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Formation of ripple pattern on silicon surface by grazing incidence ion beam sputtering  [PDF]
Safiul A. Mollick,D. Ghose
Physics , 2009,
Abstract: Off-normal low energy ion beam sputtering of solid surfaces often leads to morphological instabilities resulting in the spontaneous formation of ripple structures in nanometer length scales. In the case of Si surfaces at ambient temperature, ripple formation is found to take place normally at lower incident angles with the wave vector parallel to the ion beam direction. The absence of ripple pattern on Si surface at larger angles is due to the dominance of ion beam polishing effect. We have shown that a gentle chemical roughening of the starting surface morphology can initiate ripple pattern under grazing incidence ion beam sputtering, where the ripple wave vector is perpendicular to the ion beam direction. The characteristics of the perpendicular mode ripples are studied as a function of pristine surface roughness and ion fluence. The quality of the morphological structure is assessed from the analysis of ion induced topological defects.
Flatness measurement using a grazing incidence interferometer
Alcalá Ochoa, N;Mendiola, G;Landgrave, J.E.A.;
Revista mexicana de física , 2007,
Abstract: the purpose of this work is to report results of flatness measurements using a grazing incidence interferometer. we show that this interferometer provides enough accuracy to measure nominally flat polishing tools and rough surfaces. in order to calculate the deformation of the surface under test, an interferogram is analyzed with digital imaging techniques based on fourier methods. we found experimentally that the entire surface topography can be recovered with errors lower than ~ 0.6 μm, or ~ λeqv/6, where λeqv = 3.6441 μm is the equivalent wavelength of the interferometer.
Active Microstructured Optical Arrays of Grazing Incidence Reflectors  [cached]
Richard Willingale,Charlotte Feldman,Alan Michette,Tim Button
X-Ray Optics and Instrumentation , 2010, DOI: 10.1155/2010/856836
Abstract: The UK Smart X-Ray Optics (SXO) programme is developing active/adaptive optics for terrestrial applications. One of the technologies proposed is microstructured optical arrays (MOAs), which focus X-rays using grazing incidence reflection through consecutive aligned arrays of microscopic channels. Although such arrays are similar in concept to polycapillary and microchannel plate optics, they can be bent and adjusted using piezoelectric actuators providing control over the focusing and inherent aberrations. Custom configurations can be designed, using ray tracing and finite element analysis, for applications from sub-keV to several-keV X-rays, and the channels of appropriate aspect ratios can be made using deep silicon etching. An exemplar application will be in the microprobing of biological cells and tissue samples using Ti Kα radiation (4.5 keV) in studies related to radiation-induced cancers. This paper discusses the optical design, modelling, and manufacture of such optics.
Depth resolved grazing incidence scattering from the solid-liquid interface  [PDF]
Max Wolff,Peter Kuhns,Andrew J C Dennison,Georg Liesche,Philipp Gutfreund,Sarah Rogers
Physics , 2013,
Abstract: We have applied small angle scattering in grazing incidence beam geometry on a time-of-flight neutron instrument. Due to the broad wavelength distribution provided for a specific incident beam angle the penetration depth of the neutron beam is varied over a broad range in a single measurement. The near surface structure of polymer micelles close to silicon substrates with distinct surface energy is resolved. It is observed that the very near-surface structure strongly depends on the surface coating whereas further away from the surface bulk like ordering is found. A more pronounced ordering is found close to surfaces with high surface energy.
Grazing incidence interaction of Sn particles with EUV Lithography ruthenium mirrors  [PDF]
Valentino Rigato
Physics , 2010,
Abstract: The new EUV Lithography tools for IC High Volume Manufacture at 22nm make use of EUV radiation at \lambda = 13.5nm. High power Laser (LPP) and Discharge (DPP)EUV light sources are based on Sn plasmas for the optimum conversion of electrical power to in-band radiation. Sn-fueled sources emit debris such as Sn particles in a rather wide energy spectrum: from thermalized Sn to several tens keV fast ions. Tin interaction with the collector mirrors surfaces facing the high power EUV light source leads to the degradation of the optical performance and productivity of the litho tool, therefore debris must be suppressed and the surface modification of the mirror materials during the particle irradiation must be carefully investigated both theoretically and experimentally. For DPP Sn-fueled sources the collector is a grazing incidence mirror that reflects the EUV light in the grazing angle range from about 1\degree to 20\degree. The most used material for these collector mirrors is Ru. The knowledge of the interaction process of Sn particles at different energies and angles with Ru mirrors is crucial to understand mirror degradation and to tune the parameters of the source and of the debris suppression devices to reach optimal mirror lifetime. We carried out a study of the modification of the ruthenium surface exposed to the simultaneous flux of thermalized and energetic Sn at grazing incidence, for energies varying from 300eV to 30keV. The computational study is performed with the Monte Carlo codes TRIDYN and TRIM.SP based on binary collision approximation assumptions. These tools allow to follow dynamically and at steady state the evolution of the surface composition and to model surface binding energy and density for predicting sputtering, reflection, ion-assisted deposition and depth profiles in the nm surface region.
The Coherent Forward Scattering Amplitude in Transmission and Grazing Incidence M?ssbauer Spectroscopy  [PDF]
L. Deák,L. Bottyán,D. L. Nagy,H. Spiering
Physics , 2014, DOI: 10.1103/PhysRevB.53.6158
Abstract: The theory of both transmission and grazing incidence M\"ossbauer spectroscopy is re-analyzed. Starting with the nuclear susceptibility tensor a common concise first order perturbation formulation is given by introducing the forward scattering amplitude into an anisotropic optical scheme. Formulae of Blume and Kistner as well as those of Andreeva are re-derived for the forward scattering and grazing incidence geometries, respectively. Limitations of several previously intuitively introduced approximations are pointed out. The grazing incidence integral propagation matrices are written in a form built up from 2x2 matrix exponentials which is particularly suitable for numerical calculations and practical fitting of both energy domain (conventional source experiment) and time domain (synchrotron radiation experiment) M\"ossbauer spectra.
Displaced Sensor Array for Improved Signal Detection Under Grazing Incidence Conditions
Raed M. Shubair;Rashid S. Nuaimi
PIER , 2008, DOI: 10.2528/PIER07103005
Abstract: This paper proposes a displaced sensor array (DSA) configuration for estimating the angles of arrival of narrowband sources arriving at grazing incidence directions. Unlike the conventional uniform linear array (ULA) where all the array elements are aligned along one axis, the proposed DSA configuration comprises two displaced ULAs aligned on two parallel axes in the vertical plane. The steering vectors of the two parallel arrays differ from each other by only two multiplicative phase terms that represent the space factors due to the vertical separation and horizontal displacement of the two arrays. This makes the computational load of using MUSIC algorithm with the proposed DSA configuration identical to that of ULA yet the accuracy is much higher especially for cases involving narrowband sources arriving at grazing incidence angles. Simulation results obtained show that the proposed DSA configuration outperforms the conventional ULA in terms numerical accuracy and angular resolution.
Morphological Symmetry Breaking During Epitaxial Growth at Grazing Incidence  [PDF]
Jianxin Zhong,Enge Wang,Qian Niu,Zhenyu Zhang
Physics , 2000, DOI: 10.1103/PhysRevLett.84.3895
Abstract: It is shown that, in submonolayer growth at off-normal incidence, even much less than one percent of transfer from the condensation energy of the deposited atoms into adatom motion is sufficient to induce a net adatom current from the illuminated edge of a two-dimensional island to the other edges, thereby breaking the island symmetry. Such a symmetry breaking phenomenon is most pronounced for deposition at grazing incidence. Comparison between our theoretical predictions and existing experimental results confirms the general validity of the model.
Reflection of keV light ions from solids at oblique and grazing incidence  [PDF]
Vukani? Jovan,Simovi? Rodoljub
Nuclear Technology and Radiation Protection , 2009, DOI: 10.2298/ntrp0903188v
Abstract: The particle reflection coefficient of light keV ions backscattered from heavy targets has been determined by two different analytical approaches: by the single collision model in the case of nearly perpendicular incidence and by the small-angle multiple scattering theory in the case of glancing angles of incidence. The obtained analytical formulae are approximately universal functions of the scaled transport cross-section describing the reflection of all light ions from heavy targets. Going from perpendicular to grazing incidence, the transition from pure single to pure multiple scattering type of reflection is observed. For larger values of the scaling parameter the results of these theories cover the whole region of ion incident angles and the present estimates of the particle reflection coefficient are in good agreement with the results obtained from the empirical formula of Tabata et al.
Image processing for grazing incidence fast atom diffraction: the $β_2$(2x4) reconstruction of the GaAs(001) surface  [PDF]
Maxime Debiossac,Philippe Roncin
Physics , 2015,
Abstract: Grazing incidence fast atom diffraction (GIFAD, or FAD) has developed as a very sensitive technique most suited for well ordered crystalline surfaces. Such high quality surfaces are routinely fabricated in molecular beam epitaxy (MBE) chamber and a GIFAD setup has been installed allowing in situ operation. Focusing here on static condition, i.e. before or after the growth process, the paper describes in details the few steps needed to measure the relative intensities of the diffraction spots. Care is taken to outline the underlying physical assumptions.
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