Electrochemical Study of Under-Potential Deposition Processes on Transition Metal Surfaces

Electrochemical Study of Under-Potential Deposition Processes on Transition Metal Surfaces

Date: August 2006
Creator: Flores Araujo, Sarah Cecilia
Description: Copper under-potential deposition (UPD) on iridium was studied due to important implications it presents to the semiconductor industry. Copper UPD allows controlled superfilling on sub-micrometer trenches; iridium has characteristics to prevent copper interconnect penetration into the surrounding dielectric. Copper UPD is not favored on iridium oxides but data shows copper over-potential deposition when lower oxidation state Ir oxide is formed. Effect of anions in solution on silver UPD at platinum (Pt) electrodes was studied with the electrochemical quartz crystal microbalance. Silver UPD forms about one monolayer in the three different electrolytes employed. When phosphoric acid is used, silver oxide growth is identified due to presence of low coverage hydrous oxide species at potentials prior to the monolayer oxide region oxide region.
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Mining, Milling, and Smelting Methods, San Manuel Copper Corporation, Pinal County, Arizona

Mining, Milling, and Smelting Methods, San Manuel Copper Corporation, Pinal County, Arizona

Date: 1962
Creator: Dale, Vernon B.
Description: Report issued by the U.S. Bureau of Mines discussing the mining, milling, and smelting practices of copper in Pinal County, Arizona. Physicality, history, geology, methods, and uses are presented. This report includes maps, tables, illustrations, and photographs.
Contributing Partner: UNT Libraries Government Documents Department
ReSource, Volume 15, 2004

ReSource, Volume 15, 2004

Date: 2004
Creator: University of North Texas
Description: ReSource magazine includes articles and notes about research at University of North Texas in various academic fields.
Contributing Partner: University Relations, Communications & Marketing department for UNT
Study of Interactions Between Diffusion Barrier Layers and Low-k Dielectric Materials for Copper/Low-k Integration

Study of Interactions Between Diffusion Barrier Layers and Low-k Dielectric Materials for Copper/Low-k Integration

Date: December 2003
Creator: Tong, Jinhong
Description: The shift to the Cu/low-k interconnect scheme requires the development of diffusion barrier/adhesion promoter materials that provide excellent performance in preventing the diffusion and intermixing of Cu into the adjacent dielectrics. The integration of Cu with low-k materials may decrease RC delays in signal propagation but pose additional problems because such materials are often porous and contain significant amounts of carbon. Therefore barrier metal diffusion into the dielectric and the formation of interfacial carbides and oxides are of significant concern. The objective of the present research is to investigate the fundamental surface interactions between diffusion barriers and various low-k dielectric materials. Two major diffusion barriers¾ tatalum (Ta) and titanium nitride (TiN) are prepared by DC magnetron sputtering and metal-organic chemical vapor deposition (MOCVD), respectively. Surface analytical techniques, such as X-ray photoelectronic spectroscopy (XPS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) are employed. Ta sputter-deposited onto a Si-O-C low dielectric constant substrate forms a reaction layer composed of Ta oxide and TaC. The composition of the reaction layer varies with deposition rate (1 Å-min-1 vs. 2 Å-sec-1), but in both cases, the thickness of the TaC layer is found to be at least 30 Å on the basis of ...
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The Electrodeposition of Zinc

The Electrodeposition of Zinc

Date: August 1939
Creator: Flanagin, Charles E.
Description: This thesis examines the use of zinc for electroplating and compares its use to other metals. Experiments conducted to gather data indicated circumstances which resulted in optimal results.
Contributing Partner: UNT Libraries
Iron and Copper Metabolism of Young College Women on Self-Selected Diets

Iron and Copper Metabolism of Young College Women on Self-Selected Diets

Date: 1947
Creator: Holt, Nora Flowayne
Description: The object of this study is to determine the copper and iron intake in food and the output in the urine and feces of women students living in the Home Management House eating a self-selected diet.
Contributing Partner: UNT Libraries
Synthesis and Characterization of Copper Releasing Polymer Nanoparticles

Synthesis and Characterization of Copper Releasing Polymer Nanoparticles

Date: May 2011
Creator: Harris, Alesha N.
Description: Polymeric nanoparticles were synthesized and loaded with Cu²⁺ to explore the therapeutic potential for catically active transition metal ions and complexes other than cisplatin. Two types of nanoparticles were synthesized to show the potential for polymer based vectors. Copper loading and release were characterized via inductively coupled plasma mass spectrometry (ICP MS), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and elemental analysis. Results demonstrated that Cu could be loaded to the nano-sized carriers in an aqueous environment, and that the release was pH-dependent. The toxicity of these particles was measured in HeLa cells where significant toxicity was observed in vitro via dosing of high Cu-loaded nanoparticles. No significant toxicity was observed in cells dosed with Cu-free nanoparticles.
Contributing Partner: UNT Libraries
Process Evaluation and Characterization of Tungsten Nitride as a Diffusion Barrier for Copper Interconnect Technology

Process Evaluation and Characterization of Tungsten Nitride as a Diffusion Barrier for Copper Interconnect Technology

Date: August 2005
Creator: Ekstrom, Bradley Mitsuharu
Description: The integration of copper (Cu) and dielectric materials has been outlined in the International Technology Roadmap for Semiconductors (ITRS) as a critical goal for future microelectronic devices. A necessity toward achieving this goal is the development of diffusion barriers that resolve the Cu and dielectric incompatibility. The focus of this research examines the potential use of tungsten nitride as a diffusion barrier by characterizing the interfacial properties with Cu and evaluating its process capability for industrial use. Tungsten nitride (β-W2N) development has been carried out using a plasma enhanced chemical vapor deposition (PECVD) technique that utilizes tungsten hexafluoride (WF6), nitrogen (N2), hydrogen (H2), and argon (Ar). Two design of experiments (DOE) were performed to optimize the process with respect to film stoichiometry, resistivity and uniformity across a 200 mm diameter Si wafer. Auger depth profiling showed a 2:1 W:N ratio. X-ray diffraction (XRD) showed a broad peak centered on the β-W2N phase. Film resistivity was 270 mohm-cm and film uniformity < 3 %. The step coverage (film thickness variance) across a structured etched dielectric (SiO2, 0.35 mm, 3:1 aspect ratio) was > 44 %. Secondary ion mass spectroscopy (SIMS) measurements showed good barrier performance for W2N between Cu and SiO2 ...
Contributing Partner: UNT Libraries
Electrodeposition of adherent copper film on unmodified tungsten.

Electrodeposition of adherent copper film on unmodified tungsten.

Access: Use of this item is restricted to the UNT Community.
Date: May 2004
Creator: Wang, Chen
Description: Adherent Cu films were electrodeposited onto polycrystalline W foils from purged solutions of 0.05 M CuSO4 in H2SO4 supporting electrolyte and 0.025 M CuCO3∙Cu(OH)2 in 0.32 M H3BO3 and corresponding HBF4 supporting electrolyte, both at pH = 1. Films were deposited under constant potential conditions at voltages between -0.6 V and -0.2 V vs Ag/AgCl. All films produced by pulses of 10 s duration were visible to the eye, copper colored, and survived a crude test called "the Scotch tape test", which stick the scotch tape on the sample, then peel off the tape and see if the copper film peels off or not. Characterization by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray photon spectroscopy (XPS) confirmed the presence of metallic Cu, with apparent dendritic growth. No sulfur impurity was observable by XPS or EDX. Kinetics measurements indicate that the Cu nucleation process in the sulfuric bath is slower than in the borate bath. In both baths, nucleation kinetics do not correspond to either instantaneous or progressive nucleation. Films deposited from 0.05 M CuSO4/H2SO4 solution at pH > 1 at -0.2 V exhibited poor adhesion and decreased Cu reduction current. In both borate and sulfate baths, small ...
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Leaching Oxidized Copper Ores: Effect of Strength of Acid in Leaching Solvent

Leaching Oxidized Copper Ores: Effect of Strength of Acid in Leaching Solvent

Date: July 1931
Creator: Sullivan, John D.
Description: Report issued by the U.S. Bureau of Mines on the leaching of copper ores. The different strengths and cycles of solvents to extract impurities from the ore are presented. This report includes tables and graphs.
Contributing Partner: UNT Libraries Government Documents Department
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