Smooth multilayer films suitable for x-ray mirrors

Haelbich, R.-P.; Segmüller, Armin; Spiller, Eberhard

doi:10.1063/1.90743

Cited by 89 publications

(10 citation statements)

References 11 publications

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“…The WRe mixture contained 70% W and 30% Re. In earlier experiments it was determined that this composition grows in an amorphous [12] and smooth structure [13]. The deposition rate of all materials was approximately 0.01 nm/s.…”

Section: Methodsmentioning

confidence: 99%

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Ion-induced interface layer formation in W/Si and WRe/Si multilayers

Kessels¹,

Verhoeven²,

Tichelaar³

et al. 2005

Surface Science

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Section: Methodsmentioning

confidence: 99%

“…Effects at the top and the deeper interfaces of two multilayer systems, W/Si and WRe/Si, have been studied. The first system has been selected for its frequent use in X-ray fluorescence analysis, while WRe/Si was chosen to explore the material dependence after indications of a smoother layer growth of WRe as compared to W [12,13].…”

Section: Introductionmentioning

confidence: 99%

Ion-induced interface layer formation in W/Si and WRe/Si multilayers

Kessels¹,

Verhoeven²,

Tichelaar³

et al. 2005

Surface Science

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“…8 The details of the microstructure and growth technique have also been discussed in Ref. 8. With electron-beam lithography and ion milling 9 the films were cut into wires with two types of widths.…”

Section: Ibm Thomas J Watson Research Center Yorktown Heights New mentioning

confidence: 99%

Quantum Localization in Amorphous W-Re Alloys

Chaudhari

Habermeier

1980

Phys. Rev. Lett.

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The resistance of amorphous W-Re wires between 2 and 20 °K has been measured. Wires with a resistance of approximately 10 kft show a different temperature dependence from that of wires with a resistance of over 200 k£2. The latter show a relative increase in resistance as the temperature is decreased or the magnetic field is increased. These wires also show an anomalous dependence of resistance on width and length. These results are discussed in the perspective of Thouless's suggestion of maximum metallic resistance.Thouless 1 has proposed that the temperature and length dependence of the conductance of a metallic wire deviates from its usually expected behavior when the resistance of the sample exceeds some critical value. This value ranges from 10 to 30 kS2. Similar ideas have been advanced byAdkins, 2 Licciardello and Thouless, 3 and Abrahams et al. 4 Several authors have searched for quantum localization in wires 5,6 and in composite materials. 7 We have carried out a series of electrical resistance measurements on amorphous W-Re alloys. Our samples show, qualitatively, the deviations predicted by Thouless. In addition, we have measured the temperature dependence of the resistance in a magnetic field and find enhanced magnetoresistance below 20 K. The magnetic-field dependence of quantum localization in metallic wires has not been predicted theoretically.We chose the amorphous alloys for a number of reasons. Because of positional disorder, we expect localization to be present. The resistivity of the amorphous samples is usually high. This has significant advantages in the fabrication of high-resistance metallic wires. The temperature dependence of the resistivity is generally small, so that small changes can be followed readily. In addition, the amorphous films can be deposited to yield relatively smooth films with little or no granularity that is characteristic of polycrystalline films. We chose the amorphous W-Re alloys for their stability to crystallization and general ability to withstand handling during the fabrication of the wires. These alloys have a superconducting-transition temperature which can be varied with composition. We used the superconducting transition temperature as a monitor of our film quality. Our films are nominally only 50 A thick and we were concerned about oxidation or other deleterious effects during the fabrication of the relatively high-resistance wires. Observing the same superconducting transition temperature in the high-and low-resistance films was therefore a reassuring sign that the quality of the highresistance wire had not been changed during fabrication.The films were grown by electron-beam evaporation onto oxidized silicon substrates. 8 The details of the microstructure and growth technique have also been discussed in Ref. 8. With electron-beam lithography and ion milling 9 the films were cut into wires with two types of widths. In one case, the width was varied between approximately 700 to 5000 A and in the other it was 20 pirn. The resistivity of the films measured at ...

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“…Pioneering work in this field has started already in the 1970s [1][2][3]. X-ray mirrors consist of flat or curved substrates and reflection coatings deposited on top of the substrate surfaces.…”

Section: Introductionmentioning

confidence: 99%

Ion beam sputtering of x-ray multilayer mirrors

et al. 2008

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Ion beam sputtering has been applied for polishing, figuring and multilayer coating on silicon and quartz glass Substrates for the fabrication of x-ray mirrors. For high-performance x-ray optics extremely low microroughnesses of the substrates have to be achieved. Particularly for low d-spacing multilayers (d = 1...2 nm) even small improvements of the surface quality result in significant performance gains of the mirrors. By ion beam polishing silicon substrate surfaces could be smoothed from 0.18 nm rms to 0.11 rim rms (AFM scan length = 5 mu m). Furthermore figuring of spherical substrates into elliptical or parabolic surface contours has been developed and applied. Spherical quartz glass substrates with initial rms roughnesses of 0.73 nm and 0.52 nm show reduced roughnesses after figuring and multilayer coating of 0.26 nm and 0.10 nm using AFM scan lengths of 20 pm and 5 pm, respectively. The testing of the ion beam figured mirrors for the application as parallel beam and focussing optics shows very promising results: The comparison of collimating mirrors, produced either by ion beam figuring or bending, shows very similar x-ray intensities. However, the ion beam figured mirrors open the perspective for further reduced figure errors, improved long-term stability and 2-dimensional focusing

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Smooth multilayer films suitable for x-ray mirrors

Abstract: Multilayer coatings consisting of very smooth ReW and carbon films used as near-normal-incidence reflectors show theoretical performance in the 150–200-Å wavelength region and should allow the fabrication of useful normal-incidence mirrors for wavelengths as short as 50 Å.

Cited by 89 publications

References 11 publications

Ion-induced interface layer formation in W/Si and WRe/Si multilayers

Ion-induced interface layer formation in W/Si and WRe/Si multilayers

Quantum Localization in Amorphous W-Re Alloys

Ion beam sputtering of x-ray multilayer mirrors

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