Engineering Commons^™

Experimental Ion Implantation System For Decaborane Ions, Vijay Babaram

Theses

Future generations of Si technology will require ultra shallow junctions (tens of nm) in the drain and source regions of MOS transistors. Fabrication of such shallow p-type junctions requires implantation of boron at ultra low energies (< 1 keV), below the limits of standard ion implantation technology. A proposed solution involves implantation of B₁₀H_x⁺ ions in which boron atoms carry less than 10% of the beam energy.

This thesis is a part of the feasibility study of this new technology. An experimental ion implantation system was designed and built at Ion Beam and Thin Film Lab, NJIT. The system was tested and the mass analyzing magnet was calibrated using argon ions. Decaborane ions, …

Selective Area Deposited Blue Gan-Ingan Multiple-Quantum Well Light Emitting Diodes Over Silicon Substrates, J. W. Yang, A. Lunev, Grigory Simin, A. Chitnis, M. Shatalov, M. Asif Khan, Joseph E. Van Nostrand, R. Gaska

Faculty Publications

We report on fabrication and characterization of blue GaN–InGaN multi-quantum well (MQW)light-emitting diodes(LEDs) over (111) silicon substrates. Device epilayers were fabricated using unique combination of molecular beam epitaxy and low-pressure metalorganic chemical vapor depositiongrowth procedure in selective areas defined by openings in a SiO₂mask over the substrates. This selective area deposition procedure in principle can produce multicolor devices using a very simple fabrication procedure. The LEDs had a peak emission wavelength of 465 nm with a full width at half maximum of 40 nm. We also present the spectral emission data with the diodes operating up to 250 …

Electroluminescent Display Device Including Active Polymer Layer, Aemilianus G. J. Staring, David Braun, Karel E. Kuijk

Electrical Engineering

Control device for an electroluminescent display device, comprising an active layer of a semiconducting polymer of, for example pixels arranged in the form of a matrix, reducing flicker and crosstalk. The control device may be based on voltage control at which voltages across the pixels are at least 1.6 V, but is preferably based on current control, at which the duration of the data pulses determines the grey level.

Characteristics Of Free-Standing Hydride-Vapor-Phase-Epitaxy-Grown Gan With Very Low Defect Concentration, P. Visconti, K. M. Jones, Michael A. Reshchikov, F. Yun, R. Cingolani, Hadis Morkoç, S. S. Park, K. Y. Lee

Electrical and Computer Engineering Publications

A free-standing 300-μm-thick GaN template grown by hydride vapor phase epitaxy has been characterized for its structural and optical properties using x-ray diffraction, defect delineation etch followed by imaging with atomic force microscopy, and variable temperature photoluminescence. The Ga face and the N face of the c-plane GaN exhibited a wide variation in terms of the defect density. The defect concentrations on Ga and N faces were about 5×105 cm−2 for the former and about 1×107 cm−2 for the latter. The full width at half maximum of the symmetric (0002) x-ray diffraction peak was 69 and 160 arc sec …

Bias-Assisted Photoelectrochemical Etching Of P-Gan At 300 K, J. E. Borton, C. Cai, M. I. Nathan, P. Chow, J. M. Van Hove, A. Wowchak, Hadis Morkoç

Electrical and Computer Engineering Publications

Photoelectrochemical (PEC)etching of p-type GaN has been realized in room temperature, 0.1 M KOH solutions. PECetching of GaN was achieved by applying a positive bias to the surface of the p-GaN layer through a deposited titanium mask. The applied bias reduces the field at the semiconductor surface, which induced the dissolution of the GaN. The effect of bias on etch rate and morphology was examined. It was found that insulating the Ti mask from the KOH solution with Si3N4 significantly increases the etch rate. The rms roughness of the etched region decreased as the bias voltage increased. Etch rates …

Dislocation Density In Gan Determined By Photoelectrochemical And Hot-Wet Etching, P. Visconti, K. M. Jones, Michael A. Reshchikov, R. Cingolani, Hadis Morkoç, R. J. Molnar

Electrical and Computer Engineering Publications

Defects in GaN layers grown by hydride vapor-phase epitaxy have been investigated by photoelectrochemical (PEC)etching, and by wet etching in hot H3PO4acid and molten potassium hydroxide (KOH). Threading vertical wires (i.e., whiskers) and hexagonal-shaped etch pits are formed on the etched sample surfaces by PEC and wet etching, respectively. Using atomic-force microscopy, we find the density of “whisker-like” features to be 2×109 cm−2, the same value found for the etch-pit density on samples etched with both H3PO4 and molten KOH. This value is comparable to the dislocation density obtained in similar samples with tunnelingelectron microscopy, and is also consistent with …

Observation Of Electronic Raman Scattering From Mg-Doped Wurtzite Gan, K. T. Tsen, C. Koch, Y. Chen, Hadis Morkoç, J. Li, J. Y. Lin, H. X. Jiang

Electrical and Computer Engineering Publications

Electronic Raman scattering experiments have been carried out on both molecular beam epitaxy and metal-organic chemical vapor deposition-grown Mg-doped wurtzite GaN samples. Aside from the expected Raman lines, a broad structure (full width at half maximum≅15 cm−1)observed at around 841 cm−1 is attributed to the electronic Raman scattering from neutral Mg impurities in Mg-doped GaN. Our experimental results demonstrate that the energy between the ground and first excited states of Mg impurities in wurtzite GaN is about one-half of its binding energy.

Well-Width Dependence Of The Ground Level Emission Of Gan/Algan Quantum Wells, A. Bonfiglio, M. Lomascolo, G. Traetta, R. Cingolani, A. Di Carlo, F. Della Sala, P. Lugli, A. Botchkarev, H. Morkoç

Electrical and Computer Engineering Publications

We have performed a systematic investigation of GaN/AlGaN quantum wells grown on different buffer layers (either GaN or AlGaN) in order to clarify the role of strain, structural parameters, and built-in field in determining the well-width dependence of the ground level emission energy. We find that identical quantum wells grown on different buffer layers exhibit strong variation of the ground level energy but similar well-width dependence. The data are quantitatively explained by an analytic model based on the envelope function formalism which accounts for screening and built-in field, and by a full self-consistent tight binding model.

Characterization Of Poly-Si Thin Films Deposited By Magnetron Sputtering Onto Ni Prelayers, Elena A. Guliants, Wayne A. Anderson

Electrical and Computer Engineering Faculty Publications

A method of producing a polycrystalline silicon thin film on a foreign substrate without subsequent annealing has been developed. Thermally evaporated 5–100 nm thick Nifilms served as prelayers for magnetron sputtered Si thin films. A continuous film was obtained as a result of metal induced growth of polysilicon during low temperature (below 600 °C) deposition. The film uniformity is promising for large area device applications. The influence of the Ni prelayer thickness on the grain size of thus obtained films was investigated. Atomic force microscopy and cross-sectional scanning electron microscopy studies revealed features in the 150–600 nm size range while …

Optimal Distributed Binary Hypothesis Testing With Independent Identical Sensors, Q. Zhang, P. K. Varshney, R. D. Wesel

Electrical Engineering and Computer Science - All Scholarship

We consider the problem of distributed binary hypothesis testing with independent identical sensors. It is well known that for this problem the optimal sensor rules are a likelihood ratio threshold tests and the optimal fusion rule is a K-out-of-N rule [1]. Under the Bayesian criterion, we show that for a fixed K-out-of-N fusion rule, the probability of error is a quasiconvex function of the likelihood ratio threshold used in the sensor decision rule. Therefore, the probability of error has a single minimum and a unique optimal threshold achieves this minimum. We obtain a sufficient and necessary condition on the optimal …

On The Error Performance Of 8-Vsb Tcm Decoder For Atsc Terrestrial Broadcasting Of Digital Television, Dojun Rhee, Robert H. Morelos-Zaragoza

Faculty Publications

The error performance of various 8-VSB TCM decoders for reception of terrestrial digital television is analyzed. In previous work, 8-state TCM decoders were proposed and implemented for terrestrial broadcasting of digital television. In this paper, the performance of a 16-state TCM decoder is analyzed and simulated. It is shown that not only a 16-state TCM decoder outperforms one with 8-states, but it also has much smaller error coefficients.

Small Planar Monopole Covers Multiband Brans, Max Ammann, L. E. Doyle

Conference papers

The use of a single antenna which can cover a wide range of frequencies is a desirable feature for future wireless communications systems. The emerging self-organising and ad-hoc networks require more than an octave of bandwidth to facilitate multiband operation. A shorted planar monopole antenna is optimised for future wireless networking bands by suitable choice of planar dimension and feedgap separation. The antenna offers a return-loss greater than 10 dB from 1.60 GHz to 5.90 GHz. The radiation pattern is shown to be quasi-omnidirectional within the 10 dB return-loss bandwidth. Antenna properties are compared with the simple planar monopole.

A Review Of Battery Exchange Technology For Refueling Of Electric Vehicles, C. Arthur Maccarley

Electrical Engineering

The limited energy storage and long recharge time and of electric vehicle batteries have motivated several alternatives to in-vehicle slow charging. Solutions generally fall into three categories: (1) fast charging, in which batteries are charged in-vehicle at an accelerated rate, (2) battery material reloading or refueling, in which the energy-carrying elements of the battery are physically replaced or replenished, and (3) battery interchange, involving the complete exchange of the battery pack, usually with the aid of some semi-automated mechanism. Among these options, the last, battery interchange, has tended to receive the least industry attention, but has been an expansive topic …

Ambiguity Function Of An Ultrawideband Random Noise Radar, Muhammad Dawood, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

The University of Nebraska has developed an ultra-wideband (UWB) random noise radar system which transmits an ultra-wideband random noise (Gaussian) waveform with a uniform power spectral density (PSD) in the 1-2 GHz frequency range. The ability of the system to characterize the Doppler shift of moving targets exhibiting varying linear and rotational velocities was clearly demonstrated [l, 2]. In this paper, we look at the range and range rate resolution issues by analyzing the Woodward’s ambiguity function [3]. In general, the radar signal ambiguity function is defined as the normalized response of a filter matched to a return signal with …

Class Project On Airborne Radar System Design And Development For Remote Sensing Applications, Ram M. Narayanan, K. Jon Ranson

Department of Electrical and Computer Engineering: Faculty Publications

A unique experiment on remote sensing education has recently been undertaken involving an educational institution (University of Nebraska-Lincoln) and a government agency involved in remote sensing (NASA Goddard Space Flight Center). The centerpiece of this experiment is the assignment of an airborne radar system design project to students enrolled in a senior undergraduate and graduate level class on Radar Systems. The class was split into two competing teams. A fictitious request for proposal (RFP) was issued by NASA GSFC, and the teams responded to the RFF’ by proposing and defending competing designs. The teams also prepared final design reports, and …

A Comparative Study Of Uwb Fopen Radar Imaging Using Step-Frequency And Random Noise Waveforms, Xiaojian Xu, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

The detection and identification of targets that are obscured by foliage have been topics of great interest. Several experimental developments of such ultrawideband (UWB) radars have been published. By operating in the VHF and UHF frequency bands and using either LFM or step-frequency waveforms, these radars have demonstrated promising images of terrain and man-made objects obscured by dense foliage [l]. The University of Nebraska has developed a new technique that permits coherent processing of backscatter data acquired by a radar that transmits UWB random noise signals. This technique has been used in various applications, such as ground penetration detection of …

Bottom-Up Design Of Artificial Neural Network For Single-Lead Electrocardiogram Beat And Rhythm Classification, Srikanth Thiagarajan

Doctoral Dissertations

Performance improvement in computerized Electrocardiogram (ECG) classification is vital to improve reliability in this life-saving technology. The non-linearly overlapping nature of the ECG classification task prevents the statistical and the syntactic procedures from reaching the maximum performance. A new approach, a neural network-based classification scheme, has been implemented in clinical ECG problems with much success. The focus, however, has been on narrow clinical problem domains and the implementations lacked engineering precision. An optimal utilization of frequency information was missing. This dissertation attempts to improve the accuracy of neural network-based single-lead (lead-II) ECG beat and rhythm classification. A bottom-up approach defined …

A Hierarchical Channel Selection Scheme For Macro/Micro Cellular Networks, Ayesha Zaheer

Retrospective Theses and Dissertations

Hierarchical channel allocation schemes for cellular networks offer a promising approach to solve the pressing problem of increasing the cellular servicing capacity in spite of the limited radio spectrum available. We propose a hierarchical channel selection scheme for handling handoffs and new calls in micro/macro cellular systems. The scheme is intended to improve the performance and quality of service of these systems by increasing the cell channel utilization, reducing the handoff blocking probability and improving the responsive to new calls.

The proposed scheme is based on several design enhancements including an overflow buffer, which is used for handoff calls that …

Signal Integrity In Deep Submicron Cmos Chip Design, Jignesh Suresh Sonchhatra

Retrospective Theses and Dissertations

Advancement in CMOS technology has become a driving force in the advancement of today's IC design arena. In the past few years, considerable research has been done on the CMOS devices and circuits. Constant efforts have been made to realize smaller and smaller devices by reducing the channel length of the transistors and scaling down various other device parameters. Consequently, various problems have arisen such as interconnect delay, signal integrity and signal coupling.

The purpose of this thesis is to review and understand current problems in IC design and come up with various solutions to them. Efforts have been made …

Mekanisma Pengujian Alu Menggunakan Teknik Boundary Scan, Abdul Aziz Ahmad Zaki Zamani

Student Works (2000-2009)

ALU testing mechanism using Boundary Scan technique is a project which is develop to be the tester for testing the digital circuit, integrated circuit and computer chip. The goal of this project is to develop a mechanism and as well building an ALU chip so that we will able to test and determine whether the chips are in a good shape and condition. This project contains two parts: one is lo develop an ALU and second is to develop the boundary scan chip. ALU is a unit or a component for a cligital circuit or a integrated circuit which is …

Litar Aritmetik Reja, Abd. Mutalib Leorna Shazerine

Student Works (2000-2009)

Projek Ilmiah Tahap Akhir II, iaitu WXES 3182 adalah suatu latihan akademik di dalam penyelidikan, rekabentuk, pembangunan dan komunikasi yang melibatkan prinsip-prinsip sains komputer. Projek WXES 3182 ini merupakan kursus pelengkap bagi pelajar-pelajar tahun akhir untuk mendapatkan penganugerahan Sarjana Muda Sains Komputer. Projek WXES 3182 ini adalah kesinabungan daripada projek WXES 3181 Kajian penyehdikan yang telah dijalankan adalah berkaitan dengan konsep sistem nombor reja dan litar aritmetik reja. Laporan latihan ilmiah tahap akhir II ini, merangkumi pembangunan projek WXES 3181 dan WXES 3182. laporan ini terdiri daripada lapan bahagian dan diantaranya ialah pengenalan kepada projek, kajian literasi, metodologi yang digunakan …

Vhdl Description For Ip Engine, Bathich Zeliall

Student Works (2000-2009)

Developing hardware support for network layer protocol processing is a very complex and demanding task. However. for optimal performance hardware acceleration can be required. To cope with the situation. this project present a high-level design approach. which targets the development of configurable and reusable components. Therefore it obtains the integration of advanced tools for the development of the IP Engine into the design environment. This process is illustrated based on a TCP/IP header analysis and validation component for which initial performance results are presented. The development of this Engine is embedded in an approach to develop flexible and configurable protocol …

Structural Characterization Of Rapid Thermal Oxidized Si1−X−YGeXCY Alloy Films Grown By Rapid Thermal Chemical Vapor Deposition, W. K. Choi, J. H. Chen, L. K. Bera, W. Feng, K. L. Pey, J. Mi, Cary Y. Yang, A. Ramam, S. J. Chua, J. S. Pan, A. T.S. Wee, R Liu

Electrical and Computer Engineering

The structural properties of as-grown and rapid thermal oxidized Si_1−x−yGe_xC_y epitaxial layers have been examined using a combination of infrared, x-ray photoelectron, x-ray diffraction, secondary ion mass spectroscopy, and Raman spectroscopy techniques. Carbon incorporation into the Si_1−x−yGe_xC_y system can lead to compressive or tensile strain in the film. The structural properties of the oxidized Si_1−x−yGe_xC_y film depend on the type of strain (i.e., carbon concentration) of the as-prepared film. For compressive or fully compensated films, the oxidation process drastically reduces the carbon content so that …

Erbium-Ytterbium Codoped Fiber Amplifiers, Wai Yee Chan

Student Works (2000-2009)

The amplification characteristics of an Erbium/Ytterbium codoped fiber amplifier(EYDFA) pumped in both the 800nm and 980nm pump bands is reported. With -3m long Er-Yb fiber, the 813nm pumped-EYDFA shows small-signal gain exceeding 20dB over a 20nm bandwidth in the l.Sµm region where the peak gain of 38.4dB is achieved at 1535nm. A low noise figure of ~3.6d8 is also achieved at 1550nm. However, it is found that 980nm pumped­EYDF A suffers lower gain due to the effect of nonsaturable absorption by Yb³⁺ ions which causes high pump poWer loss, thus degrades the signal amplification in Er³⁺ system. Compared to the …

Pendarab Titik Apungan 32bit Bertalian Paip, Noorzaily Mohamed Noor

Student Works (2000-2009)

Tesis ini menghuraikan sebuah pendarab titik apungan 32bit bertalian paip 18MHz yang direkabentuk menggunakan bahasa perihalan perkakasan YHDL, peralatan sintesis Synopsys FPGA Express dan ·peralatan pemetaan Xilinx Alliance, PTA ini menggunakan 1007 CLB dan 100 10B di mana peranti pemetaan yang digunakan ialah xc4036xl-bg432-2 daripada pustaka XC4000 Xilinx FPGA. Pendarab ini mengandungi tiga tahap talian paip yang belainan fungsi. Tahap pertama melaksanakan penjanaan dedarab dan penambahan dedarab secara carry save dan penambahan eksponen. la menggunakan algoritma Booth tertib kedua dan pepohon Wallace dengan pemampat 4-2. Tahap kcdua pula melakukan penambahan bawaan rambatan akhir, penormalan mantisa dan pembetulan eksponen manakala tahap …

Monaural Cue Sound Localizer, John G. Harris, Chiang Jung Pu, Jose C. Principe

Electrical and Computer Engineering Faculty Research & Creative Works

We describe the first single microphone sound localization system and its inspiration from theories of human monaural sound localization. Reflections and diffractions caused by the external ear (pinna) allow humans to estimate sound source elevations using only one ear. Our single microphone localization model relies on a specially shaped reflecting structure that serves the role of the pinna. Specially designed analog VLSI circuitry uses echo-time processing to localize the sound. A CMOS integrated circuit has been designed, fabricated, and successfully demonstrated on actual sounds.

Series Operation Of Direct Current Xenon Chloride Excimer Sources, Ahmed El-Habachi, Wenhui Shi, Mohamed Moselhy, Robert H. Stark, Karl H. Schoenbach

Bioelectrics Publications

Stable, direct current microhollow cathode discharges in mixtures of hydrochloric acid, hydrogen, xenon, and neon have been generated in a pressure range of 200–1150 Torr. The cathode hole diameter was 250 μm. Sustaining voltages range from 180 to 250 V at current levels of up to 5 mA. The discharges are strong sources of xenon chloride excimer emission at a wavelength of 308 nm. Internal efficiencies of approximately 3% have been reached at a pressure of 1050 Torr. The spectral radiant power at this pressure was measured as 5 mW/nm at 308 nm for a 3 mA discharge. By using …

Electroporation Dynamics In Biological Cells Subjected To Ultrafast Electrical Pulses: A Numerical Simulation Study, R. P. Joshi, K. H. Schoenbach

Bioelectrics Publications

A model analysis of electroporation dynamics in biological cells has been carried out based on the Smoluchowski equation. Results of the cellular response to short, electric pulses are presented, taking account of the growth and resealing dynamics of transient aqueous pores. It is shown that the application of large voltages alone may not be sufficient to cause irreversible breakdown, if the time duration is too short. Failure to cause irreversible damage at small pulse widths could be attributed to the time inadequacy for pores to grow and expand beyond a critical threshold radius. In agreement with earlier studies, it is …

Application Of Wavelets And Principal Component Analysis In Image Query And Mammography, Sol Neeman Ph.D.

Engineering Studies Faculty Publications and Creative Works

Breast cancer is currently one of the major causes of death for women in the U.S. Mammography is currently the most effective method for detection of breast cancer and early detection has proven to be an efficient tool to reduce the number of deaths. Mammography is the most demanding of all clinical imaging applications as it requires high contrast, high signal to noise ratio and resolution with minimal x-radiation. According to studies [36], 10% to 30% of women having breast cancer and undergoing mammography, have negative mammograms, i.e. are misdiagnosed. Furthermore, only 20%-40% of the women who undergo biopsy, have …

Nonlinear Self-Organization In Photorefractive Materials, Partha P. Banerjee, Nickolai Kukhtarev, John O. Dimmock

Electrical and Computer Engineering Faculty Publications

This chapter discusses self-organization and its effects in optics. One of the most exciting and potentially useful areas of current research in optics involves the understanding and exploitation of self-organization in nonlinear optical systems. This self-organization may sometimes lead to the evolution of complex spatial patterns that can be regarded as the nonlinear eigenmodes of the system. Generation of these patterns is characteristically marked by the presence of intensity thresholds. In a nonlinear system with complicated temporal dynamics, it turns out that one cannot retain purity in spatial dimensionality. It is therefore equally important to investigate the dynamics of the …