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Through its participation to European programs, SAGEM has worked on the design and manufacturing of normal incidence collectors for EUV sources. By opposition to grazing incidence, normal incidence collectors are expected to collect more light with a simpler and cheaper design. Designs are presented for the two current types of existing sources: Discharge Produced Plasma (DPP) and Laser Produced Plasma (LPP). Collection efficiency is calculated in both cases. It is shown that these collectors can achieve about 10 % efficiency for DPP sources and 40 % for LPP sources. SAGEM works on the collectors manufacturability are also presented, including polishing, coating and cooling. The feasibility of polishing has been demonstrated with a roughness better than 2 angstroms obtained on several materials (glass, silicon, Silicon Carbide, metals...). SAGEM is currently working with the Institut d'Optique and the Laboratoire des Materiaux Avances on the design and the process of EUV coatings for large mirrors. Lastly, SAGEM has studied the design and feasibility of an efficient thermal control, based on a liquid cooling through slim channels machined close to the optical surface.

We experimentally demonstrate the high-sensitivity optical monitoring of moving micromirrors, made of low-loss dielectric coatings upon silicon resonators of various shapes and sizes. The very high optical finesses obtained (\mathcal{F}\simeq 30\,000 ) have allowed us to measure the thermal noise of the micromirrors at room temperature with a shot-noise limited sensitivity at the 10^{-19}\,{\rm m}/\sqrt{\rm Hz} level and to completely characterize their mechanical behavior, in excellent agreement with the results of a finite-element computation. Applications of such optomechanical systems range from quantum optics experiments to the experimental demonstration of the quantum ground state of a macroscopic mechanical resonator.

Thick germanium carbide (GeC) and boron phosphide (BP) films are successfully grown on various zinc sulfide and germanium substrates at temperatures up to 450 degree(s)C by reactive radio-frequency sputtering (RRFS). The sputtering conditions are respectively a germanium target within a medium of methane-argon for GeC films and a high density boron target in a sputtering medium of phosphine-argon for BP films. The rain erosion resistance of GeC and BP films protected or not by diamond-like carbon (DLC) coating on top are measured for water drop diameter of 1.2 mm or 2 mm with an impact velocity ranging from 210 m/s to 265 m/s on the Saab-Scania whirling-arm rig facilities (Linkoping, Sweden). Rain erosion resistance of BP films for a wavelength band in the 8 micrometers to 10 micrometers range shows no damage for a speed up to 250 m/s with an exposure time up to 10 min, whereas the GeC rain erosion resistance shows no damage up to 235 m/s for the same exposure time. The transmission of each film is well correlated to its optical absorption at 10.6 micrometers . The GeC absorption can be reduced down to 40 cm-1 whereas the BP absorption stays around 220 cm-1 for sputtered films. So the compromise between the optical performance and the rain erosion resistance can be achieved by the use of GeC or BP films.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Large mirrors (∅350 mm) having extremely low optical loss (absorption, scattering, wavefront) were coated for the VIRGO interferometer. The new generation of mirrors needs to have a better wavefront and lower mechanical loss. To improve the component wavefront, the corrective coating technique was used. By doping the tantalum pentoxide layers, we improved, for the first time to our knowledge, the multilayer mechanical loss. The first results are discussed.

SiO(x)N(y) thin films deposited by rf magnetron sputtering to realize low-loss optical multilayers have been studied. We have analyzed the variations of the optical and physicochemical properties of oxynitride layers according to the deposition parameters: the gas partial pressures, the rf power, and the target composition. A linear variation of the layer refractive index as a function of the oxygen partial pressure was observed as well as a strict substitution of O atoms by N atoms. Thanks to IR spectrophotometric analyses, a model of the oxynitride amorphous structure was proposed and confirmed by Bruggeman and Gained approximation methods. Finally, the absorption level of the oxynitride layers was studied by photothermal deflection spectroscopy.

We present here experimental results on sixty different compositions of the ternary arsenic-tellurium-selenium system. The parameters considered here are: electrical conductivity and its thermal dependence, and transformation temperatures deduced from differential thermal analysis measurements. The synthesis of results leads to the vitrification area for glasses obtained by air quenching and gives rise to an analysis of the influence of the relative concentration of two elements with respect to the third considered as a parameter. DTA studies permit the separation of two different areas in the vitrification surface, corresponding to materials involving or not involving crystallization processes. We have investigated the possible existence of binary or ternary molecular structures in the vitrification region. The results presented here lead to the conclusion that no ternary molecular structure occurs in the AsTeSe system. Nevertheless it seems possible to conclude that one binary molecular structure can be built around As2Se3.

The kinematic viscosity of As1-x Sx liquids exhibits a strong continuous change when x reaches a critical value xc s = 0.525. In the Arrhenius' representation the apparent activation energy changes abruptly at x = xc s this transition is attributed to a structural change from a dissociated to a polymeric associated liquid. The high viscosity range corresponds exactly to the easy glass forming compositions. La viscosite cinematique des liquides As1-x Sx presente une transition importante a x = xc s = 0.525. En representation d'Arrhenius, l'energie d'activation change brusquement pour x = xc s Cette transition indique une profonde modification de structure correspondant au passage d'une zone polymerique a forte association vers une zone fortement dissociee. Les compositions correspondant a la zone fortement associee a haute viscosite sont aussi celles qui permettent d'obtenir des verres homogenes par refroidissement lent du liquide.

The kinematic viscosity behaviour of As x Se 1− x molten chalcogenides is relatively well described by an Arrhenius equation: ν = ν 0 exp( W / kT ), for x between 0 and 0.8. The ν ( x ) and W ( x ) evolutions suggest that all these liquids present a polymeric structure, even outside the easy glass forming region. The tendency of atoms to form separate molecules, previously observed in the As-S system, remains small and only causes a slight inflexion in the ν ( x ) and W ( x ) isotherm curves near x = 0.5.

International audience; A review is presented summarizing the specific nuclear microanalysis methods applied in our laboratory to study amorphous semiconductor thin films. For backscattering, ~3 MeV Li ions are applicable when depth resolution and sensitivity are required while up to 8 MeV a-particles allow larger depths to be probed and elemental interferences to be solved. These features are predominant for diffusion studies between metal electrodes and chalcogenide films. On the other hand hydrogen profiling using the 1H(15N, αγ) resonant nuclear reactions is described and analytical problems associated with its use are discussed. Applications to the elaboration conditions of hydrogenated (a)Si is developed.