Dissertations / Theses on the topic 'GaAs Schottky diodes'
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1
Chegroune, Kamel. "Realisation et caracterisation de diodes schottky submillimetriques metal-gaas." Toulouse 3, 1986. http://www.theses.fr/1986TOU30166.
Abstract:
Le premier chapitre effectue la synthese des connaissances theoriques sur le fonctionnement des diodes en statique et en dynamique (ondes submillimetriques). Les mecanismes physiques regissant le comportement des diodes en haute frequence sont discutes. L'objet du deuxieme chapitre est la presentation des methodes mises en oeuvre pour realiser les composants (nettoyages, depot electrolytiques par courant pulse, microlithographie par faisceaux d'electrons). Le but est de diminuer la geometrie des diodes 0
2
Daboo, Cyrus. "Surface plasmon enhanced quantum efficiency of GaAs-Au Schottky diodes." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386416.
3
Elguennouni, Driss. "Réalisation d'un ensemble automatisé de mesures d'admittance : application à l'étude des diodes Schottky Al/GaAs et YSi1,7/Si." Grenoble 1, 1989. http://www.theses.fr/1989GRE10092.
Abstract:
La comprehension de la structure metal-semiconducteur fait l'objet de nombreuses etudes, depuis longtemps, tant sur le plan theorique qu'experimental. Le memoire presence l'etude de la diode schottky m/sc par mesure d'admittance principalement sous polarisation directe pour determiner et comparer les distributions d'etats d'interface obtenues pour quelque systeme typique. En particulier, les mesures d'admittances sont etendues ici pour la premiere fois jusqu'a 0,1 hz. Le travail est divise en trois parties: la premiere partie donne les principes et decrit les caracteristiques d'un ensemble automatise construit au cours de cette these permettant la mesure et l'admittance jusqu'a 0,1 hz (rc10##4); la deuxieme partie est une analyse theorique. D'une part, de l'effet des etats d'interface, sur la capacite et la conductance de la diode en fonction de la polarisation, la frequence et la temperature. D'autre part, des phenomenes de transport sous polarisation directe, en tenant compte des porteurs et majoritaires dans la zone quasineutre; la troisieme partie est la synthese des resultats experimentaux, mettant en evidence la variation des caracteristiques des etats d'interface en fonction du mode de preparation de la surface du semiconducteur avant le depot du metal, et expliquant le comportement inductif de la structure sous polarisation directe
4
Carton, Patrick. "Caractérisation de GaAs massif et contraste EBIC des dislocations." Lille 1, 1990. http://www.theses.fr/1990LIL10052.
Abstract:
Nous nous sommes intéressés au cours de cette étude aux propriétés de recombinaison des porteurs minoritaires sur les dislocations. L'étude du contraste EBIC de dislocations perpendiculaires à la surface, de caractère et de dislocations de croissance a été effectuée sur des échantillons massifs d'arséniure de gallium de type n (n6. 1016 cm3). Nous avons utilisé pour cela, des diodes de Schottky perpendiculaires au faisceau d'électrons. Le contraste EBIC a été mesuré à forte tension d'accélération en fonction du courant de faisceau des électrons incidents à 300 k et pour une valeur du courant de faisceau a 77 k. Les paramètres physiques du matériau tels la longueur de diffusion l des porteurs minoritaires et le niveau de dopage influencant la valeur du contraste de la dislocation, une caractérisation préalable de l'échantillon dans des zones proches des dislocations a été nécessaire. L'étude de l a 300 k et a 77 k a permis de montrer que celle-ci est contrôlée par les niveaux légers à basse température et par les niveaux profonds à température ambiante. Une variation de la largeur de la zone de charge d'espace a pu être détectée à basse température et est sans doute due à l'ionisation d'un centre profond qui pourrait être el2. Les résultats expérimentaux de contraste EBIC des dislocations sont du même ordre de grandeur que ceux calculés à partir d'un modèle physique faisant l'hypothèse d'une recombinaison intrinsèque. Les valeurs expérimentales sont environ deux fois plus faibles que les valeurs calculées; ceci nous conduit à introduire un rayon de recombinaison effectif inférieur au rayon d'écran de read utilise dans les calculs. Nous avons également pu mettre en évidence que les niveaux associés aux dislocations sont plus éloignés du niveau de fermi que les niveaux associés aux dislocations
5
Bouillaud, Hugo. "Fabrication et optimisation des caractéristiques thermiques de diodes Schottky de la filière GaAs et reportées sur SiHR pour des applications de multiplication de fréquences." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILN043.
Abstract:
Les besoins exponentiels liés aux applications exploitant le domaine THz nécessitent d'accroitre l'éventail des sources disponibles et d'optimiser leur fabrication. Dans ce travail de thèse, nous nous sommes intéressés aux diodes schottky en vue de la réalisation de multiplicateurs de fréquences. Notre travail de recherche expérimental a consisté en l'optimisation des caractéristiques de diodes schottky de filière GaAs, par le développement et la mise en œuvre d'un procédé de fabrication innovant. Dans un premier temps, nous avons réalisé des diodes schottky GaAs sur substrat GaAs de différentes tailles, pour élaborer des composants de référence. Nous avons ensuite fabriqué un composant de type flip-chip pour une application de multiplication à 150 GHz en boitier guide d'ondes. Enfin, dans le but d'améliorer les performances en puissance des diodes, nous avons optimisé leur dissipation thermique en transférant leur structure épitaxiale sur un substrat bénéficiant d'une meilleure conductivité thermique : le SiHR (silicium haute résistivité). Le procédé technologique complet de ces fabrications est détaillé, puis la dernière partie de l'étude est consacrée à leurs caractérisations. D'une part, nous avons évalué les éventuelles variations sur les caractéristiques des diodes GaAs sur GaAs, induites par les différentes tailles. D'autre part nous avons comparé les deux technologies sur les substrats SiHR et GaAs. Ce travail montre l'apport que peut présenter ce type de technologie reportée, où une diminution significative de la résistance thermique des composants est observée, et est associée à un gain notable sur la résistance sérieThe exponential needs associated with applications exploiting the THz domain require to expand the range of available sources and optimize their fabrication processes. In this thesis, we focused on schottky diodes for its use as frequency multipliers. Our experimental research involved optimizing the characteristics of GaAs schottky diodes through the development and implementation of an innovative fabrication process. First, we fabricated GaAs schottky diodes on GaAs substrate with several aspect ratios in order to make a reference in terms of device. Then we fabricated a flip-chip device for a 150 GHz frequency multiplication application in a waveguide block. Finally, in order to enhance the power handling of the diodes, we optimized their thermal dissipation by transferring their epitaxial structure onto a substrate with higher thermal conductivity : SiHR (high resistivity silicon). The complete technological processes for these fabrications are detailed, and the last part of the study is dedicated to their characterization. On one hand, we assessed any variations in the characteristics of GaAs diodes on GaAs induced by the different aspect ratios. On the other hand, we compared the two technologies on SiHR and GaAs substrates. This work demonstrates the potential of this type of transferred technology, where a significant reduction of thermal resistance is observed and is associated with a notable improvement of the series resistance
6
Haris, Norshakila. "Three-dimensional multilayer integration and characterisation of CPW MMIC components for future wireless communications." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/threedimensional-multilayer-integration-and-characterisation-of-cpw-mmic-components-for-future-wireless-communications(89ddea33-4de2-43ba-b8dc-dbc032b868e7).html.
Abstract:
The development of monolithic microwave integrated circuits (MMICs) has enabled the expansion of multiple circuit elements on a single piece of semiconductor, enclosed in a package with connecting leads. Attributable to the widespread use of wireless circuits and sub-systems, MMICs meet stringent demands for smaller chip area, low loss and low cost. These require highly integrated MMICs with compact features. This thesis provides valuable insight into the design of compact multifunctional MMICs using three-dimensional (3-D) multilayer technology. The proposed technology offers compact, hence low-cost solutions, where all active and passive components are fabricated vertically on the same substrate and no expensive via hole or backside processing is required. The substrate used in this work contains pre-fabricated 0.5 µm pseudomorphic High Electron Mobility Transistor (pHEMT) GaAs active devices. The performances of the uncommitted and committed pHEMTs are compared in terms of their DC, small-signal and large-signal RF measurements and modelling results. Committed pHEMT refers to the pHEMT that is connected to multilayer circuit, whereas uncommitted pHEMT is not. The effect of integrating committed pHEMTs with multilayer passive components is studied and the suitability of the multilayer fabrication processing is assessed. Using this technology, two pHEMT Schottky diodes with 120 µm and 200 µm gate widths are designed, fabricated and extensively characterised by I-V, C-V and S-parameter measurements. The information gained from the measurements is then used to extract all unknown equivalent circuit model parameters using high-frequency on-wafer microwave probing. The measured results showed good agreement with the modelled ones over the frequency range up to 40 GHz. Preliminary demonstrations of the use of these pHEMT Schottky diodes in microwave limiter and detector circuit applications are also discussed, showing promising results. Finally, the implementation of 3-D multilayer technology is shown for the first time in single-pole single-throw (SPST) and single-pole double-throw (SPDT) switches design by utilising the pre-fabricated pHEMTs. The design and analysis of the switches are demonstrated first through simulation using TriQuint's Own Model - Level 3 (TOM3). Three optimised SPST and SPDT pHEMT switching circuits which can address applications ranging from L to X bands are successfully fabricated and tested. The performance of the pHEMT switches is comparable to those of the current state-of-the-art, while simultaneously offering compact circuits with the advantages of integration with other MMIC components. All works reported in this thesis should facilitate foundry design engineers towards further development of 3-D multilayer technology.
7
Vildeuil, Jean-Charles. "Caractérisation et modélisation basse fréquence de transistors PHEMT AlGaAs/InGaAS/GaAs : bruits du canal, de la grille et corrélation." Montpellier 2, 2000. http://www.theses.fr/2000MON20151.
Abstract:
La realisation d'un oscillateur a haute purete spectrale passe obligatoirement par une phase de conception assistee par ordinateur afin de determiner la topologie optimale du circuit oscillateur en terme de bruit de phase. Le bruit de phase de l'oscillateur etant etroitement lie au bruit basse frequence du transistor utilise, ici des phemts (pseudomorphic high electron mobility transistors), il faut etudier le comportement en bruit de fond du composant. L'objet de ce travail est donc sur le plan pratique l'elaboration de schemas equivalents rendant compte du fonctionnement statique ou dynamique du transistor et prenant en compte les differentes sources de bruit basse frequence presentes dans le composant. Ces modeles seront ensuite utilises pour la simulation precise des oscillateurs concus. Apres une breve description des caracteristiques des oscillateurs, nous presentons dans ce memoire le principe de fonctionnement des transistors hemt et les phenomenes mis en jeu pour aboutir aux equations de conduction. A partir de ces equations, une methodologie de caracterisation a permis d'extraire l'ensemble des parametres electriques rendant compte de maniere satisfaisante du fonctionnement du composant. Les mesures experimentales relatives aux bruits de fond du drain et de l'electrode de commande ont egalement ete analysees dans le detail. Enfin, la fonction de coherence entre le bruit associe a la grille et celui associe au drain est etudiee. La simulation presentee permet de valider les schemas equivalents et les modeles proposes.
8
Jung, Cécile. "Conception et fabrication de circuits intégrés basés sur les nano-diodes Schottky GaAs fonctionnant aux fréquences THz et sub-THz pour les récepteurs hétérodynes spatiaux dédiés à l'astrophysique." Paris 11, 2009. http://www.theses.fr/2009PA112240.
Abstract:
L'objectif de ce travail de thèse est de concevoir et réaliser des circuits mélangeurs à 330GHz et à 183GHz pour la détection hétérodyne en astrophysique. Ces circuits sont basés sur les diodes Schottky, permettant ainsi un fonctionnement à température ambiante. Le thème principal de la thèse consiste à élaborer un protocole de fabrication de diodes Schottky submicroniques et à les intégrer dans des circuits mélangeurs. Ces circuits seront assemblés dans un bloc de test et caractérisés en termes de performances RF. Ce travail de thèse pourra être utilisé pour des circuits à plus hautes fréquences, aussi bien pour les mélangeurs que pour les multiplicateurs. Un processus de fabrication entièrement basé sur la lithographie électronique a été développé, permettant la réalisation de diodes Schottky ayant des anodes submicroniques et le perfectionnement de leurs caractéristiques électriques. De nombreuses études spécifiques d'optimisation de contact ohmique et de contact Schottky ont permis d'obtenir des résistances en séries inférieures à 10Ω et des meilleurs facteurs d'idéalité entre 1,08 et 1,15. Deux types de circuits ont été réalisés. L'un pour un fonctionnement à 330GHz composé d'une paire d'anodes anti-parallèles sur une membrane de 10μm. L'autre, pour une fréquence de fonctionnement à 183GHz, consiste en un circuit MMIC comprenant une paire d'anodes anti-parallèles sur une membrane de 50μm. Un des composants à 330GHz a été intégré dans un bloc mélangeur et ses performances RF ont été caractérisées. Le résultat préliminaire a été encourageant avec une température de bruit de 1800K pour une perte en conversion de 8dBThe objective of this thesis is to design and integrate circuits mixers at 330GHz and 183GHz for heterodyne detection in astrophysics. These circuits are based on Schottky diodes, allowing operation at room temperature. The main point of the thesis is to develop a protocol for fabrication of submicron Schottky diodes and to integrate them in circuits mixers. These circuits are integrated in a test block and characterized in terms of RF performances. This thesis work may be used for circuits at higher frequencies, for both mixers and multipliers. A fabrication process entirely based on electron beam lithography has been developed, allowing the realization of Schottky diodes with submicronic anodes and improvement of their electrical characteristics. Many studies for specific optimization of the ohmic and schottky contacts have yielded to series resistances below 10Ω and to best ideality factors between 1,08 and 1,15. Two types of circuits have been made. One for operation at 330GHz composed of a pair of anti-parallel anodes on a 10μm membrane. The other, for a frequency of 183GHz, consists of a MMIC circuit including a pair of anti-parallel anodes on a 50μm membrane. One of the components to 330GHz has been integrated into a mixer bloc, its RF performances have been characterized. The preliminary result was encouraging with a noise temperature of 1800K for a conversion loss of 8dB
9
Debrie, Francis. "Élaboration d'une technologie auto-alignée par gravure plasma de métaux réfractaires pour transistors à effet de champ à hétérojonction (AlGaAs/GaAs)." Toulouse, INPT, 1986. http://www.theses.fr/1986INPT046H.
Abstract:
L'auto-alignement est etudie depuis peu sur le tecfet (transistor a effet de champ a heterojonction algaas/gaas) par certains laboratoires etrangers. Le procede retenu dans les travaux de l'auteur fait appel a la gravure plasma de metaux refractaires et a un auto-alignement des metallisations de contacts ohmiques sur la grille. La gravure permet la realisation de grilles submicroniques en "t", par photolithographie optique, de matiere reproductible grace a un systeme de detection specialement etudie. Une technologie auto-alignee en 4 etapes a ete mise au point: isolement par mesa, grille en tiwsi, contacts ohmiques evapores en augeni/au, metallisation finale en tiptau. Les resultats obtenus sur mesfet sont comparables a ceux obtenus par d'autres laboratoires: gm=140ms/mm et idss=210ma/mm. Les premieres caracterisations en hyperfrequences permettent d'entrevoir des resultats prometteurs a terme: mag=6,9 et 4,7db; msg512,2 et 11,1db; facteur de stabilite k=1,85 et 2,32 avec une frequence maximale de 22ghz. Sur tegfet la technologie est plus delicate et les premiers resultats sont moins probants. La caracterisation sur plaquette 2 pouces donne typiquement: gm=80ms/mm, idss-64ma/mm et des tensions de claquage inferieures a -10v pour des courants inverses de -1ua. Ces resultats peuvent etre ameliores par la diminution des resistances de contact et de la longueur de grille. Des solutions sont envisagees et sont decrites
10
Gottwald, Frank-Hermann. "Rauschen von mm-Wellenmischern mit GaAs-Schottky-Dioden." [S.l. : s.n.], 1998. http://deposit.ddb.de/cgi-bin/dokserv?idn=955903629.
11
Chegroune, Kamel. "Réalisation et caractérisation de diodes Schotty submillimétriques métal-GaAs." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb375966485.
12
Lindner, Thomas. "Organisch modifizierte Ag/GaAs-Schottky-Kontakte." [S.l. : s.n.], 2000. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10047762.
13
Sambell, Alistair John. "Modification of Schottky barriers on GaAs and other III-V semiconductors using a-Si:H interfacial layers." Thesis, University of York, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280533.
14
Tang, Wing-man. "MISiC Schottky-diode hydrogen sensors with different gate insulators." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40987772.
15
Tang, Wing-man, and 鄧詠雯. "MISiC Schottky-diode hydrogen sensors with different gate insulators." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40987772.
16
Chen, Gang, and 陈刚. "MIS Schottky-diode hydrogen sensors with different gate insulators or substrates." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49799575.
Abstract:
Hydrogen, one of the cleanest energies, is very attractive in the near future. However, it could be hazardous to store, transport and use hydrogen gas because leakage can cause explosion if sparks appear. Therefore, it is essential to develop sensors to detect the hydrogen leakage in order to prevent potential accidents. In this research, Metal-Insulator-Semiconductor (MIS) Schottky-diode hydrogen sensors with different gate insulators (Ta2O5, La2O3, LaTiON, and HfTiO) or substrates (Si, SiC, and InGaN/GaN MQW) were prepared in order to study their hydrogen sensing performances.
Firstly, two sensors based on Si and SiC with Ta2O5 as gate insulator were prepared and compared. Owing to high permittivity (~25), good thermal stability and low electrical defects, Ta2O5 was chosen as the insulator. The differences in sensitivity and response time between the two sensors were ascribed to the difference in the surface morphology of Ta2O5 between the SiC sensor (mean surface roughness was 0.39 nm) and its Si counterpart (mean surface roughness was 0.22 nm).
Secondly, due to the high permittivity (~25) and good thermal stability of La2O3, the high permittivity (~20), low interface-state density, and low leakage current of LaTiON, Si sensors with these two dielectrics as gate insulator were developed. The sensitivity of the La2O3 sensor could exceed 7.0 at 150 oC, and the sensor exhibited good hydrogen sensing performance at up to 250 oC. On the other hand, the maximum sensitivity of the LaTiON sensor could reach 2.5 at 100 oC. For the LaTiON sensor, the Poole-Frenkel model controlled the carrier transport at high temperatures (150 ~ 200 oC) while the thermionic emission was the dominant conduction mechanism at lower temperatures (from room temperature to 150 oC). For the La2O3 sensor, the hydrogen reaction kinetics was confirmed, and an activation energy of 10.9 kcal/mol was obtained for this sensor.
Thirdly, the La2O3 gate insulator used in the previous work was applied to make MIS sensor on SiC substrate for higher-temperature applications. Its maximum sensitivity and response time at high temperature (260 oC) are 4.6 and 20 s, respectively. The electrical conduction mechanisms were explained in terms of Fowler-Nordheim tunneling (below 120 oC) and the Poole-Frenkel effect (above 120 oC).
Finally, in order to see whether the unique structure of InGaN/GaN multiple quantum wells (MQWs) can be utilized for the MIS Schottky-diode hydrogen sensor, three sensors were made on InGaN/GaN MQWs substrate, one without gate insulator, one
Finally, in order to see whether the unique structure of InGaN/GaN multiple quantum wells (MQWs) can be utilized for the MIS Schottky-diode hydrogen sensor, three sensors were made on InGaN/GaN MQWs substrate, one without gate insulator, one
In summary, the quality of the gate insulator plays an important part in the performance of the hydrogen sensors. SiC and InGaN/GaN MQW substrates are suitable for high-temperature (from ~200 to ~500 oC) applications while the low-cost sensors based on Si substrate can function well below about 200 oC. Hydrogen sensors with these high-k materials (Ta2O5, La2O3, LaTiON, and HfTiO) as gate insulator can produce good electrical characteristics, high sensitivity, and fast response.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
17
Mehdi, Hussein. "Etude de la passivation du GaAs(100) par nitruration par plasma N2 sous ultra-vide." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC063/document.
Abstract:
La passivation de la surface des semi-conducteurs III-V est une technique adaptée pour éliminer les effets indésirables qui perturbent le bon fonctionnement des dispositifs optoélectroniques. L’objectif de ce travail est de passiver la surface du GaAs par nitruration par plasma N2 généré par deux sources de nitruration différentes : la GDS (Glow Discharge Source) et l’ECR (Electron Cyclotron résonance). Une première étude basée sur des mesures AR-XPS, des simulations DFT et un modèle cinétique raffiné a permis d’identifier les trois étapes principales du processus de nitruration en mettant en évidence plusieurs phénomènes physiques. Une deuxième étude des effets de la passivation du GaAs par la couche mince de GaN créée en surface permet d’optimiser les paramètres expérimentaux du processus de nitruration pour tendre vers une passivation optimale. Ainsi, la structure des couches de GaN élaborés est déterminée par diffraction d’électrons lents (LEED) après une cristallisation par un recuit à 620°C et par des images MEB. De plus, la passivation chimique de la surface des couches de GaAs nitrurées après exposition à l’air est étudiée par des mesures AR-XPS et l’amélioration de la photoluminescence du GaAs après nitruration est mise en évidence par des mesures µPL. Finalement, le processus de nitruration a révélé un intérêt pour optimiser les paramètres électriques des diodes Schottky à base de GaAsThe surface passivation of III-V semiconductors is a suitable process to eliminate the side effects which disrupt the smooth operation of the optoelectronic devices. The aim of this thesis is to investigate passivation of the GaAs surface by nitridation using N2 plasma generated by two different sources: the GDS (Glow discharge source) and ECR (Electron Cyclotron Resonance). Our first study based on AR-XPS measurements, DFT simulations and a refined kinetic model permits identification of the three main steps of the nitriding process exhibiting several physical phenomena. Our second study of the GaAs passivation effects by growing a GaN thin layer on the surface makes it possible to optimize the experimental parameters of the nitriding process in order to tend towards optimal passivation. Firstly, the elaborated GaN layer structure is obtained by LEED patterns after their crystallization by an annealing at 620°C as well as the surface morphology obtained by SEM images. Then, chemical passivation of the nitrided GaAs layers is studied by AR-XPS measurements and the photoluminescence improvement of the GaAs substrate after nitridation is highlighted by µPL measurements. Finally, the nitridation process benefits electrical parameters of the Schottky diodes based on GaAs, optimizing them
18
Tang, Wing-man, and 鄧詠雯. "Development of high-quality gate insulators to improve the performanceof MISiC Schottky-diode hydrogen sensors." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29736754.
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Pasquali, Valerio. "Fabrication and measurement of strain-free GaAs/AlAs quantum dot devices." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066631.
Abstract:
Dans cette thèse, nous nous intéressons à la croissance de boîtes quantiques par formation de nano-trous in-situ par « droplet-etching » ainsi qu’à la fabrication et caractérisation de dispositifs basés sur ces nanostructures. La thèse comporte sept chapitres. Le premier chapitre est une introduction au sujet et les méthodes expérimentales sont présentées dans le second chapitre. Les méthodes de fabrication ainsi que les résultats expérimentaux obtenus sont discutés dans le troisième chapitre.Nous montrons que l’utilisation in-situ de la méthode de droplet-etching permet de modifier localement l’épaisseur d’un puits quantique à modulation de dopage et créer des boîtes quantiques dans le puits où existe un gaz bidimensionnel d’électrons. Ces nanostructures constituent des diodes n-i Schottky que nous avons étudié. Les effets de ces boîtes quantiques non-contraintes et les fluctuations d’épaisseur à l’échelle nanométrique du puits quantique sur la mobilité du gaz bidimensionnel d’électrons sont discutés dans le quatrième chapitre et cinquième. Le sixième chapitre présente la fabrication d’une jonction p-n latérale basée sur l’échantillon de puits quantique avec des boîtes. Nous discutons les différentes étapes de fabrication et analysons leur influence sur le dispositif, ainsi que leurs propriétés optiques. En particulier, nous démontrons l’électroluminescence d’une boîte unique localisée dans une jonction p-n latérale. Finalement, le dernier chapitre conclue ce travail et en présente les perspectivesIn this thesis the formation of quantum dots (QD) via in-situ droplet nanohole etching, the fabrication and characterization of devices based on these nanostructures is described. The thesis consists of seven chapters. In the first chapter an introduction is given to present the topic to the reader. In the second chapter the experimental methods are presented. In the third chapter, the fabrication method is described and the experimental results obtained in this project are discussed. It will be shown the use of in-situ droplet etching to locally modify the thickness of a modulation doped quantum well, to create QDs embedded in a quantum well(QW) where a two dimensional electorn gas (2DEG) is confined by modulation doping and the embedding of these nanostructures in a n-i-Schottky diode. The effect of these strain-free dots, and the related nanoscale thickness fluctuations of the quantum well, on the 2DEG mobility are discussed in the fourth and in particular in the fifth chapter. In the sixth chapter, the fabrication of a lateral p-n junction based on the QW sample with embedded QD is presented. Following describing the fabrication stages and analysing the influence of each stage on the device, the optical properties of the junction will be discussed. In particular, it will be shown the electroluminescence of a single dot located at lateral the p-n junction. Finally, in the last chapter the conclusion of this work and the future projects are presented
20
Pasquali, Valerio. "Fabrication and measurement of strain-free GaAs/AlAs quantum dot devices." Electronic Thesis or Diss., Paris 6, 2017. http://www.theses.fr/2017PA066631.
Abstract:
Dans cette thèse, nous nous intéressons à la croissance de boîtes quantiques par formation de nano-trous in-situ par « droplet-etching » ainsi qu’à la fabrication et caractérisation de dispositifs basés sur ces nanostructures. La thèse comporte sept chapitres. Le premier chapitre est une introduction au sujet et les méthodes expérimentales sont présentées dans le second chapitre. Les méthodes de fabrication ainsi que les résultats expérimentaux obtenus sont discutés dans le troisième chapitre.Nous montrons que l’utilisation in-situ de la méthode de droplet-etching permet de modifier localement l’épaisseur d’un puits quantique à modulation de dopage et créer des boîtes quantiques dans le puits où existe un gaz bidimensionnel d’électrons. Ces nanostructures constituent des diodes n-i Schottky que nous avons étudié. Les effets de ces boîtes quantiques non-contraintes et les fluctuations d’épaisseur à l’échelle nanométrique du puits quantique sur la mobilité du gaz bidimensionnel d’électrons sont discutés dans le quatrième chapitre et cinquième. Le sixième chapitre présente la fabrication d’une jonction p-n latérale basée sur l’échantillon de puits quantique avec des boîtes. Nous discutons les différentes étapes de fabrication et analysons leur influence sur le dispositif, ainsi que leurs propriétés optiques. En particulier, nous démontrons l’électroluminescence d’une boîte unique localisée dans une jonction p-n latérale. Finalement, le dernier chapitre conclue ce travail et en présente les perspectivesIn this thesis the formation of quantum dots (QD) via in-situ droplet nanohole etching, the fabrication and characterization of devices based on these nanostructures is described. The thesis consists of seven chapters. In the first chapter an introduction is given to present the topic to the reader. In the second chapter the experimental methods are presented. In the third chapter, the fabrication method is described and the experimental results obtained in this project are discussed. It will be shown the use of in-situ droplet etching to locally modify the thickness of a modulation doped quantum well, to create QDs embedded in a quantum well(QW) where a two dimensional electorn gas (2DEG) is confined by modulation doping and the embedding of these nanostructures in a n-i-Schottky diode. The effect of these strain-free dots, and the related nanoscale thickness fluctuations of the quantum well, on the 2DEG mobility are discussed in the fourth and in particular in the fifth chapter. In the sixth chapter, the fabrication of a lateral p-n junction based on the QW sample with embedded QD is presented. Following describing the fabrication stages and analysing the influence of each stage on the device, the optical properties of the junction will be discussed. In particular, it will be shown the electroluminescence of a single dot located at lateral the p-n junction. Finally, in the last chapter the conclusion of this work and the future projects are presented
21
Wang, Hui. "Conception et modélisation de circuits monolithiques à diode Schottky sur substrat GaAs aux longueurs d'onde millimétriques et submillimétriques pour des récepteurs hétérodynes multi-pixels embarqués sur satellites et dédiés à l'aéronomie ou la planétologie." Phd thesis, Observatoire de Paris, 2009. http://tel.archives-ouvertes.fr/tel-00608222.
Abstract:
Ce travail de recherche propose une nouvelle approche et la topologie d'un récepteur hétérodyne en ondes millimétriques intégré à deux pixels fonctionnant à la température ambiante, dédié aux sciences planétaire et de l'atmosphère. Des récepteurs hétérodynes multi-pixels à diode Schottky aux longueurs d'onde millimétriques et submillimétriques peuvent permettre une cartographie plus rapide et plus cohérente tout en évitant d'utiliser des systèmes cryogéniques. Des micro-composants intégrés permettent de construire des récepteurs hétérodynes à grand nombre de pixels. Une solution consiste aussi à intégrer plusieurs fonctions: un multiplicateur de fréquence et un ou plusieurs mélangeurs dans une même structure et créer une sous-unité compacte. Dans notre configuration, une seule source d'oscillateur local pompe deux mélangeurs simultanément en utilisant un diviseur de puissance en guide d'onde. Les mélangeurs et le multiplicateur de fréquence sont intégrés dans la même structure afin de réduire les pertes supplémentaires. Cette topologie compacte peut être appliquée aux plus hautes fréquences et étendue linéairement pour des récepteurs aux plus grand nombre pixels.
22
Laurent, Sabine. "Orientation optique et relaxation du spin du trion dans les boîtes quantiques d'InAs/GaAs." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00007028.
Abstract:
Le spin électronique dans les semi-conducteurs fait actuellement l'objet de nombreuses investigations. Il pourrait en effet constituer, en tant que système quantique à 2 niveaux, l'élément de base d'un futur ordinateur quantique: un quantum-bit. Une des limites physiques d'un tel ordinateur provient en premier lieu de la décohérence de la superposition des états up et down de ce quantum-bit. La problématique est donc d'obtenir un système dans lequel ce temps de cohérence soit suffisamment long pour permettre de futures manipulations quantiques. Dans ce contexte, les boîtes quantiques semi-conductrices chargées avec un seul électron se présentent comme des candidats prometteurs. Ces systèmes, de part leur dimensions nanométriques, ont en effet la propriété de posséder une structure électronique discrétisée, ce qui supprime les principaux mécanismes responsables de la relaxation du spin. Ce travail de thèse tend donc à déterminer le temps de relaxation du spin dans une boîte.
23
Ullah, Md Barkat. "Growth of Zn-polar BeMgZnO/ZnO heterostructure with two dimensional electron gas (2DEG) and fabrication of silver Schottky diode on BeMgZnO/ZnO heterostructure." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4992.
Abstract:
Title of dissertation: GROWTH OF Zn POLAR BeMgZnO/ZnO HETEROSTRUCTURE WITH TWO DIMENSIONAL ELECTRON GAS (2DEG) AND FABRICATION OF SILVER SCHOTTKY DIODE ON BeMgZnO/ZnO HETEROSTRUCTURE
By Md Barkat Ullah, Ph.D
A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering at Virginia Commonwealth University.
Virginia Commonwealth University,2017
Major Director: Dr. Hadis Morkoç, Professor, Electrical and Computer Engineering
This thesis focuses on growth of Zn polar BeMgZnO/ZnO heterostructure on GaN/sapphire template with two dimensional electron gas (2DEG) for the application of UV photodetector/emitter and high speed electronics. The motivation of using BeMgZnO as a barrier layer originates from the need to reach plasmon-LO phonon resonance in order to obtain minimum longitudinal optical (LO) phonon lifetime.
Presence of 2DEG was realized in BeMgZnO/ZnO heterostructure only when the Zn polarity was achieved during the nucleation growth of ZnO on GaN/sapphire template. It was found that, polarity of ZnO on (0001) GaN/sapphire template can be controlled by the oxygen to Zn ratio used during the nucleation growth.
To obtain high structural and optical quality of BeMgZnO quaternary alloy, growth kinetics of BeMgZnO layer has been studied at the temperature range from 450°C-500°C. We have achieved the growth of single crystal Be.03Mg00.15ZnO alloy at 500 °C, more than 100°C higher compared to what reported in literature, on the (0001) GaN/sapphire template through the control of Zn/(Be+Mg) flux ratio. We have also observed a thermodynamic limitation of Mg incorporation into the wurtzite BeMgZnO alloy where the excess Mg adatom accumulated in the growing surface as a MgO rich cluster.
Two dimensional electron gas with high (1.2×1013cm-2) sheet carrier density was achieved at the Be0.03Mg0.41ZnO/ZnO interface through strain engineering by incorporating Be into MgZnO ternary alloy. To obtain the similar sheet carrier density it would require above 60% of Mg in MgZnO/ZnO heterostructure with reduced structural quality. A systematic comparison of sheet carrier density has been made with the already reported results from Zn polar MgZnO/ZnO heterostructure as well as with the theoretical calculation.
Silver Schottky diode on Be0.02Mg0.26ZnO/ZnO heterostructure with barrier height 1.07 eV and ideality factor 1.22 was obtained with 8 order of rectification ratio. The temperature-dependent electrical characteristics were studied by using temperature dependent current-voltage (I-V) measurements. Richardson constant value of 34.8 Acm-2K-2 was found experimentally which was close to the theoretical value of 36 Acm-2K-2 known for Be0.02Mg0.26ZnO alloy.
24
Polischuk, Vladimir. "Etude et réalisation de structure à base de silicium poreux en vue de la détection de gaz." Ecully, Ecole centrale de Lyon, 1999. http://www.theses.fr/1999ECDL0016.
Abstract:
Ce travail de thèse visait à étudier les potentialités du silicium poreux comme support d'un élément sensible pour les capteurs de gaz. Afin de comprendre les mécanismes de formation du silicium poreux nous avons eu recours à l'électrochimie fondamentale de silicium. Ainsi, les mesures I-V de l'interface silicium/solution d'acide fluorhydrique ont mis en évidence deux mécanismes compétitifs : la formation électrochimique de l'oxyde de silicium et sa dissolution par HF. De même, la nature de l'oxyde de silicium est discutée dans le cadre des diagrammes d'équilibres tension-ph du système silicium-eau. Dans le but de développer de nouveaux capteurs de gaz, nous avons élaboré des couches de silicium poreux modifiées ultérieurement par un métal catalytique. Dans le cas des structures de type diode (Pd/Sp/Si), l'épaisseur de la couche de silicium poreux contrôle les processus de transport de courant. La quantité du palladium déposée influe beaucoup sur la sensibilité des structures sous gaz. Ainsi, ce sont les structures avec une couche ultramince de palladium qui présentent les meilleures réponses à l'hydrogène. En s'appuyant sur le modelé d'une hétérojonction métal/silicium poreux/si ayant une couche mince de silicium poreux, nous avons relie ce phénomène a la variation des porteurs libres de la zone de charge d'espace du silicium. La mesure de la différence de potentiel de contact nous a permis d'étudier l'effet de l'adsorption d'hydrogène sur la surface de palladium supporte sur du silicium poreux. Malgré nos attentes, les structures a base du silicium poreux ont montré une faible amélioration de la sensibilité par rapport aux structures traditionnelles Pd/SiO2/Si. Par contre, elles étaient plus performantes en ce qui concerne la cinétique, donc le temps de réponse deux fois plus rapide.
25
Perng-Cherng, Wang, and 王鵬程. "Gamma-ray irradiation effects on Metal/GaAs Schottky diodes." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/83444803238440843589.
Abstract:
碩士中正理工學院
電機工程研究所
86
ABSTRACT Irradiation is known to damage semiconductor material by causing atomic displacement and/or ionization. The main effect of atomic displacement and ionization on semiconductor devices is the creation of recombination centers and, hence, the reduction of the minority-carrier lifetime. The type, size, and degree of damage or defect created depend on the energy, atomic mass, charge, fluence and dose of the incident species, and the temperature of the material during irradiation. In particular, The defect may be led to a complete device failure. Which may be operated in satellites or nuclear power plants, and will cause a safety related issue. The superior high-temperature and high-frequency properties of Gallium Arsenide than silicon make it ideal for space communication component or power plant component fabrications. Among them, metal/GaAs Schottky diode(SD) is the essential structure . In this study we investigate the variations of the electrical properties of Gamma rays irradiated Au,Al,Ag/GaAs SD. Interesting correlation between the irradiation and the electrical properties, have been observed.
26
Sithole, Enoch Mpho. "Electrical characterisation of Schottky barrier diodes fabricated on GaAs by electron beam metallisation." Diss., 2002. http://hdl.handle.net/2263/29753.
Abstract:
The electrically active defects introduced in GaAs by electron beam deposition (EB) of Ta were characterised. The effect of electron beam deposition on the electrical properties of GaAs was evaluated by current-voltage (I-V), capacitance¬voltage (C- V) and deep level transient spectroscopy (DL TS). However, when electronic devices are formed by EB, defects may be introduced into the semiconductor material, depending on the properties of the metal being deposited. Depending on the application, these defects may have either advantages or detrimental effects on the performance of such a device. I-V measurements indicated that the EB induced damage results in an increase in ideality factor and decrease in the barrier height with increasing the applied substrate bias, while C- V measurements showed that EB deposition also caused a decrease in the barrier height. DL TS studies on the same material in the temperature range of 20 - 350 K showed that at least three electrically active defects are introduced during EB deposition, with energies (0.102 ± 0.004, 0.322 ± 0.014 and 0.637 ± 0.029 eV) within the band gap. DL TS data was used to construct concentration profiles of these defects as a function of depth below the surface. It was found that the defect concentration increases with increasing substrate bias during the deposition, irrespective of the direction of the applied bias. This may be related to the I-V characteristics of the SBDs. The SBDs investigated by IV measurements showed that GaAs yields SBDs with poorer characteristic. The influence of EB deposition on the device properties of SBDs fabricated on GaAs is presented. These device properties were monitored using a variable temperature I-V and C- V apparatus. In order to have an understanding of the change in electrical properties of these contacts after EB deposition, it is necessary to characterise the EB induced defects. DL TS was used to characterise the defects in terms of their D L TS signature and defect concentration.Dissertation (MSc (Physics))--University of Pretoria, 2006.
Physics
unrestricted
27
Tung, Chieng-Chi, and 董建圻. "Preparation and Ethanol Sensing Characteristics of Self-Assembled Monolayers Modified Au/GaAs Schottky Diodes." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/75106537552180634472.
Abstract:
碩士國立成功大學
化學工程學系碩博士班
96
In this work, a series of novel sensors based on the self-assembled organo-functionalized Au/GaAs Schottky diodes were fabricated for ethanol detection. Firstly, the contact angle, reflection absorption infrared spectroscope, and cyclic voltammetry techniques were used for the characterization of self-assembled monolayers (SAMs). The current-vcoltage (I-V) rectifying properties of SAMs functionalized devices were investigated. Moreover, the ethanol sensing performances of these devices were studied under various ethanol concentrations, temperatures and applied voltages. The dependences of ethanol sensing performances on the Au thickness, carbon numbers and terminal functional groups (e.g., –COOH、 –OH and –CH3) of SAMs were investigated. From experimental results, it revealed that, in the Au thickness ranging of 20-200 nm, the surface roughness of Au layer increased with decreasing the Au thickness, resulting in less adsorption amounts of SAMs on Au surface. For the carboxyl-terminated SAMs/Au, the hydrophilicity, order and stability were increased with increasing carbon numbers. Besides, the SAMs tended to produce more active sites. From the result of I-V rectifying properties, the current of SAMs modified Au/GaAs device increased with decreasing the Au thickness. From the results of ethanol detection, it indicated that as the carbon number increased from 3 to 6, the sensitivity of the studied devices were increased. Whereas, when the carbon number was above 6, the current was reduced owing to the decrease of induced electrostatic potential. In addition, as the aliphatics replaced by aromatics the device showed an enhancement in the ethanol sensitivity. It also found that the terminated functional group of SAMs played an important role on the sensing performance of device. The ethanol sensitivity decreased in the order as –COOH > –OH > –CH3. Under the ethanol concentrations of 1.95-4.55% EtOH/N2 and temperature of 298-308K, the sensitivity of device was increased with either increasing the ethanol concentration or decreasing the sensing temperature. In conclusion, among various preparation conditions, the Au/GaAs Schottky diodes modified by the carboxyl-terminated alkylthiol SAMs with a carbon number of 6 and with a Au thickness of 50 nm showed the best ethanol sensing performance.
28
Bing-JiaLin and 林秉頡. "Study on Nitrogen Oxides Sensors Based on Self-Assembled Alkanedithiol modified Au/GaAs Schottky Diodes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/40755028973888100846.
Abstract:
碩士國立成功大學
化學工程學系碩博士班
98
In this work, novel nitrogen oxides gases sensors based on Au/GaAs Schottky diodes modified with alkanedithiol monolayers were fabricated and studied. At first, Au/GaAs Schottky diodes were fabricated, and then the Au electrode was modified with alkanedithiol monolayer by immersing the diode in an alkanedithiol/ethanol solution. Experimentally, effects of immersion time, concentration, and structure of alkanedithiol on the adsorption amount, stability, and hydrophobicity of monolayers were investigated by using cyclic voltammetry and contact angel analysis. Moreover, the sensing characteristics of the studied devices on nitrogen oxides were investigated under various gas concentrations and temperatures. From the result of immersion, the adsorption amounts of alkanedithiol were not only increased with increasing immersing time but also increased with increasing the concentration and carbon number (N) of alkanedithiol. When the alkanedithiol concentration was increased from 10 μm to 0.7 mM, the adsorption amount reached to a monomolecular saturation. As the immersion time approached to 36 hr, the adsorption reached to the equilibrium. Besides, the stability of structure and adsorption amounts of monolayer were increased with increasing carbon number of alkaneditiol in the N range of 3-10. From results of NO and NO2 sensing performances, the effect of structure of alkanedithiol played great important role on the sensitivity and electric property of the studied device. As the N value increased, the sensitivity of device was consistently increased, since the adsorption amount of monolayer was increased and the molecule architecture tended to self-ordered. As comparing sensing performances among devices modified with different terminal groups, i.e., –SH, -COOH, -OH, and -CH3, it was found that the device modified with alkanedithiol (terminal group: -SH) showed the highest sensitivity. This was inferred that -SH group could form thiolntirite or thiolnitrate by reacting with nitrogen oxide and nitrogen dioxide, respectively. Hence, high selectivity could be obtained, which would not be easily affected by the ambience. Furthermore, the sensitivity of the studied device was increased with increasing the concentration of nitrogen oxides in the range of 1-100ppm. However, the sensitivity was decreased as the operating temperature was increased. In conclusion, the Au/GaAs Schottky diodes modified with alkanedithiol monolayer had been successfully fabricated and could be served as nitrogen oxides sensors. Among various studied devices, 1,10-decanedithiol modified Au/GaAs device showed the best sensing characteristics on NO and NO2. The sensitivities of this device for sensing NO and NO2 were 35.3(100 ppm NO/N2) and 49.5(100 ppm NO2/N2), respectively, at 298 K.
29
LI, NIAN-YI, and 李念宜. "GaSb/GaAs heteroepitaxial growth by metal organic chemical vapor deposition and the study of schottky diodes." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/47650524725474541941.
Abstract:
碩士國立成功大學
電機工程研究所
78
GaSb-bascd化合物由於具有長波長光響應的特懷, 波長在1.24μm(AtGaSb) 至4.3μm (InCaAsSb)及8 至12μm(InAsSb／InSb量子井應力結構) 範圍內具有極低的傳輸損失 , 其電子與電洞移動率亦高於Inp 系列, 故極適合應用於光電元件的研究。本文係採 用有機金屬汽相沈積法成長銻化鎵(GaSb)同質, 祑質磊晶怪於銻化鎵及砷化鎵基板上 并建立最佳成長條件以做為InAs／GaSb高速元件、InGaSb／GaSb、GaAsSb／GaSb等超 晶格應力結構發展之基礎。 本實驗室自行建立的新MOCVD系統專以研究銻為主的Ⅲ-V 半導體材料, 并對量子井及 超晶格元件之制造上亦有初步的考量與設計, 以期成長高品質, 低背影濃度之磊晶層 。 首先對銻化鎵、砷化鎵基板之清潔步驟及銻化鎵磊晶膜的制程做了詳細的說明, 而后 探討在改變成長參數狀況下, 銻化鎵表面形成及光與電特性之變化。在所有成長條件 下, 銻化鎵晶膜為正型特性, 其在長速率隨〔TEG 〕莫耳分率線性的增加而與〔TMSb 〕菲耳分率無關, 對成長溫度更是密切地相關。〔TMSb〕／〔TEG〕比例在6∼8之間, 可得到鏡似無缺隱的表面, 但過大的莫耳分率將會嚴重地影響到晶膜之品質。 在金屬／銻化鎵蕭基二極體方面, 吾人由不同金屬測量其電流—電壓特性發現不同方 向的銻化鎵基板, 基位障(barrier height)被不同的表面能態(surface states)所箝 住。由於(111)銻化鎵比(100)銻化鎵基板擁有較多的dangling bonds, 而此懸浮的鍵 結容易造成載子的陷阱, 進而箝住金屬與銻化鎵間的能障, 使得吾人難以得到高位障 的蕭基二極體。在熱穩定特性探討中, 吾人發現把／銻化鎵接觸在高溫時(450℃) 易 形成Ga Pd 復合物而將蕭基二極體能障降低形成歐姆接觸, 故利用有限反應(limit r eaction)的觀念研制雙層金／鈀／銻化鎵蕭基二極體, 發現在450 ℃30分鐘退火下, 依然擁有良好的蕭基特性。
30
Your, Chih-Kaun, and 游智寬. "Deep Level Transient Spectroscopy of Schottky Diode on GaAsP." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/58339227180210308477.
Abstract:
碩士國立交通大學
電子物理學系
83
GaAs1-XPX III-V compound alloys is still the primary material for light-emitting diodes(LEDS) fabrication. The existence of deep level impurities reduces their luminescence efficiency. Therefore, it's important to improve the quality of the alloys for device and display applications. In this research ,deep level transient spectroscopy (DLTS) was used to determine the deep level traps. In all the studied,there are two electron traps found ,labeled E1&E2. E1 is a bulk defect and has an activation energy Ea=0.12±0.03eV. According to the depth profile, E1 possibly resulted from Te and native defect. E2 is a surface defect and can be found only near the interface between the metal and the semiconductor.This surface defect can be reduced and change structure by high temperature annealing. Samples grown at different temperatures have also been measured and carrier recombination rate was found inversely proportional to the LED output power.
31
Gottwald, Frank-Hermann [Verfasser]. "Rauschen von mm-Wellenmischern mit GaAs-Schottky-Dioden / von Frank-Hermann Gottwald." 1998. http://d-nb.info/955903629/34.
32
Cheng, Chin-Chuan, and 鄭錦泉. "Investigation of GaAs-AlGaAs Based Schottky Diode- and Transistor-Type Hydrogen Sensors." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/32476678792611833350.
Abstract:
博士國立成功大學
微電子工程研究所碩博士班
93
The sensitive hydrogen detection of a field effect transistor, based on the gas-induced work function change at a specific gas-sensitive layer, was first presented in 1975. Today, the development of sensors is focused on new devices and materials with provide improved sensitivity, selectivity and stability. In this dissertation, some hydrogen-sensing GaAs-AlGaAs -based devices including Schottky diode and high electron mobility transistor (HEMT) are fabricated and studied. These studied devices are operated and measured under different hydrogen concentrations and different temperature. First, in order to study the influence of Fermi-level pinning effect on hydrogen sensing properties, the Pt/AlGaAs MOS and MS Schottky diodes hydrogen sensors are fabricated and systemically studied. From experimental results, it is known that the MOS-type hydrogen sensor exhibits higher hydrogen detecting sensitivity and shorter hydrogen response time than those of MS-type hydrogen sensor. Second, a novel hydrogen sensor based on a Pt/oxide/AlGaAs/InGaAs/GaAs HEMT is fabricated and demonstrated. In order to understand the hydrogen adsorption mechanism in the HEMT device, different measurement conditions are used. From experimental results, it is known that less hydrogen atoms can form dipolar at the interface between the Pt metal and oxide layer with increasing operation temperature. The comparison of different catalytic metals (Pd and Pt) in hydrogen sensing response is presented. From the experimental result, the HEMT hydrogen sensor based on the Pd/oxide/AlGaAs/InGaAs/GaAs exhibits higher response, especially under the hydrogen concentration is smaller than 100 ppm H2/air ambient. Finally, a HEMT hydrogen sensor based on a Pd/oxide/inGaP/AlGaAs/InGaAs/GaAs is fabricated and investigated. Due to larger energy bandgap of InGaP layer, the hydrogen-sensing characteristics are more stable when the operation temperature is larger than 1000C. The experimental results provide the promise for high-performance solid-state hydrogen sensor, optoelectronic integrated circuit (OEIC) and micro electro-mechanical system (MEMS) applications.
33
Lo, Shih-Pin, and 羅時斌. "Optimized ESD Protection Schottky Diode for GaAs pHEMT RF SPST Switch Application." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/67207290589127645701.
Abstract:
碩士國立中央大學
電機工程研究所
95
This thesis is about that proceeding with the research for the ESD protection ability to the Schottky diode layout parameter of GaAs. According to the result of ESD test, we can find that the gate periphery of the diode and HBM voltage can be direct proportion. While the gate width is 37.5 μm, gate length is 1.5 μm , the Gate Finger Number is 8, the voltage of the ESD test can be up to more than 1250 voltage for the HBM voltage. We also do the simulation and prove to the heat effect of the diode. To make optimized Schottky Diode of the GaAs be applied in the micro-wave switch of GaAs pHEMT. According to the result, the insertion loss is under 1.1dB, isolation is over 33 dB, power handling capability(P1dB)(OFF state) is above of 1W(30dBm), the area is 0.3-mm2. Through the ESD-HBM test at the same time, the ESD bearing ability reaches above 1000V.
34
Saini, Kamaljeet Singh. "A novel GaAs-quartz based approach towards larger band-width Schottky diode frequency multipliers /." 2003. http://wwwlib.umi.com/dissertations/fullcit/3062131.
35
Pan, Hsi-Jen, and 潘繫仁. "Investigation of GaAs- and InP-Based Heterojunction Bipolar Transistors and Schottky Diode Hydrogen Sensors." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/20517581385455318918.
Abstract:
博士國立成功大學
電機工程學系
89
Heterojunction bipolar transistors (HBT’s) based on III-V compound semiconductor material systems have many prospects in digital and microwave applications due to the excellent high-speed performances combined with high current driving capability. In this dissertation, we present the HBT’s based on the GaAs- and InP-based material systems grown by low pressure-metal organic chemical vapor deposition (LP-MOCVD). We focus on the improved designs of conventional device structures, including the applications of InP/InGaAlAs material system used for the single HBT’s as well as the -doping related structure and the step graded layers used for the B-C junctions in the respective InGaP/GaAs and InP/InGaAs double HBT’s. The effects of different emitter, base and collector together with the emitter-base (E-B) and base-collector (B-C) junction structures on relevant DC characteristics are investigated on the basis of the theoretical calculations. On the other hand, the III-V compound semiconductor materials incorporated with palladium have been realized for the sensors with high sensitivity to hydrogen. In this dissertation, we also propose the hydrogen response, sensing mechanisms, and interface adsorption properties of the GaAs- and InP-based Schottky diode hydrogen sensors. The hydrogen adsorption behaviors are modeled by a theoretical simulation. The quaternary In0.53GaxAlyAs alloy lattice-matched to InP has an outstanding material property of variable band lineup and a wide tunable bandgap ranging depending on the alloy composition. For the aluminum composition of 0.22, the nearly continuous conduction band can be achieved between the InP emitter and the InGaAlAs base. This band lineup can effectively eliminate the undesired effects arising from the large potential spike at the E-B heterojunction such as the large offset voltage. Furthermore, to avoid poor quality related to high aluminum content, the InGaAlAs alloy with a bandgap of 0.93eV corresponding to the aluminum composition of 0.13 is chosen. The DC characteristics in contrast to the InP/InGaAs HBT’s including the higher breakdown voltage, lower output conductance, and better temperature stability are obtained particularly for the high-temperature operation. The superlattices structures incorporated into the InGaP/GaAs double HBT’s are the significant attempts to obtain the functional device characteristics and investigate the carrier transport mechanisms. The uniform and modulated widths of barriers are respectively utilized in the specific superlattice structures. The distinct electron transport of resonant tunneling through the miniband in superlattice structures can therefore be significantly dominated by the electric field behaviors across the barriers. Due to the insertion of the delta-doping related structure at the B-C heterojunction, the excellent transistor characteristics such as the low saturation voltage, low offset voltage, high breakdown voltage are obtained at low current regimes. Furthermore, at higher current regimes, the barrier width designs result in the double- and quaternary-negative difference resistance (NDR) phenomena in agreement with the theoretical prediction at 300K. By taking advantage of the effective mass filtering, the good hole confinement can be achieved by utilizing the tunneling barrier instead of the wide-gap emitter in the HBT’s. Furthermore, both the composite collector structures with the InGaAsP step-graded layers and an delta-doped InGaAs spacer can improve the current blocking effect. Due to less carrier multiplication, the step-graded junction DHBT has better breakdown characteristics and severe self-heating effect as compared to the employment of delta-doped InGaAs spacer. The high-frequency characteristics of the HBT’s with the techniques of self-aligned and no-self-aligned base contact are comparatively studied. The simulation and analysis of the delay times are performed based on the parasitic resistance and capacitance to find the influence on microwave characteristics. For the GaAs- and InP-based Pd metal-oxide-semiconductor (MOS) Schottky diodes, two main effects, i.e., the removal of Fermi-level pinning effect caused by the amphoteric native defects or the donor level in the oxide and the reduction of Pd metal work function dominate the hydrogen sensing mechanism. The reaction kinetics incorporating the water formation upon hydrogen adsorption is investigated to estimate the initial heat of adsorption. The interface coverage dependent heat of adsorption plays an important role in hydrogen response under steady-state conditions. From the experimental results and the theoretical prediction, both devices have a very high detection sensitivity and a wide sensing range under atmospheric conditions.
36
Liao, hsuan-I., and 廖軒逸. "Analyzing the Circuit Modal of InAs Quantum Dots in GaAs Schottky Diode Using Method of Bode Plot." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/20490564873423766508.
Abstract:
碩士國立交通大學
電子物理系所
103
We used three parameters, RS, RQD, and CS, to describe the characteristics of GaAs Schottky diode with 3.3 ML InAs quantum dots (QDs) at room temperature. And then, the QDs sample is applied on a low-pass filter, and the properties of sample can be probed using the method of Bode plot. We found that the frequency and gain of out-put signals for low-pass filter can be modulated by the three parameters: RS, RQD, and CS. The high-frequency gain is controlled by RS, and the low-frequency gain is controlled by RQD, and the pole and zero positions are controlled by CS. Besides, These parameters can be accurately determined using the analysis of Bode Plot under various applied bias. Furthermore, the properties of QDs under illumination can be also probed using the illuminated Bode Plot. According to the admittance-spectrum under illumination, the activation energy of QDs is reduced by light. Therefore, we found that the out-put gain and frequency are related to the activation energy of QDs.
37
Wang, Jia-Feng, and 王家峰. "The transient-measurement-analysis of the capacitor properities under illumination on GaAs Schottky diode with InAs quantum dots." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/87875679246945172395.
Abstract:
博士國立交通大學
電子物理系所
103
In this study, the transient measurements of the GaAs Schottky diode with InAs quantum dots (QDs), or with GaAsN quantum well (QW), are investigated. The measured capacitance of GaAs Schottky diode can be modulated by the embedded QDs (QW) under illumination, this modulation for capacitance is attributed to the large potential drop (about 2V) caused by the charged QDs (QW). So we can show a significant capacitive property of QDs (QW) charged by photocurrent, and show that the generation of photocurrent is related to the EL2 defect and Ga vacancy in GaAs Schottky layer. According to the results above, the equivalent RC circuit modal of sample can be established, and the formula of several measurements (C-V, I-V, C-t, and I-t) are derived. The measured capacitance and current are determined by the relation between the charging time constant of QDs and the sweeping rate of applied bias. Besides, by analyzing the experiments of the QDs sample with strain-relaxation- induced misfit-defect, we also demonstrate that the defect around the QDs can improve the capacitive property. At last, we show that the GaAs Schottky diode is applied on the oscillator and on the signal-amplifier, and an optical-controlled IC circuit with Schottky diode is also demonstrated in this study.