Optical Response Near the Soft X-Ray Absorption Edges and Structural Studies of Low Optical Contrast System Using Soft X-Ray Resonant Reflectivity

Abstract

Fine structure features of energy-dependent atomic scattering factor near the atomic absorption edge, are used for structural analysis of low-Z containing thin film structures. The scattering contrast undergoes large and abrupt change as the incident photon energy approaches the natural frequency of the atom and is sensitive to variation in atomic composition and atomic density. Soft X-ray resonant reflectivity is utilized for determination of composition at the buried interfaces with subnanometer sensitivity. This is demonstrated through characterization of Mo/Si multilayers near Si L-edge. We also demonstrate the possibility of probing variation of atomic density in thin films, through the characterization of Fe/B 4 C structure, near B K-edge. Sensitivity of soft X-ray resonant reflectivity to native oxide is demonstrated through characterization of BN films near B K-edge.

Explaining the x-ray nonlinear susceptibility of diamond and silicon near absorption edges

“…We did not measured the pump intensity in the case of Si, therefore it was not possible to obtain the non linear susceptibility in unit of cm 2 /StC. Interestingly, the enhancement of |χ (2) | is not observed at the Si L 1 absorption edge around 150 eV since f 1 does not present any negative excursion in the L 1 edge energy region 17 . Therefore, the sign change in f 1 is a crucial condition for the resonant enhancement of |χ (2) | 2 at a given absorption edge.…”

“…However, their atomic-like assumption is clearly insufficient in the vicinity of absorption edges because of condensed matter effects 17 . For this reason, we have calculated the atomic scattering factor from the program FDMNES (standing for finite difference method near-edge structure) 25 , which is a first-principles, free and open source code.…”

“…Henke et al 16 have provided a complete tabulation of values for the atomic scattering factor f 1 calculated for all the elements Z = 1−92 in the energy range from 50 eV to 30 keV. However, their atomic like assumption is clearly insufficient in the vicinity of absorption edges because of condensed-matter effects 17 . For this reason, we have calculated the atomic scattering factor from the program FDMNES (standing for finite difference method nearedge structure) 25 , which is a first-principles, free and open source code.…”

Probing spectroscopic like information using resonant scattering

“…The interaction at resonant energies is a fingerprint of chemical elements and the valence state. Techniques based on x-ray resonant principle provide an opportunity for studying different properties and associated parameters in condensed matter physics [1][2][3][4]. Here, we demonstrated the novel idea through depth profile study of chemical composition of multielement thin film system near boron K-absorption edge.…”

Optical and structural characterization of orthorhombic LaLuO3 using extreme ultraviolet reflectometry

“…Extreme ultraviolet reflectometry (EUVR) allows for non-destructive structural characterization of thin films and layer systems, with determination of their thickness, density and roughness parameters [1][2][3]. This metrology method is equally applicable to metals and dielectrics, not restricted by the sample conductivity.…”