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1
Pratapgarhwala, Mustansir M. "Characterization of Transistor Matching in Silicon-Germanium Heterojunction Bipolar Transistors". Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7536.
Testo completoAbstract (sommario):
Transistor mismatch is a crucial design issue in high precision analog circuits, and is investigated here for the first time in SiGe HBTs. The goal of this work is to study the effects of mismatch under extreme conditions including radiation, high temperature, and low temperature.
One portion of this work reports collector current mismatch data as a function of emitter geometry both before and after 63 MeV proton exposure for first-generation SiGe HBTs with a peak cut-off frequency of 60 GHz. However, minimal changes in device-to-device mismatch after radiation exposure were experienced.
Another part of the study involved measuring similar devices at different temperatures ranging from 298K to 377K. As a general trend, it was observed that device-to-device mismatch improved with increasing temperature.
2
Cerutti, Robin. "Transistors à grilles multiples adaptés à la conception". Grenoble INPG, 2006. http://www.theses.fr/2006INPG0174.
Testo completoAbstract (sommario):
"En technologie MOS sur silicium, les transistors de type "double grille" (DG) sont considérés comme les meilleurs candidats pour les nœuds technologiques 32 et 22 nm de ITRS. Avec l'apparition de différentes architectures (FINFET, TriGate, Planar DG,. . . ) il est important de concevoir une intégration simple et compatible avec les requêtes circuit. Ce travail de thèse prend en compte les intéractions entre la conception et la technologie afin de définir des technologies tridimensionelles basées sur le module SON ("Silicon On Nothing"). De nouveaux transistors ont été inventés et développés et "ensemble des résultats morphologiques et électriques sont présentés pour confirmer le potentiel de ces composants en tant que plateforme technologique. "Double Gate transistors are nowadays considered as the best candidate for the 32 and 22 nm technological node using silicon technologies. Within the amount of multi-gate technologies that show up ( Finfet, TriGate, Planar DG,. . ) , it is mandatory not only to be able to create transistors but also to define simple architectures that are directly compatible with circuit designs. This phd is the result of a work linking directly design and integration in order to process new tri-dimensionnal technology based on SON technique ( 'Silicon On Nothing'). New transistors have bee invented and processed and morphological and electrical results are shown in order to prove the potential of our components within the future technological platforms
3
Lee, Yi-Che. "Development of III-nitride transistors: heterojunction bipolar transistors and field-effect transistors". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53472.
Testo completoAbstract (sommario):
The fabrication processes development for on III-nitride (III-N) heterojunction bipolar transistors (HBTs), heterojunction field-effect transistors (HFETs) and metal-insulator-semiconductor field-effect transistors (MISFETs) were performed. D.c, microwave and quasi-static I-V and C-V measurements were carried out to characterize the fabricated III-N transistors and diodes. The GaN/InGaN direct-growth HBTs (DG-HBTs) grown on free-standing GaN (FS-GaN) substrates demonstrated a high current gain (hfe) > 110, high current density (JC) > 141 kA/cm2, and high power density (Pdc) > 3 MW/cm2. The first III-N DG-HBT showing fT > 8 GHz and fmax > 1.3 GHz were also demonstrated on sapphire substrates. Recessed-gate AlGaN/AlN/GaN HFETs demonstrated Vth = 0 V with 0.17 V deviation across the sample. Baliga's figure of merit is 240 MW/cm2 was achieved. Current collapse was eliminated and the dynamic on-resistance was reduced by 67% after using a remote-oxygen-plasma treatment. Normally-off recessed-gate AlGaN/AlN/GaN MISFETs with Vth = 0.9 V were also fabricated with the remote-oxygen-plasma treatment. Low leakage current (< 1 pA/mm), high on-off ratio (> 2.2E11) are achieved. These achievements suggest that high-performance III-N transistors are very promising for high-power switching and microwave amplification. Findings concerning remaining process issues and implications for future research are also discussed.
4
Ozório, Maíza da Silva. "Estudo de compósitos de tips-pentaceno para aplicações em transistores /". Presidente Prudente, 2016. http://hdl.handle.net/11449/152818.
Testo completoAbstract (sommario):
Orientador: Neri AlvesBanca: Edson Laureto
Banca: Carlos José Leopoldo Constantino
Resumo: Um dos atuais desafios da eletrônica orgânica é a obtenção de semicondutores com alta mobilidade que forme filmes com boa morfologia quando depositado/impresso por solução, resultando em boa uniformidade e reprodutibilidade dos dispositivos. O poli(3- hexiltiofeno) (P3HT) e o 6,13-(triisopropilsililetinil)pentaceno (TP) estão entre os semicondutores orgânicos mais utilizados. O TP tem como característica a formação de estruturas cristalinas, e desse modo, apresenta mobilidade muito maior que o P3HT, no entanto é difícil de obter filmes com boa morfologia e resultados reprodutíveis. Visando um material semicondutor que apresente mobilidade significativamente melhor que a do P3HT e uma morfologia melhor que a do TP, estudou-se compósitos a partir da mistura destes materiais (P3HT:TP) para aplicação em transistores orgânicos de efeito de campo (OFETs), utilizando óxido de alumínio anodizado (Al2O3) tratado com HMDS como dielétrico de gate. Para análise da morfologia dos compósitos semicondutores de P3HT:TP usou-se microscopia eletrônica de varredura (MEV), microscopia de força atômica (AFM) e microscopia óptica (MO). Análise óptica foi feita através de medidas de fotoluminescência (PL) e de tempo de decaimento por fotoluminescência. Espectroscopia Raman e FTIR foram utilizadas para análises estruturais. No modo transistor a caracterização foi feita através de curvas de saída e transferência. Através das caracterizações elétricas determinou-se os parâmetros do semicondutor, tais ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: One of the current challenges of organic electronics is the development of semiconductors with high mobility to form films with good morphology when deposited/printed by solution, resulting in good uniformity and reproducibility of the devices. The poly (3-hexylthiophene) (P3HT) and 6,13-(triisopropilsililetinil)pentacene (TP) are among the most widely used organic semiconductors. The TP films are constituted by crystalline lamellar structures, and thus has greater mobility than the P3HT, however, it is difficult handling it to obtain films with good morphology and reproducible results. Targeting a semiconductor material with significantly better mobility than that of P3HT and better morphology than that of TP, we studied composites of these materials (P3HT: TP) for using in organic field effect transistors (OFETs). The transistor was prepared depositing the solution of the semiconductor composite, by spin coating, on the aluminium oxide, obtained by anodization and treated with HMDS, followed by the thermal evaporation of gold on the top, to form the drain and source electrodes. For analysis of the morphology of the composites semiconductors (P3HT: TP) was used scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical microscopy (OM). Optical analysis was performed using photoluminescence (PL) measurements and decay time by photoluminescence. FTIR and Raman spectroscopy were used to structural analysis. In mode transistor, characterization was performed u... (Complete abstract click electronic access below)
Mestre
5
Ricci, Simona. "Liquid-gated transistors for biosensing applications". Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/670786.
Testo completoAbstract (sommario):
En aquesta tesi, hem estudiat diferents aspectes relacionats amb transistors orgànics, en particular transistors orgànics electroquímics d’efecte de camp (EGOFETs) i transistors orgànics electroquímics (OECTs). Els dispositius EGOFET es van fabricar dipositant a partir de dissolucions de semiconductors orgànics (OSC) basats en molècules conjugades barrejats amb polímers aïllants, mitjançant la tècnica de Bar-assisted meniscus shearing (BAMS). BAMS és una tècnica ràpida, de baix cost i escalable que permet la formació de pel·lícules cristal·lines i uniformes. Els EGOFET van ser estudiats pel desenvolupament d’un biosensor per a la detecció de la proteïna α-sinucleina, que és un biomarcador per a malalties neurodegeneratives, incloses les malalties de Parkinson. A més, es van utilitzar dispositius OECT també per a la detecció de α-sinucleina, per estudiar el possible ús d’aquests dispositius com a immunosensors, camp molt poc explorat en la literatura. Finalment, es va fabricar un EGOFET completament flexible basat en un nou semiconductor molecular. Per primera vegada, s’ha estudiat la resposta elèctrica sota tensió mecànica per a un EGOFET.En esta tesis, hemos estudiado diferentes aspectos relacionados con los transistores orgánicos activados por líquido, en particular los transistores de efecto de campo orgánicos activados por electrolitos (EGOFET) y los transistores electroquímicos orgánicos (OECT). Los dispositivos EGOFET se fabricaron depositando a partir de soluciones pequeñas moléculas de semiconductores orgánicos (OSC) mezclados con polímeros aislantes, a través de la técnica de Bar-assisted meniscus shearing (BAMS). BAMS es una técnica rápida, de bajo costo y escalable que permite la formación de películas finas cristalinas y uniformes. Los EGOFET se estudiaron para el desarrollo de un biosensor para la detección de un biomarcador de enfermedades neurodegenerativas, incluidas las enfermedades de Parkinson, es decir, la alpha-sinucleína. Además, se emplearon dispositivos OECT para la biodetección de α-sinucleína, para estudiar el posible uso de estos dispositivos como inmunosensores, campo que aún está menos explorado en la literatura. Finalmente, se fabricó un EGOFET totalmente flexible basado en una pequeña molécula semiconductora mezclada con un polímero aislante y se evaluó su respuesta eléctrica bajo tensión mecánica, por primera vez, hasta donde sabemos, para dispositivos EGOFET.
In this thesis, we have studied different aspects related to liquid-gated organic transistors, in particular electrolyte-gated organic field-effect transistors (EGOFETs) and organic electrochemical transistors (OECTs). EGOFET devices were fabricated by depositing from solution small molecules organic semiconductors (OSC) blended with insulating polymers, through the bar-assisted meniscus-shearing technique (BAMS). BAMS is a rapid, low-cost and scalable technique that allows the formation of crystalline and uniform thin films. The EGOFETs were studied for the development of a biosensor for the detection of a biomarker for neurodegenerative diseases, including Parkinson’s diseases, namely α-synuclein. Further, OECT devices were employed for the biosensing of α-synuclein, to give an insight into the possible use of these devices as immunosensors, field which is still less explored in literature. Finally, an all-flexible EGOFET based on a small molecule OSC blended with an insulating polymer thin film, was fabricated and its electrical response under bending strain was evaluated, for the first time, as far as we know, for liquid-gated OFETs.
6
Tachi, Kiichi. "Etude physique et technologique d'architectures de transistors MOS à nanofils". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00721968.
Testo completoAbstract (sommario):
Il a été démontré que la structure gate-all-around en nanofils de silicium peut radicalement supprimer les effets de canaux courts. De plus, l'introduction d'espaceurs internes entre ces nanofils peut permettre de contrôler la tension de seuil, à l'aide d'une deuxième grille de contrôle. Ces technologies permettent d'obtenir une consommation électrique extrêmement faible. Dans cette thèse, pour obtenir des opérations à haute vitesse (pour augmenter le courant de drain), la technique de réduction de la résistance source/drain sera débattue. Les propriétés de transport électronique des NWs empilées verticalement seront analysées en détail. De plus, des simulations numériques sont effectuées pour examiner les facultés de contrôle de leur tension de seuil utilisant des grilles sépares.
7
Acosta, Sandra Massulini. "Projeto de amplificadores operacionais CMOS utilizando transistores compostos em "sea-of-transistors"". reponame:Repositório Institucional da UFSC, 1997. https://repositorio.ufsc.br/handle/123456789/111588.
Testo completo
8
Huang, Yong. "InAlGaAs/InP light emitting transistors and transistor lasers operating near 1.55 μm". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37298.
Testo completoAbstract (sommario):
Light emitting transistors (LETs) and transistor lasers (TLs) are newly-emerging optoelectronic devices capable of emitting spontaneous or stimulated light while performing transistor actions. This dissertation describes the design, growth, and performances of long wavelength LETs and TLs based on InAlGaAs/InP material system. First, the doping behaviors of zinc (Zn) and carbon (C) in InAlGaAs layers for p-type doping were investigated. Using both dopants, the N-InP/p-In0.52(AlxGa1-x)0.48As/N-In0.52Al0.48As LETs with InGaAs quantum wells (QWs) in the base demonstrate both light emission and current gains (β). The device performances of Zn- and C-doped LETs have been compared, which is explained by a charge control analysis involving the quantum capture and recombination process in the QWs. A TL based on a C-doped double heterostructure (DH-TL) with single QW was designed and fabricated. The device lases at 77 K with a threshold current density (Jth) of 2.25 kA/cm2, emission wavelength (λ) at ~1.55 µm, and β of 0.02. The strong intervalence band absorption (IVBA) is considered as the main intrinsic optical loss that prohibits the device from lasing at room temperature. Based on a threshold condition analysis taking into account the strong IVBA, it is found that room-temperature lasing of a DH-TL is achieved only when the base thickness and doping level are within a specific narrow range and improved performance is expected in a separate confinement heterostructure (SCH) TL.
9
Xu, Ziyan Niu Guofu. "Low temperature modeling of I-V characteristics and RF small signal parameters of SiGe HBTs". Auburn, Ala., 2009. http://hdl.handle.net/10415/1925.
Testo completo
10
Krumm, Jürgen. "Circuit analysis methodology for organic transistors = Methodik zur Schaltungsanalyse für organische Transistoren". kostenfrei, 2008. http://deposit.d-nb.de/cgi-bin/dokserv?idn=989071553.
Testo completo
11
Birkin, Peter Robert. "Microelectrochemical enzyme transistors". Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240628.
Testo completo
12
Ridley, Brent (Brent Alan) 1974. "Printed inorganic transistors". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/62382.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2003.Includes bibliographical references (leaves 146-175).
Forty years of exponential growth of semiconductor technology have been predicated on the miniaturization of the transistors that comprise integrated circuits. While complexity has greatly increased within a given area of processed silicon, the cost per area has not decreased. Current fabrication methods are further hindered by high facility costs and environmentally unfriendly processing. Moving to a new means of semiconductor fabrication may drastically reduce both financial and environmental costs. One such approach is based on the extension of printing techniques to the fabrication of electronic devices. Such printed electronics are envisioned to enable applications in flexible displays and electronic paper, personal fabrication, wearable computing, and disposable medical diagnostics. This dissertation focuses on the development of printable materials, specifically inorganic semiconductor inks. At the outset of this research, organic semiconductors were the only materials known and pursued as printable semiconductors. The ability to process organic semiconductors in common organic solvents makes them amenable to a wide range of printing technologies, but their electrical performance is fundamentally limited and their utility is confined to applications in which only low speeds are required. The goal of this thesis was to demonstrate the feasibility of printing inorganic materials, the same materials that are used to fabricate high quality semiconductor devices. Cadmium selenide was studied as a model inorganic semiconductor and silicon was studied because of its commercial dominance. The insolubility and high processing temperatures of inorganic semiconductors, both of which can prevent
(cont.) their use in printed electronics, were overcome through the use of nanoparticle inks. At very small sizes, nanoparticles can be highly soluble in organic solvents and can have a pronounced melting point depression. Leveraging these size-dependent properties, the first semiconductor nanoparticle inks were developed using cadmium selenide and the first all-printed inorganic thin film transistors were demonstrated. Printed active layers in thin film transistors attained a semiconductor mobility of 1 cm²V⁻¹s⁻¹and an ON/OFF ratio in excess of 10⁴. Further development of inorganic nanoparticle inks and efforts to extend this approach to silicon are described, addressing silicon nanoparticle synthesis, purification, and ink formulation.
Brent Ridley.
Ph.D.
13
Kaphle, VIkash. "Organic Electrochemical Transistors". Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1576594504410991.
Testo completo
14
Khelifi, Wafa. "Modélisation multi-ports des transistors hyperfréquences". Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0100/document.
Testo completoAbstract (sommario):
Ce document traite de la caractérisation et la modélisation des transistors multi-ports. Une caractérisation des transistors pHEMT à base de l'AsGa est réalisée. Une importance particulière est donné aux méthodes de caractérisation RF sous pointes. En effet, une étude sur les méthodes d’épluchage est réalisée. Ensuite, après avoir relevé un défaut dans la méthode choisie (à savoir la méthode Pad-Open-Short), une solution est proposée concernant les standards non idéaux. Finalement, des modèles non linéaires 3 et 4 ports sont développés, ils ont pour objectifs de réduire le temps, des phases de conception et de fiabiliser le prototypage des fonctions micro-ondes utilisant ces composants. Les travaux présentés ici sont dédiés à l’amélioration de la modélisation électrique des transistors axée, comme leur application, sur la bande KuThis paper presents an approach for the de-embedding and modeling of multi-port transistors. First, the proposed de-embedding method is an extension of a three step method (Pad-Open-Short) for accurate on wafer (MMIC) S-parameters measurements. The novelty of this approach lies in the fact that the proposed de-embedding method for multi-port devices takes into account the imperfections of the standards. Then, we present two approach for the modeling of 3 and 4 ports GaAs HEMT transistors. The non-linear model was developed from I-V and S-parameters measurements. The methodology for 3-port device modeling allows us to determine accurate non-linear model in high frequencies. The second approach is dedicated for the distributed modeling of a 4-port transistor. The original electrical models of multi-port transistors developed in this thesis aims to reduce the time and the design phases, and to make reliable the prototyping of microwave functions using these components. The work presented here is therefore dedicated to improving the electrical modeling of transistors focused as their application on the Ku band
15
Turner, Gary Chandler. "Zinc Oxide MESFET Transistors". Thesis, University of Canterbury. Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/3439.
Testo completoAbstract (sommario):
Zinc oxide is a familiar ingredient in common household items including sunscreen and medicines. It
is, however, also a semiconductor material. As such, it is possible to use zinc oxide (ZnO) to make
semiconductor devices such as diodes and transistors. Being transparent to visible light in its
crystalline form means that it has the potential to be the starting material for so-called 'transparent
electronics', where the entire device is transparent. Transparent transistors have the potential to
improve the performance of the electronics currently used in LCD display screens.
Most common semiconductor devices require the material to be selectively doped with specific
impurities that can make the material into one of two electronically distinct types – p- or n-type.
Unfortunately, making reliable p-type ZnO has been elusive to date, despite considerable efforts
worldwide. This lack of p-type material has hindered development of transistors based on this
material.
One alternative is a Schottky junction, which can be used as the active element in a type of transistor
known as a metal-semiconductor field effect transistor, MESFET. Schottky junctions are traditionally
made from noble metal layers deposited onto semiconductors. Recent work at the Canterbury
University has shown that partially oxidised metals may in fact be a better choice, at least to zinc
oxide.
This thesis describes the development of a fabrication process for metal-semiconductor field effect
transistors using a silver oxide gate on epitaxially grown zinc oxide single crystals. Devices were
successfully produced and electrically characterised. The measurements show that the technology has
significant potential.
16
Bakhtiar, Hazri CHARLES JEAN PIERRE. "CARACTERISATION DE STRUCTURES MOS SUBMICRONIQUES ET ANALYSE DE DEFAUTS INDUITS PAR IRRADIATION GAMMA. EXTRAPOLATION AUX DEFAUTS INDUITS DANS LES OXYDES DE CHAMP DES TRANSISTORS BIPOLAIRES /". [S.l.] : [s.n.], 1999. ftp://ftp.scd.univ-metz.fr/pub/Theses/1999/Bakhtiar.Hazri.SMZ9934.pdf.
Testo completo
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Kisner, Alexandre 1982. "Desenvolvimento de Microssensores do tipo ISFETs a base de Nanoeletrodos de Ag e Au". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248385.
Testo completoAbstract (sommario):
Orientador: Lauro Tatsuo KubotaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-08T22:44:52Z (GMT). No. of bitstreams: 1 Kisner_Alexandre_M.pdf: 3973690 bytes, checksum: 2810b47ecfaaac028a1bf271a3fc25a0 (MD5) Previous issue date: 2007
Conjuntos de transistores de efeito de campo sensíveis a íons (ISFETs) foram desenvolvidos no presente trabalho. Implementou-se durante a fabricação destes uma etapa adicional de anodização que possibilitou a formação de uma fina camada de alumina porosa sobre suas portas. Esta serviu como dielétrico e também molde para o crescimento de nanocristais de Ag e Au sobre os dispositivos. Os transistores desenvolvidos foram divididos em dois conjuntos, onde as dimensões de porta de cada conjunto foram de 10 x 50 mm e 50 x 50 mm. Utilizando-se um processo simples de anodização, obteve-se sobre a porta dos transistores uma fina camada de alumina de aproximadamente 60 nm de espessura, contendo uma alta densidade de poros (~ 10 poros/cm) com diâmetro médio de 30 + 6 nm e distribuídos de forma regular. A implementação desta possibilitou não só um aumento significativo na área de porta, bem como molde para o crescimento de nanoestruturas de Ag e Au sobre os transistores, atuando assim como nanoeletrodos de porta. Os testes destes como sensores para soluções com diferentes valores de pH, mostraram que os dispositivos apresentam um curto tempo de resposta (t < 30 s) e que as nanoestruturas metálicas são capazes de aumentar a sensibilidade dos dispositivos em relação àqueles formados apenas por alumina. Os primeiros testes para a detecção de moléculas como glutationa, demonstraram que os ISFETs fabricados são capazes de detectar esta, mesmo sendo uma espécie com baixa densidade de carga, em concentrações submicromolares
Arrays of ion-sensitive field effect transistors (ISFETs) were developed in this work. An additional step in the fabrication process was employed to implement a thin film of porous anodic alumina on the gate. This porous layer works as dielectric and template to the vertical growth of Ag and Au nanocrystals on the gate. The produced ISFETs were divided in two groups, which the gate dimensions were 10 x 50 mm and 50 x 50 mm. Using a simple anodizing process, a 60 nm thickness porous anodic alumina was developed on the gate. This porous film presented a high density porosity (~ 10 pores/cm) with an average pore diameter of 30 + 6 nm and a regular distribution on the gate of those ISFETs. This porous film lead to a significant increase in the gate area and also worked as a template to the growth of Ag and Au nanocrystals, which were used as gate nanoelectrodes. The results of such sensors to detect different pH of the solutions showed that the produced ISFETs present a short response time (t < 30 s). Moreover, the presence of such Ag and Au nanostructures increased the sensors sensitivity in comparison to those observed without nanoelectrodes. The first results to detect species such as glutathione, indicated that the ISFETs are even sensitive to detect small charged species in a submicromolar concentration range
Mestrado
Quimica Analitica
Mestre em Química
18
Li, Jian Ming. "Evaluation des possibilités fréquentielles des transistors bipolaires de puissance haute tension". Grenoble INPG, 1989. http://www.theses.fr/1989INPG0049.
Testo completoAbstract (sommario):
Cette étude vise les possibilités d'utilisation des T. B. P. H. T. Dans les convertisseurs à résonance à des fréquences de quelques centaines de kHz et des puissances de quelques dizaines de kw. Pour atteindre cet objectif, une modélisation analytique uni-dimensionnelle du semi-conducteur est proposée: elle permet d'obtenir les caractéristiques de la commande de base aux fréquences correspondantes et d'analyser les performances fréquentielles des circuits de base aux fréquences correspondantes et d'analyser les performances fréquentielles des circuits de base classiques. Les synthèses de commande et les interrupteurs du type “CASCODE” sont représentés. Deux convertisseurs à résonance réalisés, un onduleur de tension 200 kHz-10 kW et un onduleur de courant 100 kHz-20 kW montrent la faisabilité de l'objectif en optimisant la commande des T. B. P. H. T
19
Suvar, Erdal. "SiGeC Heterojunction Bipolar Transistors". Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3674.
Testo completoAbstract (sommario):
Heterojunction bipolar transistors (HBT) based on SiGeC havebeen investigated. Two high-frequency architectures have beendesigned, fabricated and characterized. Different collectordesigns were applied either by using selective epitaxial growthdoped with phosphorous or by non-selective epitaxial growthdoped with arsenic. Both designs have a non-selectivelydeposited SiGeC base doped with boron and a poly-crystallineemitter doped with phosphorous.
Selective epitaxial growth of the collector layer has beendeveloped by using a reduced pressure chemical vapor deposition(RPCVD) technique. The incorporation of phosphorous and defectformation during selective deposition of these layers has beenstudied. A major problem of phosphorous-doping during selectiveepitaxy is segregation. Different methods, e.g. chemical orthermal oxidation, are shown to efficiently remove thesegregated dopants. Chemical-mechanical polishing (CMP) hasalso been used as an alternative to solve this problem. The CMPstep was successfully integrated in the HBT process flow.
Epitaxial growth of Si1-x-yGexCy layers for base layerapplications in bipolar transistors has been investigated indetail. The optimization of the growth parameters has beenperformed in order to incorporate carbon substitutionally inthe SiGe matrix without increasing the defect density in theepitaxial layers.
The thermal stability of npn SiGe-based heterojunctionstructures has been investigated. The influence of thediffusion of dopants in SiGe or in adjacent layers on thethermal stability of the structure has also been discussed.
SiGeC-based transistors with both non-selectively depositedcollector and selectively grown collector have been fabricatedand electrically characterized. The fabricated transistorsexhibit electrostatic current gain values in the range of 1000-2000. The cut-off frequency and maximum oscillation frequencyvary from 40-80 GHz and 15-30 GHz, respectively, depending onthe lateral design. The leakage current was investigated usinga selectively deposited collector design and possible causesfor leakage has been discussed. Solutions for decreasing thejunction leakage are proposed.
Key words:Silicon-Germanium-Carbon (SiGeC),Heterojunction bipolar transistor (HBT), chemical vapordeposition (CVD), selective epitaxy, non-selective epitaxy,collector design, high-frequency measurement, dopantsegregation, thermal stability.
20
Hein, Moritz. "Organic Thin-Film Transistors". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-167894.
Testo completoAbstract (sommario):
Organic thin film transistors (OTFT) are a key active devices of future organic electronic circuits. The biggest advantages of organic electronics are the potential for cheep production and the enabling of new applications for light, bendable or transparent devices. These benefits are offered by a wide spectrum of various molecules and polymers that are optimized for different purpose.
In this work, several interesting organic semiconductors are compared as well as transistor geometries and processing steps. In a cooperation with an industrial partner, test series of transistors are produced that are intensively characterized and used as a basis for later device simulation. Therefore, among others 4-point-probe measurements are used for a potential mapping of the transistor channel and via transfer line method the contact resistance is measured in a temperature range between 173 and 353 K.
From later comparison with the simulation models, it appears that the geometrical resistance is actually more important for the transistor performance than the resistance of charge-carrier injection at the electrodes. The charge-carrier mobility is detailed evaluated and discussed. Within the observed temperature range a Arrhenius-like thermal activation of the charge- carrier transport is determined with an activation energy of 170 meV. Furthermore, a dependence of the electric field-strength of a Poole-Frenkel type is found with a Poole-Frenkel factor of about 4.9 × 10E−4 (V/m) −0.5 that is especially important for transistors with small channel length. With these two considerations, already a good agreement between device simulation and measurement data is reached. In a detailed discussion of the dependence on the charge-carrier density and from comparison with established the charge-carrier mobility models, an exponential density of states could be estimated for the organic semiconductor.
However, reliability of OTFTs remains one of the most challenging hurdles to be understood and resolved for broad commercial applications. In particular, bias-stress is identified as the key instability under operation for numerous OTFT devices and interfaces. In this work, a novel approach is presented that allows controlling and significantly alleviating the bias-stress effect by using molecular doping at low concentrations. For pentacene as semiconductor and SiO2 as gate oxide, we are able to reduce the time constant of degradation by three orders of magnitude. The effect of molecular doping on the bias-stress is explained in terms of the shift of Fermi level and, thus, exponentially reduced proton generation at the pentacene/oxide interface. For transistors prepared in cooperation with the industrial partner, a second effect is observed that can be explained by a model considering a ferroelectric process in the dielectric and counteracts the bias-stress behavior.
21
Rawcliffe, Ruth. "Polymer field-effect transistors". Thesis, Imperial College London, 2006. http://hdl.handle.net/10044/1/8889.
Testo completo
22
Zhu, Wen Wei. "Organic thin film transistors". Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19597.
Testo completoAbstract (sommario):
Organic thin film transistors (OTFTs) have been fabricated using four different semiconducting polymers: poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV), polyhedral oligomeric silsesquioxanes (POSS) poly (2-methoxy-5-(2'-ethyl-hexyloxy)-l,4-phenylene vinylene) (MEH-PPV-POSS), poly[N-(3-methylphenyl)-N,N-diphenylamine-4,4'-diyl] (poly-TPD), and polyhedral oligomeric silsesquioxanes (POSS) poly (N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine (poly-TPD-POSS). These OTFTs were fabricated on heavily doped «-type silicon wafers with thermally grown silicon dioxide layer was used as gate insulator. Except for MEH-PPV, the OTFTs studied in this work are the first for the above organic semiconductor materials. From results of current-voltage measurements, it was observed that the present OTFTs showed I-V characteristics of typical /^-channel thin film transistors. Some of the fabricated OTFTs showed performance with relatively large field-effect mobilities (>10~4 cm2 V"1 s"1). The mobility of semiconducting polymer with polyhedral oligomeric silsesquioxanes (POSS) was at least one order of magnitude larger than that of parent polymer without the POSS. The largest mobility value was obtained on poly-TPD-POSS (4.34 x 10"4 cm2 V"1 s"1) in room atmosphere and at room temperature. Thermal annealing under different conditions was carried out on the polymers and the effects on carrier field-effect mobilities were examined. The thermal annealing can increase slightly the field-effect mobilities of the polymers without POSS. However, no significant effect was observed on the field-effect mobilities of the polymers with POSS.
23
Georgakopoulos, Stamatis. "Polymer field-effect transistors". Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582857.
Testo completoAbstract (sommario):
High Ionisation Potential (IP) amorphous conjugated polymers are very practical semiconductors and promising candidates for printing applications as they exhibit 1) high air-stability due to the high IP, and 2) reproducible electrical performance due to the uniformity of amorphous morphology. However they generally exhibit low mobilities on the order of 10-3 cm2Ns and below. This work is based mainly on two high-IP amorphous conjugated polymers poly(indenofluorene-triarylamine) (PIFTAA) and poly(indenofluorene- phenanthrene) (PIFPA). The long term ambient stability of PIFTAA and PIFPA with IPs of 5.45 eV and 5.79 eV respectively is characterised in Field-Effect Transistors (FETs) over a period of 4 and 2 months respectively. FET parameters such as the turn-on voltage and subthreshold slope are found to be generally stable, and the charge carrier mobility is found to degrade at an approximate rate of 10% per month, which is amongst the lowest reported values for organic semiconductors. PIFT AA and particularly PIFPA exhibit high field-effect saturation mobilities of 0.03 - 0.04 cm2Ns and 0.2 - 0.3 cm2Ns respectively, which are unusually high for amorphous conjugated polymers. The morphologies are examined by atomic force microscopy, grazing incidence wide angle x-ray scattering, and differential scanning calorimetry, and no evidence of crystallinity is detected, suggesting that the conjugated polymers are indeed amorphous. To investigate charge transport in PIFTAA and PIFPA, FETs of multiple channel lengths are fabricated, providing mobility data for multiple electric fields, and measured over a range of temperatures. In addition to PIFT AA and PIFP A, the measurements are performed on typical amorphous conjugated polymers poly(triarylamine) (PTAA) and poly(indenofluorene-triarylamine-triarylamine) (PIFTAATAA), with mobilities of 0.003 cm2/Vs and 0.004 cm2Ns respectively. The gate voltage dependence of the mobility extracted from FET measurements, as well as the lIT2 fit of the mobility with temperature is consistent with a Gaussian Density of States. The indenofluorene copolymers PIFTAA, PIFTAATAA, and PIFPA exhibit clear negative electric field dependence of the mobility, signature of high spatial disorder in the polymer films. The temperature dependence of the mobility is fed into the Gaussian Disorder Model, which indicates that the source of the high mobility for PIFPA is mainly strong intermolecular coupling indicated by the high pre-factor mobility as well as low energetic disorder along the path of charge flow. These results challenge the widely accepted concept that high crystallinity is a requirement for mobility exceeding 0.1 cm2/Vs in organic semiconductors.
24
Chua, L. L. "Organic field-effect transistors". Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597679.
Testo completoAbstract (sommario):
In this thesis, we demonstrated that divinyltetramethyldisiloxane-benzocyclobutene (BCB), which has previously been used as an isolation dielectric in III-IV semiconductor devices, in fact makes an excellent gate dielectric material in OFETs after suitable purification. Robust ultra-thin films with high glass transition temperature and high dielectric breakdown strength can be obtained by simple spin-coating followed by rapid-thermal-anneal to above 250°C. With this material, we were able to demonstrate remarkable performance in polymer OFETs and explore several aspects of their physics. In Chapter 2, we introduce the use of BCB as a good candidate for solution-processable organic gate dielectric. Pinhole-free ultra-thin gate dielectric film as thin as 50nm can be made from this material. With this gate dielectric, robust continual cyclic operation of poly[(9,9-dioctylfluorene-2,7-diyl)-alt-(phenylene-(N-(p-2-butylphenyl-imino-phenylene)) (TFB) FETs at 120°C was achieved. Previously, the thinnest practical solution-processable gate dielectric thickness was >300 nm-thick. In Chapter 3, we demonstrated self-organised polymer semiconductor/dielectric FETs fabricated using a spontaneous and an unusual vertical phase separation of the TFB polymer semiconductor and the BCB dielectric materials during film spinning. This method enables the formation of semiconductor and dielectric layers at the same time without exposing their interface to air. Using these devices, we established that a critical root-mean-square interface roughness of 0.7 nm (measured on the 100 nm length scale) could be tolerated without loss of mobility of the devices, probably related to the hopping of the carries at the interface. In Chapter 4, we demonstrated using this non-trapping BCB dielectric the generality of n-type field-effect conduction across a wide range of polymer organic semiconductors. We showed that this was previously suppressed by interface trapping of the accumulated electrons by the –OH group in the gate dielectrics that have often been used. We found electron mobilities very similar to, if not larger than, hole mobilities across a range of organic semiconductors. Therefore, many (though not all) π-conjugated materials are by their nature ambipolar and can support both electron and hole conduction nearly equally well. Their previous classification into “n-type” and “p-type” materials is thus somewhat arbitrary. Finally, in Chapter 5, we used BCB as the top gate dielectric and fabricated fully functional double-gate OFETs over a bottom gate dielectric. We showed that such devices exhibit electrostatic coupling of the two gates occurs to produce an “AND” logic gate.
25
Yang, Ming-Hsun. "Carbon nanotube based transistors". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613983.
Testo completo
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Liu, Jiang. "Light-Emitting Electrochemical Transistors". Doctoral thesis, Linköpings universitet, Fysik och elektroteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-104925.
Testo completoAbstract (sommario):
Since the discovery of conductive polymers in 1977, the implementation of organic conjugated materials in electronic applications has been of great interest in both industry and academia. The goal of organic electronics is to realize large-area, inexpensive and mechanically-flexible electronic applications. Organic light emitting diodes (OLEDs), as the first commercial product made from organic conjugated polymers, have successfully demonstrated that organic electronics can make possible a new generation of modern electronics. However, OLEDs are highly sensitive to materials selection and requires a complicated fabrication process. As a result, OLEDs are expensive to fabricate and are not suitable for low-cost printing or roll-to-roll process. This thesis studies an alternative to OLEDs: light-emitting electrochemical cells (LECs). The active materials in an LEC consist of a conjugated light-emitting polymer (LEP) and an electrolyte. Taking advantage of electrochemical doping of the LEP, an LEC features an in-situ formed emissive organic p-n junction which is easy to fabricate. We aim to control the electrochemical doping profile by employing a “gate” terminal on top of a conventional LEC, forming a lightemitting electrochemical transistor (LECT). We developed three generations of LECTs, in which the position of the light-emitting profile can be modified by the voltage applied at the gate electrode, as well as the geometry of the gate materials. Thus, one can use this structure to achieve a centered light-emitting zone to maximize the power-conversion efficiency. Alternatively, LECTs can be used for information display in a highly integrated system, as it combines the simultaneous modulation of photons and electrons. In addition, we use multiple LECs to construct reconfigurable circuits, based on the reversible electrochemical doping. We demonstrate an LEC-array where several different circuits can be created by forming diodes with different polarity at different locations. The thereby formed circuitry can be erased and turned into circuitry with other functionality. For example, the diodes of a digital AND gate can be re-programmed to form an analogue voltage limiter. These reprogrammable circuits are promising for fully-printed and large-area reconfigurable circuits with facile fabrication.
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Vaziri, Sam. "Graphene Hot-electron Transistors". Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186044.
Testo completoAbstract (sommario):
Graphene base transistors (GBTs) have been, recently, proposed to overcome the intrinsic limitations of the graphene field effect transistors (GFETs) and exploit the graphene unique properties in high frequency (HF) applications. These devices utilize single layer graphene as the base material in the vertical hot-electron transistors. In an optimized GBT, the ultimate thinness of the graphene-base and its high conductivity, potentially, enable HF performance up to the THz region. This thesis presents an experimental investigation on the GBTs as well as integration process developments for the fabrication of graphene-based devices. In this work, a full device fabrication and graphene integration process were designed with high CMOS compatibility considerations. To this aim, basic process modules, such as graphene transfer, deposition of materials on graphene, and formation of tunnel barriers, were developed and optimized. A PDMS-supporting graphene transfer process were introduced to facilitate the wet/dry wafer-scale transfer from metal substrate onto an arbitrarily substrate. In addition, dielectric deposition on graphene using atomic layer deposition (ALD) was investigated. These dielectric layers, mainly, served as the base-collector insulators in the fabricated GBTs. Moreover, the integration of silicon (Si) on the graphene surface was studied. Using the developed fabrication process, the first proof of concept devices were demonstrated. These devices utilized 5 nm-thick silicon oxide (SiO2) and about 20 nm-thick aluminum oxide (Al2O3) as the emitter-base insulator (EBI) and base-collector insulator (BCI). The direct current (DC) functionality of these devices exhibited >104 on/off current ratios and a current transfer ratio of about 6%. The performance of these devices was limited by the non-optimized barrier parameters and device manufacturing technology. The possibility to improve and optimize the GBT performance was demonstrated by applying different barrier optimization approaches. Comparing to the proof of concept devices, several orders of magnitude higher injection current density was achieved using a bilayer dielectric tunnel barrier. Utilizing the novel TmSiO/TiO2 (1 nm/6 nm) dielectric stack, this tunnel barrier prevents defect mediated tunneling and, simultaneously, promotes the Fowler-Nordheim tunneling (FNT) and step tunneling (ST). Furthermore, it was shown that Si/graphene Schottky junction can significantly improve the current gain by reducing the electron backscattering at the base-collector barrier. In this thesis, a maximum current transfer ratio of about 35% has been achieved.QC 20160503
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Mitter, Chang Su. "Insulated gate bipolar transistor (IGBT) simulation using IG-Spice". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-03022010-020115/.
Testo completo
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AL-SHADEEDI, AKRAM. "LATERAL AND VERTICAL ORGANIC TRANSISTORS". Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1492441683969202.
Testo completo
30
Lamontagne, Maurice. "Development of a statistical model for NPN bipolar transistor mismatch". Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-053007-105648/.
Testo completo
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Nguyen, Van Hoang. "Transistor Quantique InAs à Electrons Chauds : Fabrication submicronique et étude à haute fréquence". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20084/document.
Testo completoAbstract (sommario):
Transistor Quantique InAs à Electrons Chauds: Fabrication submicronique et étude à haute fréquenceL'objectif de cette thèse est le développement de la technologie d'un transistor à électrons chauds constitué d'une hétérostructure quantique InAs/AlSb et exploitant un transport électronique résonant ultrarapide, le QHET (Quantum Hot Electron Transistor). Ce travail a permis l'étude approfondie de ses propriétés et performances à haute fréquence. L'étude aborde tous les aspects, de la conception, la croissance épitaxiale, la technologie de fabrication à la caractérisation statique et dynamique. Ce travail de thèse s'est effectué principalement à l'Institut d'Electronique du Sud (IES), sous la direction de Roland Teissier, et pour partie à l'Institut d'Electronique de Microélectronique et Nanotechnologie (IEMN) sous la direction de Mohamed Zaknoune. Nous avons, dans premier temps, mis en œuvre à l'IES une technologie double mésa afin de fabriquer les transistors avec l'émetteur de 10x10µm². La technologie en grande dimension est aisément réalisable et surtout reproductible. Elle nous a permis de travailler sur un grand nombre de structures transistor fabriquées par epitaxie par jets moléculaires (EJM) sur substrats InAs, afin d'en étudier le transport électronique et d'optimiser leur dessin. Le premier résultat marquant a été d'augmenter le gain statique jusqu'à une valeur de 15 grâce à une modification de la structure de l'émetteur qui une injection plus efficace puis l'utilisation d'une base fine de 85Å, qui améliore le temps de transit. Dans un deuxième temps, nous avons travaillé au sein de l'IES sur l'évolution de la technologie vers des dimensions intermédiaires dont la dimension la plus petite est de 1 µm de largeur. Cette technologie nous a donné une amélioration de performance des QHET grâce à la réduction des résistances et des capacités parasites des composants. Nous avons aussi travaillé à l'IEMN pour développer une technologie submicronique qui permet d'atteindre une largeur d'émetteur de 0.3 µm grâce à l'utilisation de la lithographie électronique. Cette technologie de fabrication plus performante nous a permis de mieux comprendre le fonctionnement du QHET. Et d'atteindre une régime de fonctionnement à forte densité de courant jusqu'à près de 1MA/ cm². Enfin, nous avons développé la structure et la technologie qui vont nous permettre d'évaluer la réponse à haute fréquence des QHET. Un point important a été de à disposer de la structure active du transistor sur un substrat isolant qui permette de réduire les éléments parasites durant la mesure en fréquence. Nous avons développé deux solutions : le transfert de substrat et la croissance métamorphique directement sur un substrat GaAs isolant.Les composants fabriqués par transfert de susbtrat présentent des valeurs de fréquence de transition FT de 77GHz et de fréquence d'oscillation FMAX de 88GHz. Les échantillons métamorphiques ont démontré de meilleures performances avec un FT de 170GHz et un FMAX supérieur à 200GHz. Ces résultats constituent les meilleurs dynamiques de transistors à électrons chauds à température ambiante. Ces études ont également fait progresser la compréhension du transport à haute fréquence dans ces composants. Ils permettent de comprendre les limitations actuelles et de proposer des pistes d'améliorationThis work aims to develop a new high speed transistor in a vertical transport configuration that exploits the favourable transport properties of III-V semiconductor heterostructures based on InAs. This transistor is similar to a heterojunction bipolar transistor (HBT), but has theoretical assets to overcome the fundamental high speed limits of electron transport in HBT. Our approach uses the concept of hot electron transistor in an original InAs/AlSb quantum heterostructure, that we called a quantum hot electron transistor (QHET) or quantum cascade transistor (QCT). This research was almost done in Southern Electronics Institute (IES) under supervision of Dr. Roland Teissier and other work was realized in Micro-Nanotechnology Electronics Institute (IEMN) under supervision of Dr. Mohamed Zaknoune. The QHET is a unipolar vertical transport device made of a InAs/AlSb quantum heterostructure. Its first advantage over npn HBTs is the low base sheet resistance of 250 Ω/□ , accessible with moderate n-type doping levels (typically 1018 cm-3), which is a key parameter for high speed operation. Secondly, electron transport in the short (typically 100nm) bulk InAs collector is mostly ballistic with calculated transit times much shorter than in InP-based devices. We already developed the design and technology of QHET and demonstrated its resonant transports at cryogenic temperature and its improved static operation in smaller device. From these results, we come to develop our QHET structures to achieve high current gain. Using quantum design of thin base, the current gain is about 15. We fabricated QHET with emitter width scaled down to 0.3µm, using a state of the art electron beam lithography process. The junctions are defined using selective chemical etching. The base contact is self-aligned on the emitter contact. We achieved base resistance lower than 50Ω, comparable to state of the art HBTs. The small dimension allowed reaching the high current density regime of up to 1 MA/cm² required for high frequency operation. The static current gain is about 10, but could be increased up to 14 using a new quantum design. The collector breakdown voltage is greater than 1.2 V.Towards high frequency measurement, the substrate must be non-conducting material but InAs substrate is not available. Two technologies were proposed: transferred substrate and metamorphic substrate. For transferred substrate technology, we obtained a response of cutoff frequency of 77 GHz for FT and 88 for FMAX. For metamorphic substrate technology, we performed the growth of the transistor structures on a semi-insulating GaAs substrate. We used a thin GaSb buffer layer for metamorphic growth of the active part of the transistor, with an adequate growth procedure that allows forming mainly 90° misfit dislocations at the interface between the GaAs and GaSb. This technique permits more convenient and reliable processing of the devices, as compared to use of the more standard AlSb thick buffer layer. The frequency response was determined from S-parameters measured with a network analyser up to a frequency of 70 GHz. The measured gains, after de-embedding of the connection parasitic for a device with 0.5x4µm² emitter for JC=350kA/cm² (Ic= 6.0mA, Ib= 0.7mA, Vce=1.3V). The frequency dependence is not conventional on this device, with a resonance in the current gain close to 10 GHz and a slope different from -20 dB/decade for Mason's unilateral gains. Nevertheless, we could extract the cut-off frequencies FT=172 GHz from H21 and FMAX =230 GHz using -20dB/decade extrapolation of maximum stable gain (MSG). The present results confirmed the validity of this novel device concept. In addition, this is the first demonstration of the ability of a hot electron transistor to operate at high frequency at room temperature
32
Mori, Carlos Augusto Bergfeld. "Estudo comparativo do efeito de autoaquecimento em transistores FinFET e SOI UTBB". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-04052018-103903/.
Testo completoAbstract (sommario):
Devido às dimensões cada vez mais reduzidas dos transistores e a utilização de novos materiais com baixa condutividade térmica, o desempenho de transistores avançados é afetado pelo autoaquecimento. Dispositivos sob os efeitos de autoaquecimento sofrem um aumento da sua temperatura, fazendo com que a mobilidade seja reduzida, além de comprometer a confiabilidade e gerar atrasos de sinal, trazendo impactos na eficiência de circuitos analógicos, bem como afetando o desempenho de circuitos digitais. Apesar da relevância do fenômeno, muitos estudos não o levam em consideração devido à dificuldade de sua verificação, uma vez que os métodos utilizados para transistores avançados requerem estruturas ou equipamentos especiais, que são raramente disponíveis. Dessa forma, três novas técnicas são desenvolvidas neste trabalho com o objetivo de viabilizar o estudo do efeito utilizando estruturas convencionais e medidas em corrente contínua: (i) a condutância de saída média; (ii) o método da assinatura na eficiência do transistor; (iii) a estimativa da resistência térmica utilizando somente medidas em corrente contínua. Os dois primeiros métodos são focados em uma análise qualitativa do autoaquecimento, permitindo uma verificação preliminar eficiente da presença e relevância do efeito, enquanto o terceiro método permite a extração da resistência térmica a partir do inverso da eficiência do transistor utilizando um processo iterativo, consequentemente possibilitando a obtenção do aumento da temperatura do canal devido ao autoaquecimento, com boa precisão e maior simplicidade em relação aos métodos disponíveis na literatura (com erro máximo menor que 6% para transistores de múltiplas portas em relação ao método de medidas pulsadas). Com essas técnicas, são feitas comparações da elevação de temperatura do canal entre transistores de múltiplas portas (também chamados de FinFET ou transistores 3D) e transistores de silício sobre isolante com camada de silício e óxido enterrado extremamente finos (SOI UTBB), usando simulações tridimensionais para obter condições similares de potência. Em dispositivos com menores comprimentos de canal, os FinFETs apresentaram temperaturas cerca de 60 K acima dos UTBBs.Due to the reduction of devices\' dimensions and the use of new materials with low thermal conductivity, self-heating affects the performances of advanced transistors. Devices under self-heating effects suffer an increase of their temperature, causing mobility reduction, besides compromising reliability and generating signal delays, bringing impacts to the efficiency of analog circuits, and affecting the performance of digital circuits. Despite the relevance of the phenomenon, many studies do not consider it, given the difficulty to assess it, since the methods used for advanced transistors require special structures or equipment, which are rarely available. Hence, three new techniques are developed in this work, with the objective of permitting the study of the effect utilizing conventional structures and direct current measurements: (i) the mean output conductance method; (ii) the signature in the transistor efficiency method; (iii) the thermal resistance estimative using only direct current measurements. The first two methods are focused on a qualitative analysis of the self-heating, allowing an efficient preliminary verification of the presence and relevance of the effect, while the last allows the extraction of the thermal resistance from the inverse of the transistor efficiency through an iterative process, consequently making it possible to obtain the temperature rise in the channel due to the self-heating with a good precision and greater simplicity when compared to other methods available in the literature (with maximum error smaller than 6% for multiple gate transistors when compared to the pulsed method). With these techniques, comparisons between multiple gate transistors (also known as FinFET or 3D transistors) and silicon-on-oxide with ultra-thin body and buried oxide (SOI UTBB) are performed, utilizing three-dimensional simulations to obtain similar power conditions. In devices with smaller channel length, FinFETs presented temperatures approximately 60 K above the UTBBs.
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Nogueira, Gabriel Leonardo. "Preparação e caracterização de um transistor orgânico de efeito de campo com arquitetura vertical /". Bauru, 2016. http://hdl.handle.net/11449/144580.
Testo completoAbstract (sommario):
Orientador: Neri AlvesBanca: Ivo Alexandre Hummelgen
Banca: Clarissa de Almeida Olivati
Resumo: O transistor orgânico de efeito de campo com arquitetura vertical (VOFET) possibilita contornar as principais limitações de um transistor orgânico de efeito de campo (OFET) convencional. Nesta estrutura, as camadas são empilhadas verticalmente, de modo que os eletrodos de fonte e dreno são separados pela camada semicondutora e o comprimento do canal definido pela espessura do filme semicondutor. Para o VOFET proposto, utilizou-se Al e Al2O3 (obtido por anodização) como eletrodo e dielétrico de gate, respectivamente. O filme semicondutor foi obtido pela deposição por spincoating de P3HT dissolvido em clorofórmio. Os eletrodos de fonte e dreno foram obtidos por evaporação térmica a vácuo. Ao utilizar Al e Au como fonte e dreno, respectivamente, foi possível estudar os dispositivos de dois terminais que compõe o VOFET. Com base nesses dispositivos, importantes parâmetros da estrutura vertical foram determinados, como capacitância do dielétrico (~265 nF/cm2), densidade de portadores e mobilidade do P3HT (NA = 9,2 x 1016 cm-3 e μ = 1,5x10-4 cm2V-1s-1). Para utilizar Sn como eletrodo de fonte, o filme foi avaliado por meio de medidas de resistência e capacitância, aliadas à analise morfológica por AFM. Observa-se que a adição de uma camada de PMMA sobre o Al2O3 melhora o desempenho do VOFET. Para o VOFET formado por Al2O3/PMMA (20 nm/14 nm), com Sn e Al como fonte e dreno, foram calculados os valores de densidade de corrente (Jeff = 7x10-3 mA/cm2), voltagem e campo limiar (VTH = -... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: A way of circumvent the limitations of conventional organic field-effect (OFET), is by using the vertical organic field-effect transistor (VOFET). Inn tbis structure, with layers stacked vertically, the semiconductor is sandwiched between source and drain electrodes, where the channel length is determined by the thickness of the semiconductor film. In this study, we report a VOFET with Al and Al3O3 (obtained by anodization) as electrode and dielectric of gate, respectively. The semiconductor film was obtained by spin-coating of the P3HT in chloroform. We obtained the source and drain electrodes by vacuum thermal evaporation. The use of Al and Au as source and drain, respectively, enabled the investigation of the two devices contained in the vofet (MIM capacitor, Schotky diode and MIS capacitor). Important parameters were determinate, as dielectric capacitance (~265 nF/cm2), charrier density and mobility of P3HT (Na=9,2 x 1016 cm-3 e u = 1,5x10-4 c2V-1s-1), etc. To use Sn as source electrode, the film (by evaporation) was investigated by measurements of resistance and capacitance, combined with morphological analysis by AFM. We observed that the addiction of PMMA layer on Al2O3 improves the performance of VOFET. For VOFET obtained by using Al2O3/PMMA (20 nm/14 nm) as dielectric layer, with Sn and Al as source and drain, respectively, were calculate the values of current density (Jeff=7x10-3 mA/cm2), threshold voltage and electric field (Vth=-8V e Eth=330MV/m). Thereat, we obtained a VOFET by evaporation of a thin film of Sn as perforated source electrode
Mestre
34
Morais, Rogério Miranda. "Desenvolvimento de transístores para a eletrônica impressa /". Presidente Prudente, 2020. http://hdl.handle.net/11449/192597.
Testo completoAbstract (sommario):
Orientador: Neri AlvesResumo: Nesta tese de doutorado são apresentados resultados a respeito da fabricação e caracterização de dois tipos de transístores com eletrólito no gate (EGTs, do inglês Electrolyte Gated Transistors): Transístores eletroquímicos orgânicos (OECTs, do inglês Organic Electrochemical Transistors) e transístores de dupla camada elétrica (EDLTs, do inglês Electric Double Layer Transistor). Os dispositivos foram produzidos utilizando inkjet printing e screen printing para imprimir soluções à base de polímeros como o poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), precursores de óxido de zinco e de nanopartículas de óxido zinco. Como eletrólito de gate foram utilizadas faixas auto sustentáveis de íon gel à base de celulose. Esse último foi desenvolvido por pesquisadores do CEMOP/CENIMAT e combina a alta mobilidade iônica dos eletrólitos líquidos com a plasticidade dos eletrólitos sólidos. Sua estrutura em gel possibilita que o material seja moldado ou cortado de acordo com a aplicação. Os ECTs foram fabricados em arquitetura planar sobre substrato de vidro ou de papel, onde foram impressos: PEDOT:PSS como semicondutor e carbono como eletrodos. Os resultados mostram uma forte dependência de parâmetros como: corrente no estado ligado (Ion), no estado desligado (Ioff), transcondutância, razão Ion/Ioff, morfologia da superfície do substrato e a rugosidade. Os EDLTs foram fabricados usando síntese de auto combustão e foto-ativação química para produzir dispositivos com baix... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: On this doctoral thesis is presented results of the manufacture and characterization of two types of Electrolyte-gated Transistors (EGTs): Organic Electrochemical Transistors (OECTs) and electric double-layer transistors (EDLTs). Devices were manufactured using inkjet printing and screen printing to print solutions based on polymers such as poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS), zinc oxide precursors and zinc oxide nanoparticles. Self-sustainable bands of cellulose-based ion gel were used as gate electrolyte. The last was developed by researchers from CEMOP/CENIMAT and combines the high ion mobility of liquid electrolytes with the plasticity of solid electrolytes. This gel structure allows this material to be shaped or cut according to the application. The ECTs were manufactured in planar architecture over glass or paper substrates, where they were printed: PEDOT: PSS as semiconductor and carbon as electrodes. The results presents a strong dependence on parameters such as: on-state current (Ion), off-state current (Ioff), transconductance, Ion/Ioff ratio, surface morphology of the substrate and roughness. The EDLTs were manufactured using auto-combustion synthesis and chemical photo-activation process to produce devices with low processing temperatures in a way to be used in flexible, plastic or paper substrates. These devices are based on nanoparticles of zinc oxide as a semiconductor channel, fully printed and with heat treatment below 200 oC.... (Complete abstract click electronic access below)
Doutor
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Belkhir, Amina. "Contribution à la modélisation des transistors organiques". Reims, 2009. http://theses.univ-reims.fr/exl-doc/GED00001089.pdf.
Testo completoAbstract (sommario):
Ce travail porte sur l’étude de la modélisation du transistor organique ainsi que son implémentation numérique. L’objectif est la prise en compte des spécificités des matériaux organiques dans le calcul des caractéristiques courant-tension du transistor, de manière à permettre une analyse physique du comportement des transistors, et par suite de pouvoir agir sur les paramètres technologiques de fabrication, et améliorer les performances des composants et des circuits. Dans un premier temps, un modèle semi-analytique 1D a été développé, sur la base du modèle du transistor MOS silicium en prenant en compte un certain nombre d’effets parasites (résistances ohmiques des contacts, injection non linéaire au contact source). L’impact des phénomènes d’injection sur l’extraction des paramètres essentiels du transistor (mobilité effective et tension de seuil) ont pu être clairement soulignés. De plus, l’existence de champs électriques très élevés au contact injectant a été mise en évidence. Ensuite, il est apparu utile de développer un modèle numérique du calcul du courant drain pour prendre en compte d’avantage de spécificités des matériaux organiques (densités d’états, autres modèles d’injection, profils de mobilités, etc. ). Ce modèle est basé sur le calcul distribué du potentiel dans le canal. Dans un premier temps, la résolution numérique de l’équation de Poisson a été implémentée pour calculer la charge accumulée. Cela a également permis de souligner clairement les différences entre la tension de seuil effective UT-eff et la tension UONSET. Ce travail préliminaire pose les bases nécessaires à la poursuite de l’analyse physique de la caractéristique courant-tensionThis study focuses on organic transistor modeling, and its numerical implementation. Considering the specificities of organic materials, current-voltage characteristics of the transistor are calculated. First, a semi-analytical 1D transistor model was developed, derived from the silicon MOS model, including a number of parasitic effects (contact resistances, non-linear injection at the source contact). The impact of the injection phenomena on the extraction of key parameters (effective mobility and threshold voltage) has been clearly highlighted, and successful comparison with experimental results was established. Moreover, the existence of very high electric fields at the injecting contact was shown. The usual gradual channel approximation fails in the presence of these high fields, and 2D Poisson equation is used to evidence a depleted zone formation near the source contact. The 1D model fails to accurately describe organic transistor behavior near threshold, as well as to take into account some specific properties of disordered organic materials, such as gaussian density of states, injection and transport through localized states, etc. . . Therefore, a distributed model has been developed. Numerical resolution of the Poisson equation has been implemented to calculate the accumulated charge in the presence of an electric field gradient along the channel. One result of this preliminary work was to clearly highlight the difference between the effective threshold voltage UT-eff and the onset voltage UONSET. This work paves the way for deeper analysis of the current-voltage characteristic of organic transistors
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Razafindrakoto, Mirijason Richard. "Modèle hydrodynamique de transistor MOSFET et méthodes numériques, pour l'émission et la détection d'onde électromagnétique THz". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS035/document.
Testo completoAbstract (sommario):
Du fait de ses propriétés intéressantes, le domaine de fréquence térahertz (THz) du spectre électromagnétique peut avoir de nombreuses applications technologiques, de l'imagerie à la spectroscopie en passant par les télécommunications. Toutefois, les contraintes technologiques empêchant l'émission et la détection efficaces de ces ondes par des systèmes conventionnels ont valu à cette partie du spectre électromagnétique le nom de gap THz. Au cours des deux dernières décennies, plusieurs solutions novatrices sont apparues. Parmi elles, l'utilisation de transistors à effet de champ s'est imposée comme une solution originale, bon marché, avec un fort potentiel d'intégration. Le mécanisme identifié fait intervenir l'interaction entre les ondes THz et des ondes de courant (dites ondes plasma) dans le canal du transistor. Le canal du transistor agit tel une cavité pour ces ondes plasma. Le dispositif peut alors se comporter de manière résonante ou non-résonante en fonction de divers paramètres. Dans ce manuscrit, nous étudions numériquement ces différents régimes à l'aide de modèles hydrodynamiques. Les modèles utilisés élargissent les phénomènes pris en compte dans de précédentes études théoriques. Les résultats portent sur la détection d'ondes THz par des transistors et dans une moindre mesure sur leur émission. Dans le régime non-résonant, nous étudions dans quelle mesure la plage de linéarité de détection peut être étendue. Dans le régime résonant, nous montrons l'existence de nouvelles fréquences de résonance, permettant d'élargir le spectre d'intérêt de ces détecteursDue to its interesting properties, the electromagnetic THz frequency range may lead to numerous technological applications, ranging from imaging to spectroscopy or even communications. However, technological constraints prevented the efficient emission and detection of such waves with conventional electronics, leading to the idea of the terahertz gap. In the last decades, multiple novel solutions to resolve this gap have been proposed. Amongst these, one may find the use of simple field effect transistors as the most promising one. Their production benefits from currently available CMOS technology thus drastically decreasing the fabrication cost of such a device while allowing it to be easily integrated within electronic circuits. The mechanism behind the emission and detection is the interaction between THz electromagnetic radiations and current oscillations, that is plasma waves, in the transistor's channel. This channel forms a cavity for plasma oscillations, hence, the device may act either resonantly or non-resonantly, depending on various parameters. This thesis deals with the numerical simulation of the transistor in different regimes using hydrodynamical models. These models account for multiple phenomena that have been considered in previous theoretical studies. Some theoretical results on both the emission and detection of THz radiation are presented. In the non-resonant case, we study how one can increase the linear regime of detection. In the resonant case, we show the existence of unexpected resonance frequencies, enlarging the detection spectrum of such detectors
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Chen, Qiang. "Scaling limits and opportunities of double-gate MOSFETS". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/15011.
Testo completo
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Aurangabadkar, Nilesh Kirti Kumar. "Simulations of analog circuit building blocks based on radiation and temperature-tolerant SIC JFET Technologies". Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-05162003-114102.
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Villarroel, Marquez Ariana A. "Multimodal sensing polymer transistors for cell and micro-organ monitoring". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0449.
Testo completoAbstract (sommario):
Le développement de nouveaux matériaux pour augmenter les performances des capteurs biologiques est très important lorsqu'on sait que les signaux électriques constituent la base des évènements biologiques fondamentaux comme l’activité cérébrale, le battement du coeur ou la sécrétion hormonale. Ces signaux cellulaires sont souvent enregistrés avec des sondes qui nécessitent des modifications génétiques ou chimiques. Cependant, des signaux intrinsèques pourraient être exploités directement. Des matrices de microélectrodes extracellulaires (MEAs) et des transistors électrochimiques à base de polymères (OECTs) sont par exemple sensibles aux flux ioniques. Ils sont, de plus, non-invasifs et donnent des informations importantes sur l’activité cellulaire. Cependant, ils ne peuvent différencier les espèces ioniques impliquées dans les signaux pour l’obtention d’une image précise de l’activité électrique. Ce travail de thèse a ainsi consisté dans : le développement de polymères bivalents ion-sensibles et conducteurs électroniques, la démonstration de leur biocompatibilité avec des cellules bêta-pancréatiques, la fabrication de transistors OECTs intégrant ces matériaux et la preuve de concept de son applicabilité comme plateforme non-invasive pour la détection de flux ioniquesThe generation of novel materials to harness the power of biological sensors is extremely attractive because precisely configured electrical activities form the base of key biological events such as brain activity, heart beat or vital hormone secretion. Cellular signals are often recorded using probes that require genetic or chemical manipulation. Intrinsic signals offer the huge advantage to harness these properties without further transformations. Extracellular microelectrode arrays (MEAs) and polymer-based organic electrochemical transistor arrays (OECTs) rely on the movement of ions, are non-invasive and provide some information on cell activity. However, they cannot resolve fluxes of specific species as targeted ions to obtain a precise picture of cell/organ activity. In this context, this work has consisted on the development of multimodal ion-sensing polymers, demonstration of their biocompatibility to beta-cells, the engineer of original OECTs incorporating these materials and demonstration of their viability as non-invasive platform of electrical cell activity and specific ion fluxes
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Kim, Jungbae. "Organic-inorganic hybrid thin film transistors and electronic circuits". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34683.
Testo completoAbstract (sommario):
Thin-film transistors (TFTs) capable of low-voltage and high-frequency operation will be required to reduce the power consumption of next generation electronic devices driven by microelectronic components such as inverters, ring oscillators, and backplane circuits for mobile displays. To produce high performance TFTs, transparent oxide-semiconductors are becoming an attractive alternative to hydrogenated amorphous silicon (a-Si:H)- and organic-based materials because of their high electron mobility vlaues and low processing temperatures, making them compatible with flexible substrates and opening the potential for low production costs. Practical electronic devices are expected to use p- and n-channel TFT-based complementary inverters to operate with low power consumption, high gain values, and high and balanced noise margins. The p- and n-channel TFTs should yield comparable output characteristics despite differences in the materials used to achieve such performance. However, most oxide semiconductors are n-type, and the only high performance, oxide-based TFTs demonstrated so far are all n-channel, which prevents the realization of complementary metal-oxide-semiconductor (CMOS) technologies.
On the other hand, ambipolar TFTs are very attractive microelectronic devices because, unlike unipolar transistors, they operate independently of the polarity of the gate voltage. This intrinsic property of ambipolar TFTs has the potential to lead to new paradigms in the design of analog and digital circuits. To date, ambipolar TFTs and their circuits, such as inverters, have shown very limited performance when compared with that obtained in unipolar TFTs. For instance, the electron and hole mobilities typically found in ambipolar TFTs (ATFTs) are, typically, at least an order of magnitude smaller than those found in unipolar TFTs. Furthermore, for a variety of circuits, ATFTs should provide balanced currents during p- and n-channel operations. Regardless of the selection of materials, achieving these basic transistor properties is a very challenging task with the use of current device geometries.
This dissertation presents research work performed on oxide TFTs, oxide TFT-based electronic circuits, organic-inorganic hybrid complementary inverters, organic-inorganic hybrid ambipolar TFTs, and ambipolar TFT-based complementary-like inverters in an attempt to overcome some of the current issues. The research performed first was to develop low-voltage and high-performance oxide TFTs, with an emphasis on n-channel oxide TFTs, using high-k and/or thin dielectrics as gate insulators. A high mobility electron transporting semiconductor, amorphous indium gallium zinc oxide (a-IGZO), was used as the n-channel active material. Such oxide TFTs were employed to demonstrate active matrix organic light emitting diode (AMOLED) display backplane circuits operating at low voltage.
Then, high-performance hybrid complementary inverters were developed using unipolar TFTs employing organic and inorganic semiconductors as p- and n-channel layers, respectively. An inorganic a-IGZO and pentacene, a widely used organic semiconductor, were used as the n- and p-channel semiconductors, respectively. By the integration of the p-channel organic and n-channel inorganic TFTs, high-gain complementary inverters with high and balanced noise margins were developed. A new approach to find the switching threshold voltage and the optimum value of the supply voltage to operate a complementary inverter was also proposed.
Furthermore, we proposed a co-planar channel geometry for the realization of high-performance ambipolar TFTs. Using non-overlapping horizontal channels of pentacene and a-IGZO, we demonstrate hybrid organic-inorganic ambipolar TFTs with channels that show electrical properties comparable to those found in unipolar TFTs with the same channel aspect ratios. A key characteristic of this co-planar channel ambipolar TFT geometry is that the onset of ambipolar operation is mediated by a new operating regime where one of the channels can reach saturation while the other channel remains off. This allows these ambipolar TFTs to reach high on-off current ratios approaching 104. With the new design flexibility we demonstrated organic-inorganic hybrid ambipolar TFT-based complementary-like inverters, on rigid and flexible substrates, that show a significant improvement over the performance found in previously reported complementary-like inverters. From a materials perspective, this work shows that future breakthroughs in the performance of unipolar n-channel and p-channel semiconductors could be directly transposed into ambipolar transistors and circuits. Hence, we expect that this geometry will provide new strategies for the realization of high-performance ambipolar TFTs and novel ambipolar microelectronic circuits.
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Ditz, Marc William Legori. "S-parameter modeling of two-port devices using a single, memoryless nonlinearity". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-03172010-020656/.
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Gondro, Elmar. "Hochfrequenz-Modellierung des MOS-Transistors". [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967606586.
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Chu, Kan Man. "Modeling of tunnel oxide transistors". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29076.
Testo completoAbstract (sommario):
Two improvements to a comprehensive analytic model which describes the steady-state current in a metal-insulator-semiconductor tunnel junction are reported. The first modification replaces the conventional two-band representation of the thin oxide band structure with a one-band model. In this approach the electron barrier height for tunneling is always less than the hole barrier height by an amount equal to the semiconductor band gap. The second improvement enables the energy dependence of the electron and hole tunneling probability factors to be taken into account. This is accomplished by expressing the tunneling probabilities as short-term series expressions. The capability of the model to accurately predict the electrical characteristics of metal-insulator-semiconductor (MIS) tunnel junctions is demonstrated by simulating the d.c. and a.c. performance of three major types of transistor with tunnel oxide emitters, namely the tunnel emitter transistor (TETRAN), MIS-emitter transistor (MISET) and polysilicon emitter transistor (PET). Experimental data for the d.c. characteristics of all these devices are available and are found to be well- described by the predictions of the models. No experimental data for the limits of high frequency operation of the TETRAN, MISET and pnp PET have yet been reported. The models presented here suggest what those limits can be expected to be.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Panda, Durga Prasanna. "Nanocrystalline silicon thin film transistors". [Ames, Iowa : Iowa State University], 2006.
Cerca il testo completo
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Qian, Feng. "Thin film transistors in polysilicon /". Full text open access at:, 1988. http://content.ohsu.edu/u?/etd,162.
Testo completo
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Larsson, Oscar. "Polyelectrolyte-Based Capacitors and Transistors". Doctoral thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-67852.
Testo completoAbstract (sommario):
Polymers are very attractive materials that can be tailored for specific needs and functionalities. Based on their chemical structure, they can for instance be made electrically insulating or semiconducting with specific mechanical properties. Polymers are often processable from a solution, which enables the use of conventional low-cost and high-volume manufacturing techniques to print electronic devices onto flexible substrates. A multitude of polymer-based electronic and electrochemical devices and sensors have been developed, of which some already has reached the consumer market. This thesis focuses on polarization characteristics in polyelectrolyte-based capacitor structures and their role in sensors, transistors and supercapacitors. The fate of the ions in these capacitor structures, within the polyelectrolyte and at the interfaces between the polyelectrolyte and various electronic conductors (a metal, a semiconducting polymer or a network of carbon nanotubes), is of outermost importance for the device function. The humidity-dependent polarization characteristics in a polyelectrolyte capacitor are used as the sensing probe for wireless readout of a passively operated humidity sensor circuit. This sensor circuit can be integrated into a printable low-cost passive sensor label. By varying the humidity level, limitations and possibilities are identified for polyelectrolyte-gated organic field-effect transistors. Further, the effect of the ionic conductivity is investigated for polyelectrolyte-based supercapacitors. Finally, by using an ordinary electrolyte instead of a polyelectrolyte and a high-surface area (supercapacitor) gate electrode, the device mechanisms proposed for electrolyte-gated organic transistors are unified.
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Fjer, Mouhsine. "Strained Si heterojunction bioploar transistors". Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1290.
Testo completoAbstract (sommario):
This dissertation addresses the world’s first demonstration of strained Si Heterojunction Bipolar Transistors (sSi HBTs). The conventional SiGe Heterojunction Bipolar Transistor (SiGe HBT), which was introduced as a commercial product in 1999 (after its first demonstration in 1988), has become an established device for high-speed applications. This is due to its excellent RF performance and compatibility with CMOS processing. It has enabled silicon-based technology to penetrate the rapidly growing market for wide bandwidth and wireless telecommunications once reserved for more expensive III–V technologies. SiGe HBTs is realised by the pseudomorphic growth of SiGe on a Si substrate, which allows engineering of the base region to improve performance. In this way the base has a smaller energy band gap than the emitter, which increases the gain. The energy band gap of SiGe reduces with increasing Ge composition, but the maximum Ge composition is limited by the amount of strain that can be accommodated within a given base layer thickness. Therefore, a new innovation is necessary to overcome this limitation and meet the continuous demand for high speed devices. Growing the SiGe base layer over a relaxed SiGe layer (Strain Relaxed Buffer) can increase the amount of Ge that can be incorporated in the base, hence, increasing the device performance. In this thesis, experimental data is presented to demonstrate the realisation of sSi HBTs. The performance of this novel device has been also investigated and explained using TCAD tool.
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Tavares, Pedro Alexandre Cadinha. "Superconducting Josephson vortex flow transistors". Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248330.
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Robins, Ian. "Gas sensitive field effect transistors". Thesis, King's College London (University of London), 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318466.
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Cobden, David Henry. "Individual defects in mesoscopic transistors". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386908.
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