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To develop the high reflectance mirror for the short wavelength range of the water window region (λ=2.42–2.73  nm), Cr/V multilayers with B_4C barrier layers are studied. The grazing incidence x-ray reflectometry results show that the multilayer interface widths are significantly reduced down to 0.21–0.31 nm, after the introduction of 0.1 nm B_4C barrier layers at both interfaces. The [B_4C/Cr/B_4C/V] multilayer with a large number of bilayers of N=300 maintains the same small interface widths while the surface roughness is only 0.2 nm. According to the transmission electron microscope measurements, the layer structure improvement with barrier layers can be attributed to the suppression of the crystallization of vanadium inside the structure. Using the interface engineered multilayer, a maximum soft x-ray reflectance of 24.3% is achieved at λ=2.441  nm, under the grazing incidence of 42°.

The photonic bandgap of periodic multilayers with diffuse interfaces is calculated by considering an empirical model for the interdiffusion profile. The model for the diffuse profile is based on the error function Erf and a characteristic parameter σ. The model is valid for multilayer structures with an arbitrary layer thickness. It is shown that the width of the bandgap varies with the value of σ and the Brillouin zone boundary. Numerical examples are presented. It is suggested that measuring the ratio of the width of the bandgaps at different orders, that is, determining experimentally the ratio of the widths of the different Bragg peaks on a reflectivity curve, can allow estimation of the thickness of the interdiffusion layer.

L’optique du rayonnement X est conditionnée par le fait que l’indice optique est un nombre complexe dont la partie réelle (indice de réfraction) est légèrement inférieure à l’unité et dont la partie imaginaire n’est pas négligeable. Autrement dit, les matériaux sont peu réfringents et peu transparents à ce rayonnement. Du fait que l’indice de réfraction est légèrement inférieur à 1, la réflexion spéculaire par un miroir homogène ne peut se faire efficacement que dans les conditions de réflexion totale externe (RTE) pour un angle d’incidence supérieur à l’angle critique, c’est-à-dire en pratique sous incidence rasante (voir encadré). La faible réfringence et l’opacité des matériaux empêchent la réalisation de lentilles semblables à celles mises en oeuvre pour le rayonnement visible. De ces contraintes, il découle que les dispositifs optiques destinés à l’imagerie et à la dispersion spectrale du rayonnement X sont des instruments souvent très élaborés qui font appel à des technologies de pointe.

We present the results of the thermal stability of Mg/Co multilayers in the EUV range. The annealing study is performed up to a temperature of 400°C. The X-ray reflectivity at 0.154 nm is used in order to determine the structural parameters (thickness, roughness and density) of the layers. The measurements of the EUV reflectivity around 25 nm show that the reflectivity decreases when the annealing temperature increases above 300°C. X-ray emission spectroscopy is performed to determine the chemical state of the Mg atoms within the Mg/Co multilayer. The results show a small oxidation after annealing at 305°C, which increases greatly at 400°C. Scanning electron microscopy images of cross sections of the multilayer show a change of the surface morphology above 305°C. This large change of morphology and the oxidation explain the large reflectivity loss.

Mg-based multilayers, including SiC/Mg, Co/Mg, B_4C/Mg, and Si/Mg, are investigated for solar imaging and a He II calibration lamp at a 30.4?nm wavelength. These multilayers were fabricated by a magnetron sputtering method and characterized by x-ray reflection. The reflectivities of these multilayers were measured by synchrotron radiation. Near-normal-incidence reflectivities of Co/Mg and SiC/Mg multilayer mirrors are as high as 40.3% and 44.6%, respectively, while those of B_4C/Mg and Si/Mg mirrors are too low for application. The measured results suggest that SiC/Mg, Co/Mg multilayers are promising for a 30.4?nm wavelength.

Nous pr?sentons une ?tude qui s'inscrit dans le cadre du d?veloppement des sources X coh?rentes bas?es sur le principe de la ??r?trodistribution?? ?par une structure multicouche. L'intensit? du rayonnement diffus? par une structure multicouche La/B4C irradi?e par un rayonnement monochromatique a ?t? enregistr?e en fonction de l'?nergie du rayonnement incident dans le domaine 90 et 180?eV recouvrant la r?gion 4d du lanthane, pour diff?rents angles d'incidence et de diffusion. De forts maximums d'intensit? diffus?e sont observ?s pour des ?nergies incidentes qui varient fortement avec l'angle de diffusion. Un des 2 principaux pics a ?t? interpr?t? comme d? ? une diffusion Raman associ?e ? la configuration finale 5p5 du lanthane, combin?e ? la diffraction de Bragg du rayonnement diffus? par la structure multicouche. Un mod?le cin?matique bas? sur la conservation de l'?nergie et des impulsions a permis de mod?liser ce ph?nom?ne que nous avons appel? diffusion Raman-Bragg. L'origine des autres structures observ?es est discut?e.

Electron-induced X-ray emission spectroscopy (EXES) combined with a semi-empirical electron scattering model, which describes the ionizations inside a material under electron irradiation, is used to determine the depth profile of shallow and ultra-shallow dopants in silicon. Two approaches are presented, depending on whether the shape of the profile is known or not. To test the method, X-ray intensities of implanted phosphorus atoms at various energies and doses in silicon are measured at a wide range of incident electron energies. From the experimental data combined with the model, the resulting profile parameters are determined. Comparison of secondary ion mass spectrometry and EXES associated with the electron scattering model shows that the proposed method is suitable for determining the shallow implant profiles with a depth resolution of one nanometer.

We present a study of the interface between a NiTi film deposited by magnetron d.c. sputtering and a SiO2film obtained by thermal oxidation. Electron‐induced X‐ray emission spectroscopy (EXES) is used to characterize the physicochemical environment around the Si atoms at the NiTi/SiO2interface, and to obtain information about the interfacial reactivity. From analysis of the Si 3p valence states, the composition and the thickness of the interfacial zone before and after annealing are deduced. The composition of the passivation layer, located at the surface of the metallic film, is determined by EXES and X‐ray Photoelectron Spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd.

We present a study of the interface between a NiTi film deposited by magnetron d.c. sputtering and a SiO2 film obtained by thermal oxidation. Electron-induced X-ray emission spectroscopy (EXES) is used to characterize the physicochemical environment around the Si atoms at the NiTi/SiO2 interface, and to obtain information about the interfacial reactivity. From analysis of the Si 3p valence states, the composition and the thickness of the interfacial zone before and after annealing are deduced. The composition of the passivation layer, located at the surface of the metallic film, is determined by EXES and X-ray Photoelectron Spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd.

We have studied the solid/solid interface between Mo and SiO2films deposited, respectively, by magnetron d.c. sputtering and plasma‐enhanced chemical vapour deposition (PECVD). The sample depth profile was characterized by SIMS. We used electron‐induced x‐ray emission spectroscopy to characterize the interface from the valence Si 3p and O 2p spectral densities, which are very sensitive to the physicochemical environment, and the Si 2p→ 1s transition, which is sensitive to the oxidation degree of the silicon atoms. By gradually decreasing the emissive thickness, which is a function of the primary electron energy, we have shown the presence of an interfacial compound 2–4 nm thick that is not seen by SIMS. We suggest that this compound is an MoSiO mixed oxide in which the silicon atoms have an oxidation degree equal or close to that of silica. Copyright © 2000 John Wiley & Sons, Ltd.