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Articles 25261 - 25290 of 27367

Full-Text Articles in Engineering

Varying Current Electro-Synthesis Of Glyoxalic Acid In Pairs In The Fixed-Bed Electrolytic Cell, Yin-Sheng Chen, Xin-Sheng Zhang, Ying-Chun Dai, Wei-Kang Yuan Feb 2002

Varying Current Electro-Synthesis Of Glyoxalic Acid In Pairs In The Fixed-Bed Electrolytic Cell, Yin-Sheng Chen, Xin-Sheng Zhang, Ying-Chun Dai, Wei-Kang Yuan

Journal of Electrochemistry

As for the process of the electro oxidation of glyoxal to glyoxalic acid, the electrolytic result of either fixed bed electrolytic cell or varying current electrolysis was better than that of either flat plate electrolytic cell or constant current electrolysis. The average current density of varying current electro synthesis of glyoxalic acid in pairs was 1535 A/m2 and the current efficiency were 85.3% and 86.7% and the selectivity were 93.9% and 94.0% for the anodic oxidation and cathodal reduction respectively. The initial composition of anodic electrolyte was 7% glyoxal and 8% hydrochloric acid (W/W) and the cathodal electrolyte consisted …

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Electrochemical Synthesis And Characterization Of The Nickel Electropolyurushiol Coordination Polymer, Feng Gao, Guo-Cai Shen, Jie-Yuan Tang, Wen-Gong Zhang Feb 2002

Electrochemical Synthesis And Characterization Of The Nickel Electropolyurushiol Coordination Polymer, Feng Gao, Guo-Cai Shen, Jie-Yuan Tang, Wen-Gong Zhang

Journal of Electrochemistry

The nickel electropolyurushiol coordination polymer (EPU Ni2+) was obtained by the reaction between nickel chloride isopropyl alcohol solution with electropolyurushiol (EPU). The electrochemical polymerization of urushiol and the preparation of nickel electropolyurushiol coordination polymer were investigated. The coordination polymer was characterized by XPS, FT-IR, DMTA and AES methods, and its composition and structure were determined.The content of Ni2+ reached up to 7.5%. It was shown that there was certain coordination between Ni2+ and electropolyurushiol in the coordination polymer, thus cross-inks were formed. Therefore the glass transition temperature of the coordination polymer increased and heat resistance was …

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Electrosynthesis Of Glyoxylic Acid In A Packed Bed Reactor, Jin-Hong Fan, Jun Li, Yu-Zhong Su, Hao-Qi Gao Feb 2002

Electrosynthesis Of Glyoxylic Acid In A Packed Bed Reactor, Jin-Hong Fan, Jun Li, Yu-Zhong Su, Hao-Qi Gao

Journal of Electrochemistry

Glyoxylic acid was produced by electroreduction of oxalic acid in a packed bed reator. The cathodic and anodic electrolytes were super-saturated oxalic and hydrochloric acid aqueous solutions separated by a super-acid ion-exchange membrane. The current efficiency and yield of glyoxylic acid were studied under different structured packed bed reactors and different electrode materials, temperatures and current densities. The results indicated that the current efficiency of synthsis of glyoxylic acid was over 66.2% and the concentration of glyoxylic acid could reach 2.02% after 45min electrolysis with cathode of lead particles and anode of graphite board under conditions of temperature 32 ℃, …

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Further Evidence For Surface Properties Of Porous Silicon Resulting In Electroluminescence, Zhan-Jun Zhang, Bin Wu, Jing-Jian Li, Zhong-Fan Liu, Sheng-Min Cai Feb 2002

Further Evidence For Surface Properties Of Porous Silicon Resulting In Electroluminescence, Zhan-Jun Zhang, Bin Wu, Jing-Jian Li, Zhong-Fan Liu, Sheng-Min Cai

Journal of Electrochemistry

The electroluminescence of porous silicon in solutions at positive biases was investigated by luminescence spectrometer. The electroluminescence of porous silicon in solutions mainly depended on its surface properties. The elelctroluminescence was much enhanced when the sample of porous silicon was electrolyzed once again which had undergone an electroluminescence test. The tests of both cyclic voltammetry and the luminescence of the sample of porous silicon prepared by repeated electrolysis provided further evidence that the electroluminescence of porous silicon in solutions at positive biases stemmed from the oxidation of Si-H on the surface of porous silicon. The voltage tunable emitting for porous …

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An Investigation Of Inhibition Mechanism Of Cerium For Aluminum Alloy 2024-T3, Min-Hua Shao, Yan Fu, Rong-Gang Hu, Chang-Jian Lin Feb 2002

An Investigation Of Inhibition Mechanism Of Cerium For Aluminum Alloy 2024-T3, Min-Hua Shao, Yan Fu, Rong-Gang Hu, Chang-Jian Lin

Journal of Electrochemistry

Cerium compounds are promising inhibitors for aluminum alloy. However, the inhibition mechanism is not very clear. Scanning microreference electrode (SMRE) technique was used to probe the potential imaging of Al 2024 T3 in NaCl and CeCl3 solution. The results of SMRE showed that in NaCl solution a severe localized corrosion occurred on the surface of Al 2024 specimen at once and maintained for a long time. The corrosion activity of Al alloy in CeCl3 decreased with immersion time and disappeared finally. Additionally, the competition of inhibition and aggression between Ce3+ and Cl- on Al alloy was …

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Photoelectrochemistry Of La3+ Doped Semiconductor Porous Films Sensitized By Ru(Bpy)2(Ncs)2 Dye, Li Zhang, Yan-Jie Ren, Sheng-Min Cai Feb 2002

Photoelectrochemistry Of La3+ Doped Semiconductor Porous Films Sensitized By Ru(Bpy)2(Ncs)2 Dye, Li Zhang, Yan-Jie Ren, Sheng-Min Cai

Journal of Electrochemistry

The La3+-doped TiO2 nanoparticles were prepared with hydrothermal method.The photoelectrochemical properties of La3+-doped TiO2 nanoporous-film electrode sensitized by Ru(bpy)2(NCS)2 were studied. The conversion efficiency of light to electricity and the energy conversion efficiencies were ineased with the depth of La3+-doped TiO2 nanoporous-film electrode.

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Study On The Orthogonal Test Of Al-Substituted α-Ni(Oh)2 Prepared By Complexation-Precipitation Method, Hui Chen, Jian-Ming Wang, Tao Pan, Hui-Ming Xiao, Jian-Qing Zhang Feb 2002

Study On The Orthogonal Test Of Al-Substituted α-Ni(Oh)2 Prepared By Complexation-Precipitation Method, Hui Chen, Jian-Ming Wang, Tao Pan, Hui-Ming Xiao, Jian-Qing Zhang

Journal of Electrochemistry

Al-substituted α-Ni(OH)2 was prepared by a complexation-precipitation method and characterized by XRD.The electrochemical performance was tested by the charge-discharge method. The experimental results of orthogonal test showed that the effect order of some key preparative conditions on the electrochemical performance of Al-substituted α-Ni(OH)2 was the concentration of aqueous ammonia, the content of aluminum and pH value.The optimum prepareative conditions for obtaining the sample with maximum specific discharge capacity (304 mAh·g-1) were 0.5 mol·L-1 aqueous ammonia, 15 mol% Al content and pH 11.0.

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Uncertainty In Determination Of Hydrogen Diffusion Coefficient In Metal Hydride Electrode Based On The Transition Region Of Diffusion-Controlled Impedance, Xian-Xia Yuan, Nai-Xin Xu Feb 2002

Uncertainty In Determination Of Hydrogen Diffusion Coefficient In Metal Hydride Electrode Based On The Transition Region Of Diffusion-Controlled Impedance, Xian-Xia Yuan, Nai-Xin Xu

Journal of Electrochemistry

Hydrogen diffusion coefficient in MlNi3.75Co0.65 Mn0.4Al0.2 metal hydride electrode has been determined with transition region of diffusion-controlled impedance. Multiple solutions were obtained at each data point because of the periodic characteristic of some functions used in the calculation, and the maximum difference between the solutions reached several orders of magnitude. On the other hand, the solutions varied for different data points in the transition region of diffusion-controlled impedance of the same experimental plot. It could be concluded that this method is not so well defined and some modification is required.

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The Determination Of The Best Modified Way And Microscopical Analysis For Enzyme/Immunoelectrodes, Sa-Ying Dong, Hong-Ren Wang, Yu-Zhu Gao, Guang-Zhang Chen, Ming-Xiang Lv, Bo-Yi Tian Feb 2002

The Determination Of The Best Modified Way And Microscopical Analysis For Enzyme/Immunoelectrodes, Sa-Ying Dong, Hong-Ren Wang, Yu-Zhu Gao, Guang-Zhang Chen, Ming-Xiang Lv, Bo-Yi Tian

Journal of Electrochemistry

In this paper, the electrochemical response characteristics of enzyme and immuno electrodes were studied by cyclic voltammetry under different conditions. Our goals were to determine the best modified way of bioelectrode, which was the base of biosensor's application. 30U GOD and 0.8 mg/mL SEC1 antibody were suitable to bioelectrode preparation and detection. The microscopical analysis was finished with scan microscopy.

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Preliminary Study On Direct Ethanol Fuel Cell, Shu-Qin Song, Li-Kang Chen, Jian-Guo Liu, Zhao-Bin Wei, Qin Xin Feb 2002

Preliminary Study On Direct Ethanol Fuel Cell, Shu-Qin Song, Li-Kang Chen, Jian-Guo Liu, Zhao-Bin Wei, Qin Xin

Journal of Electrochemistry

The performance of a direct ethanol fuel cell based on Nafion115 was reported.PtRu/C and Pt/C were used as ethanol anode and oxygen cathode catalysts in a single cell of size 9 cm2 .The effects of temperature, oxygen pressure, the flow rate of ethanol, and oxygen, and ethanol concentration were tentatively studied. The experimental results showed that the cell open circuit voltage 0.608 V, the cell voltage 0.329 V at 50 mA/cm2, and the peak power density 19.25 mW/cm2 were reached under the conditions of Tcell =85 ℃, PO2 =0.5 MPa, Cethanol =1.0 mol/L …

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Bs News Feb 2002

Bs News

Building Services Engineering

No abstract provided.

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Design And Fabrication Of Polarization Filter Implementing A Wire Grid Array, Eric Poortinga Jan 2002

Design And Fabrication Of Polarization Filter Implementing A Wire Grid Array, Eric Poortinga

Journal of the Microelectronic Engineering Conference

For decades optical lithography has continually been extended past the conceived limitations of the technology. By optimizing photoresist performance and stepper settings it is possible to image features smaller then the wavelength of light being used to image. This ability allows structures to be designed such that the optical properties of the material change from what would occur at larger scales. One such structure is the wire grid array consisting of parallel metal lines on a quartz substrate. A wire grid array with a period smaller then the wavelength of incident radiation acts as a polarizer. The Incident field perpendicular …

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Investigation Of Lens Aberrations Through Use Of Phase Shifting Structures At 365nm Technology, James Guerrero Jan 2002

Investigation Of Lens Aberrations Through Use Of Phase Shifting Structures At 365nm Technology, James Guerrero

Journal of the Microelectronic Engineering Conference

As CMOS technology pushes feature dimensions beyond the sub-wavelength threshold, the effect of lens aberrations in the imaging system becomes more relevant. Therefore, it becomes important that the optical engineer completely understands the effects lens aberrations have on aerial image and resist profile. It is also important to have a tool and a process that can accurately describe and measure the aberrations in the exposure system. With full characterization of the lens systems and through use of a lithographic simulator, it becomes possible to predict the imaging effects and ultimately critical dimensions and pattern placement. In any exposure system there …

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Interferometric Lithography Optical System Utilizing A 442nm Hecd Laser, Frank C. Cropanese Jan 2002

Interferometric Lithography Optical System Utilizing A 442nm Hecd Laser, Frank C. Cropanese

Journal of the Microelectronic Engineering Conference

An interferometric optical lithography system utilizing a 442nm Helium Cadmium (HeCd) laser source has been developed. The HeCd laser was passed through a 2μm diffraction grating etched into a phase shift quartz mask to generate two mutually coherent light beams. The ±V’ diffraction orders were collected and interfered at angles ranging from o to 90° with respect to the substrate normal. Incident angles of 13, 26, 34, and 47° were implemented to produce corresponding pitches of 1.0, 0.5, 0.4 and 0.3μm, respectively. The smallest line width that was fabricated approached 0.10μm. In order to synthesize the behavior of conventional projection …

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Intrafield Distortion Characterization, Brian Martinick Jan 2002

Intrafield Distortion Characterization, Brian Martinick

Journal of the Microelectronic Engineering Conference

Distortion of printed photoresist patterns exists in all photolithographic tools and can be generated by numerous factors. These noncorrectable overlay errors are the direct result of lens imperfections, machine inaccuracy, and reticle error. Any one of these factors can have extreme effects on pattern placement and quality. This study involved characterizing this anomaly and was the first of its kind at the Semiconductor & Microsystems Fabrication Laboratory (SMFL). Incorporating a unique test reticle, crosshairs were printed on silicon wafers. These features were measured via Manufacturing Electron Beam Exposure System (MEBES) market analysis to reveal any pattern migration. This analysis involves …

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Design, Fabrication, And Testing Of Crystalline Silicon Source/ Drain Finfets, Jesse J. Siman Jan 2002

Design, Fabrication, And Testing Of Crystalline Silicon Source/ Drain Finfets, Jesse J. Siman

Journal of the Microelectronic Engineering Conference

Crystalline silicon source/drain FInFET structures were designed, fabricated, and tested at the RIT Semiconductor & Microsystems Fabrication Laboratory (SMFL). Process development was completed using hand calculations, simulations, and similar processing techniques based upon mature RIT semiconductor manufacturing processes. The design under investigation is a dog-bone structure fabricated on SOT substrates. The crystalline silicon source/drain FinFETs exhibited a field effect behavior for all transistor sizes fabricated, however the smaller 1μm FinFETs were more susceptible to background noise. The smallest device, a 1x2μm FInFET yielded VT=1.53V and a drive current of 510 μA with VG=5V. The largest device, …

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Raised Polysilicon Source / Drain Finfet Fabrication, Christopher T. Harvey Jan 2002

Raised Polysilicon Source / Drain Finfet Fabrication, Christopher T. Harvey

Journal of the Microelectronic Engineering Conference

The F1nFET is a novel transistor that is fabricated using silicon on insulator (SOl) technology. The body of the transistor is etched out of the top layer of silicon. The device’s polysilicon source I drain are deposited. The gate is self-aligned to the source drain. Contact cuts are made and metal is etched and patterned. The devices did not show field effect as anticipated. Analysis suggested breakdown of the gate oxide.

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Analog Ic Design And Fabrication, James Tom Jan 2002

Analog Ic Design And Fabrication, James Tom

Journal of the Microelectronic Engineering Conference

The purpose of this project was to test the performance of analog integrated circuits and to characterize the MOSFET SPICE parameters. The data that can be obtained from this testing can be helpful for further research in the area of Analog IC design. The Semiconductor & Microsystems Fabrication Laboratory (SMFL) is a constantly evolving facility, with equipment constantly entering and leaving the lab. The process technology used was the RIT Subμ-CMOS Process, a vehicle used to teach students about process integration, semiconductor manufacturing, and the effects of process technology and device operation. Therefore, the Sub-Micron process must adapt to changes …

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Development Of Silicon Nitride Etch Process, Robin Catalano Jan 2002

Development Of Silicon Nitride Etch Process, Robin Catalano

Journal of the Microelectronic Engineering Conference

Silicon nitride has been extensively used as a hard mask for the local oxidation of silicon (LOCOS) for the processing of CMOS devices. Plasma etching is an ideal etch process for patterning the silicon nitride. An optimized etch process was developed for silicon nitride using the LAM-490 plasma etcher. A designed experiment was created, executed, and analyzed. The parameters investigated were SF6 flow, He flow, pressure, power, and electrode gap. The responses examined were silicon nitride uniformity, silicon nitride etch rate, silicon nitride to oxide selectivity and silicon nitride to photoresist selectivity. Through analysis of the experimental results optimal …

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Silicon Dry Etch Process For Shallow Trench Isolation, Nathaniel Langdon Jan 2002

Silicon Dry Etch Process For Shallow Trench Isolation, Nathaniel Langdon

Journal of the Microelectronic Engineering Conference

Shallow Trench Isolation (STI) holds many advantages to that of its predecessor isolation technology in that STI increases the packing density, has superior latch-up immunity, smaller channel-width encroachment, and better planarity, allowing for smaller and thus faster and/or less power hungry devices. The goal of this project was to develop an anisotropic silicon etch process for use in the Drytek Quad 482 Reactive Ion Etch system, yielding a depth of at least 0.5μm and steep sidewall angle of the trench. For this study, varying plasma chemistries of consisting sulfur hexafluoride, oxygen and argon are examined to etch the bulk silicon …

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Development Of A Pecvd Tetraethylorthosilicate (Teos) Fill Process For Shallow Trench Isolation, Erik P. Dolatowski Jan 2002

Development Of A Pecvd Tetraethylorthosilicate (Teos) Fill Process For Shallow Trench Isolation, Erik P. Dolatowski

Journal of the Microelectronic Engineering Conference

As transistors have decreased in size and increased in packing density, a need has arisen for an alternative to the LOCOS method of isolation. Shallow trench isolation (STI) offers superior packing density and stronger immunity to latch up with other side benefits. A TEOS oxide fill for STI is a good choice because its mobile chemical precursors offer a high level of conformality. A plasma enhanced deposition of this oxide allows for greater control over film characteristics. A designed experiment was created to examine the effects of temperature, RF power, and substrate position (measured through electrode spacing) on the oxide …

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Copper Gate Mos Capacitors Utilizing Chemical-Mechanical Planarization, Luc Dupre Jan 2002

Copper Gate Mos Capacitors Utilizing Chemical-Mechanical Planarization, Luc Dupre

Journal of the Microelectronic Engineering Conference

Applying chemical mechanical planarization techniques to form the gate for a Cu/Ti/SiO2/Si capacitor stack has shown to be a viable alternative to conventional etching techniques used in the fabrication of MOS devices. Furthermore, it is reported that CMP does not compromise the integrity of the dielectric nor does it have an adverse affect on device performance.

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Fabrication And Characterization Of Silicon Nitride Sacrificial Replacement Gate Technology, Elias Mohammad Ullah Jan 2002

Fabrication And Characterization Of Silicon Nitride Sacrificial Replacement Gate Technology, Elias Mohammad Ullah

Journal of the Microelectronic Engineering Conference

Silicon Nitride (Si3N4) sacrificial replacement gate were fabricated using the nitride cast method. The purpose of the Si3N4 cast was to develop a stand-in gate, which is then replaced by metal after source/drain formation. The technique was developed by using hot phosphoric acid etch (at 160 ° C) to form nitride cast. The phosphoric acid has nitride etch rate of about 4nm/min and good selectivity over oxide and good uniformity over silicon. A cross sectional analysis was done to view process steps.

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Fabrication Of Interdiffused Dual Work Function Metal Gate Cmos Capacitors, Michael Meagher Jan 2002

Fabrication Of Interdiffused Dual Work Function Metal Gate Cmos Capacitors, Michael Meagher

Journal of the Microelectronic Engineering Conference

Metal gate CMOS capacitors were formed using a metal interdiffusion process at RIT. First silicon dioxide was grown on the wafer. The first metal, titanium, was deposited. Then the second metal, nickel, was deposited. The nickel was selectively etched away from the top of half the capacitors to form the different work function regions. The wafers were then heated so that the nickel diffused into the titanium. The work function could not be determined of the metal gates because the MOS capacitors did not function correctly. The capacitance stayed constant across the allowable gate voltage. This is likely due to …

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Low Energy Ion Implant Capabilities At Rit, Brian J. Miga Jan 2002

Low Energy Ion Implant Capabilities At Rit, Brian J. Miga

Journal of the Microelectronic Engineering Conference

With the ever-decreasing size of device geometries today, all aspects of processing must allow for proper scaling of device parameters including junction depths. Currently in industry this challenge is met with ultra-low-energy ion implants combined with rapid thermal annealing to create the necessary profiles. It is also important to have good uniformity and throughput in order for the process to be acceptable in a manufacturing environment. Since the installation of RIT’s Varian 350D last year, there have been no implants performed at less than 3OKeV. In order to develop future processes for the student-run factory and open research possibilities, ion …

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0.5 Μ Nmos Devices: Process And Fabrication, Sean Houlihan Jan 2002

0.5 Μ Nmos Devices: Process And Fabrication, Sean Houlihan

Journal of the Microelectronic Engineering Conference

The purpose of this paper is to describe the design and the process used to fabricate NMOS devices. The goal of the experiment was to design and build the smallest NMOS transistor that has been fabricated in the SMLF manufacturing facility. A NMOS transistor is short for n-channel metal oxide silicon field effect transistor (NMOSFET or NMOS). NMOS uses electrons as the majority carrier, a major advantage in terms of device speed. The educational reasons for doing this experiment is to prove the viability of the Canon, being able to complete multi-layer aligning and to increase RIT’s ability to process …

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Electron Injection By Means Of A Ballistic Source, Erik M. Wheeler Jan 2002

Electron Injection By Means Of A Ballistic Source, Erik M. Wheeler

Journal of the Microelectronic Engineering Conference

The need for more robust micro electro-mechanical systems (MEMS) devices is greatly increasing. But, along with new technologies come problems, which need to be addressed. One of the more important problems is stiction. Stiction is the strong interfacial adhesion present between contacting crystalline microstructure surfaces. This often causes many MEMS devices to fail. A new method of overcoming stiction has been disclosed. Electrons are stored at the interface between silicon dioxide and silicon nitride to create a force when an external applied electric field is applied to a MEMS component containing the stored charge. The purpose of this project was …

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Micromechanical Optical Modulator, Matt Shepard Jan 2002

Micromechanical Optical Modulator, Matt Shepard

Journal of the Microelectronic Engineering Conference

A novel device was designed and fabricated using Microelectronic and Microeletromechanical systems (MEMS) process procedures. The device was designed to modulate a known wavelength of light using antireflective properties. The mask design was laid out in IC Design portion of Mentor Graphics software package. Device lengths ranging from l5Oum to 300um in length were created including different orientations of etch holes designed for the removal of the sacrificial material. Theoretical modeling of the device, including the applied voltage vs. beam deflection was performed using two-dimensional Fortran program. The result indicates that the smaller devices require a larger amount of voltage …

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Micro Shutters On Quartz Substrate, Vimalan Rajalingam Jan 2002

Micro Shutters On Quartz Substrate, Vimalan Rajalingam

Journal of the Microelectronic Engineering Conference

Micro shutters are micro mechanical devices that fulfill optical and/or electrical functions. The use of such devices has gained momentum in the recent years as their minute size and high speed are viewed to be advantageous for use as optical or electrical switches. The particular type of device targeted in this project is generally referred to as a micro-actuator. It is a device that is curled in its natural state and uncurls when an external voltage is applied to it. When a transparent plate (E.g.: quartz substrate) containing thousands of such shutters can be inserted in a telescope for example, …

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Incorporation Of Spc Charts Into Mesa For The Subμ-Cmos Process, Kautilya Sachdeva Jan 2002

Incorporation Of Spc Charts Into Mesa For The Subμ-Cmos Process, Kautilya Sachdeva

Journal of the Microelectronic Engineering Conference

In a manufacturing process environment, It is important to have precise control over all of the steps involved in making the final product. The device yield goes down when the tools go out of specification. This is where the use statistical process control (SPC) charts, aids in the improvement of the entire manufacturing process. SPC charts help by letting the engineer for the tools understand whether the process is resulting in mean of the data that is higher away from the target or vice-versa (is the data reaching the upper control limit or lower control limit). The project explains the …

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