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ABSTRACT: Results from a spectromicroscopic study of the formation of TiSi2 in patterned structures are reported. An x-ray spectromicroscope was used to acquire spectra and images with photoabsorption signals using synchrotron radiation. A patterned TiSi2 sample with feature sizes ranging from 100 μm to 0.1 μm was studied. The silicidation reactions were carried out in ultrahigh vacuum using rapid thermal processing. Lateral variations in the local chemistry of the titanium silicide could be directly imaged and are attributed to the formation of the C54 phase in large areas and the C49 phase at feature edges and in narrow features. © 1997 American Institute of Physics.
Applied Physics Letters 07/1997; 71(1):55-57. · 3.84 Impact Factor
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ABSTRACT: We present a study of the effect of multilayer‐surface‐roughness‐induced scattering in the image formation of the Schwarzschild objective (SO) used in the spectromicroscope MAXIMUM. The two mirrors comprising the SO are coated with Ru/B 4 C multilayers that have a peak reflectivity at 130 eV. We had long observed that a diffuse x‐ray background surrounds the focused x‐ray spot. The spatial resolution remains at 0.1 μm in spite of this. However, since a significant fraction of the flux is lost to the background, since too large an area of the sample is illuminated, and since the S/N ratio is degraded, the origins of this effect merit investigation. This diffuse background resulting from x‐ray scattering at the surface of the mirrors was mapped out using bidirectional knife edge scans. Complementary surface roughness simulations were carried out with the ray‐tracing program SHADOW. AFM experiments were also done to directly measure the surface roughness and power spectrum of representative multilayers. Following curve fitting, it was possible to classify Gaussian components in both the measured and simulated profiles as arising from scattering occurring at either the convex primary mirror or the concave secondary mirror. Together with geometrical analysis, these techniques permitted us to track the image formation process of an actual optical system in the presence of surface roughness. © 1996 American Institute of Physics.
Review of Scientific Instruments 10/1996; · 1.37 Impact Factor
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ABSTRACT: The MAXIMUM scanning x‐ray microscope, developed at the Synchrotron Radiation Center (SRC) at the University of Wisconsin – Madison, was implemented on the Advanced Light Source (ALS) in August of 1995. The microscope’s initial operation at SRC successfully demonstrated the use of a multilayer‐coated Schwarzschild objective for focusing 130 eV x‐rays to a spot size of better than 0.1 micron with an electron energy resolution of 250 meV. The performance of the microscope was severely limited because of the relatively low brightness of SRC, which limits the available flux at the focus of the microscope. The high brightness of the ALS is expected to increase the usable flux at the sample by a factor of 1000. We will report on the installation of the microscope on bending magnet beamline 6.3.2 at the ALS and the initial measurement of optical performance on the new source, and preliminary experiments on the surface chemistry of HF‐etched Si will be described. © 1996 American Institute of Physics.
Review of Scientific Instruments 10/1996; · 1.37 Impact Factor
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John T. Welnak, H. Solak,
J. Wallace,
F. Cerrina,
F. Barbo,
M. Bertolo,
A. Bianco,
S. Di Fonzo,
S. Fontana,
W. Jark,
F. Mazzolini,
R. Rosei,
A. Savoia,
J.H. Underwood,
G. Margaritondo
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ABSTRACT: High brightness, third‐generation synchrotrons allow diffraction‐limited performance and large flux for scanning photoemission microscopes. A new microscope, SuperMAXIMUM, is being developed at the University of Wisconsin Center for X ray Lithography in collaboration with the Sincrotrone Trieste. The beamline, being built in Trieste, uses a variable angle spherical grating monochromator (VASGM). A combination of rotation of a plane mirror and rotation of the spherical grating keeps the slit positions and beam directions fixed. The microscope objectives are normal‐incidence, multilayer‐coated Schwarzschild objectives. The project, which is nearing completion, utilizes novel designs for optics alignment, sample rastering mechanics, and software control. We will discuss the project status, new designs, and techniques. © 1996 American Institute of Physics.
Review of Scientific Instruments 10/1996; · 1.37 Impact Factor
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J. Welnak,
Z. Dong, H. Solak,
J. Wallace,
F. Cerrina,
M. Bertolo,
A. Bianco,
S. Di Fonzo,
S. Fontana,
W. Jark,
F. Mazzolini,
R. Rosei,
A. Savoia,
J. H. Underwood,
G. Margaritondo
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ABSTRACT: X ray microscopy excels on high‐brightness sources, such as the Advanced Light Source and ELETTRA, where there is a good match between the source and optics phase spaces. In these conditions, diffraction‐limited operation becomes possible with large flux. We will discuss the development of a second‐generation x ray scanning spectromicroscope; an evolution of the MAXIMUM project at the University of Wisconsin. The new tool is called SuperMAXIMUM and will be installed on ELETTRA in Trieste, Italy. © 1995 American Institute of Physics.
Review of Scientific Instruments 03/1995; · 1.37 Impact Factor
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W. Ng,
A. K. Ray-chaudhuri,
S. Liang,
S. Singh, H. Solak,
F. Cerrina,
G. Margaritondo,
L. Brillson,
A. Franciosi,
J. H. Underwood,
J. B. Kortright,
R. C. C. Perera
Synchrotron Radiation News 03/1994; 7(2):25-29.
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W. Ng,
A.K. Ray-Chaudhuri,
S. Liang,
S. Singh, H. Solak,
J. Welnak,
F. Cerrina,
G. Margaritondo,
J.H. Underwood,
J.B. Kortright,
R.C.C. Perera
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ABSTRACT: We present new results from the soft X-ray scanning photoemission microscope: MAXIMUM. The microscope is installed at the U41 undulator at the Synchrotron Radiation Center at the University of Wisconsin. The instrument is based on a multilayer-coated Schwarzchild objective, operating at 95 eV, and it has demonstrated spatial resolution better than 0.1 μm and electron energy resolution of 300 meV. We review the design and the implementation of the microscope. We also present recent results as well as a summary of the research programs that are being conducted with MAXIMUM.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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W. Ng,
A. K. Raychaudhuri,
S Liang,
S Singh, H. Solak,
J. Welnak,
F. Cerrina,
G. Margaritondo,
J H Underwood,
J. B. Kortright,
R. C. C. Perera
[show abstract]
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ABSTRACT: We present new results from the soft X-ray scanning photoemission microscope: MAXIMUM. The microscope is installed at the U41 undulator at the Synchrotron Radiation Center at the University of Wisconsin. The instrument is based on a multilayer-coated Schwarzchild objective, operating at 95 eV, and it has demonstrated spatial resolution better than 0.1 mum and electron energy resolution of 300 meV. We review the design and the implementation of the microscope. We also present recent results as well as a summary of the research programs that are bei conducted with MAXIMUM.
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J. Welnak,
Z. Dong, H. Solak,
J. Wallace,
F. Cerrina,
M. Bertolo,
A. Bianco,
S. Difonzo,
S. Fontana,
W Jark,
F Mazzolini,
R. Rosei,
A Savoia,
J H Underwood,
G. Margaritondo
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ABSTRACT: We performed a spectromicroscopy experiment to find evidence of lateral inhomogeneities in the band bending for the Al/GaS system. Microimages of the interface tuned on the Al 2p con levels revealed localized chemical inhomogeneities in proximity of the edge of the Al overlayer. A careful analysis of the photoemission spectra supports these conclusions and relates the inhomogeneities to band bending variations. The micron-size lateral scale for these features is similar to that of other interfaces. (C) 1999 Elsevier Science B.V. All rights reserved.
