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Within the last three decades Scanning Probe Microscopy has been developed to a powerful tool for measuring surfaces and their properties on an atomic scale such that users can be found nowadays not only in academia but also in industry. This development is still pushed further by researchers, who continuously exploit new possibilities of this technique, as well as companies that focus mainly on the usability. However, although imaging has become significantly easier, the time required for a safe approach (without unwanted tip-sample contact) can be very time consuming, especially if the microscope is not equipped or suited for the observation of the tip-sample distance with an additional optical microscope. Here we show that the measurement of the absolute tip-sample capacitance provides an ideal solution for a fast and reliable pre-approach. The absolute tip-sample capacitance shows a generic behavior as a function of the distance, even though we measured it on several completely different setups. Insight into this behavior is gained via an analytical and computational analysis, from which two additional advantages arise: the capacitance measurement can be applied for observing, analyzing, and fine-tuning of the approach motor, as well as for the determination of the (effective) tip radius. The latter provides important information about the sharpness of the measured tip and can be used not only to characterize new (freshly etched) tips but also for the determination of the degradation after a tip-sample contact/crash.

A magnetic measuring microscope with a spatial resolution of 3 μm in the determination of current dipole coordinates is described. For the primary transducer, a film Hall transducer with sensitive-zone dimensions of 250 × 400 μm is used. The transducer is positioned at a distance of 3 mm from the plane of scanning. Superresolution as compared to the sensor dimensions and distance from the object was reached by using a priori information about the scanned object. A means of calibration of the magnetic microscope and measurement of its metrological characteristics is proposed. The effectiveness and consistency of the obtained estimate of coordinates is shown by comparison of the random error in measurements of current dipole coordinates with the Cramer–Rao bound. The measuring microscope can be applied in studying elements of functional electronics.

The app described in this article was presented at the student design competition of the 2016 IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium. As sponsored by Technical Committee MTT-25 on RF nanotechnology, the competition's objective was to develop user-friendly interfaces to facilitate the design and application of RF nanotechnology. To this end, the app is capable of simulating the capacitance and charge distribution of the probe-sample interaction on a nanoscale in near-field scanning microscopes, such as the scanning microwave microscope (SMM), the atomic force microscope (AFM), and the scanning tunneling microscope (STM).

A tapping mode scanning probe microscopy (TM SPM) system for surface measurement in nanoscale is developed, of which the main element is a scanning probe consisting of quartz tuning fork and a long sharp tungsten tip. Quartz tuning fork is a very good resonant element with piezoelectrical characteristic, and it acts as an actuator and a force sensor simultaneously in the probe. The vertical spatial resolution of the TM SPM is up to sub-nanometer (0.11 nm) and the measuring force is in micro Newton magnitude (about 30 μN). In the scanning operation, the probe vibrates at its resonant frequency, so that the amplitude or frequency (or phase) of the resonant tuning fork is very sensitive to external forces (Its quality factor in air is about 3138). Using the TM SPM constructed by this probe, silicon samples are scanned. Their topography and phase images which indicate the surface material characteristics are reconstructed effectively with a high resolution and low destructiveness. Soft materials, such as Protein structure can also be scanned theoretically without damage. In addition, because of the using of the long sharp tungsten tip, the system has the capacity of measuring micro structures with large aspect ratio, such as large micro steps, deep micro trenches, etc.

Polarization interferometric nonlinear confocal microscope has been developed to observe a submicron size object in high contrast. The microscope succeeded in resolving the inside of a 200-nm-diameter polymeric nanoparticle. According to CTF (contrast transfer function) measurement and three-dimensional imaging with the microscope, the best spatial resolution for the microscope is 10 nm.

A scanning SQUID probe microscope, in which a superconducting quantum interference device (SQUID) is combined with a scanning probe microscope, has been developed using a needle probe with high magnetic permeability. The probe played a key role of a flux guide from the sample to the SQUID. An rf-SQUID magnetometer used with a substrate resonator had been adopted in the initial setup. The magnetic sensitivity was not so high though the spatial resolution was good. In this paper, the flux transfer from the sample to the SQUID through the probe was investigated by using the magnetic field simulations. The result showed that the flux was decreased by a factor of more than 1,000 from the probe tip to the SQUID. The critical drop was occurred around the end of the probe. It suggested the magnetic coupling between the SQUID and the probe should be improved. The additional gap distance was needed in the initial rf-SQUID because of the thickness of the substrate resonator used with the rf-SQUID. Therefore, new rf-SQUIDs, which could be operated without a resonator, were fabricated to reduce the gap distance between the SQUID and the probe. The gap distance affected the quality of the magnetic images.

In this study, we tried to develop the scanning near-field polarization microscope (SNPM) and challenge to observe magnetization of the magnetic nanodot in the arrays. The CoPt dot arrays with a size of 25 nm and a pitch of 150 nm were adopted. The nanodots change contrast after changing the direction of the external magnetic field. This implied that our prototyped SNPM system had the resolution of less than 25 nm. So, it is demonstrated that SNPM is an effective tool for the observation of magnetization of the magnetic nanodot on the nanometer scale.

Electric force microscope (EFM) testing is based on Coulombic force interactions between an EFM probe and a test point. An electric signal on an interconnected line creates an electric force between the tip and the device under test which causes a detectable bending of the cantilever. This bending amount is optically detected and electrically analyzed by a lock-in amplifier. In capacitive coupling method, an electrode is placed in close proximity to a pad on the wafer. The voltage transients on the pad induce weak displacement currents on the electrode. This effect can be used to detect electrical pulses propagating through an IC. For current measurements, scanning magnetoresistive probe has also been suggested to detect currents in a contactless manner.

International audience; The design, fabrication and experimental validation of a novel near-field scanning millimeter-wave microscope (NSMM) built inside a scanning electron microscope (SEM) is presented. The instrument developed can perform hybrid characterizations by providing simultaneously atomic force, complex microwave impedance and electron microscopy images of a sample with nanometer spatial resolution. By combining the measured data, the system offers unprecedentable capabilities for tackling the issue between spatial resolution and high frequency quantitative measurements.

In this paper, we report a miniaturized laser scanning microscope. Unlike conventional microscopes, the optical fiber used here for the excitation laser and signal’s transmission largely improves our microscope’s mobility, and thus eliminates the space constraints of the sample stage. This miniaturized microscope can be motorized along XYZ axis and rotated in theta direction. Based on this modified microscope, we take images of test targets and a micrometer, and compare the resolution and signal to background ratio between its confocal and non-descanned detection modules. We also present the imaging results of Hela cells on a tilted sample stage to simulate the imaging of large and irregular samples. Therefore, this miniaturized microscope has the potential to be utilized for in vivo imaging of large animals.

Methods of determining the basic metrological characteristics of a near-field scanning optical microscope, i.e., scale factor and spatial resolution, defined as the diameter of the optical probe, are proposed. The use of the proposed method for calibration of the near-field scanning optical microscope directly in the course of measurements of the parameters of biological objects is investigated.

A four-channel Kirkpatrick-Baez microscope working at multiple energy bands is developed for multiframe X-ray imaging diagnostics at the Shenguang-II laser facility. The response to the multiple energy bands is realized by coating the double-periodic multilayers on the reflected surfaces of the microscope. Because of the limited size of the microstrips in the X-ray framing camera, the image separation is controlled by the conical angle of the reference cores during microscope assembly. This study describes the optical and multilayer design, assembly, and alignment of the developed microscope. The microscope achieves a spatial resolution of 4-5 mm in the laboratory and 10-20 mm at Shenguang-II laser facility within a 300 mm field of view. The versatile nature of the developed microscope enables the multiple microscopes currently installed in the laser facility to be replaced with a single, multipurpose microscope.

A method for measuring the scan nonlinearity of a scanning electron microscope is discussed. This method is tested using a mass-produced microscope and demonstrates good results.

The medium-term storage stability and reproducibility defined in the course of calibration of the scale factor of scanning electron microscopes are established with the use of an MShPS-2.0K measure. Conclusions are drawn to the effect that the dependence of the scale factor on the working distance may lead to some scatter of the measurement results and that direct comparison of the dimensions of the measured subject and a reference object obtained with the same parameters of the microscope is required to increase the measurement accuracy.

Known methods for determining the resolution of a scanning electron microscope are discussed. It is shown that none of them can unambiguously characterize the scanning electron microscope.

Atomic force microscope (AFM) – is device widely used in many scientific fields for nano-scale surface scanning. AFM also can be used to probe mechanical stiffness, electrical conductance, resistivity, magnetism and other properties. The main limitation of AFM implementation is relatively low scanning speed. This speed depends from dynamical characteristics of AFM sensor and from surface roughness of scanned sample. Our research is focused on increasing scanning speed of AFM microscope assuming AFM mechanical sensor as sensitive dynamic system. Our proposed method enables increase of scanning speed by modifying some features of mechanical sensor by adding non-linear force to the surface of cantilever of AFM sensor. Proposed method is modelled theoretically using Simulink features. This paper presents research of mechanical sensor of AFM. After performed research, obtained results are presented on graphical form. At the end of paper discussion presented and conclusions are drawn.

International audience; A near-field scanning microwave microscope based on an interferometric technique is proposed in this work. To ensure an optimal spatial resolution, crucial parameters of the evanescent microwave probe are finely studied including the tip apex, the stand-off distance and the scanning step size. © 2016 EuMA.

This paper presents an assembled comb-drive XYZ-microstage with large displacements for the scanning of magnetic resonance force microscopy (MRFM) at cryogenic environment. The scanning XYZ-microstage with little affection to the thermal variation and magnetic fields is required. The comb-drive XYZ-microstage is assembled with an XY-microstage, two Z-actuators and a silicon base substrate using a microassembly technology. For measurements, a sample of 1, 1-Diphenyl-2-picrylhydrazyl radical (DPPH) is glued onto the assembled XYZ-microstage. The imaging system is consisted of the scanning XYZ-microstage with DPPH sample, a sensitive cantilever sensor with a small magnetic particle, a fiber-optic interferometer to detect the vibration of the cantilever and a radio frequency (RF) coil. The measurements are performed at low pressure in a vacuum chamber. The vibration of the cantilever sensor based on magnetic force from electron spin resonance (ESR) spectroscopy can be detected through adjusting the magnetic field intensity of the RF coil.

We report on the design and performance of a high stability scanning confocal microscope for optical microscopy at low temperatures. By scanning the beam in a cold objective lens system, we achieve wide fields of view without compromising image quality. Photoluminescence from single nitrogen-vacancy centers in high purity diamond is used to illustrate the imaging and stability performance of the microscope. © 2010 American Institute of Physics.

Limitations on the calculation of high-resolution detail in electron microscope images of defects in crystals are discussed and it is shown how images of crystals with arbitrary strain can be calculated by means of a reinterpretation of the normal dynamical equations. An alternative approach, which in some cases is preferable for numerical calculations, is the method of periodic continuation. These methods, and various approximations to them, are applied to the study of high resolution images of edge dislocations. It is shown that at the 5 A level of resolution, the column approximation is adequate for calculating the important features of weak-beam images of an edge dislocation with an extended core. However, when applied to the calculation of lattice fringes near a core, it may lead to serious error. Calculations are presented which show that, because of spherical aberration, care is required in the interpretation of lattice-fringe images near a dislocation core even for thin crystals.

In this paper cantilever detection methods of microscopy that allow to get an image of surface with high spatial resolution are discussed. The functionality of the scanning tunneling microscope and principle of its operation are analyzed. Basing on the simulated data, it is possible to show how microscope operating parameters affect the results of its measurements.

The scan nonlinearity of scanning electron microscopes is estimated with the use of a relief element with known geometric form of the profile. The mean value of the step of the test relief structure, which is determined as a test sample is moved along the scanning axis X, is measured. It is experimentally demonstrated that with a 5× magnification, the maximum relative deviation from the mean value of the step of the test structure for a given microscope does not exceed 0.4%.

We have developed a scanning magnetic microscope (SMM) based on a magnetic tunneling junction (MTJ) magnetoresistive (MR) sensor. The microscope is based on commercially available components employing two sets of scanning stages and a MTJ sensor. Spatial resolution and noise sensitivity were investigated using two MTJ sensors, one having high spatial resolution and the other low noise but coarser spatial resolution. We present measurements of magnetic field images from ferrite concentration calibration standards and a stainless steel welded specimen both imaged using a magnetoresistive scanning microscope. A sensitivity of ~ 10 μT/FN was obtained from standards with defined ferrite numbers (FN). This microscope represents a new powerful tool for the characterization and investigations of delta ferrite concentrations in stainless steel welded samples.

A two-axes nano-scanner for a scanning probe microscope (SPMs) was developed. The flexure-guided nano-scanner can move SPM samples or the probe itself along the x and y axes. The theoretical stiffness and resonant frequency of the flexure guide were obtained by using Castigliano’s theorem. An optimal nano-scanner that maximize the scanning speed under appropriate constraints was designed. The optimal results were compared with the results of a finite element analysis. The scanner performance was evaluated by using various experiments and was compared with the optimal design results. Finally, atomic force microscope images obtained by using the proposed nano-scanner are presented.

The structure and operating principle of the NanoSkan-3Di scanning probe microscope are briefly described. An investigation of the metrological characteristics of this measuring system using linear TGZ-type gratings demonstrated the high level of reproducibility of the measurements and showed that the results agree with the data obtained in a calibration at the PTB (Germany).

We have developed an STM–SQUID microscope that combined a scanning tunneling microscope (STM) and a SQUID probe microscope for the purpose of high–resolution magnetic field measurement. We were able to obtain a spatial resolution of 1 μm or less by polishing the tip of the needle on the SQUID probe microscope to 100 nm or less, and by using a magnetic probe, which was the flux guide, as the STM probe. In this study, we took magnetic images of typical ferromagnetic materials, such as bulk iron and bulk nickel using the STM–SQUID microscope. We successfully observed the magnetic domain structures of these magnetic materials. However, topographic artifacts were also observed in the STM–SQUID images due to the background magnetic field from the sample. The future subject for resolution and quality improvement became clear.

The possibility of investigating a nanomaterial structure using a near field scanning microscope with a carbon nanotube, used as a microprobe, is demonstrated.

A polycrystalline solar cell with several grains was investigated by the laser-SQUID (Superconducting QUantum Interference Device) microscope. The laser-SQUID microscopy detects the magnetic field generated by a photo-induced current. This technique enables nondestructive and noncontact evaluation of semiconductor samples. A needle made of high permeability material was used to transmit the magnetic field near the sample to the SQUID. The needle and the SQUID were shifted in the x - and y -directions from the center of a laser spot. The laser-SQUID microscope images varied with needle position. This indicated the possibility of current estimation using a laser-SQUID microscope. In this study the sample was also evaluated using Laser Beam Induced Current (LBIC) which is widely used for evaluation of the conversion efficiency distribution of solar cells. The laser-SQUID microscope image was compared with the LBIC image and was found to be similar. This result showed that laser-SQUID microscopy can be used for the electrical evaluation of solar cells without contact, and furthermore has the possibility of estimation of the photocurrent direction.

Atomic Force Microscopy (AFM) permits measurements on biological samples below the limits of light microscopy resolution under physiological environments and other controlled conditions. Consequently, AFM has become an increasingly valuable technique in cell biology. One of the most exciting advances in AFM instrumentation has been its integration with the light microscope. This permits investigators to take advantage of the power and utility of light microscopy and scanning probe microscopy simultaneously. In combining a light microscope with an AFM, scanner components must be specifically designed so that they do not adversely impact the light microscope's optical imaging capabilities. For example, an AFM-ILM (inverted light microscope) hybrid system should be fully compatible with the highest quality, off-the-shelf 0.50–0.55 NA numerical aperture (NA) OEM objectives and condensers.

We have developed a STM-SQUID probe microscope that combines a SQUID probe microscope and a scanning tunneling microscope (STM). We improved the spatial resolution of the SQUID probe microscope by transmitting the magnetic field to the SQUID by use of a high permeability permalloy probe. It can measure topography of the sample surface and the magnetic field of the sample at the same time using the permalloy probe as a STM probe. In the present study, we have measured the magnetic field distribution generated by a meander line whose line plus spacing were 10 μm. The meander line is useful for estimating the performance of the STM-SQUID probe microscope because we can quantify the magnetic field of a meander line to which a current is applied. We also measured the magnetic field on the sample surface by a magnetic force microscopy (MFM) and compared these measurements to those obtained with the STM-SQUID probe microscope. The MFM measurement was influenced by the sample surface. However, this effect was not observed in the STM-SQUID measurement.

Conventional variable temperature scanning probe microscopes (SPMs) became available about 20 years ago. The main idea was to look at structures at lower temperatures (≈ 50 K) where the thermal mobility is reduced and imaging of structures (i.e. molecules on a surface) was easier to achieve. Conventional variable temperature SPM microscopes [1 3] always cool the sample only. The rest of the instrument, including the scanner with the tunnelling tip, stays at room temperature. This design has a lot of advantages with respect to exibility and an open design. However, the sample is always faced a warm tip and the instrument needs a careful design to minimize thermal drift. With this design approach it has been possible to reduce the remaining thermal drift to values lower than 50 pm/s [1]. Imaging surfaces at low temperatures deliver good results, however this setup is not ideal for spectroscopy measurements due to the remaining drift between the tip and the surface. In conventional variable temperature designs it is therefore required to perform spectroscopy experiments quickly. In the last decade tunnelling spectroscopy has received more and more importance in surface science. In addition to imaging a surface or a surface with molecular structures, tunnelling spectroscopy is required to learn more about these new structures and their interaction with the surface or the environment. Due to the lack of spectroscopy performance of conventional variable temperature designs, research moved to low temperature scanning tunneling microscopy (STM) designs where the complete STM is kept at a low temperature (4 K or 77 K) by using bath cryostats. However, these instruments often require a system solution due to their complex design with shielded nitrogen and helium tanks [4, 5].

Scanning near-field acoustic microscope (SNAM) combines the ultrasonic detection technology with scanning near-field microscopy. The main characteristic of such microscope is that the acoustic wave is produced or detected in near-field area whether ultrasonic transducer acts as generator or detector. The resolution of SNAM can reach to nanometer scale. First, two typical SNAMs, scanning electron acoustic microscope and scanning probe acoustic microscope, will be introduced in this paper. The working principle of our homemade SNAM based on a commercial scanning probe microscope will be reported, together with some recent results from this homemade SNAM.

The nanofabrication of superconductors yields various interesting features in superconducting properties. A variety of different imaging techniques have been developed for probing the local superconducting profiles. A scanning pulsed laser microscope has been developed by the combination of the XYZ piezo-driven stages and an optical fiber with an aspheric focusing lens. The scanning laser microscope is used to understand the position-dependent properties of a superconducting MgB 2 stripline of length 100 μm and width of 3 μm under constant bias current. Our results show that the superconducting stripline can clearly be seen in the contour image of the scanning laser microscope on the signal voltage. It is suggested from the observed image that the inhomogeneity is relevant in specifying the operating conditions such as detection efficiency of the sensor.

Scanning Hall probe microscopy (SHPM) is a novel scanned probe magnetic imaging technique whereby the stray fields at the surface of a sample are mapped with a sub-micron semiconductor heterostructure Hall probe. In addition an integrated scanning tunnelling microscope (STM) or atomic force microscope (AFM) tip allows the simultaneous measurement of the sample topography, which can then be correlated with magnetic images. SHPM has several advantages over alternative methods; it is almost completely non-invasive, can be used over a very wide range of temperatures (0.3–300 K) and magnetic fields (0–7 T) and yields quantitative maps of the z-component of magnetic induction. The approach is particularly well suited to low temperature imaging of vortices in type II superconductors with very high signal:noise ratios and relatively high spatial resolution (>100 nm). This paper will introduce the design principles of SHPM including the choice of semiconductor heterostructure for different measurement conditions as well as surface tracking and scanning mechanisms. The full potential of the technique will be illustrated with results of vortex imaging studies of three distinct superconducting systems: (i) vortex chains in the “crossing lattices” regime of highly anisotropic cuprate superconductors, (ii) vortex–antivortex pairs spontaneously nucleated in ferromagnetic-superconductor hybrid structures, and (iii) vortices in the exotic p-wave superconductor Sr2RuO4 at milliKelvin temperatures.

An optical scanning near-field microscope was developed. A cryostat for obtaining low temperatures in the range of 1.8–300 K was designed. The microscope control unit and software were advanced taking into account the temperature range. A room-temperature measurement technique was refined on test aluminum gratings on glass with a period of 4 µm. An optimum size of the scan field, which makes it possible to neglect piezoceramics nonlinearities, was determined.

We report on the design and first tests of a novel instrument aimed at combining the benefits of scanning force microscopy with those of X-ray spectroscopy. For this we built an instrument combining a scanning transmission X-ray microscope with a beam-deflection atomic force microscope in a coaxial geometry. This allows to combine X-ray absorption spectroscopy and high resolution topography in-situ. When replacing the conventional scanning probe tip by a coaxially shielded tip the instrument will allow detection of the photoelectrons produced by resonant X-ray absorption. This could yield spectroscopic information with a spatial resolution approaching the values achievable with atomic force microscopy.

A major disadvantage of scanning probe microscopy is the slow speed of image acquisition, typically less than one image per minute. This paper describes three techniques that can be used to increase the speed of a conventional scanning probe microscope by greater than one hundred times. This is achieved by the combination of high-speed vertical positioning, sinusoidal scanning, and high-speed image acquisition. These techniques are simple, low-cost, and can be applied to many conventional microscopes without significant modification. Experimental results demonstrate an increased scan rate from 1 to 200 Hz. This reduces the acquisition time for a 200 � 200 resolution image from 3 min to 1 s.

Deep-Level Spectroscopy, based on transformation and analysis of capacitance or charge transients, following the excitation of the sample by voltage pulses, yields information on electrically active defects in semiconductors, hardly obtainable by other methods. Our microscope performs Isothermal Charge-Transient Spectroscopy (IQTS). It samples the transients from 2micros to tens of ms and beyond with a resolution of hundreds of electrons. By means of a small heated stage the temperature of the sample can be varied between room temperature and about 200 degrees C. From the shift of IQTS peak maxima with temperature, the activation energy and capture cross-section of defects can be obtained. We have shown that quantitative determination of concentration is possible but it requires careful analysis and simulation, since the analysed volume depends besides on the experimental conditions also on the properties of the analysed structure.

Scanning probe microscopy is a frequently used nanometer-scale surface investigation technique. Unfortunately, its applicability is limited by the relatively low image acquisition speed, typically seconds to minutes per image. Higher imaging speeds are desirable for rapid inspection of samples and for the study of a range of dynamic surface processes, such as catalysis and crystal growth. We have designed a new high-speed scanning probe microscope (SPM) based on micro-electro mechanical systems (MEMS). MEMS are small, typically micrometer size devices that can be designed to perform the scanning motion required in an SPM system. These devices can be optimized to have high resonance frequencies (up to the MHz range) and have very low mass (10(-11)kg). Therefore, MEMS can perform fast scanning motion without exciting resonances in the mechanical loop of the SPM, and hence scan the surface without causing the image distortion from which conventional piezo scanners suffer. We have designed a MEMS z-scanner which we have integrated in commercial AFM (atomic force microscope) and STM (scanning tunneling microscope) setups. We show the first successful AFM experiments.

A new electron diffraction microscope based on a conventional scanning electron microscope (SEM), for obtaining atomic-level resolution images without causing serious damage to the specimen, has been developed. This microscope in the relatively low-voltage region makes it possible to observe specimens at suitable resolution and record diffraction patterns. Using the microscope we accomplished 10-kV diffractive imaging with the iterative phase retrieval and reconstructed the structure of a multi-wall carbon nanotube with its finest feature corresponding to 0.34-nm carbon wall spacing. These results demonstrate the possibility of seamless connection between observing specimens by SEM and obtaining their images at high resolution by diffractive imaging.

Zusammenfassung Die Vermessung von mikro-strukturierten technischen Oberflächen ist eine aktuelle Kernfragestellung der Messtechnik. In diesem Beitrag werden 3D-Rekonstruktionsverfahren von rasterelektronenmikroskopischen Aufnahmen, insbesondere die photometrische Methode, vorgestellt. Zur Verifikation des entwickelten Modells wurde ein Rasterelektronenmikroskop mit zwei Detektoren versehen.

Scanning tunnelling microscopy enables for imaging of conductive surfaces with a resolution down to the atomic level. However, virtually all commercial scanning tunnelling microscopes use piezo tube scanners and capacitance gauges what limits the operating range to typically less than 100 μm in the scanning axes and 10 μm in probing direction. Traceability of measured dimensions to the length unit metre can only be ensured by frequent calibration with the help of standards for pitch and step height. To improve the metrological characteristics of the measurement technique scanning tunnelling microscopy and to broaden its field of application, a directly traceable long range metrological scanning tunnelling microscope was set-up using a laser-interferometrically controlled nanopositioning unit with an operating range of 25 · 25 · 5 mm 3 as scanner and a passive tunnelling current measuring probing system as a null indicator. Line scan repeatability of 5 nm has been achieved at 1 nm vertical resolution.