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Reactive Ion Beam Etching of GaAs and Related Compounds in an Inductively Coupled Plasma of Cl(2)-Ar Mixture
Reactive ion beam etching (RD3E) of GaAs, GaP, AIGaAs and GaSb was performed in a Cl2-Ar mixture using an Inductively Coupled Plasma (ICP) source. `The etch rates and yields were strongly affected by ion energy and substrate temperature. The RJBE was dominated by ion-assisted etching at <600 eV and by physical sputtering beyond 600 eV. The temperature dependence of the etch rates revealed three different regimes, depending on the substrate temperature: 1) sputtering-etch limited, 2) products-resorption limited, and 3) mass-transfer limited regions. GaSb showed the overall highest etch rates, while GaAs and AIGaAs were etched at the same rates. The etched features showed extremely smooth morphologies with anisotropic sidewalls.
Date:
November 23, 1998
Creator:
Abernathy, C. R.; Hahn, Y. B.; Hays, D.; Lambers, E. S.; Lee, J. W.; Pearton, S. J. et al.
Object Type:
Article
System:
The UNT Digital Library
Inductively Coupled Plasma Etching in ICl- and IBr-Based Chemistries: Part I. GaAs, GaSb and AlGaAs
High density plasma etching of GaAs, GaSb and AIGaAs was performed in IC1/Ar and lBr/Ar chemistries using an Inductively Coupled Plasma (ICP) source. GaSb and AlGaAs showed maxima in their etch rates for both plasma chemistries as a function of interhalogen percentage, while GaAs showed increased etch rates with plasma composition in both chemistries. Etch rates of all materials increased substantially with increasing rf chuck power, but rapidly decreased with chamber pressure. Selectivities > 10 for GaAs and GaSb over AlGaAs were obtained in both chemistries. The etched surfaces of GaAs showed smooth morphology, which were somewhat better with IC1/Ar than with IBr/& discharge. Auger Electron Spectroscopy analysis revealed equi-rate of removal of group III and V components or the corresponding etch products, maintaining the stoichiometry of the etched surface.
Date:
November 23, 1998
Creator:
Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Hobson, W.S.; Jung, K.B. et al.
Object Type:
Article
System:
The UNT Digital Library
Inductively Coupled Plasma Etching in ICl- and IBr-Based Chemistries: Part II. InP, InSb, InGaP and InGaAs
A parametric study of Inductively Coupled Plasma etching of InP, InSb, InGaP and InGaAs has been carried out in IC1/Ar and IBr/Ar chemistries. Etch rates in excess of 3.1 prrdmin for InP, 3.6 prnh-nin for InSb, 2.3 pm/min for InGaP and 2.2 ~rrdmin for InGaAs were obtained in IBr/Ar plasmas. The ICP etching of In-based materials showed a general tendency: the etch rates increased substantially with increasing the ICP source power and rf chuck power in both chemistries, while they decreased with increasing chamber pressure. The IBr/Ar chemistry typically showed higher etch rates than IC1/Ar, but the etched surface mophologies were fairly poor for both chemistries.
Date:
November 23, 1998
Creator:
Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Hobson, W.S.; Jung, K.B. et al.
Object Type:
Article
System:
The UNT Digital Library
Effect of Inert Gas Additive Species on Cl(2) High Density Plasma Etching of Compound Semiconductors: Part 1. GaAs and GaSb
The role of the inert gas additive (He, Ar, Xe) to C12 Inductively Coupled Plasmas for dry etching of GaAs and GaSb was examined through the effect on etch rate, surface roughness and near-surface stoichiometry. The etch rates for both materials go through a maximum with Clz 0/0 in each type of discharge (C12/'He, C12/Ar, C12/Xc), reflecting the need to have efficient ion-assisted resorption of the etch products. Etch yields initially increase strongly with source power as the chlorine neutral density increases, but decrease again at high powers as the etching becomes reactant-limited. The etched surfaces are generally smoother with Ax or Xe addition, and maintain their stoichiometry.
Date:
December 23, 1998
Creator:
Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Jung, K.B.; Pearton, S.J. et al.
Object Type:
Article
System:
The UNT Digital Library
Calibration of the MACHO photometry database
The MACHO Project is a microlensing survey that monitors the brightnesses of -60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. The database presently contains more photometric measurements than previously recorded in the history of astronomy. We describe the calibration of the MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. This allows for proper comparison with all other observations on the Kron-Cousins standard system. The highest precision calibrations are for -9 million stars in the LMC bar. For these stars, independent photometric measurements in field-overlap regions indicate standard deviations {sigma}{sub V} = {sigma}{sub R} = 0.020 mag. Calibrated MACHO photometry data are compared with published photometric sequences and with new Hubble Space Telescope observations. We additionally describe the first application of these calibrated data: the construction of the �efficiency� color-magnitude diagram which will be used to calculate our experimental sensitivity for detecting microlensing in the LMC.
Date:
October 23, 1998
Creator:
Alcock, A.
Object Type:
Article
System:
The UNT Digital Library
Technical review of the SWELL product. Second quarterly progress report
This progress report describes design and marketing efforts made to reduce the cost of the product, and reassess its market potential in light of reduced manufacturing costs and modified design. Marketing has looked at applications in agriculture, the turf grass industry, and golf coarse applications. The new controller offers energy efficiency in control of valves and minimization of costs associated with hard wired systems.
Date:
March 23, 1998
Creator:
Alexanian, G.
Object Type:
Report
System:
The UNT Digital Library
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 30, Ed. 1 Wednesday, September 23, 1998
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
September 23, 1998
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 51, Ed. 1 Friday, October 23, 1998
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
October 23, 1998
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 72, Ed. 1 Monday, November 23, 1998
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
November 23, 1998
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Xe precipitates at grain boundaries in Al under 1 MeV electron irradiation.
Crystalline nanoprecipitates of Xe have been produced by ion implantation into mazed bicrystalline Al at 300 K, in which the matrix grain boundaries are mainly 90 deg tilt boundaries. Within Al grains, Xe nanocrystals are fee, isotactic with the Al and cuboctohedral in shape with {l_brace}111{r_brace} and {l_brace}100{r_brace} facets. With an off-axial imaging technique, the nanocrystals were structure imaged against a relatively featureless matrix background. In contrast to metal precipitates in Al, such as Pb, Xe precipitates straddling a matrix grain boundary are bicrystals as small as approximately 2 nm in diameter. Larger Xe precipitates tend to avoid boundaries which are inclined away from asymmetrical orientation and which thus have a significant twist component. Under the 1 MeV electron irradiation employed for HREM observation, small Xe nanocrystals near a grain boundary may migrate to the boundary and coalesce with other Xe precipitates. The structural observations are rationalized on a simple geometrical interpretation.
Date:
October 23, 1998
Creator:
Allen, C. W.
Object Type:
Article
System:
The UNT Digital Library
University Press (Beaumont, Tex.), Vol. 74, No. 27, Ed. 1 Friday, January 23, 1998
Semiweekly newspaper from Lamar University in Beaumont, Texas that includes local, national, and campus news along with advertising.
Date:
January 23, 1998
Creator:
Andris, Tonya
Object Type:
Newspaper
System:
The Portal to Texas History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Festival of the Arts
Photograph of a scene during the Festival of the Arts, at the Myriad Gardens, with the Oklahoma City Skyline in the background.
Date:
April 23, 1998
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History