been shown recently that the present definition of the backscattering factor is based on a simplified model of electron transport that breaks down for low primary energies and/or more grazing-incidence angles. A new term, the backscattering correction factor (BCF) has therefore been introduced that is based on an advanced model of electron transport. Third, much progress has been recently made in the theory of electron transport and the data for electron-scattering parameters which should improve the reliability of calculated backscattering correction factors. Finally, the BCF from the advanced theoretical model has been found to depend on numerous parameters defining the solid, the selected Auger transition, and the experimental configuration. Since the derivation of a simple predictive formula for the BCF does not seem to be feasible, a computer-controlled database has been developed to provide BCFs for a user-specified material and experimental configuration. Examples are given of BCFs from the advanced and simplified models for Ag M₄N₄₅N₄₅ Auger electrons from silver.

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Fragment ion analysis of protein samples is crucial for structural evaluation of proteins. Interpretation of fragment ions from bioplolymers, however, is often difficult because fragmentation mechanisms in secondary ion mass spectrometry have not been clarified. Therefore employment of chemometrics is necessary to obtain detailed information from time-of-flight secondary ion mass spectrometry (TOF-SIMS) data of complex samples. In this study, multivariate curve resolution (MCR) was applied to extract a pure component spectrum from a TOF-SIMS spectrum which contains mixed materials information. The model biopolymer, chicken egg white lysozyme was immobilized on a gulutaraldehyde-activated aminosilanized indium-tin oxide (ITO) glass plate by covalent bonding. A reference sample such as substrates without the protein were prepared. All samples were measured with TOF-SIMS using Bi₃⁺, and then the TOF-SIMS spectra data were analyzed using MCR with and without data preprocessing. As a result, images and spectra related to each material in the sample were obtained by MCR. The fragment ions in the extracted spectra are consistence with chemical information of each material.

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The three-dimensional atom probe (3DAP) has been used to analyze atomic-scale characterization of a number of nanostructured materials. However, it faces a problem of uncertain field evaporation mechanism by using laser at this time. Resolving this problem is very important to carry out the quantitative analysis in 3DAP. In this paper, we focused on the different reflectivity of tungsten (50 %), nickel (70 %) and aluminum (85-90 %), and measured them with changed laser power in the 3DAP. From the results, it was indicated that the shift of detection ions with the increase of laser power was different by the reflectivity of material. Also, we compared the field evaporation behavior at the laser pulse with that at the voltage pulse. According to these results, we verified the effect that affected the field evaporation mechanism due to the difference of reflectivity.

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In order to study dynamic phenomena in a microscopic region of solid surfaces, it is important to observe element, chemical-state, and molecular-orientation mappings at nanometer scale in a short time. In the previous study, we have developed a photoelectron emission microscopy (PEEM) system combined with soft X-rays from synchrotron light source, and demonstrated that the method can be applied to the observation on chemical-state mapping of silicon compounds at nanometer scale [1]. In the present work, in order to apply this method to the observation of fast phenomena, we explored the focusing of soft X-ray (1.8 - 4 keV) using a poly-capillary lens, and examined the minimum measuring time by PEEM. By adjusting the poly-capillary lens, the brightness of the measuring spot by PEEM became about 55 times higher than that without the lens. Consequently, we can take a PEEM image of a bulk sample in 10 msec. The measuring times for elemental mapping and chemical-state mapping were also examined by scanning the energy of X-ray. As a result, the typical minimum measuring times were in the order of 10 sec for elemental mapping and one minute for chemical-state mapping. It is demonstrated that the method will be applicable to the real-time observation of time-dependent phenomena in the order from msec to sec at nanometer scale.

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Shave-off depth profiling is one of the powerful methods that can be applied to the analysis of pin point and small region devices. However, acquired shave-off depth profile is affected by a long tail of the FIB because shave-off scanning mode has the distinctive position of the primary ion beam against the sample. In this study, we evaluated the influence of the long tail of the FIB in detail by the simulation method we newly proposed. The evaluation was carried out from the point of view of mainly two factors. One is thickness of the protection film. The other is the scanning speed toward the depth direction. In addition, we newly proposed the notion of 'shave-off sputtered atom yield', the important factor of shave-off depth profiling. As a result, it became possible that the determination of optimized experimental condition for the achievement of the ultimate depth resolution.

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Laser-assisted wide angle three dimensional atom probe (3DAP) has been developed in our laboratory [1]. In this study, in order to reconstruct three dimensional arrangement of atoms in more detail, the cryogenerator and field ion microscope (FIM) were installed in our 3DAP instrument, and our original preset-type specimen stage was improved. By analyzing the pure tungsten specimen with our improved 3DAP instrument, the improvement of the mass resolution and sharpening of the desorption and tomographic images were attained. Then, it was confirmed that the rising of the temperature by the laser irradiation might be suppressed by cooling down the specimen under 100 K.

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Chemical composition of internal interfaces and especially grain boundaries differs from that of the grain interior and controls materials behavior. Application of the mostly spread method of surface analysis - Auger electron spectroscopy (AES) - for measurement of nanochemistry at these buried surfaces is complicated by necessity to open the boundary by intergranular brittle fracture. Consequently, the quantification of AES spectra must also take into account redistribution of the species, segregated at the boundary, between the two fracture surfaces. In this contribution, we analyze the transformation of AES spectra onto grain boundary concentrations using the standardless methods, which are reliable for determination of thermodynamic parameters characterizing the grain boundary segregation.

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Tantalum Nitride (TaN) thin films were deposited onto n-type Si(100) and (111) substrates with SiO₂ films at room temperature by radio frequency (RF) magnetron sputtering under Ar-N₂ plasma using a tantalum target. We observed the formation of TaN thin films with a wide range of the electrical resistivity as a function of the N₂ gas flow ratio, working pressure and the sputtering power, and their origins are discussed based upon the structural properties and chemical compositions of TaN thin films before Cu films deposition. In this study, we first observed that the TaN thin films with lower resistivity exhibited TaN(200) preferentially oriented structures and had larger grain sizes. It was also found that the formation of TaO(002) made the resistivity of TaN thin films higher because of the diffusion of oxygen from SiO₂ films during deposition.

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We have measured optical second harmonic (SH) intensity from Pt nanowires with modified ellipsoidal cross sections on the MgO(110) faceted template. The observed SH intensity patterns as a function of the sample rotation angle φ around the surface normal were characterized by the effective nonlinear susceptibility arising from C_s symmetry of the Pt nanowires. The effective nonlinear susceptibility element χ₂₂₂ was observed dominantly with the suffix 2 representing the [1 -1 0] direction of the MgO substrate. Other nonlinear susceptibility elements were also detected and their origins are discussed.

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The optimal condition suitable for using a quadrupole SIMS (Q-SIMS) instrument to measure the Si concentration in GaN layers for both selectively isotopic Si-implanted GaN and epitaxially Si-doped GaN was presented. The detection of ³⁰Si¹⁴N_- molecular ions under Cs⁺ primary ion bombardment realized the best dynamic range and the lowest detection limit for Q-SIMS analysis of Si in GaN layers. The detection limits of selectively isotopic ³⁰Si and the total amount of Si naturally occurring isotopes in GaN layers can reach 2 × 10¹⁴ cm^-3 and 8 × 10¹⁵ cm^-3, respectively. We concluded that a Q-SIMS instrument was applicable for the analysis of the Si depth distribution in GaN layers.

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We applied conductive Atomic Force Microscopy (c-AFM) to characterize the electrical properties of low-temperature polycrystalline silicon. Current distribution and current-voltage characteristics are recorded using conductive-diamond covered AFM tip and low noise external amplifier. Spectroscopic ellipsometry and optical microscopy are used to determine the grain size, crystalline fraction and film thickness. The correlation between structural properties of the poly-Si fabricated with varied conditions and c-AFM results is revealed, which shows the potential of this technique as convenient method for evaluation of metal-induced-crystallized poly-Si quality.

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A new type of AFM tip characterizer used for characterizing nanostructures in the 10 nm to 100 nm range was developed. The characterizer was fabricated by preferential etching the edge of a cross sectioned Si/SiO₂ multilayer. Both isolated line structures and line-and-space structures were fabricated. The structural and practical properties of the fabricated tip characterizer were evaluated, and it was shown that it can be used to characterize AFM tip shapes in the 10 nm to 100 nm range.

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Fluorine-containing hydrophobic thin films have been treated in this study with a mixture of fluorocarbon precursors like C₂F₆, C₃F₈, and c-C₄F₈ and the unsaturated hydrocarbons of C₂H₂ using inductively coupled plasma (ICP) and pulsed plasma (PP) deposition. Process parameters for plasma polymerization such as gas ratio, gas pressure, plasma power, pulse frequency, and processing time were investigated. Surface analytical instruments such as time-of-flight secondary ion mass spectrometry (TOF-SIMS) and x-ray photoelectron spectroscopy (XPS) were used to provide useful information about the surface composition and the chemical structure of the fluorocarbon films. Film thickness and surface morphology were also observed by using FE-SEM and AFM. Water contact angle measurements and FE-SEM results show that the ICP technique provides coarser grained films and more hydrophobic surfaces as well as a higher deposition rate compared to the PP technique. TOF-SIMS and XPS analyses indicate that the ICP technique produced more fluorine-containing functional groups, including CF₂ and CF₃, than the PP technique. From the curve-fitted XPS results, it is clear that fluorocarbon films grown using the ICP technique exhibited less cross-linking and higher CF₂ concentrations than those grown using the PP technique.

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We studied the growth mechanism of Al-doped ZnO (AZO) films using seed layers for enhancing the performance of transparent conducting oxides (TCOs) in the thin film solar cells. We carried out two-step processes for the deposition of AZO films. Seed layers were deposited on glass substrate as a function of Ar/O₂ gas flow ratio. We show the results of our investigation on the micro-structural properties of AZO seed layers using transmission electron microscopy (TEM). The elemental composition and electronic structure changes with the deposition conditions were examined using energy dispersive X-ray (EDX) and reflective electron energy loss spectroscopy (REELS). The optical and electrical characteristics of AZO film using the seed layer with Ar/O₂ = 9/1 show a high haze value of 88% at 500 nm and a resistivity value of 3.7 × 10^-4 Ωcm.

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We have studied the adsorption reaction of DMS on the Rh nanoparticle fabricated by the gas evaporation method by using AFM, XPS and NEXAFS techniques. The AFM result shows that we can fabricate the Rh nanoparticle which has a small diameter with a small distribution and high dispersion of it by the gas evaporation method with the Rh wire as an evaporation source. The Rh L₃-edge NEXAFS spectra indicate that the surface and bulk of Rh nanoparticle is stable in the chemical state of Rh⁰ despite the exposure to air. The Rh 3d XPS and S K-edge NEXAFS results show the lower degree of oxidized Rh nanoparticle has the stronger bonding with atomic S than the more oxidized one.

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In order to study anode effects in Cu electroplating, we investigated the characteristics of the Cu films electrodeposited on Cu seed layer and the surface change of anodes, by using Cu (soluble) and Pt (insoluble) anodes. For the case of Cu anode, the brownish passivation layer was formed on the surface of Cu anode, and this was mainly composed of by-products which was formed by reaction of impurities in electrolyte with copper anode. In use of Pt anode, the O₂ bubbles on the anode surface were occurred. The current density in bath for the case of Cu anode was larger than that of Pt anode and increased after 300 s of plating time had elapsed. In formation of the electroplated Cu films, the deposition rate of Cu films electroplated by using Cu anode was larger and the density of film plated by using Cu anode was higher than those by Pt anode.

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In order to remove native Cu oxides formed on Cu seed layer, TS-40A and H₂SO₄ solutions were used. After various pretreatments, the changed surface of Cu seed layer was estimated by SEM and XPS. For all pretreatments, the mass of samples was decreased. The mass loss of sample treated in H₂SO₄ solution for 60 s was the largest. After TS-40A pretreatment, native Cu oxide layer is not at all removed although the carbon on Cu seed layer was removed mainly with a few loss of sample mass. By H₂SO₄ treatment after TS-40A pretreatment, most of native Cu oxides on Cu seed layer were removed with a lot of mass loss and the oxides will be eliminated by control of dipping time. Consequently, we found that the pretreatment by H₂SO₄ is suitable to obtain a Cu seed layer removed native oxide for electrodeposition.

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In three dimensional atom probe (3DAP) analysis, specimen preparation is of considerable significance. Specimens which are fabricated by the existing method are often ruptured from the part attaching the sample to the support needle because attachment force by deposition is not adequate. Specimen preparation methods which have stronger attachment force are required. In this study, we prepared some specimens using six types of cohesion methods in which the shape of contacting part between the sample and the support is different. We tested the strength of the specimens by applying the electric field to them, and searched the optimum specimen preparation method for 3DAP analysis using the results of comparison of physical strength and difficulty in fabrication of them. Then we concluded that specimen preparation method in which the sample was attached with the base needle by physical strengths of C-gas deposition in connected hole was the best way.

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Shave-off depth profiling with nano-beam SIMS, our own technique, achieves the highly precise depth profiling with nanometer-scale depth resolution by utilizing a Focused Ion Beam (FIB) micro-machining process to provide the depth profile. This method is to acquire depth profiling by the shave-off scanning mode. However, we could obtain the signals as a function of time because the FIB scanning system and the signal acquisition system were working independently. Therefore, we developed a new system to obtain the signals as a function of two-dimensional position of the FIB. As a result, we could divide a shave-off profile up to 256 along lateral direction. We defined these lateral areas “lanes” and named this new method “multilane shave-off profiling”.

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Three-dimensional (3-D) molecular imaging in polymeric biomaterials, particularly in the near surface region (1 nm to 500 nm), is extremely important for drug delivery applications, as these regions play a vital role in both the biocompatability and drug release characteristics in drug delivery systems. Although pharmaceutical companies typically use dissolution studies to monitor the rate of drug release, these studies need to be correlated with actual structural information, compositions and defects within the device. This work discusses the most recent advances and challenges in utilizing Cluster Secondary Ion Mass Spectrometry (cluster SIMS) for 3-D characterization and quantification in polymer-based drug delivery systems. The results are promising, showing the ability to quantify and image the 3-dimensional distribution of drugs in polymer layers. However, many problems still remain in terms of analysis of real-world samples, including complex sample geometries, ionization effects, and beam-induced sample damage. These problems, and how to address them, are discussed briefly here.

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We prepared ZnO-containing nanomaterials of different-sized native ZnO and isotope-enriched ⁶⁸ZnO nanoparticles (NPs) with well-characterized composition and applied them to HaCaT cells for in vitro cytotoxicity study. ToF-SIMS was applied to probe spatially-resolved intracellular changes. Elevated level of intracellular Zn correlated well with decreased ³⁹K/⁴⁰Ca upon increased ZnO NPs exposure, indicating that the dissolving behavior of ZnO NPs played an important role in inducing cytotoxicity. Furthermore, the coherency of spatial distribution between elevated Zn and decreased ³⁹K/⁴⁰Ca leads us to propose the presence of local cytotoxicity effect by ZnO NPs. Similar results were obtained irrespective of the use of native or isotope-enriched ZnO NPs, indicating the negligible contribution to cytotoxicity from intrinsic Zn²⁺.

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This preliminary study is aimed at a new approach in the protein analysis of hard tissues. Analytical methods that have been used for the identification of proteins in bones and teeth always require one critical step — demineralization. This chemical treatment is responsible for loss of proteins and it also negatively influences the possibility of protein quantification. The method of peptide mass mapping described in this paper facilitates a gentle releasing of peptides from the hard tissues without the loss of qualitative and quantitative information. Using this method led to identification of proteins from chicken thighbone, human jawbone and teeth, which proves the feasibility of this method.

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The microphase separation of diblock copolymers has been investigated by many different research groups for many years, because of the increasing use of diblock copolymers as compatibilizers, dispersants, impact modifiers, nanocarriers, and templates. In this presentation, surface characterization methods were utilized to study the surface morphology and composition produced after annealing thin polymer films. We report on the characterization of the morphology from symmetric diblock copolymers of polystyrene-b-poly(n-propyl methacrylate)(PS-PPrMA), where PS block was perdeuterated, using Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). TOF-SIMS depth profiling was obtained for the lamellar morphology of deuterated PS-PPrMA which is found to orient parallel to the surface of the substrate. This preferential orientation resulted in a periodic variation in the composition of each block that continued through the entire copolymer film. Annealing studies on dPS-PPrMA thin films with different thickness on the silicon substrates were performed to investigate the lower disorder-to-order transition (LDOT) properties of diblock copolymers.

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Influence of CO₂ and H₂O on the air oxidation reaction of Mg nanoparticles has been investigated by Mg K-edge NEXAFS technique. The water vapor in the air causes rapid progression on the air oxidation reaction of the Mg nanoparticles. The basic magnesium carbonate (4(MgCO₃).Mg(OH₂).4(H₂O) : BMC) is formed by the long term exposure to air. The NEXAFS analysis shows an existence of several intermediates of the BMC formation reaction.

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In this study, a quantitative analysis of Cu(InGa)Se₂ (CIGS) was performed using an electron probe microanalysis (EPMA) equipped with a wavelength dispersed spectroscopy (WDS), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and dynamic secondary ion mass spectrometry (dynamic SIMS). Reproducible quantitative analysis data were obtained for CIGS layers from a depth profile of SIMS and relative sensitivity factor (RSF) value calculated using the mole fraction of EPMA. In addition, to obtain a reproducible quantitative analysis for CIGS layers through SIMS depth profile, the experimental conditions were changed including the primary ion, beam energy, and beam current.

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It is very important to clarify the distribution of sugar chains on the surface of biological membranes for understanding physiological reactions in detail. However, there has been little information available on the two-dimensional distribution of sugar chains on biological surfaces on micro- to nanometer scale until now. Atomic force microscopy (AFM) has been widely used for the direct detection of specific interactions between biologically active molecules. Concanavalin A (ConA) is a well-known lectin with specific affinities for α-D-mannosyl and α-D-glucosyl residue. In this study, mannose (Man) and oligoethylene glycol (OEG) were locally immobilized on a substrate, and the two-dimensional distribution was visually mapped on micrometer scale using AFM force sensing with a ConA-modified tip. As a result, the distinct contrast between Man and OEG regions was observed based on the difference of the interaction with ConA. It is expected that distribution analysis of sugar chains on biological membranes will be realized by this method in the near future.

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X-ray absorption fine structure (XAFS) is a powerful tool to investigate electronic structures, valence states and molecular orientations at solid surfaces. In order to observe nano-scaled dynamic phenomena at solid surfaces, we have developed a micro-XAFS system using a photoelectron emission microscopy (PEEM) excited by synchrotron radiation in soft X-ray region. Here we explain the performance of our system concentrating on the recent development of quick measurements, and demonstrated that a PEEM image can be taken in a short time down to 10 msec. As an application of the system, we present the results for the real-time mapping of molecular orientations at nanometer scale for organic thin films. We demonstrated that the orientations of organic molecules in a microscopic region change during surface diffusion.

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Secondary Ion Mass Spectrometry (SIMS) has been used as an analysis tool for biological samples using cluster ions of C₆₀⁺, Bi_n⁺, etc. However, because of bad focusing of cluster ions, accurate three-dimensional analysis is difficult. On the other hand, FIB (Focused Ion Beam) using Ga⁺ ions can be focused to about 50 nm, and applied to samples of micro region such as biological samples. However, three-dimensional analysis is difficult because of surface damage by primary ions. Therefore, we have developed Shave-off section processing method. Shave-off scan is extremely unique section processing method. Raster scan of FIB is very slow in vertical direction compared with in horizontal direction. In this study, we evaluated surface damage in section processing and carried out three-dimensional analysis of biological sample using Dual FIB ToF-SIMS with Shave-off scan. We evaluated surface damage by primary ions and actually analyzed biological sample with Shave-off scan. We demonstrated the utility of this instrument by analyzing biological samples.

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Identification of double layered thin film elements by backscattered electron (BSE) contrast imaging by scanning electron microscope (SEM) was examined. A flat type sample was formed with an inner layer composed of five different element areas (Au, Ag, Ge, Cu and Fe) 50 nm thick and a thin gold outer layer 2, 5, or 10 nm thick on a silicon substrate. Dependence of BSE intensities of the sample on the acceleration voltage of incident electrons was measured from 3 to 30 kV, and the acceleration voltage sufficient to discriminate different elements shifted from 8.8 to 10.2 kV depending on the increase of the thickness of outer gold layer. Moreover, the dependence of the substrate shape was also evaluated using Ge/Au double layered spherical nano-shells. The contribution of the nano-shell diameter to the BSE intensity was tested using different sized nano-shells. The contribution was within 10% for 1.5 times difference of the diameter of nano-shells. Results between flat thin film and the nano-shell were compared and those differences were within 6% for 10 to 20 kV of acceleration voltage, which indicates that inner elements of double layered thin film objects can be identified using BSE observation of the SEM at appropriate acceleration voltage.

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Chemical mapping of biomolecules in biological samples such as tissues and cells is crucial for biological, medical and biochemical fields. Although secondary ion images of biomolecules such as phosphocholine and cholesterol distributions on tissue samples are easily obtained with time-of-flight secondary ion mass spectrometry (TOF-SIMS), the observation of minor ingredients is often difficult. In this study TOF-SIMS imaging data of skin samples were analyzed with a multivariate analysis technique, multivariate curve resolution (MCR), in order to investigate appropriate analysis conditions. Mice middorsal skin was sliced with a microtome and placed on indium-tin oxide glass plates. The samples were measured with TOF-SIMS using Bi₃⁺, and then the obtained data were analyzed with MCR under various analysis conditions for investigating appropriate conditions. As a result, it is indicated that MCR classify TOF-SIMS raw data into some categories representing different features, which makes interpretation of TOF-SIMS data easier.

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