This article is the first step in the development of a hybrid metrology combining AFM and SEM techniques for measuring the dimensions of a nanoparticle population in 3D space (X,Y,Z). This method exploits the strengths of each technique on the same set of nanoparticles. AFM is used for measuring the nanoparticle height and the measurements along X and Y axes are deduced from SEM images. A sampling method is proposed in order to obtain the best deposition conditions of SiO2 and gold nanoparticles on mica or silicon substrates. Only the isolated nanoparticles are taken into account in the histogram of size distribution. Moreover, a semi-automatic Matlab routine has also been developed to process the AFM and SEM images, measure and count the nanoparticles. This routine allows the user to exclusively select the isolated nanoparticles through a control interface. The measurements have been performed on spherical-like nanoparticles to test the method by comparing the results obtained with both techniques.

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This article reports on the evaluation of an uncertainty budget associated with the measurement of the mean diameter of a nanoparticle (NP) population by Atomic Force Microscopy. The measurement principle consists in measuring the height of a spherical-like NP population to determine the mean diameter and the size distribution. This method assumes that the NPs are well-dispersed on the substrate and isolated enough to avoid measurement errors due to agglomeration phenomenon. Since the measurement is directly impacted by the substrate roughness, the NPs have been deposited on a mica sheet presenting a very low roughness. A complete metrological characterization of the instrument has been carried out and the main error sources have been evaluated. The measuring method has been tested on a population of SiO 2 NPs. Homemade software has been used to build the height distribution histogram taking into account only isolated NP.Finally, the uncertainty budget including main components has been established for the mean diameter measurement of this NP population. The most important components of this uncertainty budget are the calibration process along Z-axis, the scanning speed influence and then the vertical noise level.

We report on the observation of strong backscattering of charge carriers in the quantum Hall regime of polycrystalline graphene, grown by chemical vapor deposition, which alters the accuracy of the Hall resistance quantization. The temperature and magnetic field dependence of the longitudinal conductance exhibits unexpectedly smooth power-law behaviors, which are incompatible with a description in terms of variable range hopping or thermal activation but rather suggest the existence of extended or poorly localized states at energies between Landau levels. Such states could be caused by the high density of line defects (grain boundaries and wrinkles) that cross the Hall bars, as revealed by structural characterizations. Numerical calculations confirm that quasi-one-dimensional extended nonchiral states can form along such line defects and short circuit the Hall bar chiral edge states.

At this time, there is no instrument capable of measuring a nano-object along the three spatial dimensions with a controlled uncertainty. The combination of several instruments is thus necessary to metrologically characterize the dimensional properties of a nano-object. This paper proposes a new approach of hybrid metrology taking advantage of the complementary nature of atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques for measuring the main characteristic parameters of nanoparticle (NP) dimensions in 3D. The NP area equivalent, the minimal and the maximal Feret diameters are determined by SEM and the NP height is measured by AFM. In this context, a kind of new NP repositioning system consisting of a lithographed silicon substrate has been specifically developed. This device makes it possible to combine AFM and SEM size measurements performed exactly on the same set of NPs. In order to establish the proof-of-concept of this approach and assess the performance of both instruments, measurements were carried out on several samples of spherical silica NP populations ranging from 5 to 110 nm. The spherical nature of silica NPs imposes naturally the equality between their height and their lateral diameters. However, discrepancies between AFM and SEM measurements have been observed, showing significant deviation from sphericity as a function of the nanoparticle size.

Both optical and tactile probes are often used in dimensional metrology applications, especially for roughness, form, thickness and surface profile measurements. To perform such kinds of measurements with a nanometre-level of accuracy (∼30 nm), Laboratoire National de Métrologie et d’Essais (LNE) has developed a new high-precision machine. The architecture of the machine contains a short and stable metrology frame dissociated from the supporting frame. It perfectly respects the Abbe principle. The metrology loop supports reference laser interferometers and is equipped either with an optical probe or a tactile probe of nanometric resolution and linear residuals. The machine allows in situ calibration of the measuring optical and tactile probes by comparison to the laser interferometer measurements, considered as a reference. In this paper, both architecture and operation of the LNE's high-precision profilometer are detailed. A brief comparison of the behaviour (linear residuals) of the confocal chromatic and tactile probes is presented. Optical and tactile scanning of V-grooves artefacts with 75, 24, 7.5, 2.4, 0.75 and 0.24 µm depths are illustrated and discussed. In addition, a comparison between optical, tactile and atomic force microscopy measurements on a VLSI SHS 880-QC is also performed. Finally, a comparison of an optical and tactile scanning of optical aspherical lens with a polymer coating is presented and discussed.

The scanning electron microscopy (SEM) technique is widely used for the characterizing of nanoparticle (NP) size, but very few papers deal with NP dimensional metrology. This article reports on a methodology with which to evaluate the uncertainty budget associated with the measurement of the mean diameter of a standard silica NP population by SEM. In this context, the effects of potential error sources have been evaluated though a metrological qualification of the instrument. The measuring method, consisting of determining the area equivalent diameter taken at middle height (D eq-FWHM ), has been tested on a reference silica NP with an indicative certification value given by SEM/TEM (number-based modal diameter). Because agglomeration phenomena can cause measurements errors, semi-automatic homemade software has been employed to build the diameter distribution histogram, selecting only isolated particles. Finally, an uncertainty budget, including the main experimental components, has been established for the mean diameter measurement of this silica NP population. The main contributors to this uncertainty budget are the resolution linked to the dimension of the electron beam diameter at the focal plane, the calibration uncertainty on reference NPs, and the measurement repeatability.

A calibration algorithm based on one-port vector network analyzer (VNA) calibration for scanning microwave microscopes (SMMs) is presented and used to extract quantitative carrier densities from a semiconducting n-doped GaAs multilayer sample. This robust and versatile algorithm is instrument and frequency independent, as we demonstrate by analyzing experimental data from two different, cantilever- and tuning fork-based, microscope setups operating in a wide frequency range up to 27.5 GHz. To benchmark the SMM results, comparison with secondary ion mass spectrometry is undertaken. Furthermore, we show SMM data on a GaAs p-n junction distinguishing p- and n-doped layers.