We present a way to analyze the chemical composition of periodical multilayer structures using the simultaneous analysis of grazing incidence hard X-Ray reflectivity (GIXR) and normal incidence extreme ultraviolet reflectance (EUVR). This allows to combine the high sensitivity of GIXR data to layer and interface thicknesses with the sensitivity of EUVR to the layer densities and atomic compositions. This method was applied to the reconstruction of the layered structure of a LaN/B multilayer mirror with 3.5 nm periodicity. We have compared profiles obtained by simultaneous EUVR and GIXR and GIXR-only data analysis, both reconstructed profiles result in a similar description of the layered structure. However, the simultaneous analysis of both EUVR and GIXR by a single algorithm lead to a ∼ 2x increased accuracy of the reconstructed layered model, or a more narrow range of solutions, as compared to the GIXR analysis only. It also explains the inherent difficulty of accurately predicting EUV reflectivity from a GIXR-only analysis.

The increasing importance of well-controlled ordered nanostructures on surfaces represents a challenge for existing metrology techniques. To develop such nanostructures and monitor complex processing constraints fabrication, both a dimensional reconstruction of nanostructures and a characterization (ideally a quantitative characterization) of their composition is required. In this work, we present a soft x-ray fluorescence-based methodology that allows both of these requirements to be addressed at the same time. By applying the grazing-incidence x-ray fluorescence technique and thus utilizing the x-ray standing wave field effect, nanostructures can be investigated with a high sensitivity with respect to their dimensional and compositional characteristics. By varying the incident angles of the exciting radiation, element-sensitive fluorescence radiation is emitted from different regions inside the nanoobjects. By applying an adequate modeling scheme, these datasets can be used to determine the nanostructure characteristics. We demonstrate these capabilities by performing an element-sensitive reconstruction of a lamellar grating made of Si 3 N 4 , where GIXRF data for the O-Kα and N-Kα fluorescence emission allows a thin oxide layer to be reconstructed on the surface of the grating structure. In addition, we employ the technique also to three dimensional nanostructures and derive both dimensional and compositional parameters in a quantitative manner.

The spatial and compositional complexity of 3D structures employed in today's nanotechnologies has developed to a level at which the requirements for process development and control can no longer fully be met by existing metrology techniques. For instance, buried parts in stratified nanostructures, which are often crucial for device functionality, can only be probed in a destructive manner in few locations as many existing nondestructive techniques only probe the objects surfaces. Here, it is demonstrated that grazing exit X‐ray fluorescence can simultaneously characterize an ensemble of regularly ordered nanostructures simultaneously with respect to their dimensional properties and their elemental composition. This technique is nondestructive and compatible to typically sized test fields, allowing the same array of structures to be studied by other techniques. For crucial parameters, the technique provides sub‐nm discrimination capabilities and it does not require access‐limited large‐scale research facilities as it is compatible to laboratory‐scale instrumentation.

Following the recent demonstration of grazing‐incidence X‐ray fluorescence (GIXRF)‐based characterization of the 3D atomic distribution of different elements and dimensional parameters of periodic nanoscale structures, this work presents a new computational scheme for the simulation of the angular‐dependent fluorescence intensities from such periodic 2D and 3D nanoscale structures. The computational scheme is based on the dynamical diffraction theory in many‐beam approximation, which allows a semi‐analytical solution to the Sherman equation to be derived in a linear‐algebraic form. The computational scheme has been used to analyze recently published GIXRF data measured on 2D Si3N4 lamellar gratings, as well as on periodically structured 3D Cr nanopillars. Both the dimensional and structural parameters of these nanostructures have been reconstructed by fitting numerical simulations to the experimental GIXRF data. Obtained results show good agreement with nominal parameters used in the manufacturing of the structures, as well as with reconstructed parameters based on the previously published finite‐element‐method simulations, in the case of the Si3N4 grating.

The effect of ion polishing in sputter deposited W/Si multilayer mirrors with a d-spacing of 2.5 nm was studied. 0.1 to 0.5 nm of Si were etched with 100 eV Ar+ ions. This process resulted in a pronounced reduction in diffused scattering, measured at wavelengths about 0.1 nm. However, CuKa X-ray specular reflectivity and AFM showed only a marginal reduction of the roughness amplitude in the systems. Furthermore, the soft X-ray reflectivity at 0.84 and 2.4 nm did not show any changes after the ion polishing as compared to the nonpolished structures. Grazing incidence X-ray reflectivity (GIXR) analysis revealed that there was no pure W present in the deposited multilayers, with WSi2 being formed instead. As a result, it was concluded that the initial roughness in W/Si multilayers grown by magnetron sputtering is not the major factor in the reflectivity deviation from the calculated value for an ideal system. Nevertheless, the grazing incidence small-angle X-ray scattering (GISAXS) analysis revealed that ion polishing reduces the vertical propagation of roughness from layer to layer by a factor of two, as well as favorably affecting the lateral correlation length and Hurst parameter. These improvements explain the reduction of diffused X-ray scattering at 0.1 nm by more than an order of magnitude, which is relevant for applications like high resolution XRD analysis.

A structural characterization of W/Si multilayers using X-ray reflectivity (XRR), scanning transmission electron microscopy (STEM) and grazing-incidence small-angle X-ray scattering (GISAXS) is presented. STEM images revealed lateral, periodic density fluctuations in the Si layers, which were further analysed using GISAXS. Characteristic parameters of the fluctuations such as average distance between neighbouring fluctuations, average size and lateral distribution of their position were obtained by fitting numerical simulations to the measured scattering images, and these parameters are in good agreement with the STEM observations. For the numerical simulations the density fluctuations were approximated as a set of spheroids distributed inside the Si layers as a 3D paracrystal (a lattice of spheroids with short-range ordering but lacking any long-range order). From GISAXS, the density of the material inside the density fluctuations is calculated to be 2.07 g cm−3 which is 89% of the bulk value of the deposited layer (2.33 g cm−3).

The structural changes in Ru-coated Y films during hydrogenation were studied in this work. In situ XRD data were used to show that the Y to YH 2 transition requires significant hydrogen loading of the Y lattice. By comparing the XRD data with the in situ spectroscopic ellipsometry data, an effective medium model for the transition was obtained. This model describes the Y to YH 2 transition well. The YH 2 to YH 3 transition is also described by an effective medium model, however, with reduced accuracy around the midpoint of the transition. By comparing the YH 2 and YH 3 crystal sizes, we show that these deviations may be due to a surface plasmon resonance. The improved understanding of the ellipsometry measurements is important for optical hydrogen sensing applications.

The structural inhomogeneities of silicon films embedded within W/Si multilayer mirrors were studied by X-ray reflection, grazing-incidence small-angle X-ray scattering (GISAXS) and X-ray photoelectron spectroscopy (XPS). In the diffuse scattering spectra, evidence of laterally and vertically ordered in-layer inhomogeneities was consistently observed. In particular, specific substructures resonant in nature (named here `ridges') were detected. The properties of the ridges were similar to the roughness determined by quasi-Bragg peaks of scattering, which required a high interlayer correlation of particles. The XPS showed the nanocrystalline nature of the Si particles in the amorphous matrix. The geometric characteristics and in-layer and inter-layer correlations of the nanoparticles were determined. In GISAXS imaging, the unusual splitting of the waists between the Bragg sheets into filament structures was observed, whose physical nature cannot yet be explained.