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Mixed-signal processing systems especially data converters can be reliably tested at high frequencies using on-chip testing schemes based on memory. In this thesis, an on-chip testing strategy based on shift registers/memory (2 k bits) has been proposed for digital-to-analog converters (DACs) operating at 5 GHz. The proposed design uses word length of 8 bits in order to test DAC at high speed of 5 GHz. The proposed testing strategy has been designed in standard 65 nm CMOS technology with additional requirement of 1-V supply. This design has been implemented using Cadence IC design environment. The additional advantage of the proposed testing strategy is that it requires lower number of I/O pins and avoids the large number of high speed I/O pads. It therefore also solves the problem of the bandwidth limitation that is associated with I/O transmission paths. The design of the on-chip tester based on memory contains no analog block and is implemented entirely in digital domain. In the proposed design, low frequency of 1 MHz has been used outside the chip to load the data into the memory during the write mode. During the read mode, the frequency of 625 MHz is used to read the data from the memory. A multiplexing system is used to reuse the stored data during read mode to test the intended functionality and performance. In order to convert the parallel data into serial data at high frequency at the memory output, serializer has been used. By using the frequencies of 1.25 GHz and 2.5 GHz, the serializer speeds up the data from the lower frequency of 625 MHz to the highest frequency of 5 GHz in order to test DAC at 5 GHz.

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T13:03:47Z No. of bitstreams: 0 / Made available in DSpace on 2016-11-11T13:03:47Z (GMT). No. of bitstreams: 0 / Este trabalho desenvolveu um novo método para a detecção de contornos em imagens digitais que apresentam objetos de interesse muito próximos e que contêm complexidades associadas ao fundo da imagem como variação abrupta de intensidade e oscilação de iluminação. O método desenvolvido utiliza lógicafuzzy e desvio padrão da declividade (Desvio padrão da declividade fuzzy - FuzDec) para o processamento de imagens e detecção de contorno. A detecção de contornos é uma tarefa importante para estimar características de escoamento bifásico através da segmentação da imagem das bolhas para obtenção de parâmetros como a fração de vazio e diâmetro de bolhas. FuzDec foi aplicado em imagens de instabilidades de circulação natural adquiridas experimentalmente. A aquisição das imagens foi feita utilizando o Circuito de Circulação Natural (CCN) do Instituto de Pesquisas Energéticas e Nucleares (IPEN). Este circuito é completamente constituído de tubos de vidro, o que permite a visualização e imageamento do escoamento monofásico e bifásico nos ciclos de circulação natural sob baixa pressão.Os resultados mostraram que o detector proposto conseguiu melhorar a identificação do contorno eficientemente em comparação aos detectores de contorno clássicos, sem a necessidade de fazer uso de algoritmos de suavização e sem intervenção humana. / t / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

This thesis investigates the fabrication and integration of nanoscale field-effect transistors based on individual semiconducting carbon nanotubes. Such devices hold great potential for integrated circuits with large integration densities that can be manufactured on glass or flexible plastic substrates. A process to fabricate arrays of individually addressable carbon-nanotube transistors has been developed, and the electrical characteristics of a large number of transistors has been measured and analyzed. A low-temperature-processed gate dielectric with a thickness of about 6 nm has been developed that allows the transistors and circuits to operate with voltages of about 1.5 V. The transistors show excellent electrical properties, including a large transconductance (up to 10 µS), a large On/Off ratio (>10^4), a steep subthreshold swing (65 mV/decade), and negligible leakage currents (~10^-13 A). For the realization of unipolar logic circuits, monolithically integrated load resistors based on high-resistance metallic carbon nanotubes or vacuum-evaporated carbon films have been developed and analyzed by four-probe and transmission line measurements. A variety of combinational logic circuits, such as inverters, NAND gates and NOR gates, as well as a sequential logic circuit based on carbon-nanotube transistors and monolithically integrated resistors have been fabricated on glass substrates and their static and dynamic characteristics have been measured. Optimized inverters operate with frequencies as high as 2 MHz and switching delay time constants as short as 12 ns. / Thema dieser Arbeit ist die Herstellung und Integration von Feldeffekt-Transistoren auf der Grundlage einzelner halbleitender Kohlenstoffnanoröhren. Solche Bauelemente sind zum Beispiel für die Realisierung integrierter Schaltungen mit hoher Integrationsdichte auf Glassubstraten oder auf flexiblen Kunststofffolien von Interesse. Zunächst wurde ein Herstellungsverfahren für die Anfertigung einer großen Anzahl solcher Transistoren auf Glas- oder Kunststoffsubstraten entwickelt, und deren elektrische Eigenschaften wurden gemessen und ausgewertet. Das Gate-Dielektrikum dieser Transistoren hat eine Schichtdicke von etwa 6 nm, so das die Versorgungsspannungen bei etwa 1.5 V liegen. Die Transistoren haben sehr gute elektrische Parameter, z.B. einen großen Durchgangsleitwert (bis zu 10 µS), ein großes Modulationsverhältnis (>10^4), einen steilen Unterschwellanstieg (65 mV/Dekade) und vernachlässigbar kleine Leckströme (~10^-13 A). Für die Realisierung unipolarer Logikschaltungen wurden monolithisch integrierte Lastwiderstände auf der Grundlage metallischer Kohlenstoffnanoröhren mit großem Widerstand oder mittels Vakuumabscheidung erzeugter Kohlenstoffschichten entwickelt und u. a. mittels Vierpunkt- und Transferlängen-Messungen analysiert. Eine Reihe kombinatorischer Schaltungen, z.B. Inverter, NAND-Gatter und NOR-Gatter, sowie eine sequentielle Logikschaltung wurden auf Glassubstraten hergestellt, und deren statische und dynamische Parameter wurden gemessen. Optimierte Inverter arbeiten bei Frequenzen von bis zu 2 MHz und haben Signalverzögerungen von lediglich 12 ns.

This thesis investigates the fabrication and integration of nanoscale field-effect transistors based on individual semiconducting carbon nanotubes. Such devices hold great potential for integrated circuits with large integration densities that can be manufactured on glass or flexible plastic substrates. A process to fabricate arrays of individually addressable carbon-nanotube transistors has been developed, and the electrical characteristics of a large number of transistors has been measured and analyzed. A low-temperature-processed gate dielectric with a thickness of about 6 nm has been developed that allows the transistors and circuits to operate with voltages of about 1.5 V. The transistors show excellent electrical properties, including a large transconductance (up to 10 µS), a large On/Off ratio (>10^4), a steep subthreshold swing (65 mV/decade), and negligible leakage currents (~10^-13 A). For the realization of unipolar logic circuits, monolithically integrated load resistors based on high-resistance metallic carbon nanotubes or vacuum-evaporated carbon films have been developed and analyzed by four-probe and transmission line measurements. A variety of combinational logic circuits, such as inverters, NAND gates and NOR gates, as well as a sequential logic circuit based on carbon-nanotube transistors and monolithically integrated resistors have been fabricated on glass substrates and their static and dynamic characteristics have been measured. Optimized inverters operate with frequencies as high as 2 MHz and switching delay time constants as short as 12 ns. / Thema dieser Arbeit ist die Herstellung und Integration von Feldeffekt-Transistoren auf der Grundlage einzelner halbleitender Kohlenstoffnanoröhren. Solche Bauelemente sind zum Beispiel für die Realisierung integrierter Schaltungen mit hoher Integrationsdichte auf Glassubstraten oder auf flexiblen Kunststofffolien von Interesse. Zunächst wurde ein Herstellungsverfahren für die Anfertigung einer großen Anzahl solcher Transistoren auf Glas- oder Kunststoffsubstraten entwickelt, und deren elektrische Eigenschaften wurden gemessen und ausgewertet. Das Gate-Dielektrikum dieser Transistoren hat eine Schichtdicke von etwa 6 nm, so das die Versorgungsspannungen bei etwa 1.5 V liegen. Die Transistoren haben sehr gute elektrische Parameter, z.B. einen großen Durchgangsleitwert (bis zu 10 µS), ein großes Modulationsverhältnis (>10^4), einen steilen Unterschwellanstieg (65 mV/Dekade) und vernachlässigbar kleine Leckströme (~10^-13 A). Für die Realisierung unipolarer Logikschaltungen wurden monolithisch integrierte Lastwiderstände auf der Grundlage metallischer Kohlenstoffnanoröhren mit großem Widerstand oder mittels Vakuumabscheidung erzeugter Kohlenstoffschichten entwickelt und u. a. mittels Vierpunkt- und Transferlängen-Messungen analysiert. Eine Reihe kombinatorischer Schaltungen, z.B. Inverter, NAND-Gatter und NOR-Gatter, sowie eine sequentielle Logikschaltung wurden auf Glassubstraten hergestellt, und deren statische und dynamische Parameter wurden gemessen. Optimierte Inverter arbeiten bei Frequenzen von bis zu 2 MHz und haben Signalverzögerungen von lediglich 12 ns.