Friction and Wear Characteristics of C/Si Bi-layer Coatings Deposited on Silicon Substrate by DC Magnetron Sputtering

The tribological behavior of carbon/silicon bi-layer coatings deposited on a silicon substrate by DC magnetron sputtering was assessed and compared to that of amorphous carbon and silicon coatings. The motivation was to develop a wear resistant coating for silicon using thin layers of amorphous carbon and silicon. Wear tests were conducted by sliding a stainless steel ball against the coating specimens under applied normal loads in the range of 20 * 50 mN. Results showed that the wear rate of the bi-layer coating was strongly dependent on the ratio of thickness between the carbon and silicon layers. The wear rate of the bi-layer coating with 25 nm thick carbon and 102 nm thick silicon layers was about 48 and 20 times lower than that of the single-layer amorphous carbon and amorphous silicon coating, respectively. In addition, the steady-state friction coefficient of the bi-layer coating could be decreased to 0.09 by optimizing the thickness of the layer. Finally, a model for the wear reduction mechanism of the carbon/silicon bi-layer coating was proposed

Fabrication and characterization of a new high density Sc/Si multilayer sliced grating

State of the art soft x-ray spectroscopy techniques like Resonant Inelastic X-ray Scattering (RIXS) require diffraction gratings which can provide extremely high spectral resolution of 105-106. This problem may be addressed with a sliced multilayer grating with an ultra-high groove density (up to 50,000 mm-1) proposed in the recent publication [Voronov, D. L., Cambie, R., Feshchenko, R. M., Gullikson, E., Padmore, H. A., Vinogradov, A. V., Yashchuk, V. V., Proc. SPIE 6705, 67050E (2007)]. It has been suggested to fabricate such a grating by deposition of a soft x-ray multilayer on a substrate which is a blazed saw-tooth grating (echellette) with low groove density. Subsequent polishing applied to the coated grating removes part of the coating and forms an oblique-cut multiline structure that is a sliced multilayer grating. The resulting grating has a short-scale periodicity of lines (bilayers), which is defined by the multilayer period and the oblique-cut angle. We fabricated and tested a Sc/Si multilayer sliced grating suitable for EUV applications, which is a first prototype based on the suggested technique. In order to fabricate an echellette substrate, we used anisotropic KOH etching of a Si wafer. The etching regime was optimized to obtain smooth and flat echellette facets. A Sc/Si multilayer was deposited by dc-magnetron sputtering, and after that it was mechanically polished using a number of diamond pastes. The resulting sliced grating prototype with ~;;270 nm line period has demonstrated a dispersive ability in the 41-49 nm photon wavelength range with a diffraction efficiency of ~;;7percent for the optimized 38th order assigned to the echellette grating of 10 mu m period

Effect of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

By 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 ML

СТРУКТУРА И ФАЗОВЫЙ СОСТАВ МНОГОСЛОЙНЫХ РЕНТГЕНОВСКИХ ЗЕРКАЛ W-Si

Методами рентгеновской дифрактометрии в жесткой области (l~0,154 нм) исследована фазовая структура, состав и строение многослойных рентгеновских зеркал (МРЗ) W/Si с толщиной слоев вольфрама tW2,7 нм слои вольфрама имеют поликристаллическую (ОЦК) структуру, а при tW<1,9 нм они аморфны. При помощи sin2Y-метода установлено, что в тонких кристаллических слоях вольфрама (tW<10 нм) может содержаться более 3 ат.% Si. Растягивающие напряжения в слоях кристаллического вольфрама не превышают 1,1 ГПа. Построение функций радиального распределения атомов позволило установить, что аморфные слои вольфрама имеют расположение атомов, близкое к b-W. Во всех образцах за счет взаимодействия на межфазных границах наблюдается формирование силицидных прослоек, в результате чего реальная толщина слоев вольфрама меньше номинальной. Аморфные силицидные прослойки, обязательно формирующиеся на стадии изготовления МРЗ, содержат дисилицид вольфрама. В зависимости от скорости осаждения дисилицид может иметь расположение атомов, близкое либо к тетрагональной фазе, t-WSi2 (~0,6 нм/с.), либо к гексагональной фазе, h-WSi2 (~0,15 нм/с.). Представлена уточненная модель строения аморфных МРЗ W/Si. Предложены механизмы формирования силицидных прослоек, согласно которым нижние силицидные прослойки (W-на-Si) формируются преимущественно за счет баллистического перемешивания атомов вольфрама и кремния, а верхние – вследствие диффузионного перемешивания. Сделана оценка коэффициентов взаимной диффузии, которые позволили установить, что осаждаемая поверхность слоев может быть разогрета, по меньшей мере, на 250° выше температуры подложки. Предложены пути снижения межфазного взаимодействия

Single shot extreme ultraviolet laser imaging of nanostructures with wavelength resolution

We have demonstrated near-wavelength resolution microscopy in the extreme ultraviolet. Images of 50 nm diameter nanotubes were obtained with a single {approx}1 ns duration pulse from a desk-top size 46.9 nm laser. We measured the modulation transfer function of the microscope for three different numerical aperture zone plate objectives, demonstrating that 54 nm half-period structures can be resolved. The combination of near-wavelength spatial resolution and high temporal resolution opens myriad opportunities in imaging, such as the ability to directly investigate dynamics of nanoscale structures

Problems of protection of urban ambient air pollution from industrial dust emissions

The development of large cities accompanied by the development of the industry hashistorically led to the fact that now residential areas are located side by side with the industrial production. For instance, exactly this situation has developed in the city of Volgograd, as well as in other Russian cities, where sometimes the distance from large enterprises to a living area is 100 m or less. In addition, small-scale entrepreneurs usually place their production directly in their past places of residence. As a result, the content of harmful substances in the air of city blocks is much higher than the standards of hygiene require. It is obvious that the current situation can be improved through the use of modern, more advanced technologies. However, increasing the efficiency of air systems to protect the city from pollution and industrial emissions is an urgent task. The authors propose a version of the system layout, designed to reduce dust emissions in urban air

Problems of protection of urban ambient air pollution from industrial dust emissions

The development of large cities accompanied by the development of the industry hashistorically led to the fact that now residential areas are located side by side with the industrial production. For instance, exactly this situation has developed in the city of Volgograd, as well as in other Russian cities, where sometimes the distance from large enterprises to a living area is 100 m or less. In addition, small-scale entrepreneurs usually place their production directly in their past places of residence. As a result, the content of harmful substances in the air of city blocks is much higher than the standards of hygiene require. It is obvious that the current situation can be improved through the use of modern, more advanced technologies. However, increasing the efficiency of air systems to protect the city from pollution and industrial emissions is an urgent task. The authors propose a version of the system layout, designed to reduce dust emissions in urban air

The influence of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

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 ({lambda} = 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