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Articles 25831 - 25860 of 27331

Full-Text Articles in Engineering

Design And Fabrication Of A Field Programmable Logic Array, Robert Cavagnaro Jan 1998

Design And Fabrication Of A Field Programmable Logic Array, Robert Cavagnaro

Journal of the Microelectronic Engineering Conference

Unlike conventional hard programmed gate arrays, the Field Programmable Logic Array (FLPA) offers the end user the ability to instantly change the outputted function of the circuit through an external electronic programming sequence. This project outlines the design and fabrication of a P Well CMOS NOR logic FPLA. Consisting of roughly 1,400 transistors, three major functional components were designed: Floating Tunnel Oxide EEPROM memory bank, an EEPROM addressing system, and a 3 input I 3 output / 2 return state programmable logic array. Fabrication was carried out at the RIT fabrication facility and upon testing the completed devices it was …

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Simox Cmos Process Design And Fabrication, Andrew Phillips Jan 1998

Simox Cmos Process Design And Fabrication, Andrew Phillips

Journal of the Microelectronic Engineering Conference

The first Thin Film Transistor (TFT) CMOS process for RIT’s Semiconductor Processing Center utilizing SIMOX wafers was developed. A standard 9 mask-set P-well CMOS process flow originally designed for bulk silicon was modified to accommodate the new starting material.

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Monolithic Integration Of Mems Structures And Cmos Circuitry, Alfredo Torrejon Jan 1998

Monolithic Integration Of Mems Structures And Cmos Circuitry, Alfredo Torrejon

Journal of the Microelectronic Engineering Conference

A modular approach, based on work done at Sandia National Laboratories, for the monolithic integration of a microelectrornechanical system (MEMS) process and an electronics process is being investigated. A preliminary outline for an integrated two-level polysilicon MEMS/p-welI CMOS process that can be fabricated in RIT’s facilities has been created. This is a MEMS-first approach that places the MEMS in an isolation trench and then seals off the MEMS during CMOS processing. A recipe based on potassium hydroxide wet etching has been developed for the isolation trench etch. Masks for a simple test chip have been created to assist in troubleshooting …

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Simulation And Tolerance Determination For Lateral Cmos Devices, Matthew Scarpino Jan 1998

Simulation And Tolerance Determination For Lateral Cmos Devices, Matthew Scarpino

Journal of the Microelectronic Engineering Conference

SUPREM4 simulation for lateral DMOSFET’s are discussed, as well as the Medici simulation of their electrical characteristics. The actual processing parameters of the device simulation are shown, and the theory surrounding device operation is discussed. The three electrical tests — IDNDS characteristic, VT determination, and the breakdown VDS are explained with the testing method used for each. The four process variations — substrate doping, well dose, well drive in temperature, and oxidation temperature are presented as well as their theoretical effects on device performance. Finally, the results of the electrical tests are presented with conclusions regarding the effects of the …

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Process Development For Porous Silicon Light-Emitting Devices, Jason Benz Jan 1998

Process Development For Porous Silicon Light-Emitting Devices, Jason Benz

Journal of the Microelectronic Engineering Conference

The primary focus of this project was to continue process development of integrated PSibased (porous silicon) LEDs. Porous silicon is a light-emitting material formed by electrochemical etching of the silicon substrate, resulting in the formation of pores and wire-like silicon structures [1]. This study investigates new strategies in the effort to advance the implementation of PSi-based LEDs with standard CMOS technology by providing devices that are substrate-based, electrically isolated, array-addressable and voltage modulated. Existing problems with porous silicon LEDs include high bias operation, low external quantum efficiency (EQE), and poor stability. This work has resulted in the fabrication of LEDs …

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Fabrication Of Thin Film Electroluminescent Devices For Display Applications, Tiffany Noble Jan 1998

Fabrication Of Thin Film Electroluminescent Devices For Display Applications, Tiffany Noble

Journal of the Microelectronic Engineering Conference

A preliminary effort in Electroluminescent (EL) device fabrication at Rochester Institute of Technology’s Microelectronic Engineering Fabrication Facilities was attempted in this study. The fabrication of several AC driven electroluminescent devices, on silicon substrates were studied. Devices were fabricated on heavily doped p-type silicon, with tantalum pentaoxide dielectric and various phosphor materials. No working devices were fabricated in this initial attempt. However, deeper understanding of the functionality of each layer was gained.

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Atmospheric Pressure Cvd Of Teos, Daniel Ma Jan 1998

Atmospheric Pressure Cvd Of Teos, Daniel Ma

Journal of the Microelectronic Engineering Conference

The goal of this project is to install an atmospheric pressure chemical vapor deposition of tetraethoxysilane (APCVD TEOS) process at RIT. The advantage of atmospheric TEOS includes, among many reasons, good uniformity, high deposition rate, superior step coverage and conformality, ease of handling, stability, and safety. In developing the process, an experimental design was utilized, using factors: deposition temperature, bubbler temperature, and N2 carrier gas flow were examined. Responses include: deposition rate on silicon, deposition rate on oxide, thickness uniformity, refractive index, refractive index uniformity, and etch rate in hydrofluoric acid. Etch rate after 30mm @ 1050°C anneal, dielectric properties, …

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Titanium Nitride Diffusion Barriers And Schottky Diodes, Andrew Woodard Jan 1998

Titanium Nitride Diffusion Barriers And Schottky Diodes, Andrew Woodard

Journal of the Microelectronic Engineering Conference

Titanium nitride was studied for use in two applications: as a barrier metal in an aluminum metallization and as a Schottky diode metal on n type silicon(ND = 1X1015/cm3). The films were reactively sputtered in an RiT magnetron configuration using a Perkin-Elmer 2400 sputtering system. Effects of heat treatment temperature on performance were studied for both applications. TiN as sputtered in this experiment was shown to be an effective barrier against Al-Si interdiffusion. Annealing temperature was shown to affect the Schottky barrier height, which ranged from 471 to 658 mV as calculated from specific contact …

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Work Function Of Refractory Metals And Nitrides From Cv Analysis, Benjamin M. Kaltaler Jan 1998

Work Function Of Refractory Metals And Nitrides From Cv Analysis, Benjamin M. Kaltaler

Journal of the Microelectronic Engineering Conference

The work function of p-type and n-type metal electrode materials deposited by RF magnetron sputtering in argon was determined by CV measurements on MOS capacitors. In addition, the work function of p-type and n-type nitride electrode materials deposited by rf magnetron sputtering in nitrogen was also determined by CV measurements on MOS capacitors. The metals deposited were molybdenum, tantalum, titanium, and aluminum. The nitrides deposited contained the metals listed previously with the exception of aluminum. The work functions were determined to be 4.70 +1- 0.49 eV for Al, 4.46 +1- 0.26 eV for Mo, and 4.22 eV for Ta. Capacitors …

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Stacked Floating Gate Eeprom, Ing-Cheng Chai Jan 1998

Stacked Floating Gate Eeprom, Ing-Cheng Chai

Journal of the Microelectronic Engineering Conference

The concept of SFGEEPROM involves the replacement of the standard EEPROM’s floating gate with a multi-layer stacked of Silicon (Si) and Silicon Dioxide (SiO2). This multi-layer stack of Si and SiO2 is either deposited via sputtering or CVD and followed by annealing (see Figure 1). Carriers will be injected from the n+ polysilicon layer into the multi-stacked layers, and those carriers will be confined to the silicon crystallites with the thin oxide barriers between silicon layers. The distribution of charge within the stack will alter the field-effect on the underlying silicon substrate. This type of structure may …

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Comparison Of Minority Carrier Lifetime Measurement By Surface Charge And Capacitance - Time Analysis, David Lundeen Jan 1998

Comparison Of Minority Carrier Lifetime Measurement By Surface Charge And Capacitance - Time Analysis, David Lundeen

Journal of the Microelectronic Engineering Conference

Minority carrier lifetimes are a useful parameter in both the design and manufacture of discrete and integrated circuits. With today’s emphasis on MOS technology, minority carriers are used as a “process cleanliness” tool in a manufacturing environment. The purpose of this project is to compare the two available carrier lifetime tests, namely the Semitest Surface Charge Analyzer (SCA) and capacitance-time and seeing if the relationship is linear. Being linear, the more process intensive capacitance-time test can be avoided and all pertinent data can be extracted via the SCA, therefore increasing product cycle time and time to market. 200A thermal oxide …

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Automated Wafer Testing, Michael Volo Jan 1998

Automated Wafer Testing, Michael Volo

Journal of the Microelectronic Engineering Conference

A test system was installed at JUT that can automatically test every die on a wafer without any operator interruption. The system integrates a Rucker & Kolls 681A wafer probe station, an HP4145 parameter analyzer, an HP Apollo work station, and a Keithley switch matrix. IC-CAP software was used for system control and data extraction. The system was designed to be flexible so additional tests can he added. Any process and any test that an HP4145 can complete manually can be tested using the automated system. Only a few variables regarding die size, device location, data extraction methods, and HP4145 …

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Preparation Of Rit For 157-Nm Lithography, Brian Lee Porter Jan 1998

Preparation Of Rit For 157-Nm Lithography, Brian Lee Porter

Journal of the Microelectronic Engineering Conference

This project investigated the feasibility of 157-nm Vacuum UltraViolet (VUV) Lithography and its’ possible utilization as a future source to extend the capabilities of optical lithography. In addition, this project undertook the initialization of VUV lithography here at JUT by the conversion of a 193-nm ArF excimer laser to a 157-nm F2 excimer laser source. The investigation of the completed body of work on 157-nm lithography led to the conclusion that this technology is viable and may represent the last frontier with respect to optical lithography. The excimer laser at RIT was successfully retrofitted for 157-nm operation and exhibited RIT’s …

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Quadrupole Apertures For 193nm Lithography, Michael Cangemi Jan 1998

Quadrupole Apertures For 193nm Lithography, Michael Cangemi

Journal of the Microelectronic Engineering Conference

Strong and weak quadrupole apertures have been optimized and fabricated for relatively dense O.12~im geometry’s. All of the apertures were optimized using PROLITH/2 simulation software. The apertures were fabricated as fused silica reticles that are inserted at the lens pupil plane. The apertures change the illumination profile that is collected by the condenser lens. Depth of focus (DOF) is increased using quadrupole illumination when trying to resolve specific pitch values.

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Development Rate Monitor: Process Integration And Resist Parameter Extraction, Joshua Roberge Jan 1998

Development Rate Monitor: Process Integration And Resist Parameter Extraction, Joshua Roberge

Journal of the Microelectronic Engineering Conference

Development rate measurement (DRM) analysis yields very accurate resist modeling parameters. A procedure for extracting these parameters was instituted for the Perkin-Elmer DRM tool at RET. New software packages for the DRM tool and ProDRM simulations were used to extract development rate parameters for current i line resists. The process established will be repeated for future resists.

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Characterization Of An Organic, Wet Develop, Broadband, Experimental Back Anti-Reflective Coating (Barc), Robert Kress Jan 1998

Characterization Of An Organic, Wet Develop, Broadband, Experimental Back Anti-Reflective Coating (Barc), Robert Kress

Journal of the Microelectronic Engineering Conference

The objective of this project is to characterize Brewer Science EXP97O11 experimental broadband back anti-reflective coating (BARC). This BARC was designed to function at both i-line (365 nm) and g-line (436 urn). The focus of this experiment is to incorporate the BARC process into existing lithography processes at RIT. A “Poor Man’s” DRM was performed on both the BARC as well as Shipley 812 photoresist to determine optimum develop time as well as optimum bake temperature for the BARC. Once the optimum conditions were found, several wafers were processes through 1st level lithography using the BARC on a polysilicon layer …

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Chemical Mechanical Pad Characterization Using Shallow Trench Isolation Structures, James K. Zelenak Jan 1998

Chemical Mechanical Pad Characterization Using Shallow Trench Isolation Structures, James K. Zelenak

Journal of the Microelectronic Engineering Conference

In this study the effects of front-side pad composition were examined for a chemical mechanical polishing process. The examination involved evaluation of film removal uniformity across the wafer surface and within each die, dishing effects, and selectivity between silicon nitride and CVD oxides. Trenches were fabricated in the substrate via dry etch, the resultant depth was 1.5 μm. The trench backfill was accomplished with a CVD low temperature oxide. Best results were obtained using a dense single layer polish pad, which exhibited imperceptible dishing and wafer polish uniformity on par with all other combinations.

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Endpoint Detection In Cmp Utilizing Thermal Imaging, Rick Anundson Jan 1998

Endpoint Detection In Cmp Utilizing Thermal Imaging, Rick Anundson

Journal of the Microelectronic Engineering Conference

The objective of this project was to develop a method for using thermal imaging to determine end-point in chemical mechanical polishing (C.M.P.) for a shallow trench isolation (S.T.L) C.M.P. process and contact layer C.M.P. process. A two-dimensional thermal imaging camera was used to measure the pad temperature during processing. The pad temperature is an indication of the friction between the pad and the wafer being processed. As the polishing process transitions from one layer of material to the next layer of material the amount of heat generated will change. For the STI layer a 0.3 to 0.4 degree Fahrenheit (F) …

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Functional Radionuclide Imaging Algorithm Based On The Appended Curve Deconvolution Technique And Its Use In The Diagnosis Of Renovascular Hypertension, İrfan Karagöz, Hi̇kmet Bayhan Jan 1998

Functional Radionuclide Imaging Algorithm Based On The Appended Curve Deconvolution Technique And Its Use In The Diagnosis Of Renovascular Hypertension, İrfan Karagöz, Hi̇kmet Bayhan

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a new method called the pixel basis functional radionuclide imaging (PBFRI) algorithm based on the appended curve deconvolution technique, in order to be able to increase the medical diagnostic capability of a conventional gamma camera, is presented together with the clinical results. In the PBFRI method, retention function of each pixel is obtained from the renograms and cardiac curves generated by processing the filtered segments of the kidney and heart, using a special deconvolution method. The deconvolution operation is done by using the Fourier transform technique. High frequency artifacts presented by the Fourier transform are removed by …

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Preparation For Sci-Tech Librarianship: Results Of A Survey, John Sandy, Mary Frances Lembo, James Manasco Jan 1998

Preparation For Sci-Tech Librarianship: Results Of A Survey, John Sandy, Mary Frances Lembo, James Manasco

Sci-Tech News

No abstract provided.

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Genetic Approach For The Determination Of Object Parameters From X Ray Projections, Tayfun Günel, Sedef Kent Jan 1998

Genetic Approach For The Determination Of Object Parameters From X Ray Projections, Tayfun Günel, Sedef Kent

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a new method is presented, based on genetic algorithms for determining object parameters such as radii and/or attenuation coefficients with some assumptions and estimating a cross-sectional image of an object from its projections obtained by X ray illumination. After it was tested for projections degraded by different random noise levels, it was observed that the genetic and fuzzy genetic algorithms improved the signal to noise ratio of the projections. The fuzzy genetic algorithm gave better results than the genetic algorithm.

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Bs News Jan 1998

Bs News

Building Services Engineering

No abstract provided.

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Adaptive Shape From Shading, Ati̇lla Gülteki̇n, Muhi̇tti̇n Gökmen Jan 1998

Adaptive Shape From Shading, Ati̇lla Gülteki̇n, Muhi̇tti̇n Gökmen

Turkish Journal of Electrical Engineering and Computer Sciences

Extracting surface orientation and surface depth from one or more images is one of the classic problems in computer vision. Shape-from-shading (SFS) deals with the recovery of 3-D shape from a single shaded image. The shape is recovered by minimizing an energy functional involving constraints such as smoothness. In this constrained problem, although the smoothness constraint helps to stabilize the minimization process, it pushes the reconstruction toward a smooth surface. In this paper, we present a new adaptive shape-from-shading method which reduces this oversmoothing by controlling the smoothness spatially over the image space. In order to improve the quality of …

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A Parallel Pipelined Computer Architecture For Digital Signal Processing, Haluk Gümüşkaya, Bülent Örenci̇k Jan 1998

A Parallel Pipelined Computer Architecture For Digital Signal Processing, Haluk Gümüşkaya, Bülent Örenci̇k

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a parallel pipelined computer architecture and its six network configurations targeted for the implementation of a wide range of digital signal processing (DSP) algorithms described by both atomic and large grain data flow graphs. The proposed architecture is considered together with programmability, yielding a system solution that combines extensive concurrency with simple programming. It is an SSIMD (Skewed Single Instruction Multiple Data) or MIMD (Multiple Instruction Multiple Data) machine depending on the algorithms implemented and the programming methodologies. The concurrency that can be exploited by the algorithms using this Parallel pipelined architecture is both temporal and spatial …

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Hierarchical Interconnection Network Architecture For Real-Time Systems, Bülent Örenci̇k Jan 1998

Hierarchical Interconnection Network Architecture For Real-Time Systems, Bülent Örenci̇k

Turkish Journal of Electrical Engineering and Computer Sciences

A hierarchical network suitable for interconnection of real-time client processes in a distributed multiprocessor environment is presented in this paper. A multi-layer {\it Communication Unit} (CU) prototype is developed for this purpose. This unit offers the client processes communication services for real-time operation. These services are structured in such a way that they do not depend on the characteristics of the communication medium. The basic hardware of the CU consists of a PC compatible card connected to the VME Bus. Client processes run on target cards (Motorola MVME-162) which are attached to the same bus. Target cards together with a …

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Imaging Tissue Conductivity Via Contactless Measurements: A Feasibility Study, Nevzat G. Gençer, M. Nejat Tek Jan 1998

Imaging Tissue Conductivity Via Contactless Measurements: A Feasibility Study, Nevzat G. Gençer, M. Nejat Tek

Turkish Journal of Electrical Engineering and Computer Sciences

The feasibility of a new imaging system is investigated. This system will be used to image electrical conductivity distribution of biological tissues via contactless measurements. This will be achieved by introducing currents in the conductive medium using time-varying magnetic fields and measuring the magnetic fields of the induced currents. Consequently, the imaging system consists of transmitter and receiver coils placed nearby the conductive body. In this study, the basic features of the coplanar and coaxial coils are studied. The validity of the simplifying assumptions for the governing field equations is investigated. It is found that, for operating frequency of 100 …

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Use Of The Magnetic Field Generated By The Internal Distribution Of Injected Currents For Electrical Impedance Tomography (Mr-Eit), Y. Zi̇ya İder, Özlem Bi̇rgül Jan 1998

Use Of The Magnetic Field Generated By The Internal Distribution Of Injected Currents For Electrical Impedance Tomography (Mr-Eit), Y. Zi̇ya İder, Özlem Bi̇rgül

Turkish Journal of Electrical Engineering and Computer Sciences

In two dimensional conventional Electrical Impedance Tomography (EIT), volume conductor is probed by means of injected currents, and peripheral voltage measurements are used as input to the reconstruction algorithm. The current that flows in the 2D object creates magnetic fields that are perpendicular to the plane of imaging. Such magnetic fields can be measured using magnetic resonance tomography. In this study, use of this magnetic field generated by the injected currents, for the purpose of reconstructing the conductivity distribution, is studied. Sensitivity matrix relating the magnetic field to the element conductivities is calculated using the Finite Element Method and Biot-Savart …

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An Interoperability Infrastructure For Developing Multidatabase Systems, Asuman Doğac, Gökhan Özhan, Ebru Kılıç, Fatma Özcan, Sena Nural, Sema Mancuhan, Cevdet Dengi, Pınar Köksal, Uğur Halıcı, Budak Arpınar, Cem Evrendilek, Vahid Sadjadi Jan 1998

An Interoperability Infrastructure For Developing Multidatabase Systems, Asuman Doğac, Gökhan Özhan, Ebru Kılıç, Fatma Özcan, Sena Nural, Sema Mancuhan, Cevdet Dengi, Pınar Köksal, Uğur Halıcı, Budak Arpınar, Cem Evrendilek, Vahid Sadjadi

Turkish Journal of Electrical Engineering and Computer Sciences

A multidatabase system (MDBS) allows the users to simultaneously access autonomous, heterogeneous databases using a single data model and a query language. This provides for achieving interoperability among heterogeneous, federated DBMSs. In this paper, we describe the interoperability infrastructure of a multidatabase system, namely METU Interoperable DBMS (MIND). The architecture of MIND is based on OMG distributed object management model. It is implemented on top of a CORBA compliant ORB, namely, ObjectBroker. The interface of the generic database object is defined in CORBA IDL and multiple implementations of this interface, one for each component DBMSs, namely, Oracle 7, Sybase, Adabas …

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Object-Oriented Computer Simulations Of Physical Systems Using Dual Reciprocity Boundary Element Methodology, J. Friedrich Jan 1998

Object-Oriented Computer Simulations Of Physical Systems Using Dual Reciprocity Boundary Element Methodology, J. Friedrich

Turkish Journal of Electrical Engineering and Computer Sciences

Models of physical systems are essential in every engineering field. This work deals with computer simulations of physical systems that can be mathematically modelled by differential equations together with sufficient boundary conditions. The computer simulations are based on object-oriented technology and the dual reciprocity boundary element method which is a universal solution scheme for various types of partial differential equations (e.g. Laplace, Poisson, diffusion, convection-diffusion, and steady Navier-Stokes equation). This technique fulfills efficiency criteria like precision, robustness, versatility, programmability, user-friendliness, need of computational time and computer memory to a very high degree. This is demonstrated by three examples: Laplace's solution …

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Performance Of Prefiltered Model-Based Frequency Estimators, Mustafa A. Altınkaya, Bülent Sankur, Emin Anarım Jan 1998

Performance Of Prefiltered Model-Based Frequency Estimators, Mustafa A. Altınkaya, Bülent Sankur, Emin Anarım

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, the performance improvement due to prefiltering of inputs in model-based frequency estimators is investigated based on simulation experiments. Initial estimates on the tone frequency locations, which are obtained via DFT peak picking type preanalysis, are used to design a prefilter to remove noise and interference. The simulations indicate that prefiltering can improve the accuracy of Pisarenko and AR frequency estimators and MUSIC and KT frequency estimators with low subspace order significantly. The SNR thresholds of model-based frequency estimators are lowered by prefiltering. Additionally, interesting trade-offs between prefiltering gain and the gain due to subspace noise filtering have …

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