Electrical and Electronics Commons^™

Characterization Of Advanced Etching Reactors Using Novel Diagnostic Tools, Vipulkumar Patel

Dissertations

Plasma etching equipment used for sub-micron integrated circuit fabrication at present are exclusively based on 13.56 MHz, capacitively coupled, parallel-plate geometry. The underlying mechanisms of plasma processes in these reactors are not well understood and there is even less understanding of how the etch-tool parameters relate to the plasma discharge characteristics which actually determine the etch process. In this thesis, new diagnostic techniques were applied for the characterization and optimization of plasma etching processes in various reactor configurations.

Specifically, diode and triode configurations were studied extensively using tuned scanning Langmuir probes. Both radial and axial distributions of plasma density were …

Improving The Jitter Performance Of Timing Recovery By Employing Delay Shifts, Xin De Lu

Theses

Many methods have been developed for evaluating the jitter performance of timing recovery circuits for binary synchronous transmission systems. These circuits consist of a nonlinear device followed by a narrowband filter tuned to the pulse repetition frequency. This thesis introduce delay shifts in the timing recovery circuits to improve the jitter performance. The function of the delay shifts is analyzed and mathematical proof of jitter performance improvement is given for the system using square-law device. Finally, the numerical results obtained from the specific examples serve to illustrate the significant improvement between the system with and without delay shifts. That is, …

Polarimetric Fiber Optic Sensor For The Measurement Of Strain, Wei Ma

Theses

In this thesis, development of a Polarimetric Fiber-Optic strain sensor is presented. The sensor uses the phenomenon that strain can deform the probing part of the fiber and hence change the polarization of the transmitted light signal. By counting the resulting fringes, we can measure the exact strain in the material. Calibration of the sensor was achieved by setting up tension tests. Optical fibers were glued on the surface of the specimen. Reference strain gages were used to record the strain in the specimens. Resulting fringes from the fiber optic sensors were then related to the strain measured by the …

An Implementation Of A Versatile Camera Calibration Technique For High-Accuracy 3d Machine Vision Metrology Using Off-The-Shelf Tv Camera And Lenses, Bolang Li

Theses

This thesis studies and implements a new versatile camera calibration technique for high-accuracy 3D machine vision metrology using off-the-shelf TV camera and lenses developed by Roger Tsai [1]. This technique builds up a unique relationship from the world coordinate system to the computer image coordinate system of calibration points by using a radial alignment constraint. The technique has advantage in terms of accuracy, speed, and versatility over existing techniques.

The fundamental knowledge for using this technique is presented in this thesis first, followed by an overview of the existing calibration techniques, and a detailed description of the new technique. The …

Modeling And Simulation Of Magnetic Micromotor Performance, Ping Wang

Theses

The objective of this research was to model the performance and optimize geometries for two types of magnetic micromotors: yoke-type (YTMM) and yokeless (YSMM). The two selected micromotor types matched the designs that have been described in the recent research literature. Modeling was accomplished using MAXWELL, an advanced 2-D and 3-D simulator. The micromotors with nickel and nickel-iron magnetic thin films for the rotor and stator were simulated for torque performance. Three-phase power supplies with overlapping and non-overlapping phases were used. Rotor diameter dimensions were varied from 285 to 600µm, and the rotor-stator air gap was varied from 3 to …

Modeling And Investigation Of Current Transport Phenomena In Schottky Structures, Yan Zeng

Theses

We have used a numerical method to describe the importance of the contribution of generation-recombination current to the I-V characteristics of Schottky barrier contacts. The current-voltage relationship is derived directly from the fundamental set of equations such as Poisson; current-density and continuity equations, without having to make many simplifications or approximations. The final result includes not only the thermionic emission or drift diffusion mechanisms of current flow, but also the generation recombination processes.

The experimental devices used for this work are very common low barrier height Schottky structures, Al/T_0.3W_0.7/n-Si/A1 and Ti_0.3W_0.7/n-Si/Al. The …

Microengineered Mass Spectrometer With Field Emission Ionization Source, Chao Sun

Theses

This thesis describes a design for a microengineered mass spectrometer. This mass spectrometer device uses VLSI processing techniques to scale down the dimensions of an existing mass spectrometer and make it portable. It can be manufactured economically and has the potential to be integrated with more complex structures and including transistor integrated circuits. An optimized device is proposed. This device is to be fabricated using two silicon substrates approximately 1cm by 1cm, where one is a cathode electron source and the other is the ion collector. External ion sources are not needed. Electrons are emitted from the array of cathode …

Aluminum Epitaxy On Silicon, Samuel Cruz Ramac

Theses

The purpose of this work was to study the effect of 4° miscut and chem¬ical pretreatment of Si(111) wafers on the epitaxial growth of Al by thermal evaporation in a UHV environment (~ 10^-9 Torr). Two chemical pretreatments of the wafers were used. One included HF only and the other included NH₄F after an initial HF treatment. The substrates were not heated dur¬ing deposition. XRD measurements of the films were done before and after annealing in a high vacuum oven for one hour at temperatures between 200 and 350°C.

The A1(200) films deposited on wafers pretreated with …

The Postbus Fault Tolerant Clos Network, Udayabhanu Sarangapani

Theses

The trend in modern computing is to develop multiprocessor systems with hundreds, even thousands, of processors and memory modules. The task of providing communication paths among all these units is not a trivial one. For a small number of functional units, direct connections could be used but for large systems interconnection networks have to be used. Multistage Interconnection Networks (MINs), provide a dynamic means for interconnecting processors and memory in a multiprocessor system. These networks are built with switches in each stage.

The Clos network is a well defined family of MINs and consists of three stages. The ordinary Clos …

Multilevel Embeddings For Massively-Parallel Hypercubes, Devenkuma P. Shah

Theses

Hierarchically structured arrays of processors have widely been used in the low and intermediate phases of image processing and computer vision. Since the pyramid structure efficiently supports local and global operations extensively required by these phases, it has been widely used for relevant algorithms. Multilevel systems keep all the advantages of the pyramid structure while providing a general hierarchical structure that is easier to be used for the development of several algorithms and may also provide higher performance.

Although the cost of pyramid machines may be tremendously high, they have limited applications. In contrast, the hypercube network is widely used …

Adaptive Two-Stage Detection Scheme In Synchronous Two-User Cdma Systems, Yong Jiang

Theses

A conventional single user detector is not optimum in the multiuser environment because the multiuser interference can not be modeled as an additive Gaussian process. Such a receiver is very vulnerable to the near far situation. The receiver that is optimum for multiuser environment has high complexity and requires a knowledge of the received signal energies. Various versions of the receiver that handle the near far situation have been proposed in the literature. In this work, an adaptive two stage scheme for a synchronous two user environment with unknown received energies is proposed. It consists of a, tandem of the …

Tantalum Silicide Variable Capacitance Rotary Micromotors : Design And Fabrication, Michael Steven Berry

Theses

Tantalum silicide was studied as an alternative microelectromechanical material by fabricating a rotary micromotor utilizing a proven design. This material was used for the rotor, stators, and bearing over a silicon substrate. It has the attraction of potentially reducing the friction which is a major problem with polysilicon-to-polysilicon bearings.

The necessity of high aspect ratio features required that a plasma or reactive ion etch with a high degree of anisotropy be developed to etch tantalum silicide films in excess of 1.5μm. A sulfur hexafluoride/Freon 115 plasma provided the necessary process control during the etches. The stress present in annealed tantalum …

Properties And Determination Of Optimal Decentralized Feedback Structure, Kangsong Han

Theses

In this thesis, the decentralized feedback structure for large scale, linear time invariant systems is studied. The internal differences and the relationship between decentralized feedback structure and centralized feedback structure are discussed. The conventional diagonal feedback structure. corresponding to the classical single loop design strategy, is first analyzed. This is followed by an arbitrary decentralized information flow constraint which is dependent upon the actual plant characteristics. Although signal flow graphs have limited use in describing decentralized control systems. the concept of a control cycle unit based on signal flow is introduced as a supplementary tool to characterize some fixed modes …

Fair And Efficient Transmission Over Gbps Dual Ring Networks, Abdelnaser M. Adas

Theses

The advances in fiber optics technology provide large bandwidth and enable the support of a wide variety of services. New network architectures have been proposed, such as Metaring and Distributed Queue Dual Bus (DQDB), that try to take advantage of the new capabilities. Because of the very small packet transmission time relative to the feedback time a challenging issue in high speed networks is the efficient and fair share of the channel bandwidth among the competing users. In this thesis we first investigate and compare the performance of the Global and Local Fairness Mechanisms (GFM and LFM, respectively). They have …

Performance Of Different Strategies For Error Detection And Correction In Arithmetic Encoding, George F. Elmasry

Theses

Lossless source encoding is occasionally used in some data compression applications. One of these encoding schemes is the arithmetic encoding.

When data is to be transmitted via communication channel, noise and impurities imposed by the channel cause errors. To reduce the effect of errors, channel encoder is added prior to transmission through the channel. Channel encoder inserts some bits that help channel decoder at the receiver end to detect and correct errors. These added error detection and correction bits are redundancy that causes reduction in the compression ratio and hence an increase in data rate through the channel. The higher …

Modeling And Analysis Of Semiconductor Manufacturing Processes Using Petri Nets, Xinyao Wang

Theses

This thesis addresses the issues in modeling and analysis of multichip module (MCM) manufacturing processes using Petri nets. Building such graphical and mathematical models is a crucial step to understand MCM technologies and to enhance their application scope.

In this thesis, the application of Petri nets is presented with top-down and bottom-up approaches. The theory of Petri nets is summarized with its basic notations and properties at first. After that, the capability of calculating and analyzing Petri nets with deterministic timing information is extended to meet the requirements of the MCM models. Then, using top-down refining and system decomposition, MCM …

Design Of A 320x122 Mwir-Ccd Ptsi-Si Imaging Radiometer With Automatic Optical Integration Time Control, Nathaniel Joseph Mccaffrey

Theses

An infrared CCD camera system was designed and developed to operate a 320X244 Schottky-barrier IR-CCD Focal Plane Array (FPA) as an imaging radiometer. The goal of this research was to develop a reliable radiometer capable of resolving temperatures between 50 and 1000°C to within 1°C accuracy using non-contact spectral thermographic methods. To accomodate this wide dynamic range, the imager was operated in a non-interlaced format with variable optical integration times ranging from 120µsec to 122msec. Variable integration control was achieved by employing a "dump and read" timing procedure. To facilitate this operation, novel circuitry was developed for dynamically controlling the …

Monolithic Silicon Opto-Electro-Mechanical Light Modulator, Ching-Horng Wu

Theses

A Fabry-Perot light beam modulator of the reflection-type has been designed with process and performance parameters optimized. This design takes advantage of the economies of surface micromaching using silicon substrates and selected thin films. High performance with a low drive voltage are achieved using electrostatic actuation of a thin polysilicon diaphragm. The diaphragm is a novel corrugated structure which has maximum compliance and maintains planarity during actuation. In addition, the corrugationsuspension used provides an improved linearity of amplitude modulation response as a function of the actuation voltage.

A preliminary version of this device has been fabricated through a contract foundry …

Investigation Of The Consumer Electronics Bus, Jaesoo Yang

Dissertations

The objectives of this dissertation are to investigate the performance of the Consumer Electronics Bus (CEBus) and to develop a theoretical formulation of the Carrier Sense Multiple Access with Contention Detection and Contention Resolution (CSMA/CDCR) with three priority classes protocol utilized by the CEBus

A new priority channel assigned multiple access with embedded priority resolution (PAMA/PR) theoretical model is formulated. It incorporates the main features of the CEBus with three priority classes. The analytical results for throughput and delay obtained by this formulation were compared to simulation experiments. A close agreement has been found thus validated both theory and simulation …

On Adaptive Censored Cfar Detection, Loizos Anastasiou Prastitis

Dissertations

In an automatic radar detection system the received signal in every range resolution cell is compared with a threshold to test for the presence of a target. A Neyman-Pearson type test is used which maximizes the probability of detection for a fixed probability of false alarm. For the simple case where the noise is homogeneous a fixed threshold is chosen to achieve the designed constant false alarm rate (CFAR). In the more realistic case the noise background is non-stationary due to clutter and interference. In this situation, the threshold used for testing a particular cell is usually set adaptively using …

Reduction Of Acoustic Feedback Oscillations By Use Of Spectrum Shifting, Youssef Abdelilah

Theses

The problem of whistling noise or self-oscillation in public address systems operating in closed halls or rooms can be very disturbing to the listeners. This noise is sustained when the positive acoustic feedback, of the public address-room system, meets the oscillation criteria. This feedback system results from the acoustic sound signal reflected off the room walls and any other obstacles in the room, originating from the public address speakers and then re-entering the microphone.

When all of the audio signal components entering the public address system are shifted by a frequency increment Δf of 6 Hz, an increase of 5 …

An Improved Human Gait Model Incorporating The Effects Of Muscle Activity And Joint Friction, Tae Ho Choi

Theses

In designing an artificial leg for an amputee, it is important to find those underlying principles which determine the normal human gait. For this purpose we have developed a model of human walking, in which it is possible to predict an optimal gait at any given speed of walking based on the principle of minimum mechanical energy consumption.

Our model is an extension of the model proposed by Mochon and McMahon (1980). Their model assumes that during the swing phase of walking mechanical energy is conserved. Non-conservative forces due to muscle activity are assumed to occur during the double support …

Studies Of Wet Thermal Oxidation Of Silicon And Porous Silicon, Nilesh A. Gharia

Theses

Wet Thermal Oxidation of Silicon in VLSI is an extremely important step in the formation of field oxides. Understanding oxidation kinetics is critical for process reproducibility. The present study aims at gaining an insight into the oxidation kinetics through large experimental data at process temperatures of 800°C, 900°C, 1000°C and 1100°C with a bubbler temperature of 98°C. Oxides with thicknesses ranging from 100A to 7000A have been grown. Rate constants are obtained for the growth kinetics. Extensive characterization studies have been performed on MOS structures produced after wet oxidation.

In addition, porous silicon which assumes a growing significance in the …

Microwave Gaas Mesfet Nonlinearity And Large-Signal Modeling, Yan He

Theses

The nonlinearity analysis for a 0.5μm gate length microwave GaAs metal-semiconductor field-effect transistor (MESFET) by HP85150B Microwave Design System was investigated. The analysis starts with the construction of a large-signal MESFET equivalent circuit model. This model consists of bias dependent elements that were extracted by the optimization of DC and small-signal S-parameter measurement data. The details on this construction procedure are included in this work. The MESFET third-order intermodulation distortion was then simulated by HP85150B Microwave Design System. Reasonable agreement was obtained between simulation and measurement results. Microwave GaAs MESFET nonlinearity principles and large-signal modeling technique review are also presented. …

Partial Vlsi Implementation Of The Architecture For Reusable Components (Arc), Deepak Kakadasam

Theses

This work describes a novel VLSI implementation of the Architecture for Reusable Components (ARC) processor, using Hardware Description Language (HDL). The main goal here is to achieve efficient execution of reusable software through proper hardware support. This involves the hard wired implementation of each instruction designed for the ARC processor.

Instructions are broken down into their logical functions, then modeled and simulated through the hierarchical design methods that HDL offers. The structural model of the processor has been developed and simulated. The purpose here has been to begin work on the design and implementation of the ARC processor.

The instructions …

Performance Analysis Of Pyramid Mapping Algorithms For The Hypercube, Jing-Chiou Liou

Theses

Comparative performance analysis of algorithms that map pyramids and multilevel structures onto the hypercube are presented. The pyramid structure is appropriate for low-level and intermediate-level computer vision algorithms. It is not only efficient for the support of both local and global operations but also capable of supporting the implementation of multilevel solvers. Nevertheless, pyramids lack the capability of efficient implementation of the majority of scientific algorithms and their cost may become unacceptably high. On a different horizon, hypercube machines have widely been used in the field of parallel computing due to their small diameter, high degree of fault tolerance, and …

Application Of Imaging Pyrometry For Remote Temperature Measurements, Michael B. Kaplinsky

Theses

The radiometric model of an IR image sensor has been developed. Based on this model, the application of imaging pyrometry to remote temperature measurements has been investigated. This analysis provides the estimation of temperature accuracy achievable by imaging pyrometry in conjunction with a number of radiometric methods. The detection of radiation emitted across the full spectral bandwidth of the imager as well as utilization of narrow-passband filters was analyzed for a target with known emissivity.

The methods of two-wavelength ratio radiometry and multi-wavelength radiometry were considered for the targets with unknown emissivity. The optimal selection of the wavelengths for the …

Modal Control Of Flexible Beam Using Smart Mateirals, Sujata Mallepalle

Theses

In this work, the dynamics and control aspects of a vibrating flexible beam using modal analysis are studied. To damp the vibrations of the system, the vibrations of each mode has to he controlled, which can he done if we know the individual mode shape. and the resonance frequency. These quantities can be derived mathematically or measured experimentally with a spectrum analyzer. Individual modal velocities can be computed by integration of the product of beam velocity and the mode shape, over the interval of beam length. The integration is carried out using numerical methods. The necessary discrete ordinates are obtained …

Optical Flow Determination And Motion Analysis, Qian Wang

Theses

Optical flow, also known as image flow, is of fundamental importance in the processing of image sequences. Various approaches to determine optical flow have been proposed --- others continue to appear. Using several sets of real image sequences, here, the results of three different approaches to the the determination of optical flow are reported, the approaches are the Gradient-based approach, the Correlation-based approach and the Correlation-feedback approach. The comparisons are primarily empirical, and they show that the performance of these different algorithms differs significantly among the different image sequences, indicating that there does not exists one superior algorithm which could …

A Programmable Integrated Power Supply For The Electrostatic-Drive Micromotor, Chao Ye

Theses

A 6-phase bipolarized, high-voltage power supply with rectangular pulse shape has been designed to study the special operational characteristics of various electrostatic-drive micromotors. In particular the design powers the variable-capacitance side-drive micromotor. This power supply provides variable frequency, variable voltage, and variable duty-cycle control. Simulation has been used extensively in the design and design verification.

The bipolarization (dual voltage polarity) of each pair of the phases reduces physical clamping of the rotor to the electrical shield beneath it. Thus, bipolarization of the voltage supplied to the stator nodes reduces charge build-up on the rotor.

The output frequency range varying from …