Cr/Sc multilayers for the soft-x-ray range

Schäfers, F.; Mertins, H.-Ch.; Schmolla, Frank; Packe, Ingo; Салащенко, Н. Н.; Shamov, E. A.

doi:10.1364/ao.37.000719

Cited by 66 publications

(36 citation statements)

References 21 publications

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“…In particular, we have worked extensively on multilayer structures based on scandium (Cr/Sc, W/Sc) [19][20][21][22][23]. We have developed a technique of deposition of such structures and made measurements of their key characteristics.…”

Section: Short Period ML Mirrorsmentioning

confidence: 99%

Multilayer optics for XUV spectral region: technology fabrication and applications

et al. 2003

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We present research investigations in the eld of multilayer optics in X-ray and extreme ultra-violet ranges (XUV), aimed at the development of optical elements for applications in experiments in physics and in scienti c instrumentation. We discuss normal incidence multilayer optics in the spectral region of \water window", multilayer optics for collimation and focusing of hard X-rays, multilayer dispersing elements for X-ray spectroscopy of high-temperature plasma, multilayer dispersing elements for analysis of low Z-elements. Our research pays special attention to optimization of multilayer optics for projection EUV-lithography ( ¶ = 13nm) and short period multilayer optics.

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Section: Short Period ML Mirrorsmentioning

confidence: 99%

Multilayer optics for XUV spectral region: technology fabrication and applications

et al. 2003

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“…As a further precaution, the proton beam was moved on the sample surface, from one pristine zone to another, so that the dose did not exceed 600 µC at a given location. The scattering cross sections on the light elements are highly non-Rutherford: in particular the 11 B(p,p) 11 B cross section is much greater than the Rutherford cross-section which explains why the 11 B peak is visible in spite of the very small quantity of boron, and the highly non-Rutherford 28 Si(p,p) 28 Si cross-section is manifested in the resonant structure obtained from the thick silicon substrate.…”

Section: Methodsmentioning

confidence: 99%

“…The multilayer was capped with a 2.5 nm-thick B 4 C layer in order to prevent it from oxidation. Working with this Cr/B 4 C/Sc multilayer enabled us to measure well-resolved Sc and Cr K lines and to detect them at reasonable grazing angles.Indeed, this kind of short-period multilayer is chosen for microscopy or spectroscopy applications in the water window range [28,29] and requires well defined layers. Possible evolution of the multilayer composition was monitored simultaneously via the elastically backscattered protons detected in a passivated implanted planar silicon (PIPS) detector, placed at 165° with respect to the direction of the proton beam.…”

mentioning

confidence: 99%

Kossel interferences of proton-induced X-ray emission lines in periodic multilayers

Guen

André

et al. 2016

Nuclear Instruments and Methods in Physics Research Section B:

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The Kossel interferences generated by characteristic x-ray lines produced inside a periodic multilayer have been observed upon proton irradiation, by submitting a Cr/B 4 C/Sc multilayer stack to 2 MeV protons and observing the intensity of the Sc and Cr K characteristic emissions as a function of the detection angle. When this angle is close to the Bragg angle corresponding to the emission wavelength and period of the multilayer, an oscillation of the measured intensity is detected. The results are in good agreement with a model based on the reciprocity theorem. The combination of the Kossel measurements and their simulation, will be a useful tool to obtain a good description of the multilayer stack and thus to study nanometer-thick layers and their interfaces.  X-ray photons from an x-ray tube [8][9][10] or synchrotron radiation [11][12][13][14]; this case is analogous to the x-ray standing wave technique [14,15] The technique requires a periodic structure to diffract the emitted radiation, thus it has been applied to study crystals and interferential multilayers. However, to the best of our knowledge, Kossel lines have never been observed in multilayers upon particle excitation. It is the aim of this paper to show that it is possible to study multilayers having a nanoscale period upon proton irradiation through the observation of Kossel lines. Experimental detailsThe multilayer used for this experiment was a Cr/B 4 C/Sc periodic multilayer, whose period was repeated 100 times. The samples were deposited by magnetron sputtering onto a silicon substrate. The thickness of the Cr, B 4 C and Sc layers are 0.60, 0.20 and 0.92 nm respectively, as deduced from x-ray reflectivity (XRR) measurements in the hard and soft xray ranges. Thus the period of the stack is 1.72 nm. Other reflectivity measurements also showed that Cr atoms are present inside the B 4 C layers [26]. The thin B 4 C barrier layers were introduced to prevent the interdiffusion between Cr and Sc layers and can also improve the thermal stability of the stack [27]. The multilayer was capped with a 2.5 nm-thick B 4 C layer in order to prevent it from oxidation. Working with this Cr/B 4 C/Sc multilayer enabled us to measure well-resolved Sc and Cr K lines and to detect them at reasonable grazing angles.Indeed, this kind of short-period multilayer is chosen for microscopy or spectroscopy applications in the water window range [28,29] and requires well defined layers. Possible evolution of the multilayer composition was monitored simultaneously via the elastically backscattered protons detected in a passivated implanted planar silicon (PIPS) detector, placed at 165° with respect to the direction of the proton beam. We present in Figure 1 the spectrum so obtained for a total proton dose of 600 µC. Protons scattered from the Cr and Sc atoms appear in the peak near 1800 keV. The area of this peak was monitored, and did not change during the measurements, indicating no measurable loss of matter induced by the beam. As a further precaution, the proton beam ...

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“…Currently at BESSY-II two experimental stations, a small reflectometer (Schä fers & Cimino, 2013) and a polarimeter (Schä fers et al, 1999), are in operation, which have been used for many years for at-wavelength reflectometry (Schä fers et al, 1998;Chkhalo et al, 2013), polarimetry (MacDonald et al, 2009;Gaupp et al, 2013) and ellipsometry measurements.…”

Section: Issn 1600-5775mentioning

confidence: 99%

The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II

et al. 2016

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A technology center for the production of high-precision reflection gratings has been established. Within this project a new optics beamline and a versatile reflectometer for at-wavelength characterization of UV-and XUV-reflection gratings and other (nano-) optical elements has been set up at BESSY-II. The Plane Grating Monochromator beamline operated in collimated light (c-PGM) is equipped with an SX700 monochromator, of which the blazed gratings (600 and 1200 lines mm À1 ) have been recently exchanged for new ones of improved performance produced in-house. Over the operating range from 10 to 2000 eV this beamline has very high spectral purity achieved by (i) a four-mirror arrangement of different coatings which can be inserted into the beam at different angles and (ii) by absorber filters for high-order suppression. Stray light and scattered radiation is removed efficiently by double sets of in situ exchangeable apertures and slits. By use of in-and off-plane bending-magnet radiation the beamline can be adjusted to either linear or elliptical polarization. One of the main features of a novel 11-axes reflectometer is the possibility to incorporate real life-sized gratings. The samples are adjustable within six degrees of freedom by a newly developed UHV-tripod system carrying a load up to 4 kg, and the reflectivity can be measured between 0 and 90 incidence angle for both s-and p-polarization geometry. This novel powerful metrology facility has gone into operation recently and is now open for external users. First results on optical performance and measurements on multilayer gratings will be presented here.

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Cr/Sc multilayers for the soft-x-ray range

Cited by 66 publications

References 21 publications

Multilayer optics for XUV spectral region: technology fabrication and applications

Multilayer optics for XUV spectral region: technology fabrication and applications

Kossel interferences of proton-induced X-ray emission lines in periodic multilayers

The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II

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