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The FurnaSEM microfurnace was installed in the chamber of a scanning electron microscope to carry out in situ experiments at high temperatures and test its limits. The microfurnace was used in combination with different types of detectors (Everhart–Thornley for the collection of secondary electrons in a high vacuum, gas secondary electron detector for the specific collection of secondary electrons in the presence of gas, and Karmen© detector for the collection of backscattered electrons at high temperature). Experiments carried out on various samples (metal alloys and ceramics) show that the microfurnace operates in both high-vacuum and low-vacuum modes. Temperature ramp rates during temperature cycles applied to the sample range from 1 to 120 °C/min (temperature rise) and 1 to 480 °C/min (controlled and natural cooling). The maximum temperature at which images were recorded up to 25 k × magnification was 1340 °C, with a residual air atmosphere of 120 Pa. The choice of a flat furnace with the sample placed directly above it has enabled innovative experiments to be carried out, such as low-voltage imaging (using a shorter working distance—up to 10 mm—than is possible with conventional furnaces), 3D imaging (by tilting the stage by up to 10°), and high-temperature backscattered electron imaging (using a dedicated detector). [ABSTRACT FROM AUTHOR]

When conducting in situ experiments at high temperatures in a scanning electron microscope using microfurnaces, controlling the temperature of a sample of a few mm3 placed in the hot zone of the furnace can be a complex task. In most cases, the temperature of the sample is estimated by means of a thermocouple placed in the hot body of the furnace, and the assumption made is that the temperature of the furnace is the temperature of the sample. In this work, a detailed understanding of the thermal response of the sample placed in the hot zone of the furnace is proposed. Temperature differences due to contact resistance between the furnace surface and the sample, the nature of the sample, and the sample geometry are calculated with a numerical model and measured experimentally on a dedicated test bench. Three technical solutions (bonding, sandwiching, and mini-crucible) for limiting temperature differences between the furnace surface and sample are proposed and validated by numerical calculations and experimental measurements. [ABSTRACT FROM AUTHOR]

The development of a new heating system dedicated to in situ scanning electron microscope (SEM) experimentation at high temperatures is reported. This system, called FurnaSEM, is a compact microfurnace, enabling heat treatments up to 1300 °C. The choice of materials for the microfurnace is explained. The design of the microfurnace is optimized by iterations of numerical simulations, and the thermal characteristics of the microfurnace are calculated numerically. The numerical results obtained are compared with the thermal characteristics of a manufactured microfurnace, measured on a specially developed dedicated test bench. This test bench includes a working chamber simulating a SEM chamber equipped with a thermal camera. The results obtained during various qualification tests enabled us to determine the main technical characteristics of the FurnaSEM microfurnace: temperature profiles on the sample support surface, energy consumption at high temperatures, and the range of achievable thermal cycles. [ABSTRACT FROM AUTHOR]

We reported here on the fabrication and characterization of a smart titanium alloy bolt based on a high-frequency piezoelectric thin-film sensor. The thin-film sensor was directly deposited on a titanium alloy bolt head with radio frequency magnetron sputtering and characterized by a scanning electron microscope and an atomic force microscope. The ultrasonic characteristics of the smart bolt, which include a pure and broad frequency spectrum peaked at 14.81 MHz, high measurement accuracy below 3%, and high repeatability free from some interference from bolt detection position change, were fully characterized. No obvious frequency shift was observed with the increase in axial preload. Based on the mono-wave method [TOF (time of flight) of longitudinal mode wave], TOF change increased linearly with preload force in the range of 0–20 kN. With the increase in temperature from 22 to 150 °C, the TOF linearly increases while the longitudinal wave velocity linearly decreases. The results indicate the prepared smart titanium alloy bolt is suitable as a smart aviation and automotive fastener. [ABSTRACT FROM AUTHOR]

This paper presents a novel piezoelectric-driven nanoindentation system for a scanning electron microscope (SEM) with an improved analog compensation (IAC) method. This system mainly consists of a piezoelectric-driven indenter head, a rectangle-shaped transducer, and a nanopositioner module. Compared with the state-of-the-art piezoelectric-driven nanoindentation system with a circle-shaped transducer, the proposed nanoindentation system is capable of multi-direction operation inside a SEM with a rectangle-shaped transducer. Self-matched semiconductor strain gauges are selected as the position sensor for the piezoelectric-actuator. The Wheatstone bridge output voltage cannot achieve a zero temperature coefficient because the temperature coefficients of self-matched semiconductor strain gauge pairs become significantly different from each other after installation in practice. An IAC method is proposed to compensate the temperature coefficients further. Compared with the existing analog compensation method, the IAC method solves the problem of amplifier saturation and improves the sensitivity of the self-matched semiconductor strain gauge pairs position sensor by 27%. The multi-direction operation results inside a standard SEM HITACHI SU5000 validate the advantage of the developed nanoindentation system. [ABSTRACT FROM AUTHOR]

Laminar-type spherical diffraction gratings overcoated with carbon-based materials were designed, fabricated, and evaluated for the purpose of enhancing the analytical sensitivity of the flat-field spectrograph in a vacuum ultraviolet region of 35–110 eV. As the design benchmark for numerical calculations, diffraction efficiency (DE) and spectral flux, which are defined by the product of the DE and numerical aperture and correlate with the analytical sensitivity of the spectrograph, were used. To simplify the feasibility study on the overcoating effects, we assumed a laminar-type grating having a grating constant of 1/1000 mm and coated with a Au layer of 30.0 nm thickness and an incidence angle of 84.0°. The optimized groove depth and duty ratio were 30.0 nm and 0.3, respectively. In addition, the optimum thicknesses of the overcoating layer were 44, 46, 24, and 30 nm for B4C, C, diamond-like-carbon, and SiC, respectively. Based on these results, we have fabricated a varied-line-spacing holographic grating overcoated with B4C with a thickness of 47 nm. For the experimental evaluation, we used the light source of Mg-L and Al-L emissions excited by the electron beam generated from an electron microscope, an objective flat-field spectrograph, and a CCD imaging detector. The experimental results showed that the spectrograph employing a new grating overcoated with the B4C layer indicated almost the same spectral resolution and 2.9–4.2 times higher analytical sensitivity compared with those obtained with a previously designed Au-coated grating having a grating constant of 1/1200 mm and used at an incidence of 86.0°. [ABSTRACT FROM AUTHOR]

The hole expansion ratio (HER) test is used to determine the stretch-flangeability of materials. Standard HER tests are performed on specimens sized a few tens of centimeters, termed macro-HER tests. This leads to significant material wastage due to the destructive nature of the tests. No information at the microstructure length scale is obtained, and the results suffer from user uncertainty in the identification of the through-thickness crack. This paper presents a novel miniature HER setup (termed micro-HER test), in which miniature specimens are tested inside a scanning electron microscope (SEM). The deformation is imaged from the top using the secondary electron detector installed in the SEM, coupled with the digital image correlation (DIC) technique, allowing for measurement of full field strains at the microstructural scale and identifying their deformation/fracture mechanisms. As a case study, six different steel grades were tested to measure their micro-HER values and compare them with the corresponding macro-HER values. The latter were found to be higher for the more ductile grades of steel. Late detection of through-thickness cracks and thicker samples leading to a higher volume of plastic deformation could contribute to this overestimation of values in macro-HER tests. DIC results from micro-HER tests on a ferrite–martensite (10% volume fraction) dual-phase steel showed high magnitudes of strain localization at the ferrite–martensite interfacial regions, indicating that such interfaces might be hotspots for failure under triaxial stress states. The challenges and errors associated with the measurements are also discussed. [ABSTRACT FROM AUTHOR]

Owing to the parasitic vibration effect of the cooling medium and pipes of X-ray optics, the vibration decoupling cooling method based on eutectic gallium–indium (EGaIn) alloy has become very crucial for fourth generation synchrotron radiation advanced light sources. However, there is an issue that the corrosion of the EGaIn alloy to the heat sink metal [e.g., copper (Cu) plate] results in the solidification and the failure of eliminating the parasitic vibration effect. To deal with the problem, a novel anti-corrosion coating based on tungsten (W) is presented in this paper. It possesses better corrosion resistance performance compared with the traditional coating of nickel (Ni). The experimental investigation was carried out, in which the EGaIn alloy was exposed to several typical metal materials in conditions of various time durations and various temperatures, which were considered as controls. Furthermore, the corrosion effects are analyzed and evaluated in two aspects of micromorphology and the chemical composition by using an optical microscope and a scanning electron microscope as well as x-ray diffraction. The results show that non obvious corrosion occurred for W, 0.33 mm and 48 µm thick transition micro-area, respectively, for Cu and Ni. In addition, new substances CuGa2 and Ni3Ga7 occurred, respectively, for Cu and Ni for 36 hours at 250 °C. The EGaIn alloy will freeze after corroding 18 µm substrate for Ni or 30 µm for Cu. Furthermore, the W coating that was prepared by magnetron sputtering has been implemented for feasibility validation. [ABSTRACT FROM AUTHOR]

We report the development of a fully automatic large-volume 3D electron backscatter diffraction (EBSD) system (ELAVO 3D), consisting of a scanning electron microscope (ZEISS crossbeam XB 1540) with a dedicated sample holder, an adapted polishing automaton (Saphir X-change, QATM), a collaborative robotic arm (Universal Robots UR5), and several in-house built devices. The whole system is orchestrated by an in-house designed software, which is also able to track the process and report errors. Except for the case of error, the system runs without any user interference. For the measurement of removal thickness, the samples are featured with markers put on the perpendicular lateral surface, cut by plasma focused ion beam (PFIB) milling. The individual effects of both 1 μm diamond suspension and oxide polishing suspension polishing were studied in detail. Coherent twin grain boundaries (GBs) were used as an internal standard to check the removal rates measured by the side markers. The two methods for Z-spacing measurements disagreed by about 10%, and the inaccurate calibration of the PFIB system was found to be the most probable reason for this discrepancy. The angular accuracy of the system was determined to be ∼2.5°, which can be significantly improved with more accurate Z-spacing measurements. When reconstructed grain boundary meshes are sufficiently smoothed, an angular resolution of ±4° is achieved. In a 3D EBSD dataset of a size of 587 × 476 × 72 μm3, we focused on the investigation of coincidence site lattice ∑9 GBs. While bearing predominantly a pure tilt character, ∑9 GBs can be categorized into three groups based on correlative 3D morphologies and crystallography. [ABSTRACT FROM AUTHOR]

Multi-tip scanning tunneling microscopy (STM) is a powerful method to perform charge transport measurements at the nanoscale. With four STM tips positioned on the surface of a sample, four-point resistance measurements can be performed in dedicated geometric configurations. Here, we present an alternative to the most often used scanning electron microscope imaging to infer the corresponding tip positions. After the initial coarse positioning is monitored by an optical microscope, STM scanning itself is used to determine the inter-tip distances. A large STM overview scan serves as a reference map. Recognition of the same topographic features in the reference map and in small scale images with the individual tips allows us to identify the tip positions with an accuracy of about 20 nm for a typical tip spacing of ∼ 1 μ m. In order to correct for effects such as the non-linearity of the deflection, creep, and hysteresis of the piezoelectric elements of the STM, a careful calibration has to be performed. [ABSTRACT FROM AUTHOR]

This paper develops a robust edge-based template matching algorithm for displacement measurement of compliant mechanisms under a scanning electron microscope (SEM). The algorithm consists of three steps. First, the Sobel gradient operator and a self-adaptive segment strategy are used to establish the shape model in which the gradient directions of the object's edge points are calculated. Second, a similarity criterion based on image gradients that is robust to illumination change and image noise is utilized for template matching to obtain the coarse results. The third step is to refine the matching results by using an orientation-guided subpixel interpolation strategy. A series of simulations is conducted, and the results show that the proposed algorithm enjoys great robustness against strong image noise and gray-value fluctuation, as well as small rotations and background interferences, and thus is suitable for processing SEM images of compliant mechanisms. Finally, the application of the proposed algorithm in the measurement of the spring constant of the flexure hinges with a straight beam form under a SEM is demonstrated. [ABSTRACT FROM AUTHOR]

Digital holography has been proposed to fulfill a need for an imaging diagnostic capable of in situ monitoring of surface erosion caused by plasma–material interaction in nuclear fusion devices. A digital holography diagnostic for 3D surface erosion measurement has been developed at Oak Ridge National Laboratory with the goal of deployment on a plasma device. A proof-of-concept in situ demonstration is planned which would involve measurement of plasma erosion on targets exposed to an electrothermal arc source. This work presents the results of an ex situ characterization of the capability and limitations of holographic imaging of targets exposed to the arc source. Targets were designed to provide a fiducial for comparison of deformed and unaffected areas. The results indicated that the average net erosion was ∼150 nm/plasma exposure, which is expected to be within the diagnostic's measurement capacity. Surface roughness averages determined by holographic image analysis showed good agreement with measurements taken with a profilometer. The limit of the holography diagnostic's x–y spatial resolution was characterized by comparison with scanning electron microscope imaging. [ABSTRACT FROM AUTHOR]

For insulators, the deposited charge on the surface after electron bombardment interferes with the total electron emission yield (TEEY) measurement. The key to measuring the TEEY of insulators is to eliminate the surface deposited charge. Being different from traditional measurement methods, we develop and demonstrate a new method for measuring the TEEY of insulators in a scanning electron microscope by preparing the micro-patterned metal on the surface of the insulators as a conducting channel. The TEEY of the insulators is measured based on the TEEY of the metal part and the metal–insulator periodic structure. By theoretical analysis, we get a criterion for judging whether the deposited charge is eliminated. The result shows that this method is reliable by measuring the TEEY of Si. Then, we obtained the TEEY of SiO2 by this method with an energy of up to 3000 eV. The measured TEEY characteristics of SiO2 are consistent with the data from the references. Moreover, the surface charge diffusion distance of the insulators can also be estimated under this measuring condition. We get that the maximum value of the TEEY of SiO2 is ∼4.2, and the surface charge diffusion distance of SiO2 is ∼1 µm. In this work, the criterion for judging whether the deposited charge is eliminated is obtained, which has not been proposed in traditional measurement methods. [ABSTRACT FROM AUTHOR]

The success of a microtube hydroforming (μTHF) process heavily depends on the material properties of microtubes, which can reveal the material response under multiaxial stress and influence the formability of hydroformed products. However, these material properties are not well understood because of the limited availability of material testing apparatus that would permit control of axial force and internal pressure simultaneously to mimic realistic μTHF loading. The main purpose of this study is to develop a set of grippers that can transfer required testing loads under fully coupled combinations of axial force and internal pressure. The grippers are designed so that they may be kept at the safe working temperature even when tests are carried out at higher temperatures. The grippers are also designed to fit in a load frame that is integrated in a scanning electron microscope for in situ material testing. The capabilities of the grippers are demonstrated by performing uniaxial and multiaxial material tests on SS304 microtubes with 1 mm outside diameter and 0.15 mm nominal tube wall thickness. The finite element simulations and experimental results show that the designed grippers can firmly hold the specimen and thus enable tensile, compression, torsion, and microtube bulge material tests to be accurately performed. [ABSTRACT FROM AUTHOR]

An in situ hydrogen (H) plasma charging and in situ observation method was developed to continuously charge materials, while tensile testing them inside a scanning electron microscope (SEM). The present work will introduce and validate the setup and showcase an application allowing high-resolution observation of H-material interactions in a Ni-based alloy, Alloy 718. The effect of charging time and pre-straining was investigated. Fracture surface observation showed the expected ductile microvoid coalescence behavior in the uncharged samples, while the charged ones displayed brittle intergranular and quasi-cleavage failure. With the in situ images, it was possible to monitor the sample deformation and correlate the different crack propagation rates with the load-elongation curves. H-charging reduced the material ductility, while increasing pre-strain decreased hydrogen embrittlement susceptibility due to the possible suppression of mechanical twinning during the tensile test and, therefore, a reduction in H concentration at grain and twin boundaries. All the presented results demonstrated the validity of the method and the possibility of in situ continuously charging of materials with H without presenting any technical risk for the SEM. [ABSTRACT FROM AUTHOR]

High temperature materials usually serve under extreme conditions. In order to ensure the safety and reliability of industrial application, it is very significant to clarify the microstructural evolution and mechanical properties at high temperature. The in situ experiment combining mechanical tensile testing and heating in the scanning electron microscope (SEM) is a feasible method to study the relationship between the microstructure, mechanical properties, and temperature. However, it was challenging to acquire images of high quality when the temperature exceeded 800 °C due to the effect of thermal electrons and the instability of loading conditions at high temperature. In this study, a mini-tensile apparatus was devised and installed in an ordinary SEM, which can achieve a stable loading of 0–2200 N and obtain high quality images in the temperature range of 1150 °C. A highly efficient heat source with multi-layer thermal insulation was designed to prevent the other parts of the apparatus from being affected by high temperature. A symmetrical tensile structure was developed to ensure that the region of interest was always within the field of view of the microscope during testing. Thermal electrons were suppressed to ensure that the sample can be clearly distinguished at 1150 °C. In order to ensure the testing reliability, standard carbon steel was used to calibrate the instrument. Finally, a Ni-based single crystal superalloy, as an example, was tested using this in situ tensile testing system at 1150 °C to verify the main functions and reliability of the apparatus. [ABSTRACT FROM AUTHOR]

van der Waals forces, electrostatic interactions, and capillary forces are the dominant force interactions at the micro- and nanoscale. This complex ensemble of surface forces is oftentimes summarized as adhesion and is important for various applications and research fields. So far, numerous measurement techniques have evolved in this field. However, there is still a lack of experimental insight into the complex interplay of van der Waals, electrostatic, and capillary forces for small force ranges below 10 nN, as this is the order of magnitude of the latter, which can shadow other interactions in ambient and even inert gas environments. To exclude capillary forces and thus to turn the van der Waals and electrostatic forces into the most significant interactions, we develop an interferometric force spectroscopy setup based on a scanning probe technique, featuring a sub-nanonewton resolution, and integrate it into the vacuum chamber of a scanning electron microscope. In this work, we describe the setup integration, show the long-term drift behavior and resolution capabilities, and conduct first measurements of adhesion energies between a silica colloidal probe and a silicon substrate. The presented setup shows its capability to reliably measure adhesive interactions in vacuum and an ambient environment with a sub-nanonewton resolution proving its potential to allow for the investigation of the separate contribution of capillary, van der Waals, and electrostatic interactions to adhesion and for a systematic experimental validation of the established adhesion theories and approximations on the micro- and nanoscale. [ABSTRACT FROM AUTHOR]

GaN nanowires are potential candidates for use in scanning probe microscopy due to their well-defined, reproducible, geometric shapes, their hardness, and their light guiding properties. We have developed and investigated probes for high resolution atomic force microscopy and scanning tunneling microscopy utilizing GaN nanowires as probes. The nanowires are n-doped and the morphology of the nanowires has been tailored for scanning probe microscopy by growing them with a sharp tip for measurements and high thickness for robustness. The individual GaN nanowires were removed from their growth substrate and attached onto commercial atomic force microscopy cantilevers or etched tungsten wires for scanning tunneling microscopy. A standard scanning electron microscope equipped with a nanoprobe, a focused ion beam column and a gas injection system was used to locate, transfer, and attach the nanowires. We evaluated the properties of the GaN probes on different substrates including HOPG, Au, SiO2, InAs, and GaAs. We demonstrate both atomic force microscopy and scanning tunneling microscopy measurements with single atomic layer resolution and evaluate the robustness of the tips by monitoring them before and after scanning. Finally, we explore the use of the tips for scanning tunneling spectroscopy demonstrating that reliable results, which can reveal information on the electronic properties of the surface-tip system, are obtainable. The fundamental properties of these probes, which are demonstrated in this work, show promise for future use of the probes in exploring semiconductor-semiconductor tunneling junctions at the nanoscale as well as for other scanning probe techniques where high resolution is required. [ABSTRACT FROM AUTHOR]

Over the life of nuclear fuel, inhomogeneous structures develop, negatively impacting thermal properties. New fuels are under development but require more accurate knowledge of how the properties change to model performance and determine safe operational conditions. Measurement systems capable of microscopic thermal transport measurements and low cost are necessary to measure these properties and integrate into hot cells where electronics are likely to fail during fuel investigation. This project develops a cheaper, smaller, and easily replaceable Fluorescent Scanning Thermal Microscope (FSTM) using the blue laser and focusing circuitry from an Xbox HD-DVD player that incorporates novel fluorescent thermometry methods to determine thermal diffusivity. The FSTM requires minimal sample preparation, does not require access to both sides of the sample, and components can be easily swapped out if damaged, as is likely in irradiated hot cells. Using the optical head from the Xbox for sensing temperature changes, an infrared laser diode provides periodic heating to the sample, and the blue laser induces fluorescence in Rhodamine B deposited on the sample's surface. Thermal properties are fit to modulated temperature models based on the phase delay response at different modulated heating frequencies. With the FSTM method, the thermal diffusivity of a Nordic gold (euro) coin was found to be 21 ± 5 mm2/s. This value is compared to laser flash and thermal conductivity microscope methods, which found the thermal diffusivity to be 30.4 ± 0.1 mm2/s and 19 ± 3 mm2/s. The system shows promise as a feasible property characterization technique with future refinement and testing in progress. [ABSTRACT FROM AUTHOR]

A new configuration of semiconductor detectors for backscattered electrons for a scanning electron microscope (SEM) is presented. The result of the optimization was the possibility to extract the information about the spatial relief (3D topology) of the sample and its subsurface structure (3D tomography) in the simplest way. The detector consists of 8 sensors-semiconductor plates, positioned in a certain way. The proposed method was tested on real structures having a surface micro relief or a subsurface volume structure. Experiments and simple calculations show increased effectiveness and a high signal-noise ratio in the proposed method. This is important, particularly for studying the radiation-sensitive biomedical tissue in SEM. [ABSTRACT FROM AUTHOR]

Here, we present a stage-scanning two-photon microscope (2PM) equipped with a temporal pulse shaper and a spatial light modulator enabling full control over spectral and spatial phases of the exciting laser pulse. We demonstrate the capability of correcting wavefronts and temporal pulse distortions without cross-dependencies induced by optical elements at the same time enhancing the fluorescence signal. We implemented phase resolved interferometric spectral modulation for temporal pulse shaping and the iterative feedback adaptive compensation technique for spatial pulse modulation as iterative techniques. Sample distortions were simulated by cover glass plates in the optical path and by chirping the exciting laser pulses. Optimization of the spectral and spatial phases results in a signal increase of 30% and nearly complete recovery of the losses. Applying a measured spatial compensation phase within a real leaf sample shows the enhancement in contrast due to wavefront shaping with local fluorescence increase up to 75%. The setup allows full independent control over spatial and spectral phases keeping or improving the spatial resolution of our microscope and provides the optimal tool for sensitive non-linear and coherent control microscopy. [ABSTRACT FROM AUTHOR]

In order to supplement manufacturers' information, this Department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications. [ABSTRACT FROM AUTHOR]

In order to supplement manufacturers’ information, this Department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications. [ABSTRACT FROM AUTHOR]

A flexural bearing mechanism has enabled the development of a self-sealing box for protecting air sensitive samples during transfer between glove boxes, micro-machining equipment, and microscopy equipment. The simplicity and self-actuating feature of this design makes it applicable to many devices that operate under vacuum conditions. The models used to design the flexural mechanism are presented in detail. The device has been tested in a Zeiss Merlin GEMINI II scanning electron microscope with Li3PS4 samples, showing effective isolation from air and corrosion prevention. [ABSTRACT FROM AUTHOR]

A versatile atomic force microscope (AFM), which can be installed in a scanning electron microscope (SEM), is introduced. The flexible design of the instrument enables correlated analysis for different experimental configurations, such as AFM imaging directly after nanoindentation in vacuum. In order to demonstrate the capabilities of the specially designed AFM installed inside a SEM, slip steps emanating around nanoindents in single crystalline brass were examined. This example showcases how the combination of AFM and SEM imaging can be utilized for quantitative dislocation analysis through the measurement of the slip step heights without the hindrance of oxide formation. Finally, an in situ nanoindentation technique is introduced, illustrating the use of AFM imaging during indentation experiments to examine plastic deformation occurring under the indenter tip. The mechanical indentation data are correlated to the SEM and AFM images to estimate the number of dislocations emitted to the surface. [ABSTRACT FROM AUTHOR]

An innovative experimental setup, PELIICAEN, allowing the modification of materials and the study of the effects induced by multiply charged ion beams at the nanoscale is presented. This ultra-high vacuum (below 5 × 10-10 mbar) apparatus is equipped with a focused ion beam column using multiply charged ions and a scanning electron microscope developed by Orsay Physics, as well as a scanning probe microscope. The dual beam approach coupled to the scanning probe microscope achieves nanometer scale in situ topological analysis of the surface modifications induced by the ion beams. Preliminary results using the different on-line characterization techniques to study the formation of nano-hillocks on silicon and mica substrates are presented to illustrate the performances of the setup. [ABSTRACT FROM AUTHOR]

An improved form of cold cathode ion source has been designed and constructed. It consists of stainless steel hollow cylinder anode and stainless steel cathode disc, which are separated by a Teflon flange. The electrical discharge and output characteristics have been measured at different pressures using argon, nitrogen, and oxygen gases. The ion exit aperture shape and optimum distance between ion collector plate and cathode disc are studied. The stable discharge current and maximum output ion beam current have been obtained using grid exit aperture. It was found that the optimum distance between ion collector plate and ion exit aperture is equal to 6.25 cm. The cold cathode ion source is used to deposit aluminum coating layer on AZ31 magnesium alloy using argon ion beam current which equals 600 μA. Scanning electron microscope and X-ray diffraction techniques used for characterizing samples before and after aluminum deposition. [ABSTRACT FROM AUTHOR]

The article offers information on various scientific instruments including the 5977B high-efficiency source gas chromatograph/mass selective detector system from Agilent Technologies, NeoScope benchtop scanning electron microscope from JEOL and a line of mechanical positioning systems from McPherson.

The article evaluates several scientific instruments and apparatus, including a femtosecond fiber laser from Calmar Laser Inc., the JSM-IT100 scanning electron microscope from JEOL USA Inc. and the Interface 5000 potentiostat from Gamry Instruments.

The scanning electron microscope is becoming a popular tool to perform tasks that require positioning, manipulation, characterization, and assembly of micro-components. However, some of these applications require a higher level of performance with respect to dynamics and precision of positioning. One limiting factor is the presence of unidentified noises and disturbances. This work aims to study the influence of mechanical disturbances generated by the environment and by the microscope, identifying how these can affect elements in the vacuum chamber. To achieve this objective, a dedicated setup, including a high-resolution vibrometer, was built inside the microscope. This work led to the identification and quantification of main disturbances and noise sources acting on a scanning electron microscope. Furthermore, the effects of external acoustic excitations were analysed. Potential applications of these results include noise compensation and real-time control for high accuracy tasks. [ABSTRACT FROM AUTHOR]

An imaging method has been developed based on charge collection in a scanning electron microscope (SEM) that allows discrimination between the amorphous and crystalline states of Phase-change Random Access Memory (PRAM) line cells. During imaging, the cells are electrically connected and can be switched between the states and the resistance can be measured. This allows for electrical characterization of the line cells in-situ in the SEM. Details on sample and measurement system requirements are provided which turned out to be crucial for the successful development of this method. Results show that the amorphous or crystalline state of the line cells can be readily discerned, but the spatial resolution is relatively poor. Nevertheless, it is still possible to estimate the length of the amorphous mark, and also for the first time, we could directly observe the shift of the amorphous mark from one side of the line cell to the other side when the polarity of the applied (50 ns) RESET pulse was reversed. [ABSTRACT FROM AUTHOR]

In this paper, a cold cathode based sheet-beam plasma cathode electron gun is reported with achieved sheet-beam current density ~1 kA/cm² from pseudospark based argon plasma for pulse length of ~200 ns in a single shot experiment. For the qualitative assessment of the sheet-beam, an arrangement of three isolated metallic-sheets is proposed. The actual shape and size of the sheet-electron-beam are obtained through a non-conventional method by proposing a dielectric charging technique and scanning electron microscope based imaging. As distinct from the earlier developed sheet beam sources, the generated sheet-beam has been propagated more than 190 mm distance in a drift space region maintaining sheet structure without assistance of any external magnetic field. [ABSTRACT FROM AUTHOR]

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a home-built set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe. [ABSTRACT FROM AUTHOR]

The wide variety of nanoscale structures and devices demands novel tools for handling, assembly, and fabrication at nanoscopic positioning precision. The manipulation tools should allow for in situ characterization and testing of fundamental building blocks, such as nanotubes and nanowires, as they are built into functional devices. In this paper, a bottom-up technique for nanomanipulation and nanofabrication is reported by using a 4-probe scanning tunneling microscope (STM) combined with a scanning electron microscope (SEM). The applications of this technique are demonstrated in a variety of nanosystems, from manipulating individual atoms to bending, cutting, breaking carbon nanofibers, and constructing nanodevices for electrical characterizations. The combination of the wide field of view of SEM, the atomic position resolution of STM, and the flexibility of multiple scanning probes is expected to be a valuable tool for rapid prototyping in the nanoscience and nanotechnology. [ABSTRACT FROM AUTHOR]

The time stability of a polarization analyzer that is used for imaging of magnetic structures in a scanning electron microscope with spin polarization analysis (spin-SEM or SEMPA) is investigated. The detector is based on the diffraction of low-energy electrons at a W(100) crystal at 104.5 eV (LEED detector). Due to the adsorption of hydrogen from residual gas, a change of the scattering conditions is found that causes an angular shift of the LEED beams as well as changes of intensity. The quality factor, which describes the efficiency of the detector in SEMPA application, however, is found to be almost constant up to a hydrogen coverage of θ ≈ 0.25. This gives stable working conditions within roughly 1 h at vacuum conditions of 10-10 mbar. [ABSTRACT FROM AUTHOR]

With dramatic reduction in sizes of microelectronic devices, the characteristic width and thickness of interconnects in large-scale integrated circuits have reached nanometer scale. Thermal fatigue damage of so small interconnects has attracted more and more attentions. In this work, thermal fatigue of Au interconnects, 35 nm thick and 0.1-5 μm wide, is investigated by applying various alternating current densities to generate cycling temperature and strain in them. A multi-probe measuring system is installed in a scanning electron microscope and a probe-type temperature sensor is for the first time introduced into the system for real-time measuring the temperatures on the pads of the tested interconnects. A one-dimensional heat conduction equation, which uses measured temperatures on the pads as boundary conditions and includes a term of heat dissipation through the interface between the interconnect and the oxidized silicon substrate, is proposed to calculate the time-resolved temperature distribution along the Au interconnects. The measured fatigue lifetimes are presented versus current density and thermal cyclic strain, and the results show that narrower Au lines are more reliable. The failure mechanism of those Au interconnects differs from what is observed in thick interconnects with relatively larger grain size. Topography change caused by localized plasticity on the less-constrained surfaces of the interconnects have not been observed. Instead, grain growing and reorienting due to local temperature varying appear, and grain boundary migration and mergence take place during high temperature fatigue in such thin and narrow interconnects. These results seem to reflect a strain-induced boundary migration mechanism, and the damage morphology also suggests that fatigue of the interconnects with decreased grain size and film thickness is controlled by diffusive mechanisms and interface properties rather than by dislocation glide. Open circuit eventually took place by melting at a region of severely damage cross-sectional area with the grain growing and reorienting. [ABSTRACT FROM AUTHOR]

The recent interest in size-dependent deformation of micro- and nanoscale materials has paralleled both technological miniaturization and advancements in imaging and small-scale mechanical testing methods. Here we describe a quantitative in situ nanomechanical testing approach adapted to a dual-beam focused ion beam and scanning electron microscope. A transducer based on a three-plate capacitor system is used for high-fidelity force and displacement measurements. Specimen manipulation, transfer, and alignment are performed using a manipulator, independently controlled positioners, and the focused ion beam. Gripping of specimens is achieved using electron-beam assisted Pt-organic deposition. Local strain measurements are obtained using digital image correlation of electron images taken during testing. Examples showing results for tensile testing of single-crystalline metallic nanowires and compression of nanoporous Au pillars will be presented in the context of size effects on mechanical behavior and highlight some of the challenges of conducting nanomechanical testing in vacuum environments. [ABSTRACT FROM AUTHOR]

We describe the design of an instrument that can fully implement a new nanopatterning method called ice lithography, where ice is used as the resist. Water vapor is introduced into a scanning electron microscope (SEM) vacuum chamber above a sample cooled down to 110 K. The vapor condenses, covering the sample with an amorphous layer of ice. To form a lift-off mask, ice is removed by the SEM electron beam (e-beam) guided by an e-beam lithography system. Without breaking vacuum, the sample with the ice mask is then transferred into a metal deposition chamber where metals are deposited by sputtering. The cold sample is then unloaded from the vacuum system and immersed in isopropanol at room temperature. As the ice melts, metal deposited on the ice disperses while the metals deposited on the sample where the ice had been removed by the e-beam remains. The instrument combines a high beam-current thermal field emission SEM fitted with an e-beam lithography system, cryogenic systems, and a high vacuum metal deposition system in a design that optimizes ice lithography for high throughput nanodevice fabrication. The nanoscale capability of the instrument is demonstrated with the fabrication of nanoscale metal lines. [ABSTRACT FROM AUTHOR]

A newly designed scanning electron microscope with polarization analysis (SEMPA or spin-SEM) for the acquisition of magnetic images is presented. Core component is the spin detector, based on the scattering of low-energy electrons at a W(100) surface in ultrahigh vacuum. The instrument has been optimized with respect to ease of handling and efficiency. The operation and performance of a general low-energy electron diffraction (LEED) detector for SEMPA have been modeled in order to find the optimum operating parameters and to predict the obtainable image asymmetry. Based on the energy dependence of the secondary electron polarization and intensity, the detector output is simulated. For our instrument with optimized performance we demonstrate experimentally 8.6% polarization asymmetry in the domain structure of an iron whisker. This corresponds to 17.2% image contrast, in excellent agreement with the predicted simulated value. A contrast to noise ratio of 27 is achieved at 5 ms acquisition time per pixel. [ABSTRACT FROM AUTHOR]

This study proposes a tuning fork probe based nanomanipulation robotic system for mechanical characterization of ultraflexible nanostructures under scanning electron microscope. The force gradient is measured via the frequency modulation of a quartz tuning fork and two nanomanipulators are used for manipulation of the nanostructures. Two techniques are proposed for attaching the nanostructure to the tip of the tuning fork probe. The first technique involves gluing the nanostructure for full range characterization whereas the second technique uses van der Waals and electrostatic forces in order to avoid destroying the nanostructure. Helical nanobelts (HNB) are proposed for the demonstration of the setup. The nonlinear stiffness behavior of HNBs during their full range tensile studies is clearly revealed for the first time. Using the first technique, this was between 0.009 N/m for rest position and 0.297 N/m before breaking of the HNB with a resolution of 0.0031 N/m. For the second experiment, this was between 0.014 N/m for rest position and 0.378 N/m before detaching of the HNB with a resolution of 0.0006 N/m. This shows the wide range sensing of the system for potential applications in mechanical property characterization of ultraflexible nanostructures. [ABSTRACT FROM AUTHOR]

The scanning electron microscope is a versatile tool and its electron beam techniques have been widely used in semiconductor material and device characterizations. One of these electron beam techniques is the electron-beam-induced current (EBIC) technique. One of the limitations of the conventional EBIC technique is that it requires charge collecting junctions which may not be readily available in junctionless samples such as bare substrates unless some special sample preparation procedure such as the fabrication of a diffused junction is done on the junctionless sample. In this paper, the technique of detecting EBIC current in junctionless samples with the use of a two-point probe is presented. It is found that the EBIC current is independent from its physical parameter when the sample thickness is greater than 4L; the width to the right of probe 2 and the width to the left of probe 1 are greater than 2L and 8L, respectively. The parameters affecting this technique of detecting the EBIC current such as the depth of the generation volume, probe spacing, and the applied bias are also discussed in this paper. A commercially available two-dimensional device simulator was used to verify this technique. [ABSTRACT FROM AUTHOR]

A compact, two-stage nanomanipulator was designed and built for use inside a scanning electron microscope. It consists of a fine stage employing piezostacks that provide a 15 μm range in three dimensions and a coarse stage based on commercially available stick-slip motors. Besides the fabrication of enhanced probes for scanning probe microscopy and the enhancement of electron field emitters, other novel manipulation processes were developed, such as locating, picking up, and positioning small nanostructures with an accuracy of ∼10 nm. In combination with in situ I-V experiments, welding, and etching, this results in a multipurpose nanofactory, enabling a new range of experiments. [ABSTRACT FROM AUTHOR]

We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators. [ABSTRACT FROM AUTHOR]

A through hole with a diameter less than 100 nm was fabricated in an Ag foil using only a focused ion beam (FIB) system and in situ measurements of the penetrating ion beam. During the drilling of the foil by a FIB of Ga+ ions, the transmitted part of the beam was measured with an electrode mounted on the back face of the foil. When the beam current penetrating through the nanopore reached a certain value, irradiation was stopped and the area of the created aperture was measured with a scanning electron microscope. The resulting area was correlated with the current of the penetrating ion beam. This suggests that we can fabricate a nanopore of the desired size by controlling the ion beam via penetrating ion beam measurements. The smallest aperture thus created was circular with diameter of 30 nm. [ABSTRACT FROM AUTHOR]

A UHV instrument is presented for in situ fabrication of nanostructures and in situ investigation of their magnetoresistance. Nanostructures of diverse shape and size are created from thin films utilizing a focused ion beam. The magnetic nanostructures are contacted via a micromanipulator, which makes it possible to address the individual structures. The system is additionally equipped with a scanning electron microscope column, which is used for damage-free navigation and control of the structuring and contacting. First magnetoresistance measurements of structures carved into a Permalloy film demonstrate the high sensitivity and the flexibility of the new setup. [ABSTRACT FROM AUTHOR]

The variable pressure scanning electron microscope (VPSEM) has expanded the scope of the SEM to allow the imaging of dynamic, electrically insulating systems. The use of water vapor as the imaging gas present in the chamber allows the successful imaging of hydrated samples. As awareness of the system capabilities becomes more well known, greater pressure has been put onto the microscopist to push the boundaries of both temperature and resolution for the study of diverse hydrated samples whose dynamics may not occur at the usual room temperatures in a VPSEM. In this article we discuss the stages in the development of a cryosystem that has led to the successful observation of the nucleation of ice from a solution in situ. This investigation also leads to further possibilities of imaging hydrated samples in the little explored temperature range of 188–238 K (from -85 to-35 °C). This study includes the exploration of how the temperature of various surfaces inside the microscope will change the system’s ability to keep a sample hydrated or in its native state. [ABSTRACT FROM AUTHOR]

A laser powered heating stage designed for application in high vacuum environment of a scanning electron microscope (SEM) is presented. It was developed to observe and characterize microstructural changes in crystalline materials at elevated temperatures up to 1000 °C. The approach utilizes the power output of a commercial infrared diode laser in order to heat up specimens without interference with the electronic system of the SEM. The heating stage can be used in combination with any standard characterization technique applicable for SEMs—electron backscatter diffraction, orientation contrast imaging, x-ray energy dispersive spectrometry, etc. The results of test measurements are presented. [ABSTRACT FROM AUTHOR]

We describe the development and the capabilities of an advanced system for nanoscale electrical transport studies. This system consists of a low temperature four-probe scanning tunneling microscope (STM) and a high-resolution scanning electron microscope coupled to a molecular-beam epitaxy sample preparation chamber. The four STM probes can be manipulated independently with subnanometer precision, enabling atomic resolution STM imaging and four-point electrical transport study of surface electronic systems and nanostructured materials at temperatures down to 10 K. Additionally, an integrated energy analyzer allows for scanning Auger microscopy to probe chemical species of nanostructures. Some testing results are presented. [ABSTRACT FROM AUTHOR]

The C-V electrical characterization of microstructures on a standard probe station is limited by the magnification of the imaging system and the precision of the probe manipulators. To overcome these limitations, we examine the combination of in situ electrical probing and a dual column scanning electron microscope/focused ion beam system. The imaging parameters and probing procedures are carefully chosen to reduce e-beam damage to the metal oxide semiconductor capacitor device under test. Estimation of shunt capacitance is critical when making femtofarad level measurements. C-V measurements of micron size metal-oxide-silicon capacitors are demonstrated. [ABSTRACT FROM AUTHOR]

The authors have developed an ultrahigh vacuum (UHV) variable-temperature four-tip scanning tunneling microscope (STM), operating from room temperature down to 7 K, combined with a scanning electron microscope (SEM). Four STM tips are mechanically and electrically independent and capable of positioning in arbitrary configurations in nanometer precision. An integrated controller system for both of the multitip STM and SEM with a single computer has also been developed, which enables the four tips to operate either for STM imaging independently and for four-point probe (4PP) conductivity measurements cooperatively. Atomic-resolution STM images of graphite were obtained simultaneously by the four tips. Conductivity measurements by 4PP method were also performed at various temperatures with the four tips in square arrangement with direct contact to the sample surface. [ABSTRACT FROM AUTHOR]