Layer Thickness Determination of Thin Films by Grazing Incidence X-Ray Experiments using Interference Effect

An international round‐robin test (RRT) was performed to investigate a method to determine the interface location and the layer thickness of multilayer films by secondary ion mass spectrometry (SIMS) depth profiling as a preliminary study to develop a new work item proposal in ISO/TC‐201. Two types of reference materials were used in this RRT. A SiGe alloy (Si 52.4 Ge 47.6 ) reference film was used to determine the relative sensitivity factors of Si and Ge. A Si/Ge multilayer reference film was used to determine the relative sputtering rates of the Si and Ge layers. The layer thicknesses were measured from the interfaces determined by a 50 atomic percent definition. Seven laboratories from 5 countries participated in this international RRT. The RRT reference expanded uncertainties for Si and Ge layers in a Si/Ge multilayer with similar thicknesses as the reference film were 0.76 and 1.17 nm, respectively. However, those in a thinner Si/Ge multilayer film were slightly larger at 1.04 and 1.59 nm, respectively. Most of the thickness ratios in the 2 Si/Ge multilayer films were consistent with the RRT reference value within their expanded uncertainties.

A method for thickness determination of thin films of amalgamable metals by total-reflection X-ray fluorescence

This work investigated the effect of adding nickel zinc ferrite thick film layer to a flexible substrate as overlay below a conductive silver patch. The ferrite thick film paste was prepared by mixing nickel zinc ferrite (NZF) nanopowders with an organic vehicle, and later using screen printing technique to print a thick film layer onto polyimide film, and later added a rectangle silver conductive patch on top of the ferrite layer. Measurement results of the flexible patch antenna with NZF thick film layer show that the thick film significantly widens the bandwidth of the antenna while having good return loss. The bending test, however, showed that there are significant changes of frequency and return loss when the antenna was bent at different angles, showing that further improvement is needed to further stabilizes the antenna parameters in bent conditions.

Determination of thin film thickness is ultimate important in many technology area, particularly those of optics and microelectronics. There are numerous ways to measure thin film thickness, many of them need after measurement numerical calculations, namely, some physical constants of the film: refractive index, absorption coefficient, or electrical conductivity, etc., need to be known beforehand in order to- carry out the calculation which. relates a certain measured physical quantity of the film: transmission spectrum, electrical resistance etc., to these constants and film thickness. The accuracy of these constants is crucial to the accuracy of the film thickness deduced from the calculation. Unfortunately, physical constants of thin films are always different significantly from those of bulk materials. The use of bulk value in the calculation inavoidably lead to inaccurate film thickness determination. There are some methods which directly measure the film thickness without numerical process and knowledge of other physical constants of the film. Among those methods, surface profile determination by stylus mechanically or by interferometry optically are frequently used. A film edge has to be created, the edge height measured directly by stylus profile or interference pattern is equal to the film thickness. There are some disadvantages for these methods, stylus may scratches the film and substrate which are soft, the range of film thickness which can be determined is limited by the optical wavelength in the interference method.

Investigation of interfacial properties of Ag–Cu/Si3N4 composite ceramic substrates by interface reaction of Si3N4 and CuO

Through-thickness analysis of the skin layer thickness of multi-layered biaxially-oriented polypropylene films by micro-thermal analysis

Development of a process modeling for residual stress assessment of multilayer thin film structure

The quantitative determination of thin film thickness using X-ray emission analysis provides an accurate, non-destructive alternative to conventional characterisation methods. This study established empirical relationships among the X-ray k-ratio, backscattering electron coefficient (η), and film thickness for two-dimensional (2D) silicon (Si) and silicon dioxide (SiO₂) films, and a silicon dioxide (SiO₂) layer on a Si substrate. Monte Carlo simulations using the McXRayLite to model the electron-solid interactions at primary beam energies of 3-10 keV and film thicknesses of 2-10 nm. The Si Kα₁ signal intensity was used to compute the k-ratios for unsupported Si and SiO₂ films, whereas both Si Kα₁ and O₂ Kα₁ intensities were used for SiO₂/Si. For the Si Kα₁ signal used, a strong linear correlation was obtained between the k-ratio and the thickness of the 2D Si and SiO₂ films, where an inverse linear relationship was observed for the SiO₂/Si sample. For the O₂ Kα₁ signal used, a strong linear correlation between the k-ratio and top-film SiO2 thickness on the Si substrate was observed. The k-ratio also exhibited a consistent dependence on the backscattering coefficient (η), confirming the influence of backscattered electrons on X-ray generation. Empirical equations were derived to predict the film thickness with uncertainties below 4%, demonstrating that the k-ratio method is a reliable and accurate tool for nanoscale thin film measurements.

In an effort to develop an improved medium for optical communication, chalcogenide glasses are being investigated for waveguide and integrated optical components. These glasses are attractive for integrated optics applications due to their good infrared transmission and high nonlinear Kerr effects. The fact that these glasses can be fabricated in thin films and optical fiber forms constitute a major advantage for future high-speed optical devices applications. However, to advance these novel characteristics, it is crucial to identify the structure/property relationship in the glass, in both bulk and film materials. Rutherford Backscattering Spectroscopy (RBS) is an analytical tool that gives very useful information regarding compositional and structural analysis of the films, as well as a precise measurement of the film's layer thickness. Results obtained showed no apparent variation in composition and small (less than 10%) density variation in single layer As<SUB>2</SUB>S<SUB>3</SUB> films. Multilayer films, which thickness were measured using SEM images, displayed compositional and density modifications associated with the annealing process. The same calculations were conducted after almost a year from the previous measurements to study changes induced due to film aging. Stoichiometric and thickness modifications, caused by aging, were observed in unannealed structures. No apparent changes were detected in annealed films. Waveguide Raman Spectroscopy was used as a complementary tool to identify the molecular features responsible for the changes.

Multilayer graphene and its stacking order provide both fundamentally intriguing properties and technological engineering applications. Several approaches to control the stacking order have been demonstrated, but a method of precisely controlling the number of layers with desired stacking sequences is still lacking. Here, we propose an approach for controlling the layer thickness and crystallographic stacking sequence of multilayer graphene films at the wafer scale via Cu-Si alloy formation using direct chemical vapour deposition. C atoms are introduced by tuning the ultra-low-limit CH4 concentration to form a SiC layer, reaching one to four graphene layers at the wafer scale after Si sublimation. The crystallographic structure of single-crystalline or uniformly oriented bilayer (AB), trilayer (ABA) and tetralayer (ABCA) graphene are determined via nano-angle-resolved photoemission spectroscopy, which agrees with theoretical calculations, Raman spectroscopy and transport measurements. The present study takes a step towards the layer-controlled growth of graphite and other two-dimensional materials.

Nitrogen-containing diamond-like carbon (N-DLC) multilayer films approximately 500 nm thick were fabricated on tungsten carbide substrates as surface protective films with high wear-resistive and conductive properties. Each layer thickness of the N-DLC multilayer films was approximately 10 nm, and the films were a periodic bilayer structure consisting of hard and soft N-DLC layers. Owing to the high abrasion resistance of the hard layer and the low aggressiveness and high adhesion of the soft layer, the multilayer films showed good polishing and wear resistances compared with the hard N-DLC monolayer film, and the electrical resistivity was about half. In the case of DLC multilayer films consisting of hard N-free DLC and N-DLC films, the decrease of each layer thickness leads to the reduction of the polishing resistance. From X-ray reflectivity analysis of ultra-thin N-free DLC films, it was indicated that the film density of an ultra-thin N-free DLC film is lower than that of a thick N-free DLC film. In the DLC multilayer film with thin N-free DLC layers, it is possible that the polishing resistance of the whole DLC film reduced because the hardness the N-free DLC layer was decreased due to the low film density of each N-free DLC layer.

Ellipsometric measurements give information on two film properties with high precision, thickness and refractive index. In the simplest case, the substrate is covered with a single homogenous, transparent film. Yet, with ellipsometry, it is only possible to determine the two film properties thickness and refractive simultaneously if the layer thickness exceeds 15 nm - a restriction well known for a century. Here we present a technique to cross this limitation: A series expansion of the ellipsometric ratio ρ to the second order of the layer thickness relative to the wavelength reveals the first and second ellipsometric moment. These moments are properties of the thin film and independent of incident angle. Using both moments and one additional reference measurement enables to determine simultaneously both thickness and refractive index of ultra-thin films down to 5 nm thickness.

The addition of one or more partially reflecting mirrors to a traditional two-mirror Fabry–Perot interferometer results in a multimirror Fabry–Perot interferometer. A superposition of all possible multiple reflected beams is described with a general theory for multimirror interferometers, featuring matrices analogous to the theory of multilayer thin films. However, the parameters in the matrix elements are mirror reflection coefficients and spacings instead of the usual refractive indices and layer thicknesses of thin films. The transmission characteristics of two-, three-, and four-mirror Fabry–Perot optical filters are described. It is shown that a suitable choice of reflection coefficients results in transmission properties that can be described approximately with Butterworth profiles, which are known from network analysis of electrical circuits.

The present investigation deals with the fabrication of silver (Ag) patch antenna with yttrium iron garnet (YIG) thick film layer inclusion as substrate overlay to enhance its performance. In this paper, YIG nanopowder was mixed with organic vehicle which consists of linseed oil, m-xylene and α-terpineol with powder ratio of 30 wt%. Then the mix was stirred at 150rpm for 3 hours at 40°C in order to obtain homogenous paste, followed by printing it onto FR4 substrate using the screen printing technique to form the YIG thick film layer before dried at 200°C. A basic square shape patch antenna by using silver paste was printed onto the YIG layer and then compared with another patch antenna which was printed without the YIG layer. The results shown that the antenna with YIG thick film layer has return loss of −19.67dB, resonant frequency 6.42GHz, bandwidth 3.13 and Q factor of 2.051, which is better compared to the antenna without the layer by 138.13%, 3.22%, 49.76% and 31.08% respectively.

In this study, the Yttrium Stabilized Zirconia (YSZ) thin films were deposited on the sapphire substrate (Al2O3) by dip-coating method using simple ethanol-based YSZ suspension. The layer thickness of YSZ films were varied by sintering at 1300°C. Phase change and structural evolution in YSZ films were observed by conducting X-ray diffraction (XRD) analyses. The microstructures and the surface morphology of the deposited films were examined using Atomic Force Microscope (AFM) and Field Emission Scanning Electron Microscope (FESEM). The XRD pattern revealed a phase change from cubic to monoclinic with an increase in YSZ layer thickness. The crystallite size was varied in the range of 9.68–42.98 nm with the changes in the layer thickness. Meanwhile, the AFM image analyses showed a layer thickness-dependent variation in the grain size (205.83–373.77 nm) and the RMS surface roughness (16.72–36.44 nm). The FESEM images of the achieved film exhibited the occurrence of a dense morphology. It was concluded that by controlling the layer thickness of the deposited films, their improved structure and morphology can be achieved.