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Articles 25561 - 25590 of 27338

Full-Text Articles in Engineering

Effects Of Nitrogen Implantation On Oxide Growth And Quality, Jason E. Meiring Jan 2000

Effects Of Nitrogen Implantation On Oxide Growth And Quality, Jason E. Meiring

Journal of the Microelectronic Engineering Conference

The effects of implanting nitrogen prior to gate oxidation are presented. Three different doses of N+, N2+, and Si+ were implanted, followed by a 20- minute 950°C dry oxide growth. Growth rate, interface quality and breakdown strength were measured. Results show up to a 70% reduction in growth rate for high dose nitrogen implants, but no change for silicon implants. The interface trap density decreased with increasing dose for all three species. Oxides grown over N2+ implanted silicon showed field strengths comparable to standard oxides.

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Tantalum Pentoxide Deposition And Applications, Mark A. Bossard Jan 2000

Tantalum Pentoxide Deposition And Applications, Mark A. Bossard

Journal of the Microelectronic Engineering Conference

A Tantalum Pentoxide deposition by reactive sputtering was optimized on a CVC-601 sputterer and working MOS transistors were made using Tantalum Pentoxide. The target was an 8” pure Tantalum target. The optimization was done over a power range of 700 to 1700W DC and over an Oxygen flow of 15 to 35%. The optimal process from this study was at 1200W and an Oxygen flow of 15% or less. A standard PMOS process was modified to use Tantalum Pentoxide using the gate dielectric. The resulting transistors worked well.

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Mosfets With Variable Gate Oxide Thickness By Selective Nitrogen Ion Implantation, Dave Rines Jan 2000

Mosfets With Variable Gate Oxide Thickness By Selective Nitrogen Ion Implantation, Dave Rines

Journal of the Microelectronic Engineering Conference

The incorporation of nitrogen in silicon has been shown to retard the oxidation growth rate. The present study produced aluminum gate PMOSFETs with varied gate oxide thickness on the same chip through selective nitrogen ion implantation. The nitrogen implant dose of 4x1014 ions/cm2 at 35 keV prior to gate oxide growth reduced the oxidation rate between 10% and 60% at the oxidation schedules employed. This active area N-implant led to no degradation in electrical parameters such as gate delay, mobility, or subthreshold swing. MOSFETs with different gate oxide thicknesses allow for different threshold voltages on the same chip and …

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Design And Fabrication Of Ring Gate Surface Junction Tunneling Devices, Eliott R. Hughes Jan 2000

Design And Fabrication Of Ring Gate Surface Junction Tunneling Devices, Eliott R. Hughes

Journal of the Microelectronic Engineering Conference

Silicon based ring gate surface junction tunneling devices (SJT) were studied due to their promise of incorporating quantum functional devices with integrated circuits. SJT devices of various gate lengths ranging from 1 μm to 50 μm were designed using Mentor Graphics tools, and were fabricated using standard CMOS processes on S1MOX substrates. SIMOX wafers were used to help reduce bulk leakage and enhance the drain impurity profile. SIMOX mesa isolation also significantly reduced the process flow.

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Erbium-Doped Silicon Based Leds, Joseph J. Miceli Jan 2000

Erbium-Doped Silicon Based Leds, Joseph J. Miceli

Journal of the Microelectronic Engineering Conference

A preliminary effort in Electroluminescent (EL) device fabrication using erbium-doped silicon based materials at Rochester Institute of Technology’s Microelectronic Engineering Fabrication Facilities was attempted in this study. Field-assisted infiltration would be used to incorporate erbium ions into a porous silicon film. The film would be oxidized and anneal to form and erbium and oxygen rich active layer suitable for light emission. Different erbium anneals (900°C to 1100°C) would be executed and results would be thoroughly examined for any differences in the electrical or luminescent characteristics. No functional devices were fabricated, but proof of erbium activation and excitation was achieved through …

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Development Of An Anisotropic, Selective Polycrystalline Silicon Dry Etch Process, Randy Supczak Jan 2000

Development Of An Anisotropic, Selective Polycrystalline Silicon Dry Etch Process, Randy Supczak

Journal of the Microelectronic Engineering Conference

The development of a polysilicon dry etch process that would result in anisotropic etch profiles as well as high selectivity to photoresist and silicon dioxide has been studied. It was found that decreasing the amount of fluorine (SF6) in the plasma significantly increased the polysilicon etch rate while only increasing the etch rate of silicon dioxide slightly. Two optimal processes were found: One that emphasized anisotropy (70% SF6 flow, 90mTorr pressure, and 200W RF power) and one that emphasized Si02 selectivity (70% SF6 flow, 23OmTorr pressure, and 200W RF power).

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Cobalt Silicide Formation And Patterning Technology, Neil S. Patel Jan 2000

Cobalt Silicide Formation And Patterning Technology, Neil S. Patel

Journal of the Microelectronic Engineering Conference

The goal of this investigation was to develop a cobalt silicide formation process as a stepping stone to investigate a novel patterning technique known as, LOCOSI (LOCal Oxidation of Silicide). Cobalt suicide films were formed by sputter depositing cobalt onto silicon wafers then annealed at temperatures varying from 750 - 1000°C using two methods. The first method was a conventional anneal using a horizontal furnace using a forming gas ambient. The second method was a RTA (Rapid Thermal Anneal) using a nitrogen ambient. The RTA process for silicidation provided essentially a continuous film with minimal cracking, whereas the furnace anneals …

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Reactive Sputtering Of Tantalum Nitrides For Diffusion Barrier Layers, Deepa Gazula Jan 2000

Reactive Sputtering Of Tantalum Nitrides For Diffusion Barrier Layers, Deepa Gazula

Journal of the Microelectronic Engineering Conference

The objective of this project is to develop a robust process to deposit Tantalum nitride barrier layer for copper metallization. TaN films were reactively sputtered in a twin cathode AC inverted cylindrical magnetron configuration using the lonTech Cyclone sputtering system. The dependence of thickness, resistivity and phase changes as a function of N2 flow rate was studied. A designed experimental approach was used to optimize resistivity and the phases formed. A 10 sccm N2 flow (with 99 sccm Ar) deposited at 4 mTorr and 2 kW pressure gave an amorphous bcc-phase Ta(N) with a low resistivity of about …

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Deconfounding The Effects Of Cu And Cr On Perceived Fe Contamination In Si Using An Spv Technique, Steven V. Nagel Jan 2000

Deconfounding The Effects Of Cu And Cr On Perceived Fe Contamination In Si Using An Spv Technique, Steven V. Nagel

Journal of the Microelectronic Engineering Conference

The effects of iron, copper, and chrome on minority carrier diffusion length measurements in p type, boron doped, silicon were investigated using a surface photovoltage (SPV) technique. Attempts were made to reproduce previous results for iron and chrome, metals which form complexes with boron. Also an attempt was made to study the effect that copper contamination would have upon the SPV results. It was found that the iron results were reproducible, FeB could be photodisassociated, and that the chrome contaminated wafers were not effected by the photodisassociation, CrB pairs were not broken. The copper contaminated wafers were found to be …

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The Effect Of Fluorine On Boron Diffusion, Michele Honan Jan 2000

The Effect Of Fluorine On Boron Diffusion, Michele Honan

Journal of the Microelectronic Engineering Conference

The role of fluorine in a BF2 implant has been investigated by implanting BF2, B alone and different combinations of B and F at equivalent implant energies. Each combination was designed to test for something, such as the effect of fluorine after B was implanted or the F damage before B was implanted. The wafers from each group received a spike anneal at 1075°C. The resulting boron profiles after implant and after spike anneal were obtained by SIMS analysis. Sheet resistance was measured and compared with the values calculated from the profiles. The junctions with boron implant …

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Rit Process And Device Simulation With Microtec, Charles R. Overbeck Jan 2000

Rit Process And Device Simulation With Microtec, Charles R. Overbeck

Journal of the Microelectronic Engineering Conference

Microtec, a diffusion-drift model simulator by Siborg Systems, Inc., was used to simulate RIT’s process for a 2-micron NFET (Long Channel), a scaled down NFET (Short Channel), and our new advanced CMOS Process NFET. The accuracy of the simulator was tested with voltage threshold curves, sub-threshold characteristic tests, potential distribution plots, doping profiles, and oxide growth measurements. Microtec proved to be able to easily model RIT’s device performance and process characteristics with only a small amount of modification.

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The Beneficial Effects Of Thin Film Stress In The Fabrication Of A Mems Device, Justin E. Brown Jan 2000

The Beneficial Effects Of Thin Film Stress In The Fabrication Of A Mems Device, Justin E. Brown

Journal of the Microelectronic Engineering Conference

Microelectromechanical systems (MEMS) are playing an increasing role in the semiconductor industry today. The modeling and manufacturing of mechanical devices on a microscopic level have made their way from the area of singularly fabricated devices for research into the bulk processing of the commercial market Many of these commercial devices are of the optical variety. And there has also been successful work done in combining integrated circuits with MEMS. Presented here is a process for the fabrication of an optical device called a microshutter. The device consists of a moveable electrode constructed of a stack of Si02/Al/SiO2 …

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Investigation Of Silicon Etching Effects For Monolithic Integration Of Mems With Cmos, Matthew J. Daniello Jan 2000

Investigation Of Silicon Etching Effects For Monolithic Integration Of Mems With Cmos, Matthew J. Daniello

Journal of the Microelectronic Engineering Conference

Monolithic integration of CMOS and MEMS is quickly proving to be a viable asset to current complex structures. However, synthesis of these technologies has proven to have multiple processing obstacles. Depending on the method used to create these devices, the hurdles include the effects of silicon etching and high temperature processing. For this experiment, previously processed CMOS wafers were obtained and a trench was etched into the silicon. “Family of curves” plots of the working CMOS wafers were taken before and after processing to study any changes in ID. Results have shown that the processing of this integration will …

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Process Development For An Anti-Reflective Micromechanical Modulator, Jason Neidrich Jan 2000

Process Development For An Anti-Reflective Micromechanical Modulator, Jason Neidrich

Journal of the Microelectronic Engineering Conference

The purpose of this Senior Design project is to design and develop the process for an Anti-Reflective Micromechanical Modulator at RIT’s facility, based on AT&T Bell Laboratories presented device, OFC ‘94). The device is fabricated using common semiconductor materials and is used to reflect a laser signal. There are 2 states of operation: the optically ON state, which reflects the signal, and the optically OFF state, which cancels the signal out through destructive interference. A three-layer mask process was designed on RIT’s IC Layout software, the levels being the Active, Metal, and Sacrificial Evacuation areas. The process steps include 4 …

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Copper Interconnect Development At Rit, Ashish Kushwaha Jan 2000

Copper Interconnect Development At Rit, Ashish Kushwaha

Journal of the Microelectronic Engineering Conference

Aluminum is the current metal of choice for metallization in the IC industry. However, serious electromigration problems, and inferior thermal stability limit its performance and reliability. Copper is an attractive alternative having higher electrical conductivity and improved electromigration performance compared to Aluminum. However, Cu is a fast diffuser in Si, Si02, and interlevel dielectrics (ILD). To eliminate this issue, a layer of diffusion barrier (DB) material which is conducting, chemically passive with Copper, has good adhesion properties with Cu and ltD and has high thermal stability is required. Damascene process for Cu was utilized to pattern the wafers in this …

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Development Of Lto Lpcvd Process For 6" Wafers At Rit, Karthika Sivagurunathan Jan 2000

Development Of Lto Lpcvd Process For 6" Wafers At Rit, Karthika Sivagurunathan

Journal of the Microelectronic Engineering Conference

Low Temperature Oxide (LTO) thin films were prepared using a Low Pressure Chemical Vapor Deposition process. By employing statistically designed experiments, the number of experimental runs required was minimized. The full-factorial experimental design was set up to examine effects temperature, gas flow and pressure had on deposition rate, wafer to wafer uniformity, within the wafer uniformity and within run uniformity. The average deposition rate found to be 112A per minute. The LTO baseline process conditions optimized based on the results of this project are: Temperature of 410C, pressure of 33OmTorr and gas flow ratio of 0.55.

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Analysis Of Wireless Networking On The University Of Arkansas Campus, Julia Lincoln Jan 2000

Analysis Of Wireless Networking On The University Of Arkansas Campus, Julia Lincoln

Inquiry: The University of Arkansas Undergraduate Research Journal

Wireless communication has already begun to change the way business and research is done today. Development of the wireless network for digital cellular phone has already improved the area of voice communications. The area of portable and mobile connectivity for computers and other devices is beginning to emerge. The research analyzes and compares a few of these wireless networks. Physical aspects such as range, interference factors, and frequency capabilities and restrictions are assessed. Capacity analysis including round trip times, latency, and throughput are done as well. Issues of authentication and addressing protocols are researched to determine optimal performance and convenience …

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Field Interpretation Of Latitude And Longitude In Arkansas: A Portable Coordinate Projection, William R. Teague Jan 2000

Field Interpretation Of Latitude And Longitude In Arkansas: A Portable Coordinate Projection, William R. Teague

Journal of the Arkansas Academy of Science

Two- and three-dimensional coordinate systems are fundamental to most quantitative mapping applications. The Geodetic, Universal Transverse Mercator (UTM),and State Plane systems have traditional roles in various science, surveying, and government agency engineering applications. The coordinates of three-dimensional Geodetic system are latitude, longitude, and height above ellipsoid (HAE).Because of its ability to cope with the intrinsically three dimensional character of the earth's surface, the Geodetic system is capable of supporting precise relative positioning and very high accuracy computations of distance between any two positions on or near the earth's surface. The two-dimensional UTMand State Plane systems are extremely useful for the …

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Mechatronic Design Of A Treaded Mobile Robot For Mine Sweeping, Andrew B. Wright Jan 2000

Mechatronic Design Of A Treaded Mobile Robot For Mine Sweeping, Andrew B. Wright

Journal of the Arkansas Academy of Science

Autonomous mobile robots, which can be programmed to exhibit cooperative behaviors, are ideal mechanisms for sweeping land mines. They can spread out to hunt for the mines, using a dispersal rule. Once a mine is located, they can congregate to surround it using a clustering rule. Should a robot be destroyed by tripping an unseen mine, the cost is minimal compared to a human life. UALR has been experimenting with coupled oscillator based rule generators for several years using fragile, indoor robots in a laboratory setting to validate the clustering and dispersal behaviors. In order to accomplish outdoor trials, a …

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B. A Java Dialectic, Douglas Lyon, Frances Grodzinsky Jan 2000

B. A Java Dialectic, Douglas Lyon, Frances Grodzinsky

School of Computer Science & Engineering Faculty Publications

Many books often gush over Java. People want to know, before they learn a language, what the drawbacks are for a language. They want to know what the strenghs are. After all, a computer language is just a tool. We shape our tools, and there after, our tools shape us! This chapter contains a dialog between three Java instructors. The participants are, Professors Good, Bad and Ugly. Professor Good is a strong proponent of Java. Professor Bad is a strong opponent of Java. Professor Ugly has been leaning toward the asthetic analysis of the language, particularly with an eye toward …

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Bs News Jan 2000

Bs News

Building Services Engineering

No abstract provided.

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An Efficient Algorithm To Determine The Periodic Steady-State Solutions Of Nonlinear Systems Using Extended Spectral Analysis, Gülay Tohumoğlu Jan 2000

An Efficient Algorithm To Determine The Periodic Steady-State Solutions Of Nonlinear Systems Using Extended Spectral Analysis, Gülay Tohumoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

A new method for the solution of nonlinear periodic systems was developed. It avoids the time domain calculations of the whole network equations. In the proposed method, by forming the augmented network as linear and nonlinear subnetworks these subnetworks are formulated in complex frequency and time domain respectively. Using spectral analysis the steady-state periodic solution of the whole nonlinear network is reached by an iterative approach. The method can be applied efficiently to weak and strong nonlinear circuits equally well. When we divide the network into a large linear subnetwork and a small nonlinear subnetwork, this method can be applied …

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Book Review: Ken Goldberg's "The Robot In The Garden", Cindy Ahuna Jan 2000

Book Review: Ken Goldberg's "The Robot In The Garden", Cindy Ahuna

SWITCH

In this book review, Cindy Ahuna summarizes Ken Goldberg's view on the relationships between technology and shared experiences of telepresence and cybernetic systems. The book, "Robot in the Garden" is a collective transcription of telerobotic research and documentation. In the article, Ahuna dissects this book as a breakdown of telerobotic and its relationship with the internet, epistemology, and subcategories of technology based around the internet. The book illustrates critical points of reference regarding telerobotic “case studies in progress; theoretical beliefs; telerobotic scenarios; arguments and parallels of epistemology; questions and approaches to mediation; differences between using the Internet and other acknowledge-based …

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Knowledge-Based Navigation For Autonomous Road Vehicles, Murat Eki̇nci̇, Franches W.J.Gibbs, Barry T. Thomas Jan 2000

Knowledge-Based Navigation For Autonomous Road Vehicles, Murat Eki̇nci̇, Franches W.J.Gibbs, Barry T. Thomas

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a computer vision system for an autonomous road vehicle (ARV) that is capable of negotiating complex road networks including road junctions in real time. The ultimate aim of the system is to enable the vehicle to drive automatically along a given complex road network whose geometric description is known. This computer vision system includes three main techniques which are necessary for an ARV: a) road following, b) road junction detection, c) manoeuvring at the road junction. The road following algorithm presents a method of executing a number of algorithms using different methods concurrently, fusing their outputs together …

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Decentralised H_{\Infty} Load Frequency Controller Design Based On Ssvs, Hasan Çi̇men Jan 2000

Decentralised H_{\Infty} Load Frequency Controller Design Based On Ssvs, Hasan Çi̇men

Turkish Journal of Electrical Engineering and Computer Sciences

The decentralised load-frequency controller design problem concerned is translated into an equivalent problem of decentralised controller design for a multi-area multi-input multi-output (MIMO) control system. It is shown that subject to a condition based on the structured singular values (SSVs), each local area load-frequency controller can be designed independently. The stability condition for the overall system can be stated as to achieve a sufficient interaction margin. It is demonstrated by computer simulation that within this general framework, local H$_{\infty}$ controllers can be designed to achieve satisfactory performances for a sample two-area power system.

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Information And Average Information Rates Of A Graphical Access Structure On Six Vertices, Mustafa Atici Jan 2000

Information And Average Information Rates Of A Graphical Access Structure On Six Vertices, Mustafa Atici

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper we study the optimal information and average information rates of secret sharing schemes which are all connected graphs on six vertices. There are $102$ connected graphs on six vertices that are not complete multipartite graphs. Of these $102$ graphs, we determined the optimal information rate of $71$ graphs, and the optimal average information rate of $88$ graphs.

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Comparison Of Simulation Algorithms For The Hopfield Neural Network: An Application Of Economic Dispatch, Tankut Yalçinöz, Hali̇s Altun Jan 2000

Comparison Of Simulation Algorithms For The Hopfield Neural Network: An Application Of Economic Dispatch, Tankut Yalçinöz, Hali̇s Altun

Turkish Journal of Electrical Engineering and Computer Sciences

This paper is mainly concerned with an investigation of the suitability of Hopfield neural network structures in solving the power economic dispatch problem. For Hopfield neural network applications to this problem three important questions have been answered: what the size of the power system is; how efficient the computational method; and how to handle constraints. A new mapping process is formulated and a computational method for obtaining the weights and biases is described. A few simulation algorithms used to solve the dynamic equation of the Hopfield neural network are discussed. The results are compared with those of a classical technique, …

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Radiation From An Impedance Loaded Parallel-Plate Waveguide, Fi̇li̇z Bi̇rbi̇r, Ali̇nur Büyükaksoy Jan 2000

Radiation From An Impedance Loaded Parallel-Plate Waveguide, Fi̇li̇z Bi̇rbi̇r, Ali̇nur Büyükaksoy

Turkish Journal of Electrical Engineering and Computer Sciences

A hybrid method consisting of employing the mode matching method in conjunction with the Fourier transform technique is used to analyze the radiation of the dominant TEM-wave from an impedance loaded parallel-plate waveguide. The hybrid method that we adopt here reduces the related boundary value problem to a scalar modified Wiener-Hopf equation of the second kind. The solution involves infinitely many unknown constants satisfying an infinite system of linear algebraic equations susceptible to a numerical treatment. Some computational results illustrating the effects of various parameters on the radiation phenomenon are also presented.

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A Pseudo Spot Price Algorithm Applied To The Pumped-Storage Hydraulic Unit Scheduling Problem, Sali̇h Fadil, Celal Yaşar Jan 2000

A Pseudo Spot Price Algorithm Applied To The Pumped-Storage Hydraulic Unit Scheduling Problem, Sali̇h Fadil, Celal Yaşar

Turkish Journal of Electrical Engineering and Computer Sciences

A lossy electric power system that contains thermal units and a pumped-storage hydraulic unit is considered in this paper. The total cost of thermal units in an operation cycle is minimized under some possible electric and hydraulic constraints of the units. The operation cycle is divided into time intervals where the system loads are assumed to remain constant. The proposed solution technique has two main parts. In the first part, the active thermal generations and active generation or pumping power of the pumped-storage unit in all time intervals are determined by using units' active generation incremental costs and pseudo spot …

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Distance Spectra For Trellis Coded Modulation Schemes On Channels With Intersymbol Interference, Sabi̇re Haciömeroğlu, Melek D. Yücel Jan 2000

Distance Spectra For Trellis Coded Modulation Schemes On Channels With Intersymbol Interference, Sabi̇re Haciömeroğlu, Melek D. Yücel

Turkish Journal of Electrical Engineering and Computer Sciences

The effect of intersymbol interference on distance spectra for trellis coded 8-PSK, 16-QAM and 32-AMPM modulation schemes is evaluated using the methods proposed by Schlegel. Distance spectra of 16-state 8-PSK scheme are computed for different intersymbol interference channels. It is seen that on channels with intersymbol interference the spectral lines are spread into a nearly continuous spectrum and the minimum Euclidean distance between codewords decreases severely. Hence, although the main contribution at large signal to noise ratios comes from the minimum Euclidean distance ( d_{free} ) , higher spectral components also become very important at moderate values of the signal …

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