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Документ Scandium-silicon multilayer X-ray mirrors with CrB2 barrier layers(Сумський державний університет, 2018) Pershyn, Yuriy P.; Devizenko, A. Yu.; Zubarev, Evgeniy N.; Kondratenko, Valeriy V.; Voronov, Dmitriy L.; Gullikson, E. M.Methods of X-ray reflectometry λ0.154 nm), cross-sectional transmission electron microscopy and re flectometry in the EUV region (λ = 41-51 nm) were used to investigate the barrier properties of CrB2 layers 0.3-1.3 nm thick in Sc/CrB2/Si multilayer X-ray mirrors (MXMs) deposited by DC magnetron sputtering. It is shown that barrier layers of ~ 0.3 nm separate Sc and Si layers completely and prevent interacting the Sc and Si layers. Thinner chromium diboride layers interact with the matrix layers forming interlayers containing mostly ScB2 on the Si-on-Sc interfaces and CrSi2 on the Sc-on-Si ones. Scandium-silicon MXMs with barrier layers on the both interfaces are shown to retain high reflectivity at the wavelength of λ ~ 47 nm.Документ Growth and structure of WC/SI multilayer X-ray mirror(Національний науковий центр «Харківський фізико-технічний інститут», 2018) Pershyn, Yuriy P.; Chumak, V. S.; Shypkova, I. G.; Mamon, Valentine V.; Devizenko, A. Yu.; Kondratenko, Valeriy V.; Reshetnyak, M. V.; Zubarev, Evgeniy N.WC/Si multilayer X-ray mirrors (MXMs) with nominal layers thicknesses of 0.2…30.3 nm (periods: 0.7…38.9 nm) were deposited by direct current magnetron sputtering and studied by X-ray diffraction and crosssectional transmission electron microscopy (TEM). Carbide and silicon layers are amorphous throughout the studied thickness range. The WC layers interact with Si layers with formation of tungsten silicides (WSi2, W5Si3) and silicon carbide in as-deposited state. The bottom interlayer (WC-on-Si) consists of two subzones of approximately equal thickness. An estimation of the thickness, density, and composition of all layers is made. Based on the experimental data, a five-layer model of the WC/Si MXM structure is suggested.Документ Mechanisms of radiation damage to Sc/Si multilayer mirrors under EUV laser irradiation(IOP Publishing Ltd, 2009) Pershyn, Yuriy P.; Zubarev, Evgeniy N.; Voronov, D. L.; Sevryukova, V. A.; Kondratenko, V. V.; Vaschenko, G.; Grisham, M.; Menoni, C. S.; Rocca, J. J.; Artioukov, Y. A.; Uspenskii, Y. A.; Vinogradov, A. V.Specific structural changes in Sc/Si multilayer mirrors irradiated with extreme ultraviolet (EUV) laser single pulses (λ = 46.9 nm) at near damage threshold fluences (0.04–0.23 J cm−2) are analysed. We have identified melting of surface layers as the basic degradation mechanism for the mirrors. Both heat generation during silicide formation and low heat conduction of the layered system significantly decreases the degradation threshold of Sc/Si multilayer mirrors compared with bulk materials. The results are relevant to the use of the multilayer mirrors for shaping and directing the intense beams produced by the new generation of coherent EUV sourcesДокумент Structural transformations in Sc/Si multilayers irradiated by EUV lasers,(SPIE, 2007) Voronov, Dmitriy L.; Zubarev, Evgeniy N.; Pershyn, Yuriy P.; Sevryukova, Victoriya A.; Kondratenko, Valeriy V.; Artioukov, Igor A.; Uspenskiy, Yuriy A.; Grisham, Michael; Vaschenko, Georgiy; Menoni, Carmen S.; Rocca, Jorge J.Multilayer mirrors for the extreme ultraviolet (EUV) are key elements for numerous applications of coherent EUV sources such as new tabletop lasers and free-electron lasers. However the field of applications is limited by the radiation and thermal stability of the multilayers. Taking into account the growing power of EUV sources the stability of the optics becomes crucial. To overcome this problem it is necessary to study the degradation of multilayers and try to increase their temporal and thermal stability. In this paper we report the results of detailed study of structural changes in Sc/Si multilayers when exposed to intense EUV laser pulses. Various types of surface damage such as melting, boiling, shock wave creation and ablation were observed as irradiation fluencies increase. Cross-sectional TEM study revealed that the layer structure was completely destroyed in the upper part of multilayer, but still survived below. The layers adjacent to the substrate remained intact even through the multilayer surface melted down, though the structure of the layers beneath the molten zone was noticeably changed. The layer structure in this thermally affected zone is similar to that of isothermally annealed samples. All stages of scandium silicide formation such as interdiffusion, solid-state amorphization, silicide crystallization etc., are present in the thermally affected zone. It indicates a thermal nature of the damage mechanism. The tungsten diffusion barriers were applied to the scandium/silicon interfaces. It was shown that the barriers inhibited interdiffusion and increased the thermal stability of Sc/Si mirrors.Документ Analysis of 46.9-nm Pulsed Laser Radiation Aftereffects in Sc/Si Multilayer X-Ray Mirrors(Springer, 2007) Pershyn, Yuriy P.; Voronov, D. L.; Zubarev, Evgeniy N.; Sevryukova, V. A.; Kondratenko, V. V.; Vaschenko, G.; Grisham, M.; Menoni, C. S.; Rocca, J. J.; Vinogradov, A. V.; Artyukov, I. A.; Uspenskii, Yu. A.Specific structural changes in Sc/Si multilayers (MLs) irradiated by nanosecond 46.9-nm single laser pulses with fluences of 0.04-5.00 J/cm2 were studied by methods of SEM and cross-sectional TEM. The threshold damage was found to be 0.08 J/cm2 The ML melts down under the fluence F >0.08 J/cm2 and the exothermic reaction of silicide formation starts. Main degradation mechanisms of MLs are discussed. The results of this study can be used for development of advanced multilayer mirrors capable handling the intense radiation conditions of new generation coherent X-ray sources.Документ Structure and mechanical stresses in TaSi 2 /Si multilayer(STC "Institute for Single Crystals", 2018) Devizenko, A. Yu.; Kopylets, I. A.; Kondratenko, V. V.; Pershyn, Yuriy P.; Zubarev, Evgeniy N.; Savitskiy, B. A.; Devizenko, I. Y.Документ Estimation of interlayer composition in WC/Si multilayer X-ray mirrors (MXMs) at nanometer scale(НТУ "ХПІ", 2016) Shipkova, I. G.; Chumak, V. S.; Reshetnyak, M. V.; Devizenko, A. Y.; Pershyn, Yuriy P.Документ Effect of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers(SPIE, 2013) Pershyn, Yuriy P.; Gullikson, Eric M.; Kondratenko, Valeriy V.; Mamon, Valentine V.; Reutskaya, Svetlana A.; Voronov, Dmitriy L.; Zubarev, Evgeniy N.; Artyukov, Igor A.; Vinogradov, Alexander VladimirovichBy methods of cross-sectional transmission electron microscopy and small-angle x-ray scattering (λ = 0.154 nm) the influence of Ar gas pressure (1 to 4 mTorr) on the growth of amorphous interfaces in Mo/Si multilayers (MLs) deposited by DC magnetron sputtering is studied. The significant reduction in the ML period, which is evident as a volumetric contraction, is observed in MLs deposited at Ar pressure where the mean-free path for the sputtered atoms is comparable with the magnetronsubstrate distance. Some reduction in the thickness of the amorphous interlayers with Ar pressure increase is found, where the composition of the interlayers is enriched with molybdenum. The interface modification resulted in an increase in EUV reflectance of the Mo/Si MLsДокумент Growth and crystallization of molybdenum layers on amorphous silicon(Elsevier Ltd, 2011) Zubarev, Evgeniy N.; Kondratenko, Valeriy V.; Pershyn, Yuriy P.; Sevryukova, Victoriya A.The structure of molybdenum layers deposited by direct current magnetron sputtering onto the amorphous silicon (a-Si) layers as function of nominal layer thickness was studied by methods of transmission electron microscopy. Molybdenum layers with nominal thickness 1.5btMo nomb1.9 nm consist of clusters which should be considered as a transient state between strongly disordered (amorphous) state and crystal one. A transition from clusters to polycrystals takes place within the thickness range of 1.9btMo nomb2.5 nm. Resulting Mo crystallites have an inequiaxial form with dimensions of (3–4)×(15–30)nm2 and consist of blocks. The lateral axis of inequiaxial crystallites is parallel to 110 direction. As the metal layer thickness increases Mocrystallites take the more regular form at the expense of recrystallization.Документ The influence of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers(American Institute of Physics, 2011) Pershyn, Yuriy P.; Gullikson, E. M.; Artyukov, I. A.; Kondratenko, V. V.; Sevryukova, V. A.; Voronov, D. L.; Zubarev, Evgeniy N.; Vinogradov, A. V.Impact of Ar gas pressure (1−4 mTorr) on the growth of amorphous interlayers in Mo/Si multilayers deposited by magnetron sputtering was investigated by small-angle x-ray scattering (l=0.154 nm) and methods of cross-sectional transmission electron microscopy. Some reduction of thickness of the amorphous inter-layers with Ar pressure increase was found, while composition of the layers was enriched with molybdenum. The interface modification resulted in raise of EUV reflectance of the Mo/Si multilayers