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Metal Lines (metal + line)

Distribution by Scientific Domains

Physics and Astronomy	60%

Selected Abstracts

Fabrication of Sub-10,nm Metallic Lines of Low Line-Width Roughness by Hydrogen Reduction of Patterned Metal,Organic Materials,

ADVANCED FUNCTIONAL MATERIALS, Issue 14 2010
Mihaela Nedelcu
Abstract The fabrication of very narrow metal lines by the lift-off technique, especially below sub-10,nm, is challenging due to thinner resist requirements in order to achieve the lithographic resolution. At such small length scales, when the grain size becomes comparable with the line-width, the built-in stress in the metal film can cause a break to occur at a grain boundary. Moreover, the line-width roughness (LWR) from the patterned resist can result in deposited metal lines with a very high LWR, leading to an adverse change in device characteristics. Here a new approach that is not based on the lift-off technique but rather on low temperature hydrogen reduction of electron-beam patterned metal naphthenates is demonstrated. This not only enables the fabrication of sub-10,nm metal lines of good integrity, but also of low LWR, below the limit of 3.2,nm discussed in the International Technology Roadmap for Semiconductors. Using this method, sub-10,nm nickel wires are obtained by reducing patterned nickel naphthenate lines in a hydrogen-rich atmosphere at 500,°C for 1,h. The LWR (i.e., 3 ,LWR) of these nickel nanolines was found to be 2.9,nm. The technique is general and is likely to be suitable for fabrication of nanostructures of most commonly used metals (and their alloys), such as iron, cobalt, nickel, copper, tungsten, molybdenum, and so on, from their respective metal,organic compounds. [source]

Average power-handling capability of the signal line in coplanar waveguides on polyimide and GaAs substrates including the irregular line edge shape effects

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 2 2005
Wen-Yan Yin
Abstract The average power-handling capability (APHC) of the signal line in finite-ground coplanar waveguides (FGCPWs) on polyimide and GaAs substrates is evaluated in this paper. In our approach, the ohmic loss of metal lines is characterized in different ways, and the effects of an irregular edge shape are also considered. The rise in temperature of the signal line is determined by single- and double-layer thermal models, with the temperature-dependent properties of the thermal conductivity of GaAs material treated appropriately. Parametric studies are carried out to investigate the overall effects of signal-line width, thickness, conductivity, edge-shape angle, and polyimide thickness on APHC. Some possible ways to enhance the APHC of these FGCPWs are also proposed. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [source]

Measuring stellar magnetic fields with the low-resolution spectropolarimeter of the William Herschel Telescope

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007
F. Leone
ABSTRACT Although the influence of magnetic fields on the structure and evolution of stars has, to a great extent, been demonstrated theoretically, observational evidence for this in non-degenerated stars is still rather scarce and is mainly restricted to bright objects (V < 10). Stellar magnetic fields are commonly measured on the basis of circular spectropolarimetry at high/middle resolution across the profile of metal lines. The level of sensitivity of telescopes and spectrographs at present makes this still an almost impossible method for faint stars. In principle, stellar magnetic fields can also be measured on the basis of low-resolution spectropolarimetry, and very important results have been obtained at the 8-m European Southern Observatory telescopes with the Focal Reducer and Low-Dispersion Spectrograph (FORS1). The trade-off between signal-to-noise ratio (S/N) and spectral resolution in measuring stellar magnetic fields justifies an attempt, presented here, to perform these measurements at the 4.5-m William Herschel Telescope. One of the stars with the weakest known magnetic field, HD 3360, and the magnetic chemically peculiar stars, HD 10783, HD 74521 and HD 201601, have been observed with the Intermediate Dispersion Spectrograph and Imaging System (ISIS) in the 3785,4480 Å range. The measured stellar magnetic fields, from Stokes I and V spectra with S/N > 600, show an internal error of ,50 G when selecting the whole interval and ,200 G within a Balmer line. Ripples in the Stokes V spectra of HD 3360 result in an instrumental positive magnetic field certainly no larger than 80 G. [source]

A catalogue of absorption lines in eight Hubble Space Telescope/STIS E230M 1.0 < z < 1.7 quasar spectra,

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2007
N. Milutinovi
ABSTRACT We have produced a catalogue of line identifications and equivalent width measurements for all absorption features in eight ultraviolet echelle quasar spectra. These spectra were selected as having the highest signal-to-noise ratio among the Hubble Space Telescope/STIS spectra obtained with the E230M grating. We identify 56 metal-line systems towards the eight quasars, and present plots of detected transitions, aligned in velocity space. We found that about 1/4,1/3 of the features in the Ly, forest region, redward of the incidence of the Ly, forest, are metal lines. High-ionization transitions are common. At the redshift range we study, z < 1.7, we see both O vi and C iv in 88,90 per cent of the metal-line systems for which the spectra cover the expected wavelength. Si iii is seen in 58 per cent, while low-ionization absorption in C ii, Si ii and/or Al ii is detected in 50 per cent of the systems for which they are covered. This catalogue will facilitate future studies of the Ly, forest and of metal-line systems of various types. [source]

High-fidelity spectroscopy at the highest resolutions

ASTRONOMISCHE NACHRICHTEN, Issue 5 2010
D. Dravins
Abstract High-fidelity spectroscopy presents challenges for both observations and in designing instruments. High-resolution and high-accuracy spectra are required for verifying hydrodynamic stellar atmospheres and for resolving intergalactic absorption-line structures in quasars. Even with great photon fluxes from large telescopes with matching spectrometers, precise measurements of line profiles and wavelength positions encounter various physical, observational, and instrumental limits. The analysis may be limited by astrophysical and telluric blends, lack of suitable lines, imprecise laboratory wavelengths, or instrumental imperfections. To some extent, such limits can be pushed by forming averages over many similar spectral lines, thus averaging away small random blends and wavelength errors. In situations where theoretical predictions of lineshapes and shifts can be accurately made (e.g., hydrodynamic models of solar-type stars), the consistency between noisy observations and theoretical predictions may be verified; however this is not feasible for, e.g., the complex of intergalactic metal lines in spectra of distant quasars, where the primary data must come from observations. To more fully resolve lineshapes and interpret wavelength shifts in stars and quasars alike, spectral resolutions on order R = 300 000 or more are required; a level that is becoming (but is not yet) available. A grand challenge remains to design efficient spectrometers with resolutions approaching R = 1 000 000 for the forthcoming generation of extremely large telescopes (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]