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in subjects: "contacts"

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Semiconductor detectors with proximity signal readout

Semiconductor-based radiation detectors are routinely used for the detection, imaging, and spectroscopy of x-rays, gamma rays, and charged particles for applications in the areas of nuclear and medical physics, astrophysics, environmental remediation, nuclear nonproliferation, and homeland security. Detectors used for imaging and particle tracking are more complex in that they typically must also measure the location of the radiation interaction in addition to the deposited energy. In such dete… more

Date: January 30, 2014

Creator: Asztalos, Stephen J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Stable Nanocrystalline Au Film Structures for Sliding Electrical Contacts

Hard gold thin films and coatings are widely used in electronics as an effective material to reduce the friction and wear of relatively less expensive electrically conductive materials while simultaneously seeking to provide oxidation resistance and stable sliding electrical contact resistance (ECR). The main focus of this dissertation was to synthesize nanocrystalline Au films with grain structures capable of remaining stable during thermal exposure and under sliding electrical contact stress… more

Date: May 2016

Creator: Mogonye, Jon-Erik

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Determination of the Actual Contact Surface of a Brush Contact

"The number of partial contact surfaces of a brush-ring contact is measured by means of a statistical method. The particular brush is fitted with wicks - that is, insulated and cemented cylinders of brush material, terminating in the brush surface. The number of partial contact surfaces can be computed from the length of the rest periods in which such wicks remain without current" (p. 1).

Date: August 1944

Creator: Holm, Ragnar

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Nanoparticle derived contacts for photovoltaic cells

Contacts are becoming increasingly important as PV devices move to higher efficiency and lower cost. The authors present an approach to developing contacts using nanoparticle-based precursors. Both elemental, alloy and compound nanoparticles can be employed for contacts. Ink based approaches can be utilized at low temperatures and utilize direct write techniques such as ink jet and screen printing. The ability to control the composition of the nanoparticle allows improved control of the contact… more

Date: October 20, 1999

Creator: Ginley, D.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ink Jet Printing Approaches to Solar Cell Contacts

We are developing inkjet printing as a low cost, high through-put approach to the deposition of front contacts for Si solar cells. High deposition rates of 1m per printing pass were achieved with a new metalorganic ink composed of silver (trifluoroacetate) in ethylene glycol. The printing conditions were optimized to achieve a relatively high line resolution of 120 m. The optimal parameters for the piezoelectric inkjet were a pulse frequency of 50 Hz and pulse amplitude of 25 V. The best resolu… more

Date: May 1, 2003

Creator: Kaydanova, T.; Miedaner, A.; Curtis, C.; Perkins, J.; Alleman, J. & Ginley, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Determination of the Built-in Electric Field near Contacts to Polycrystalline CuInSe{sub 2} - Probing Local Charge Transport Properties by Photomixing

The built-in electric field in polycrystalline CuInSe{sub 2} (CIS) near gold co-planar contacts was quantitatively revealed for the first time by the photomixing technique. A He-Ne laser beam was focused locally on the CIS sample near one of its contact. While both dc dark and photo-currents showed ohmic behavior, the high frequency ac current was non-zero for zero applied dc bias, which reveals a built-in electric field of {approx}1000V/cm. The capability of the photomixing technique to probe … more

Date: November 19, 1998

Creator: Tang, Y.; Dong, S.; Sun, G. S.; Braunstein, R. & von Roedern, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Intermixing and chemical structure at the interface between n-GaN and V-based contacts

The interface between n-type GaN and V-based contacts was characterized by soft x-ray spectroscopy. We have investigated the chemical interface structure before and after a rapid thermal annealing (RTA) step, which is crucial for the formation of an Ohmic contact. X-ray photoelectron and x-ray excited Auger electron spectra suggestthat RTA induces an accumulation of metallic Ga at the surface. Using x-ray emission spectroscopy, we find that the probed nitrogen atoms are in a VN-like environment… more

Date: June 30, 2008

Creator: Pookpanratana, S.; France, R.; Bar, M.; Weinhardt, L.; Fuchs, O.; Blum, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Magnetoconductance of Independently Tunable Tunnel-Coupled Double Quantum Wires

The authors report on their recent experimental studies of vertically-coupled quantum point contacts subject to in-plane magnetic fields. Using a novel flip-chip technique, mutually aligned split gates on both sides of a sub micron thick double quantum well heterostructure define a closely-coupled pair of ballistic one-dimensional (1D) constrictions. They observe quantized conductance steps due to each quantum well and demonstrate independent control of each ID constriction width. In addition, … more

Date: July 13, 2000

Creator: Blount, Mark A.; Moon, J. S.; Simmons, Jerry A.; Lyo, Sungkwun K.; Wendt, Joel R. & Reno, John L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Carrier photodynamics in 2D perovskites with solution-processed silver and graphene contacts for bendable optoelectronics

Article reporting on the inkjet printed, direct contact study of solution-processed, 2D perovskite-based photodetectors (PDs) formed on flexible PI substrates. Silver (Ag) and graphene (Gr) inks have been engineered to serve as efficient electrical contacts for solution-processed two-dimensional (2D) organo-halide (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 (n = 4) layered perovskites, where all inkjet-printed heterostructure PDs were fabricated on polyimide (PI) substrates.

Date: March 25, 2021

Creator: Hossain, Ridwan F.; Min, Misook; Ma, Liang-Chieh; Sakri, Shambhavi R. & Kaul, Anupama

Item Type: Article

Partner: UNT College of Engineering

open access

Multi-Layer Inkjet Printed Contacts for Si Solar Cells (Poster)

The objective of this report is to develop inkjet printing (including tools, inks, and processing conditions) for high-quality Ag contacts for Si solar cells. The conclusions are: (1) Tools and inks for the atmospheric inkjet printing of Ag metallization for Si solar cells have been developed. (2) Line widths, conductivities and thicknesses comparable to, or better than, those produced by screen printing. (3) A new fire-through ink and layered printing were found to decrease the processing temp… more

Date: May 1, 2006

Creator: Curtis, C. J.; van hest, M. F. A. M.; Miedaner, A.; Kaydanova, T.; Smith, L. & Ginley, D. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Copper electroplating process for sub-half-micron ULSI structures

We have utilized electroplating technology in a damascene process to produce low resistance copper interconnects in sub-half-micron ULSI patterns having aspect ratios of 2.4:1. The use of a pulsed-voltage plating technique allows trench filling capability without voids. Samples of 150 mm diameter were patterned and sputtered with a barrier layer, followed by a copper seed layer. Pulsed-voltage electroplating, deposited about 2 microns of copper uniformly (1 sigma < 5%) over the surface. The ele… more

Date: May 15, 1995

Creator: Contolini, Robert J.; Tarte, Lisa; Graff, Robert T.; Evans, Leland B.; Cox, J. Neal; Puich, Marc et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The Onset of Pileup in Nanometer-Scale Contacts

The interfacial force microscope (IFM) was used to indent and image defect free Au(111) surfaces, providing atomic-scale observations of the onset of pileup and the excursion of material above the initial surface plane. Images and load-displacement measurements demonstrate that elastic accommodation of an indenter is followed by two stages of plasticity. The initial stage is identified by slight deviations of the load-displacement relationship from the predicted elastic response. Images acquire… more

Date: January 18, 2000

Creator: Jarausch, K. F.; Kiely, J. D.; Houston, Jack E. & Russell, P. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Doped Contacts for High-Longevity Optically Activated, High Gain GaAs Photoconductive Semiconductor Switches

The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer that is very effective in the suppression of filament formation, alleviating current crowding. Damage-free operation is now possible with virtually infinite expected lifetime at much higher current levels than before. The inherent damage-free current capacity of the bulk GaAs itsel… more

Date: December 17, 1999

Creator: Mar,Alan; Loubriel,Guillermo M.; Zutavern,Fred J.; O'Malley,Martin W.; Helgeson,Wesley D.; Brown,Darwin James et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

[Contact information for the Lone Star Ride steering committee]

Contact information for the Lone Star Ride steering committee, and the comparison report for May - June.

Date: 2006

Creator: Lone Star Ride

Item Type: Text

Partner: UNT Libraries Special Collections

open access

Effects of pre-stressing and flux on the flow of solder on PWB copper surfaces

A variety of test methods are available to evaluate the solderability of printed wiring board [PWB] surface finishes. A new test has been developed which better simulates the capillary flow physics of typical solder assembly processing, especially surface mount soldering. The work was conducted under a cooperative research and development agreement between Sandia National Laboratories, the National Center for Manufacturing Sciences, and several PWB fabricators (AT&T, IBM, Texas Instruments, and… more

Date: December 31, 1994

Creator: Hernandez, C. L. & Hosking, F. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Longevity Improvement of Optically Activated, High Gain GaAs Photoconductive Semiconductor Switches

The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses at 23A, and over 100 pulses at 1kA. This is achieved by improving the ohmic contacts by doping the semi-insulating GaAs underneath the metal, and by achieving a more uniform distribution of contact wear across the entire switch by distributing the trigger light to form multiple filaments. This paper will compare various approaches to doping the contacts, including ion impla… more

Date: March 2, 2000

Creator: Mar,Alan; Loubriel,Guillermo M.; Zutavern,Fred J.; O'Malley,Martin W.; Helgeson,Wesley D.; Brown,Darwin James et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Micromachined VLSI 3D electronics. Final report for period September 1, 2000 - March 31, 2001

The phase I program investigated the construction of electronic interconnections through the thickness of a silicon wafer. The novel aspects of the technology are that the length-to-width ratio of the channels is as high as 100:1, so that the minimum amount of real estate is used for contact area. Constructing a large array of these through-wafer interconnections will enable two circuit die to be coupled on opposite sides of a silicon circuit board providing high speed connection between the tw… more

Date: March 31, 2001

Creator: Beetz, C.P.; Steinbeck, J. & Hsueh, K.L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A hardware review of electrical contact aging and performance in electromechanical stronglinks

Contacts from the functional switch assembly have been examined for a series of MC2969 stronglinks varying from 9 to 14 years of age. Wear tracks are apparent on the contacts as a result of oxide removal by wiping action as the switch is exercised. Typical contaminants observed on the contacts include C, O, S, Cl, F and Si, all of which vary with position on the contacts. All of the contacts show segregation of Ag into the near-surface region. Measurement of the local contact resistance on the … more

Date: September 1, 1997

Creator: Pebbles, D. E.; Ohlhausen, J. A.; Varga, K. S. & Bryan, R. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Low Resistivity Ohmic Contacts to Moderately Doped N-Gaas With Low Temperature Processing

A low-temperature process for forming ohmic contacts to moderately doped GaAs has been optimized using a PdGe metallization scheme. Minimum specific contact resistivity of 1.5 {times} 10{sup {minus}6} {minus}cm{sup 2} has been obtained with a low anneal temperature of 250 C. Results for optimizing both time and temperature are reported and compared to GeAu n-GaAs contacts. Material compositions was analyzed by x-ray photoelectron spectroscopy and circuit metal interconnect contact resisitivity … more

Date: December 31, 1994

Creator: Lovejoy, M. L.; Howard, A. J.; Zavadil, K. R.; Rieger, D. J.; Shul, R. J. & Barnes, P. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Highlights of the DARPA eletrically conductive adhesive FCA project. Quarterly report, April 1, 1996--June 30, 1996

The accomplishments are broken down into three different categories: materials development (polymer metal composite with increased bond strength), process development (reliability testing, bonding optimization evaluation, testing of bulk conductive adhesives, paste deposition process development), and equipment development (laboratory bonding equipment, cost estimation for flip chip attach methods).

Date: June 30, 1996

Creator: Saraf, R.; Roldan, J.; Sambucetti, C.; Gaynes, M.; Woychik, C. & Snyder, M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Multi-Layer Inkjet Printed Contacts for Silicon Solar Cells: Preprint

Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. The approach developed can be easily extended to other conductors such as Pt, Pd, Au, etc. Thick highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and printed circuit board (PCB) have been printed at 100-200 C in air and N2 respectively. Ag grids were inkjet-printed on Si solar cells and fired through the silicon nitride AR layer at 850 C, resulting in 8% cells. Next generation in… more

Date: May 1, 2006

Creator: Curtis, C. J.; van hest, M.; Miedaner, A.; Kaydanova, T.; Smith, L. & Ginley, D. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The influence of grain structure on the reliability of narrow Al- based interconnects

The work reported here concerns the effect of grain structure on electromigration failure in pure A1 and A1-2wt.% Cu-1 wt.% Si lines. The grain structure of fine lines were controlled by annealing after pattering to promote the formation of ``bamboo`` structures. Significant improvements in the median time to failure (MTF) and the deviation of the time to failure (DTF) were observed with the development of near-bamboo structures with polygranular-segment lengths shorter than {approximately} 5 {… more

Date: May 1, 1995

Creator: Kang, S.H.; Kim, C.l Morris, J.W. Jr. & Genin, F.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanism of electromigration failure in Al thin film interconnects containing Sc

In order to understand the role of Sc on electromigration (EM) failure, Al interconnects with 0.1 and 0.3 wt.% Sc sere tested as a function of post-pattern annealing time. In response to the evolution of the line structure, the statistics of lifetime evolved. While the addition of Sc greatly reduces the rate of evolution of the failure statistics because the grain growth rate decreases, the MTF variation was found to be very similar to that of pure Al. These observations seem to show that Sc ha… more

Date: May 1, 1995

Creator: Kim, Choong-un; Kang, S.H.; Morris, J.W. Jr. & Genin, F.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Doped Contacts for High-Longevity Optically Activated, High Gain GaAs Photoconductive Semiconductor Switches

The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 50 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer beneath the PCSS contacts which is very effective in the suppression of filament formation and alleviating current crowding to improve the longevity of PCSS. Virtually indefinite, damage-free operation is now possible at much higher current levels than before. The inherent damage-fr… more

Date: August 5, 1999

Creator: Baca, A. G.; Brown, D. J.; Donaldson, R. D.; Helgeson, W. D.; Hjalmarson, H. P.; Loubriel, G. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department