Micrometers Line Research Articles

Soft and flexible gold microelectrodes by supersonic cluster beam deposition and femtosecond laser processing

Soft and flexible microelectrodes are fabricated and patterned in a novel approach integrating supersonic cluster beam deposition (SCBD) of gold nanoparticles onto Polydimethylsiloxane (PDMS) followed by femtosecond (fs) laser processing. SCBD of gold nanoparticles in PDMS forms a nanocomposite film with mechanical properties similar to those of the elastomeric substrate. Electrically neutral metallic nanoparticles penetrate the polymeric matrix and distribute randomly up to a depth of a few hundred nanometers forming a path of ohmic conduction. High resolution patterning on soft substrates is a major challenge that was overcome by femtosecond laser ablation of micrometer lines with relatively very little thermal damage. Microelectrodes were fabricated with a width down to 3 μm. The printed metal line sheet resistance was 480 Ohm/square for the 100 nm thick film and 210 Ohm/square for the 200 nm thick film. The calculated average film specific resistivity was found to be 2.5–2.6mΩ·cm. It is ~3 orders of magnitude higher than that of physical vapor deposited gold; therefore, it is not suitable for high current interconnects but sufficient for low-current signal transmission such as for electrical and electrochemical biosensors.

MID-INFRARED SPECTRAL INDICATORS OF STAR FORMATION AND ACTIVE GALACTIC NUCLEUS ACTIVITY IN NORMAL GALAXIES

We investigate the use of MIR PAH bands, continuum and emission lines as probes of star-formation and AGN activity in a sample of 100 'normal' and local (z~0.1) emission-line galaxies. The MIR spectra were obtained with the Spitzer Space Telescope Infrared Spectrograph (IRS) as part of the Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS) which includes multi-wavelength photometry from the UV to the FIR and optical spectroscopy. The continuum and features were extracted using PAHFIT (Smith et al. 2007), a decomposition code which we find to yield PAH equivalent widths up to ~30 times larger than the commonly used spline methods. Despite the lack of extreme objects in our sample (such as strong AGNs, low metallicity galaxies or ULIRGs), we find significant variations in PAH, continuum and emission line properties and systematic trends between these MIR properties and optically derived physical properties such as age, metallicity and radiation field hardness. We revisit the diagnostic diagram relating PAH equivalent widths and [Ne II]12.8micrometers/[O IV]25.9micrometers line ratios and find it to be in much better agreement with the standard optical star-formation/AGN classification than when spline decompositions are used, while also potentially revealing obscured AGNs. The luminosity of individual PAH components, of the continuum, and with poorer statistics, of the neon emission lines and molecular hydrogen lines, are found to be tightly correlated to the total IR luminosity, making individual MIR components good gauges of the total dust emission in SF galaxies. Like the total IR luminosity, these individual components can be used to estimate dust attenuation in the UV and in Halpha lines based on energy balance arguments. We also propose average scaling relations between these components and dust corrected, Halpha derived star-formation rates.

Submicrometer ${\rm Nb}/{\rm Al}{-}{\rm AlO}_{\rm x}/{\rm Nb}$ Integrated Circuit Fabrication Process for Quantum Computing Applications

We have developed a low J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> (100-1000 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) submicrometer Nb integrated circuit fabrication process for SQUID-based quantum computing applications. The baseline process consists of 7 masking steps including Pd-Au resistor, Nb/Al-AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /Nb trilayer, two Nb wiring layers and two sputtered SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> dielectric layers. We have also fabricated wafers with an Nb ground plane. Using deep-UV lithography, inductively coupled plasma etch tools, and self-aligned lift-off for device definition, we routinely achieve micrometer lines and spaces with 400 nm minimum junction dimensions. Room temperature testing is used to select wafers in process and junction annealing has been calibrated for trimming current density. We will describe the process which has been used to produce circuits with over 100 junctions.

The N (II) 205 micron line in M82: The warm ionized medium

Detection of the 205 micrometer fine structure line of N II in the nearby starburst galaxy M82 is reported. The intensity wihin a 54 sec Full width at Half Maximum (FWHM) beam is (7.1 +/- 1.2) x 10(exp -19) W cm(exp -2). The ratio of the intensity of the recently detected 122 micrometer line to that of the 2.5 micrometer lines is = (4.2) (sup =1.6) (sub -1.2), significantly larger than the corresponding Galactic value of 1.6 +/- 0.3, reflecting higher electron densities within the central 850 pc of M82 in comparison to the Cosmic Background Explorer (COBE) Galactic average. The 2.5 micrometer line profile is consistent with other far-infrared fine-structure line profiles observed in M82. The observations are interpreted in the context of a two-component model of the ionized medium in M82. We find that a component of density as low as approximately 50 cm(exp -3) can comprise up to 70% of the total mass of warm ionized gas within the beam. The balance of the ionized mass is comprised of a component of density approximately greater than 100 cm(exp -3). A model is explored in which the dneser ionized medium constitute the boundaries of neutral surfaces which border the expanding hot plasma from the nuclear region.

(C II) 158 micron and (O I) 63 micron observations of the Galactic center regions

view Abstract Citations (18) References (51) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS [C ii] 158 Micron and [O i] 63 Micron Observations of the Galactic Center Region Mizutani, Kohei ; Maihara, Toshinori ; Matsuhara, Hideo ; Nakagawa, Takao ; Shibai, Hiroshi ; Okuda, Haruyuki ; Kobayashi, Yukiyasu ; Hiromoto, Norihisa ; Nishimura, Tetsuo ; Low, Frank J. Abstract Using the balloon-borne infrared telescope (BIRT) incorporated with a liquid-helium-cooled double-channel Fabry-Perot spectrometer, intensities and velocity profiles of (C II) 158 micrometers fine-structure lines have been observed in the Galactic center region within absolute value of l less than or equal to 0.7 deg. Intense (C II) line emission has been detected ubiquitously in almost all of the observed points. The distribution of the (C II) intensity shows a central peak at Sgr A West together with two prominent peaks at delta 1 = +/- 0.6 deg, which correspond to Sgr B1 (not Sgr B2) and Sgr C, respectively. The intensity distribution resembles but is not identical to, that of far-infrared emission. The velocity profiles of the (C II) line are resolved and can be deconvolved into multiple components, many of which can be traced to the features observed by molecular lines. The (O I) 63 micrometers line has been detected at Sgr A West and at some other points. The (O I) 63 micrometers/(C II) 158 micrometers ratios are always less than 3 in the beam of 3.7 min. These observed results can be explained as the emission generated in photodissociation regions formed in the molecular clouds complexes illuminated by intense ultraviolet (UV) radiation field in the Galactic center regions. However, contribution from ELD region is possibly present and cannot be ruled out. Publication: The Astrophysical Journal Supplement Series Pub Date: April 1994 DOI: 10.1086/191950 Bibcode: 1994ApJS...91..613M Keywords: Carbon; Fine Structure; Galactic Bulge; Infrared Astronomy; Line Spectra; Luminous Intensity; Milky Way Galaxy; Molecular Spectra; Oxygen; Velocity Distribution; Balloon-Borne Instruments; Dynamic Models; Fabry-Perot Spectrometers; Infrared Telescopes; Molecular Clouds; Photodissociation; Sagittarius Constellation; Ultraviolet Radiation; Astronomy; GALAXY: CENTER; ISM: KINEMATICS AND DYNAMICS; INFRARED: ISM: LINES AND BANDS full text sources ADS | data products SIMBAD (6)

The galactic center - 16-30 micron observations and the 18 micron extinction

Within the galactic center, ionized gas, stars, and heated dust are in close proximity to each other. Observations of the galactic center were made during two flight series on NASA aircraft flying at altitudes of more than 12 km. In both series the instrument used was a 10-channel liquid helium cooled grating spectrometer. Three 16-30 micrometers continuum spectra are presented along with two-color scans of the galactic center. No 18.71 micrometers line emission has been detected from Sgr A West. This is consistent with large dust extinction and normal S III/H II abundances. All three 16-30 micrometers continuum spectra show a broad depression centered at about 18 micrometers. This observation is attributed to absorption by cold silicate dust grains. The characteristics of a silicate model are discussed.

Abstract: Plasma etching of thin metal and dielectric films

Plasma etching as utilized by the microelectronics industry is discussed. Comparisons with wet etching processes show advantages of improved pattern definition and cost reductions. However, plasma etching differs in several important respects which warrant understanding for optimal use.The plasma is shown to be a source of reactant radicals, which upon interaction with the substrate produce volatile reaction products. Some radicals, e.g., CF3, have sufficient lifetimes to permit etching of substrates located outside of the glow discharge region. This offers major advantages in terms of high etching uniformity across wafers and long photoresist mask life. The quantity of radical reagent created under typical conditions (133 Pa, 250 cm3/min, 0.1 W/cm3) is shown to compare with the quantity of etched material, which leads to load dependence of the etching rate. It is also shown how narrow lines will etch more slowly than broad patterns and that this phenomena is related to pattern depth, photoresist thickness, and gas pressure. For films thinner than 0.5 μm, etching is very steep with almost vertical side walls. This also depends upon photoresist thickness and pressure.Specific etching processes are discussed. Important consideration must be given to relative etch rates for multilayered structures. For example, some important films listed in order of decreasing etch rate are polysilicon, monosilicon, Si3N4, Si2O2(CVD, chemical vapor deposition), SiO2(thermal), GaAsP, and Al. Thus etching polysilicon gates down to underlying SiO2, Si3N4 down to GaAsP, SiO2(CVD) glass down to Al bonding pads, and Si3N4 down to thermal SiO2, are all viable plasma etch processes.Chromium etches readily in Cl2–O2 plasmas, and an excellent process is in use for etching ultrafine patterns in chromium photoplates. Undercut is nil, and fractional micrometer lines are readily defined. Etching of gold is accomplished with CClF3 plasmas, placing the substrate directly in the glow region. Mo, W, Ti, and Ta all etch rapidly and cleanly. Processes for aluminum etching and preferential oxide etching are under development and should be available for general use within the next year.