The design and implementation of Switched-Current (SI) ladder filters is described. SI filters require only a standard digital CMOS process and the power supply voltage requirement is low. SI circuits also can be potentially operated at higher frequencies than Switched-Capacitor (SC) filters due to the low-impedance wideband nodes of the current mirrors. A simple method has been developed to design SI ladder and biquadratic fllters with maximum dynamic range that leverages the well-established design methodologies of SC filters. A standard digital 2-micron n-well CMOS process has been used to implement two high-order ladder filters and two biquadratic filters. Simulations accurately predict the measured results of the first integrated SI filters. The area and power dissipation are comparable to the switched-capacitor technique. Analysis of the factors that effect dynamic range in SI filters is presented. The factors that contribute to harmonic distortion in the current-mode circuits are characterized and the relationships to maximum signal size are established. Using measurements of the input-referred noise from SI filters, the dynamic range is obtained. / Graduation date: 1991

Computers using the tagged-token dataflow model are among the best candidates for delivering extremely high levels of performance required in the future. Instruction scheduling in these computers is determined by associatively matching data-bearing tokens in a Waiting-Matching Unit (W-M unit). At the W-M unit, incoming tokens with matching contexts are forwarded to an instruction while non-matching tokens are stored to await their matching partner. Requirements of the W-M unit are exacting. Necessary token storage capacity at each processing element (PE) is presently estimated to be 100,000 tokens. Since the most often executed arithmetic instructions require two operands, the bandwidth of the W-M unit must be approximately twice that of the ALU. The contradictory requirements of high storage capacity and high memory bandwidth have compromised the M-W units of previous dataflow computers limiting their speed. However, tokens arriving at a PE exhibit strong temporal locality. This naturally suggests the use of some caching technique. Using a recently developed CAM memory structure as a base, a token caching scheme is described which allows rapid, fully associative token matching while allowing a large token storage capacity. The key to the caching scheme is a fast and compact, articulated, first-in, first-out, content addressable memory (AFCAM) which allows associative matching and garbage collection while maintaining temporal ordering. A new memory cell is developed as the basis for the AFCAM in an advanced CMOS (Complementary Metal Oxide Semiconductor) technology. The design of the cell is discussed as well as electrical simulation results, verifying its operation and performance. Finally, estimated system performance of a dataflow computer using the caching scheme is presented. / Graduation date: 1991

Graduation date: 1991

En aquesta tesi es detalla la metodologia per obtindre sensors de gasos basats en òxid de tungstè nanoestructurat sobre suports micromecanitzats de silici. Aquesta nanoestructuració s’ha fet mitjançant una capa d’alúmina porosa como a motlle, pel que s’ha desenvolupat una metodologia per a compatibilitzar l'anodització de l’alumini, i altres metalls com el tungstè, amb els processos estàndards del silici. S’han desenvolupat dos tipus de capes nanoestructurades, nanotubs i nanopunts de WO3. Els nanotubs s’han obtingut depositant mitjançant polvorització catòdica reactiva la capa sensible sobre alúmina porosa recobrint les parets dels pors. Els nanopunts s’han obtingut anoditzant una bicapa d’alumini i tungstè, on la primera anodització crea la alúmina porosa i la segona fa créixer els nanopunts d’òxid de tungstè en la base dels pors. S’ha analitzat la composició, morfologia i funcionament com a sensors de gasos d’ambdós materials nanoestructurats i s’han comparat els resultats amb sensors basats en materials sense nanoestructuració. / En esta tesis se detalla la metodologia para obtener sensores de gases basados en óxido de tungsteno nanoestructurado sobre soportes micromecanizados de silicio. Dicha nanoestructuración se ha obtenido empleando una capa de alúmina porosa como molde, por lo que se desarrolla una metodología para compatibilizar la anodización del aluminio, y otros metales como el tungsteno, con los procesos estándares del silicio. Se han desarrollado dos tipos de capas nanoestructuradas, nanotubos y nanopuntos de WO3. Los nanotubos se han obtenido depositando por pulverización catódica reactiva la capa sensible sobre alúmina porosa recubriendo las paredes de sus poros. Los nanopuntos se han obtenido anodizando una bicapa de aluminio y tungsteno, donde la primera anodización crea la alúmina porosa y la segunda hace crecer los nanopuntos de óxido de tungsteno en la base de los poros. Se ha analizado la composición, morfología y funcionamiento como sensores de gases en ambos casos y se han comparado los resultados con los de sensores sin nanoestructuración. / This thesis shows the methodology to obtain nanostructured tungsten oxide layer as sensing material on silicon micromachined gas sensor devices. A porous anodised alumina layer was used as pattern to obtain it, so a technique has been developed to make compatible the anodising of aluminium and other metals like tungsten with the standard silicon processes. Two different nanostructuring approaches were developed, nanotube and nanodot based tungsten oxide layers. The WO3 nanotube layer has been obtained by the tungsten oxide deposition using reactive sputtering on the porous alumina layer. As a result a continuous sensing layer coats the pores without clogging them. WO3 nanodot layers were obtained by the anodising of an aluminium and tungsten bilayer, where the first anodising process grows the porous alumina layer and the second one generates the tungsten oxide nanodots in the end of the pores. Compositional and morphological studies and the study of their behaviour as gas sensors where conducted for the two nanomaterials. The results have been compared with the flat tungsten oxide layers on micromachined gas sensors.

No description available.

CMOS imagers are replacing CCD imagers in many applications and will continue to make new applications possible. CMOS imaging offers lower cost implementations on standard CMOS processes which allow for mixed signal processing on-chip. A system-on-a-chip approach offers the ability to perform complex algorithms faster, in less space, and with lower power and noise. Our transform imager is an implementation of a mixed focal plane and peripheral computation imager which allows high fill factor with high computational rates at low power. However, in order to use the technology effectively a need to verify and further understand the behavior and of the pixel elements in this transform imager was needed. This thesis presents a study of the pixel elements and mismatches and errors in the pixel array of this imager. From there, a discussion about removing offsets and an implementation of a circuit to remove the largest offsets is shown. To further enhance performance, initial work to develop light adaptive readout circuits is presented. Finally, an overview is given of a newly designed one-megapixel transform imager with many design improvements.

We have grown the high quality AlGaN/GaN heterostructure by plasma-assisted molecular beam epitaxy. We obtained the mobility of two-dimensional electron gas of the AlGaN/GaN is 9300 cm2/Vs and carrier concentration is 7.9¡Ñ1012 cm-2 by conventional van der Pauw Hall measurement at 77K. The samples made of the AlGaN/GaN heterostructure were patterned to Hall bar geometry with a width of 20£gm by conventional photolithography. After the photolithography, the nanowire was fabricated by the process of focus ion beam (FIB), and the widths of nanowire were reduced to 900 nm, 500 nm, 300 nm, 200nm, 100 nm, 80 nm and 50 nm respectively. The SiO2 layer and Al electrode were deposed on the samples to form nanowired MOSFETs. We have studied the leakage current measurement on the AlGaN/GaN nanowired MOSFETs at 300K. On the 100 nm and 200 nm width of nanowires, we did not observe the leakage current for the gate voltage work range from -2.5 to 3.0 V and from -0.5 to 0.5 V respectively.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 132-136).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains viii, 94 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 88-89).

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Electrical and Computer Engineering." Includes bibliographical references (p. 151-156).