Engineering Commons^™

Electromagneticbeamdirecting Means-Sampleanalyss System Stage, And Method Of Use, Daniel W. Thompson, Darin W. Glenn, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is an electromagnetic beam directing means for use with sample analysis systems, such as reflectometers, ellipsometers and polarimeters and the like, use of which facilitates investigation of sample systems which are not mounted to a sample analysis system sample system supporting stage. The present invention eliminates the requirement of extensive sample analysis system component realignment when alternatingly performing analysis of sample systems mounted upon, and mounted other than upon, a sample analysis system sample system supporting stage.

Influence Of Canal Geometry And Dynamics On Controllability, Theodor S. Strelkoff, Jean Luc Deltour, Charles M. Burt, Albert J. Clemmens, Jean Pierre Baume

BioResource and Agricultural Engineering

This paper presents the results of the Task Committee on Canal Automation Algorithms with regard to the influence of canal properties on the controllability of irrigation canals. While the control provided by individual algorithms was not evaluated, studies were performed to illustrate inherent hydraulic limitations—the inability of canal pools to recover rapidly from disturbances or flow perturbations. Studies were performed in nondimensional form to develop a better understanding of how pool properties influence pool response. Three such studies were performed. First, nondimensional backwater curves were developed for a range of canal conditions. The second study involved the propagation of waves …

The Restoration Of A Wwii Avenger Provides Projects For Wpi Students, Donald N. Zwiep, William W. Durgin, Nathan H. Mayo

Office of the Provost Scholarship

In 1970 WPI completely revised its traditional approach to engineering education. The resulting program, the WPI Plan, emphasized the use of projects as a distinctive process for achieving educational goals. Every student, as a degree requirement, had to successfully complete two major projects: one in a student's major field, the Major Qualifying Project (MQP) and the second, the Interactive Qualifying Project (IQP), which related science and technology to societal issues.

The IQP's related to the restoration of the WWII Avenger at Mayocraft, Inc. for the Collings Foundation in Stow, Massachusetts enabled the students working with the authors as advisors to …

Acuta Enews January 1998, Vol.27, No. 1

ACUTA Newsletters

In This Issue

School NOT Required to Contribute to USF

What's Your Biggest Challenge for 1998?

Board Report

Spotlight

Analyzing Cable Needs and Planning for the Future at CMU

Tech Partners at Cal State

Directories Are Here!

DC at a Glance

Position Available

Welcome New Members

On How To Merge Sorted Lists Coming From Different Web Search Tools, Ronald R. Yager, Vladik Kreinovich

Departmental Technical Reports (CS)

Different web search tools often complement each other. So, if we want to have a good coverage of all relevant web items, a reasonable strategy is to use different search tools and then merge the resulting lists. How to merge them? In this paper, we describe reasonable axioms for the merging procedure and describe all mergings that satisfy these reasonable axioms.

Piezoelectric Effects On The Optical Properties Of Gan/Alxga1−Xn Multiple Quantum Wells, H. S. Kim, J. Y. Lin, H. X. Jiang, W. W. Chow, A. Botchkarev, Hadis Morkoç

Electrical and Computer Engineering Publications

Piezoelectric effects on the optical properties of GaN/AlGaN multiple quantum wells(MQWs) have been investigated by picosecond time-resolvedphotoluminescence(PL)measurements. For MQWs with well thicknesses 30 and 40 Å, the excitonic transition peak positions at 10 K in continuous wave (cw) spectra are redshifted with respect to the GaN epilayer by 13 and 45 meV, respectively. The time-resolvedPL spectra of the 30 and 40 Å well MQWs reveal that the excitonic transition is in fact blueshifted at early delay times due to quantum confinement of carriers. The spectral peak position shifts toward lower energies as the delay time increases and becomes redshifted at …

Deep Centers In N-Gan Grown By Reactive Molecular Beam Epitaxy, Z.-Q. Fang, D. C. Look, W. Kim, Z. Fan, A. Botchkarev, Hadis Morkoç

Electrical and Computer Engineering Publications

Deep centers in Si-doped n-GaN layers grown by reactive molecular beam epitaxy have been studied by deep-level transient spectroscopy as a function of growth conditions. Si-doped GaN samples grown on a Si-doped n+-GaN contact layer at 800 °C show a dominant trap C1 with activation energyET=0.44 eV and capture cross-section σT=1.3×10−15 cm−2, while samples grown at 750 °C on an undoped semi-insulating GaN buffer show prominent traps D1and E1, with ET=0.20 eV and σT=8.4×10−17 cm2, and ET=0.21 eV and σT=1.6×10−14 cm2, respectively. Trap E1 is believed to be related to a N-vacancy defect, since the Arrhenius signature for E1 is …

Plasma Heating In Highly Excited Gan/Algan Multiple Quantum Wells, K. C. Zeng, R. Mair, J. Y. Lin, H. X. Jiang, W. W. Chow, A. Botchkarev, Hadis Morkoç

Electrical and Computer Engineering Publications

Time-resolvedphotoluminescence(PL)spectroscopy was used to investigate carrier distributions in a GaN/AlGaN multiple quantum well(MQW) sample under high excitation intensities necessary to achieve lasing threshold. Room temperaturePL spectra showed optical transitions involving both confined and unconfined states in the quantum well structure. Analysis of the experimental results using a microscopic theory, indicates that at high excitation the carrier distributions are characterized by plasma temperatures which are significantly higher than the lattice temperature. The implications of our findings on GaN MQW laser design are also discussed.

Deep Level Defects In N-Type Gan Grown By Molecular Beam Epitaxy, C. D. Wang, L. S. Yu, S. S. Lau, E. T. Yu, W. Kim, A. E. Botchkarev, Hadis Morkoç

Electrical and Computer Engineering Publications

Deep-level transient spectroscopy has been used to characterize electronic defects in n-type GaN grown by reactive molecular-beam epitaxy. Five deep-level electronic defects were observed, with activation energiesE1=0.234±0.006, E2=0.578±0.006, E3=0.657±0.031, E4=0.961±0.026, and E5=0.240±0.012 eV. Among these, the levels labeled E1, E2, and E3are interpreted as corresponding to deep levels previously reported in n-GaN grown by both hydride vapor-phase epitaxy and metal organic chemical vapor deposition. Levels E4 and E5do not correspond to any previously reported defect levels, and are characterized for the first time in our studies.

Optical Modes Within Iii-Nitride Multiple Quantum Well Microdisk Cavities, R. A. Mair, K. C. Zeng, J. Y. Lin, H. X. Jiang, B. Zhang, L. Dai, A. Botchkarev, W. Kim, Hadis Morkoç, M. A. Khan

Electrical and Computer Engineering Publications

Optical resonance modes have been observed in optically pumped microdisk cavitiesfabricated from 50 Å/50 Å GaN/AlxGa1−xN(x∼0.07) and 45 Å/45 Å InxGa1−xN/GaN(x∼0.15)multiple quantum well structures. Microdisks, approximately 9 μm in diameter and regularly spaced every 50 μm, were formed by an ion beametch process. Individual disks were pumped at 300 and 10 K with 290 nm laser pulses focused to a spot size much smaller than the disk diameter. Optical modes corresponding to (i) the radial mode type with a spacing of 49–51 meV (both TE and TM) and (ii) the Whispering Gallery mode with a spacing of 15–16 meV were …

Effect Of Ammonia Flow Rate On Impurity Incorporation And Material Properties Of Si-Doped Gan Epitaxial Films Grown By Reactive Molecular Beam Epitaxy, Wook Kim, A. E. Botchkarev, H. Morkoç, Z.-Q. Fang, D. C. Look, David J. Smith

Electrical and Computer Engineering Publications

Effect of ammonia flow rate on the impurity incorporation and material properties of Si-doped GaN films grown by reactive molecular beam epitaxy (RMBE) process is discussed. It appears that the ammonia flow rate has a marginal effect on the incorporation of impurities into the Si-doped GaN films except there was a little decrease in O and Si with increasing ammonia flow rate when the Si concentration in the film is higher than 1018 cm−3. Electron Hall mobility of Si-doped GaN films grown by RMBE varies with ammonia flow rate used during film growth. From deep level transient spectroscopy(DLTS) measurements for …

Current Concepts Review - Corrosion Of Metal Orthopaedic Implants, Joshua J. Jacobs, Jeremy L. Gilbert, Robert M. Urban

Biomedical and Chemical Engineering - All Scholarship

No abstract provided.

Birkman Screening And The Covariance Of The Fluid Velocity Of Fixed Beds, Ashok S. Sangani, Donald L. Koch, Reghan J. Hill

Biomedical and Chemical Engineering - All Scholarship

The phenomenon of Brinkman screening, whereby the fluid velocity disturbance produced by each particle in a fixed bed is attenuated by the forces that the fluid exerts on surrounding particles, plays a crucial role in limiting the range of velocity correlations in porous media and fixed beds. Koch and Brady [J. Fluid Mech. 154, 399 (1985)] showed theoretically that Brinkman screening leads to a finite hydrodynamic diffusion coefficient for fluid phase tracers in dilute fixed beds. In this Letter, we present the results of two simulation techniques (lattice-Boltzmann method and a multipole method) confirming the screening of the fluid velocity …

Tissue Engineering: At The Interface Between Engineering, Biology And Medicine, Brenda Ogle, Priti Gairola, Jodi Balik, Daniel L. Mooradian

Journal of the Minnesota Academy of Science

No abstract provided.

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 …

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.

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 …

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 …

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 …

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.

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, …

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(N_D = 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 …

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 …

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 …

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 …

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 …

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 …

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.

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.

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 …