Rediscovery of the Elements: Aluminum

Rediscovery of the Elements: Aluminum

Date: Summer 2006
Creator: Marshall, James L., 1940- & Marshall, Virginia R.
Description: Article describing the history of aluminum, from its use in alum to its isolation. Tourist information is given regarding locations pertinent to aluminum.
Contributing Partner: UNT College of Arts and Sciences
The Hexagon, Volume 97, Number 2, Summer 2006

The Hexagon, Volume 97, Number 2, Summer 2006

Date: Summer 2006
Creator: Alpha Chi Sigma
Description: Quarterly publication of the Alpha Chi Sigma chemistry fraternity containing articles related to chemistry research and the activities of the organization, including local chapters and groups.
Contributing Partner: UNT Libraries
Absolute Intensities of the Vacuum Ultraviolet Spectra in a Metal-Etch Plasma Processing Discharge

Absolute Intensities of the Vacuum Ultraviolet Spectra in a Metal-Etch Plasma Processing Discharge

Date: December 9, 1998
Creator: Aragon, B.P.; Blain, M.G.; Hamilton, T.W.; Jarecki, R.L. & Woodworth, J.R.
Description: In this paper we report absolute intensities of vacuum ultraviolet and near ultraviolet emission lines (4.8 eV to 18 eV ) for aluminum etching discharges in an inductively coupled plasma reactor. We report line intensities as a function of wafer type, pressure, gas mixture and rf excitation level. IrI a standard aluminum etching mixture containing C12 and BC13 almost all the light emitted at energies exceeding 8.8 eV was due to neutral atomic chlorine. Optical trapping of the WV radiation in the discharge complicates calculations of VUV fluxes to the wafer. However, we see total photon fluxes to the wailer at energies above 8.8 eV on the order of 4 x 1014 photons/cm2sec with anon- reactive wafer and 0.7 x 10 `4 photons/cm2sec with a reactive wtier. The maj ority of the radiation observed was between 8.9 and 9.3 eV. At these energies, the photons have enough energy to create electron-hole pairs in Si02, but may penetrate up to a micron into the Si02 before being absorbed. Relevance of these measurements to vacuum-W photon-induced darnage of Si02 during etching is discussed.
Contributing Partner: UNT Libraries Government Documents Department
The Electrical Properties of Native and Deposited Thin Aluminum Oxide Layers on Aluminum: Hydration Effects

The Electrical Properties of Native and Deposited Thin Aluminum Oxide Layers on Aluminum: Hydration Effects

Date: November 11, 1998
Creator: Barbour, J.C.; Copeland, R.G.; Dunn, R.G.; Missert, N.; Montes, L.P.; Son, K.-A. et al.
Description: The electronic defect density of native, anodic, and synthetic Al oxide layers on Al were studied by solid state electrical measurement as a function of hydration OF the oxide. The non-hydrated synthetic Al oxide layers, which included electron cyclotron resonance (ECR) plasma deposited oxides as well as ECR plasma grown oxides, were highly insulating with electrical transport dominated by thermal emission from deep traps within the oxide. Following hydration these oxides and the native oxides exhibited a large increase in electronic defect density as evidenced by increases in the DC leakage current, reduction in the breakdown field, and increase in AC conductance. Elastic recoil detection of hydrogen revealed that hydration leads to hydrogen incorporation in the oxide films and hydrogen injection through the films into the Al layer below. The increase in electronic defect concentration is related to this hydrogenation and may play a significant role in localized corrosion initiation.
Contributing Partner: UNT Libraries Government Documents Department
Pinhole closure measurements

Pinhole closure measurements

Date: July 20, 1998
Creator: Afeyan, B. B.; Boley, C. D.; Estabrook, K. G.; Kirkwood, R. K.; Milam, D.; Murray, J. E. et al.
Description: Spatial-filter pinholes and knife-edge samples were irradiated in vacuum by 1053-nm, 5-20 ns pulses at intensities to 500 GW/cm<sup2</sup>. The knife-edge samples were fabricated of plastic, carbon, ahnuinum, stainless steel, molybdenum, tantalum, gold and an absorbing glass. Time-resolved two-beam interferometry with a 40-ns probe pulse was used to observe phase shifts in the expanding laser-induced plasma. For all of these materials, at any time during square-pulse irradiation, the phase shift fell exponentially with distance from the edge of the sample. The expansion was characterized by the propagation velocity V<sub>2x</sub> of the contour for a 2(pi) phase shift. To within experimental error, V<sub>2x</sub>, was constant during irradiation at a particular intensity, and it increased linearly with intensity for intensities <300 GW/cn<sup>2</sup>. For metal samples, V, exhibited an approximate M<sup>-0.5</sup> dependence where M is the atomic mass. Plasmas of plastic, carbon and absorbing glass produced larger phase shifts, and expanded more rapidly, than plasmas of the heavy metals. The probe beam and interferometer were also used to observe the closing of pinholes. With planar pinholes, accumulation of on-axis plasma was observed along with the advance of plasma away from the edge of the hole. On-axis closure was not observed in square, 4-leaf ...
Contributing Partner: UNT Libraries Government Documents Department
Dynamics of Wet Oxidation of High-AL-Content III-V Materials

Dynamics of Wet Oxidation of High-AL-Content III-V Materials

Date: January 27, 1999
Creator: Ashby, C.I.H.
Description: Oxidation of layers of high-Al-content III-V materials by water vapor has become the enabling process for high-efficiency vertical cavity surface emitting lasers (VCSELS) and has potential applications for reducing substrate current leakage in GaAs-on-insulator (GOI) MESFETS. Because of the established importance of wet oxidation in optoelectronic devices and its potential applications in electronic devices, it has become increasingly important to understand the mechanism of wet oxidation and how it might be expected to affect both the fabrication and subsequent operation of devices that have been made using this technique. The mechanism of wet oxidation and the consequence of this mechanism for heterostructure design and ultimate device operation are discussed here.
Contributing Partner: UNT Libraries Government Documents Department
Aluminum: Reflective Aluminum Chips

Aluminum: Reflective Aluminum Chips

Date: January 29, 1999
Creator: Recca, L.
Description: This fact sheet reveals how the use of reflective aluminum chips on rooftops cuts down significantly on heat absorption, thus decreasing the need for air conditioning. The benefits, including energy savings that could reach the equivalent of 1.3 million barrels of oil annually for approximately 100,000 warehouses, are substantial.
Contributing Partner: UNT Libraries Government Documents Department