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Study of Gate Electrode Materials on High K Dielectrics

Description: This problem in lieu of thesis report presents a study on gate electrode materials on high K dielectrics, including poly-SiGe and Ru. The stability of poly-SiGe in direct contact with Hf silicon-oxynitride (HfSiON) is studied by rapid thermal annealing (RTA), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). By performing a series of RTA treatments we found that as RTA thermal budgets reach 1050 C for 30s, the poly-SiGe layer begins to intermix with the HfSiON film, as observed by TEM. The maximum annealing condition for the Hf0.14Si0.23O0.46N0.17 film to remain stable in contact with poly-SiGe is 1050 C for 20s in high purity N2(99.9%) ambient. We also found that after 1000 C annealing for 60s in a nitrogen ambient, the poly-SiGe crystal phase structure was changed from a columnar structure to a large grain structure. For a metal gate, Ru was studied to determine N2annealing effects on sheet resistance of Ru sample electrodes and electrical characterization of Ru/HfSiOx/Si stack. Results show that a pure Ru metal gate is not a good choice for high k materials since it is hard to etch off, and different annealing conditions can cause large changes in the electrical behavior.
Date: August 2003
Creator: Yao, Chun
Partner: UNT Libraries

The Metal-Dielectric Junction of High-Voltage Insulators in Vacuum and Magnetic Field

Description: From introduction: "This study is concerned with the shape of the electrodes of high-voltage insulator and with the method of joining them to the dielectric. The study is limited to insulators operating in vacuum, with special interest in the cases where strong magnetic fields are present. It is further limited to insulators with the high-voltage electrodes maintained at negative potential. The object of the study was to obtain information that would aid in improving the design of the insulators in two respects. First, to decrease to a minimum the number of charged particles set free which may directly or indirectly cause early failure of the insulator. Second, to increase the voltages at which partial or complete flashovers occur. Therefore, experiments were made to determine the principal phenomenon which have as their primary source the insulator under high electrical stress in vacuum."
Date: August 8, 1945
Creator: Kjofoid, M. J.; Alger, Raymond S. & Graves, D.
Partner: UNT Libraries Government Documents Department

Materials properties of hafnium and zirconium silicates: Metal interdiffusion and dopant penetration studies.

Description: Hafnium and Zirconium based gate dielectrics are considered potential candidates to replace SiO2 or SiON as the gate dielectric in CMOS processing. Furthermore, the addition of nitrogen into this pseudo-binary alloy has been shown to improve their thermal stability, electrical properties, and reduce dopant penetration. Because CMOS processing requires high temperature anneals (up to 1050 °C), it is important to understand the diffusion properties of any metal associated with the gate dielectric in silicon at these temperatures. In addition, dopant penetration from the doped polysilicon gate into the Si channel at these temperatures must also be studied. Impurity outdiffusion (Hf, Zr) from the dielectric, or dopant (B, As, P) penetration through the dielectric into the channel region would likely result in deleterious effects upon the carrier mobility. In this dissertation extensive thermal stability studies of alternate gate dielectric candidates ZrSixOy and HfSixOy are presented. Dopant penetration studies from doped-polysilicon through HfSixOy and HfSixOyNz are also presented. Rutherford backscattering spectroscopy (RBS), heavy ion RBS (HI-RBS), x-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM), and time of flight and dynamic secondary ion mass spectroscopy (ToF-SIMS, D-SIMS) methods were used to characterize these materials. The dopant diffusivity is calculated by modeling of the dopant profiles in the Si substrate. In this disseration is reported that Hf silicate films are more stable than Zr silicate films, from the metal interdiffusion point of view. On the other hand, dopant (B, As, and P) penetration is observed for HfSixOy films. However, the addition of nitrogen to the Hf - Si - O systems improves the dopant penetration properties of the resulting HfSixOyNz films.
Date: August 2002
Creator: Quevedo-Lopez, Manuel Angel
Partner: UNT Libraries

Design and Manufacture of Molding Compounds for High Reliability Microelectronics in Extreme Conditions

Description: The widespread use of electronics in more avenues of consumer use is increasing. Applications range from medical instrumentation that directly can affect someone's life, down hole sensors for oil and gas, aerospace, aeronautics, and automotive electronics. The increased power density and harsh environment makes the reliability of the packaging a vital part of the reliability of the device. The increased importance of analog devices in these applications, their high voltage and high temperature resilience is resulting in challenges that have not been dealt with before. In particular packaging where insulative properties are vital use polymer resins modified by ceramic fillers. The distinct dielectric properties of the resin and the filler result in charge storage and release of the polarization currents in the composite that have had unpredictable consequences on reliability. The objective of this effort is therefore to investigate a technique that can be used to measure the polarization in filled polymer resins and evaluate reliable molding compounds. A valuable approach to measure polarization in polymers where charge release is tied to the glass transition in the polymer is referred to as thermally stimulated depolarization current (TSDC) technique. In this dissertation a new TSDC measurement system was designed and fabricated. The instrument is an assembly of several components that are automated via a LabVIEW program that gives the user flexibility to test different dielectric compounds at high temperatures and high voltage. The temperature control is enabled through the use of dry air convection heating at a very slow rate enabling controlled heating and cooling. Charge trapping and de-trapping processes were investigated in order to obtain information on insulating polymeric composites and how to optimize it. A number of material properties were investigated. First, polarization due to charges on the filer were investigated using composites containing charged and uncharged particles using ...
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Date: December 2016
Creator: Garcia, Andres
Partner: UNT Libraries

Influence of Gamma Irradiation on RG 8/U Cable

Description: Abstract: "Static measurements have been made of the currents produced by Co-60 gamma irradiation of solid dielectric RG 8/U cable. Sensitivity curves are presented as a function of the magnitude and polarity of the collection voltage to 90 volts. It is shown that the current is due to a polarity- and voltage-sensitive ionization component and to a polarity- and voltage-insensitive component attributed to the Compton process. The total cable sensitivity at -90 volts, with saturation not achieved, was (11 +/- 1) x 10-(-12) coulomb per roentgen-meter of cable, or 0.08 percent of what one would expect from ionization in an air dielectric cable of this volume."
Date: November 1955
Creator: Kloepper, Robert M.
Partner: UNT Libraries Government Documents Department

Spectroscopic and Physical Effects of Highly Polar Groups

Description: Since the development of the understanding that the electron distribution within a molecule is chiefly responsible for its properties and behavior, factors influencing this charge distribution have been of interest to scientists. The chemical reactivity of a molecule, the physical properties, and to a large extent, structure and geometry, are all functions of the electron distribution. This study examines the issue of electronic structure from two points of view, each of them focussing on a specific component within the molecules studied. In the present work, the effects of the highly polar carbonyl group on spectroscopic parameters and physical behavior are investigated. An additional area of study is the effect of fluorine substitution on the energy levels of some halogenated ethylenes. The specific parameters examined are the ionization potentials, the absorption frequencies, and the energies of a class of excited states known as molecular Rydberg states. It was during the study of these halogenated ethylenes that the observations leading to the carbonyl compound investigations were made, so that the two areas examined are connected both experimentally and chemically.
Date: December 1981
Creator: Schander, Judith Turner
Partner: UNT Libraries

Characterizaton of Triethoxyfluorosilane and Tetraethoxysilane Based Aerogels

Description: Aerogels are highly porous, low dielectric constant (low k) materials being considered by the semiconductor industry as an interlayer dielectric. Low k materials are needed to overcome capacitance problems that limit device feature sizes. Precursors triethoxyfluorosilane (TEFS) and tetraethoxysilane (TEOS) were used to prepare bulk aerogels. Samples were prepared by sol-gel methods, and then carbon dioxide supercritically-dried. Effects of varying the water to precursor ratio were studied with respect to aerogel properties and microstructure. Methods of analysis for this study include FTIR-ATR, TEM, RBS, EDS, SEM, dielectric constant determination by impedance and surface area by gas adsorption. Si-F bonds were determined to be present in both acid- and base-catalyzed TEFS as well as HF-catalyzed TEOS. Fluorine promotes a fractal network microstructure as opposed to a particle-like microstructure. Surface area and dielectric constant were determined to increase slightly with increases in the water to precursor ratio.
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Date: December 2001
Creator: Roepsch, Jodi Ann
Partner: UNT Libraries

A test protocol to screen capacitors for radiation-induced charge loss.

Description: This report presents a test protocol for screening capacitors dielectrics for charge loss due to ionizing radiation. The test protocol minimizes experimental error and provides a test method that allows comparisons of different dielectric types if exposed to the same environment and if the same experimental technique is used. The test acceptance or screening method is fully described in this report. A discussion of technical issues and possible errors and uncertainties is included in this report also.
Date: September 1, 2008
Creator: Zarick, Thomas Andrew & Hartman, E. Frederick
Partner: UNT Libraries Government Documents Department

Separation and concentration of water-borne contaminants utilizing insulator-based dielectrophoresis.

Description: This report focuses on and presents the capabilities of insulator-based dielectrophoresis (iDEP) microdevices for the concentration and removal of water-borne bacteria, spores and inert particles. The dielectrophoretic behavior exhibited by the different particles of interest (both biological and inert) in each of these systems was observed to be a function of both the applied electric field and the characteristics of the particle, such as size, shape, and conductivity. The results obtained illustrate the potential of glass and polymer-based iDEP devices to act as a concentrator for a front-end device with significant homeland security and industrial applications for the threat analysis of bacteria, spores, and viruses. We observed that the polymeric devices exhibit the same iDEP behavior and efficacy in the field of use as their glass counterparts, but with the added benefit of being easily mass fabricated and developed in a variety of multi-scale formats that will allow for the realization of a truly high-throughput device. These results also demonstrate that the operating characteristics of the device can be tailored through the device fabrication technique utilized and the magnitude of the electric field gradient created within the insulating structures. We have developed systems capable of handling numerous flow rates and sample volume requirements, and have produced a deployable system suitable for use in any laboratory, industrial, or clinical setting.
Date: January 1, 2006
Creator: Lapizco-Encinas, Blanca Hazalia; Fiechtner, Gregory J.; Cummings, Eric B.; Davalos, Rafael V.; Kanouff, Michael P.; Simmons, Blake Alexander et al.
Partner: UNT Libraries Government Documents Department


Description: The perturbation metheds used to obtain a relative plot of the electric field and the value of R/Q are described. A method involving radial pulling of dielectric and metallic beads is proposed for the R/Q measurement. The experimental data are shown to agree with the previously presented theoretical predictions. (D.C.W.)
Date: August 22, 1963
Creator: Hahn, H. & Halama, H.J.
Partner: UNT Libraries Government Documents Department


Description: Design criteria and operating experience with the aluminum oxide bearing and journal combination as installed in canned rotor pumps in in-pile loops are described. No pump failures occurred in 8 pumps with A1/sub 2/0/sub 3/ bearings over a cumulative period of l0,000 hours due to wear or corrosion. Five failures due to slippage and/or electrical breakdown of the stator insulation are reported. (T.R.H.)
Date: November 26, 1957
Creator: Savage, H.C.
Partner: UNT Libraries Government Documents Department


Description: Progress is briefly reported on studies in dielectric spectros copy, magnetic resonance, high-field-strength research, ferroelectrics and ferromagnetics, semiconductors, single crystals, and ceramics. (T.R.R.)
Date: June 1, 1958
Partner: UNT Libraries Government Documents Department


Description: The basic theory of operation of the triggered spark gap is established, and qualitative and quantitative engineering design data are given. From the basic twoelectrode gap, a three-electrode or triggered gap model is established with its static and dynamic triggering characteristics shown. Several geometry conditions such as gap spacings trigger electrode hole sizes and insulator effects are discussed, showing their influence upon the triggering mechanism. A suggested trigger mechanism is given based on that proposed by Sletten and Lewis for the trigatron and modified to fit the present analysis. (auth)
Date: May 22, 1959
Creator: Williams, T.J.
Partner: UNT Libraries Government Documents Department


Description: Concepts of metallizing dielectric surfaces by copper re duction or immersion deposition are discussed. Step-bystep processing techniques for producing quality platedthrough connections are described. A description of the tests performed on the plated-through connections is given (C.J.G.)
Date: April 1, 1960
Creator: Voida, G. & Eich, N.J.
Partner: UNT Libraries Government Documents Department

The Optical Properties and Complex Dielectric Function of Metallic Aluminum from 0. 04 to 10⁴ eV

Description: Measurements of the optical properties of metallic aluminum are reviewed and available data are analyzed to obtain the bulk values of the optical constants and the complex dielectric function from 0.04 eV to 10 keV. The intra- and interband contributions to the dielectric function are discussed briefly, and recently proposed values for the Drude parameters describing the intraband absorption are critically considered. Factors influencing experimental measurements are discussed with emphasis on sample properties such as surface oxide layers, bulk inclusion of gases, surface roughness, and degree of crystallinity. The results of recent optical measurements are tabulated, along with recommended values of the optical properties resulting from a self-consistent Kramers-Kronig analysis of reflectance, transmission, and electron-energy-loss studies. The tabular data include the complex dielectric function, the complex index of refraction, and the reflectance and phase shift for normal incidence on a smooth, oxide-free surface. Detailed tabulations are given for the infrared, visible, and ultraviolet regions of the spectrum.
Date: March 1983
Creator: Smith, D. Y.; Shiles, E. & Inokuti, Mitio
Partner: UNT Libraries Government Documents Department

Evaluation of hydrogen trapping in HfO2 high-κ dielectric thin films.

Description: Hafnium based high-κ dielectrics are considered potential candidates to replace SiO2 or SiON as the gate dielectric in complementary metal oxide semiconductor (CMOS) devices. Hydrogen is one of the most significant elements in semiconductor technology because of its pervasiveness in various deposition and optimization processes of electronic structures. Therefore, it is important to understand the properties and behavior of hydrogen in semiconductors with the final aim of controlling and using hydrogen to improve electronic performance of electronic structures. Trap transformations under annealing treatments in hydrogen ambient normally involve passivation of traps at thermal SiO2/Si interfaces by hydrogen. High-κ dielectric films are believed to exhibit significantly higher charge trapping affinity than SiO2. In this thesis, study of hydrogen trapping in alternate gate dielectric candidates such as HfO2 during annealing in hydrogen ambient is presented. Rutherford backscattering spectroscopy (RBS), elastic recoil detection analysis (ERDA) and nuclear reaction analysis (NRA) were used to characterize these thin dielectric materials. It was demonstrated that hydrogen trapping in bulk HfO2 is significantly reduced for pre-oxidized HfO2 prior to forming gas anneals. This strong dependence on oxygen pre-processing is believed to be due to oxygen vacancies/deficiencies and hydrogen-carbon impurity complexes that originate from organic precursors used in chemical vapor depositions (CVD) of these dielectrics.
Access: This item is restricted to the UNT Community Members at a UNT Libraries Location.
Date: August 2006
Creator: Ukirde, Vaishali
Partner: UNT Libraries

The Interactions of Plasma with Low-k Dielectrics: Fundamental Damage and Protection Mechanisms

Description: Nanoporous low-k dielectrics are used for integrated circuit interconnects to reduce the propagation delays, and cross talk noise between metal wires as an alternative material for SiO2. These materials, typically organosilicate glass (OSG) films, are exposed to oxygen plasmas during photoresist stripping and related processes which substantially damage the film by abstracting carbon, incorporating O and OH, eventually leading to significantly increased k values. Systematic studies have been performed to understand the oxygen plasma-induced damage mechanisms on different low-k OSG films of various porosity and pore interconnectedness. Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and atomic force microscopy are used to understand the damage kinetics of O radicals, ultraviolet photons and charged species, and possible ways to control the carbon loss from the film. FTIR results demonstrate that O radical present in the plasma is primarily responsible for carbon abstraction and this is governed by diffusion mechanism involving interconnected film nanopores. The loss of carbon from the film can be controlled by closing the pore interconnections, He plasma pretreatment is an effective way to control the damage at longer exposure by closing the connections between the pores.
Date: August 2011
Creator: Behera, Swayambhu Prasad
Partner: UNT Libraries