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Khalil, Ibrahim. "Intermodulation distortion in GaN HEMT." Göttingen Cuvillier, 2009. http://d-nb.info/1000063275/04.
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Aroshvili, Giorgi. "GaN HEMT and MMIC Design and Evaluation." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-3085.
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Gallium Nitride based devices due to their inherent material properties are considered as one of the most promising devices to realize high power, high frequency transistors with lower power consumption in next-generation applications. Although the technology has been studied since early 1970s, there is still a vast room and expectations in its yet unachieved findings. In present work the GaN technology is explored and state-of-the-art studies of GaN based HEMTs and their application in MMICs are presented. Different designs are presented and evaluated and the results are reported. In particular the HEMT performance is studied in terms of DC in addition to large signal conditions, where the device’s performance becomes function of power levels it is driven with. The peculiarities and challenges of building an automated Load-Pull setup are outlined and analysis for further improvements is presented.
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Astre, Guilhem. "Fiabilité des dispositifs HEMT en technologie GaN." Phd thesis, Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1980/.
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Le point sensible inhérent à la commercialisation d'une technologie émergente est la maturité des processus utilisés garantissant la qualité de l'épitaxie, de la métallisation du contact de grille ou encore de la passivation. Les études de fiabilité s'imposent alors comme un aspect indissociable de la maturation de la technologie. En ce sens, les composants à grands gap représentent un réel problème car les outils classiques de caractérisation ne sont pas toujours adaptés aux contraintes imposées (thermiques, RF, DC. . . ). Dans cette thèse, nous détaillons une technique originale pour améliorer la fiabilité des dispositifs AlGaN/GaN par diffusion de deutérium et nous présentons l'ensemble des résultats issus des campagnes de mesures menées à l'aide des outils disponibles sur des lots de composants issus des filières UMS et TRT. Les principaux résultats concernent les mesures de bruit basse fréquence, la caractérisation électrique, la spectroscopie des pièges profonds et les mesures en température de courant de grille qui ont été réalisés sur des lots de composants témoins et ayant subi différents types de stressReliability in GaN based devices still motivates numerous studies because the involved degradation mechanisms are different from that in III-V narrow bandgap devices. Direct investigations on high electron mobility transistors (HEMT) are performed with low frequency noise (LFN) measurements, pulsed electrical characterization and deep level transient spectroscopy. The first part of this thesis deals with generalities on AlGaN/GaN High electron mobility transistors and their technological particularities. The second part deals with the presentation of the diagnostic tools used in this study. A low frequency noise bench developed in LAAS-CNRS allowing measurements from few hertz up to 1 MHz is described, an original method of electrical pulsed characterization has and current deep level spectroscopy bench. In the third part of this study, low frequency noise is used to assess effects of deuterium (H+ ions) in diffusion condition on the robustness of 0. 25 *2*75 µm² gate area AlGaN/GaN high electron mobility transistors (HEMT) grown on Si substrate. H+ Ions are diffused from the above AlGaN/GaN layer through the AlGaN/GaN interface and GaN layer, notably under the gated channel where the defects are located. In the fourth part, undoped AlGaN/GaN devices grown on silicon substrate have been stressed at a junction temperature of 175°C. Gate-lag and drain-lag measurements method have been performed versus different quiescent bias points and under different pulse conditions. This method allows the discrimination of each lag phenomenon as well as the thermal contribution. Thus it is possible to track and model the trapping mechanisms versus bias conditions. This electrical modeling is completed with LFN measurements and deep level transient spectroscopy, which is largely used for reliability investigations
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Astre, Guilhem. "Fiabilité des dispositifs HEMT en technologie GaN." Phd thesis, Université Paul Sabatier - Toulouse III, 2012. http://tel.archives-ouvertes.fr/tel-00767154.
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Le point sensible inhérent à la commercialisation d'une technologie émergente est la maturité des processus utilisés garantissant la qualité de l'épitaxie, de la métallisation du contact de grille ou encore de la passivation. Les études de fiabilité s'imposent alors comme un aspect indissociable de la maturation de la technologie. En ce sens, les composants à grands gap représentent un réel problème car les outils classiques de caractérisation ne sont pas toujours adaptés aux contraintes imposées (thermiques, RF, DC...). Dans cette thèse, nous détaillons une technique originale pour améliorer la fiabilité des dispositifs AlGaN/GaN par diffusion de deutérium et nous présentons l'ensemble des résultats issus des campagnes de mesures menées à l'aide des outils disponibles sur des lots de composants issus des filières UMS et TRT. Les principaux résultats concernent les mesures de bruit basse fréquence, la caractérisation électrique, la spectroscopie des pièges profonds et les mesures en température de courant de grille qui ont été réalisés sur des lots de composants témoins et ayant subi différents types de stress.
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Malik, Adil Mahmood. "Technology and physics of gate recessed GaN AlGaN FETs." [S.l. : s.n.], 2003. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-30157.
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Gonçalves, Cristiano Ferreira. "GaN HEMT transistors characterization for non–linear modelling." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21677.
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Mestrado em Engenharia Eletrónica e TelecomunicaçõesUltimamente, as redes de telecomunicações móveis estão a exigir cada vez maiores taxas de transferência de informação. Com este aumento, embora sejam usados códigos poderosos, também aumenta a largura de banda dos sinais a transmitir, bem como a sua frequência. A maior frequência de operação, bem como a procura por sistemas mais eficientes, tem exigido progressos no que toca aos transístores utilizados nos amplificadores de potência de radio frequência (RF), uma vez que estes são componentes dominantes no rendimento de uma estação base de telecomunicações. Com esta evolução, surgem novas tecnologias de transístores, como os GaN HEMT (do inglês, Gallium Nitride High Electron Mobility Transistor). Para conseguir prever e corrigir certos efeitos dispersivos que afetam estas novas tecnologias e para obter o amplificador mais eficiente para cada transístor usado, os projetistas de amplificadores necessitam cada vez mais de um modelo que reproduza fielmente o comportamento do dispositivo. Durante este trabalho foi desenvolvido um sistema capaz de efetuar medidas pulsadas e de elevada exatidão a transístores, para que estes não sejam afetados, durante as medidas, por fenómenos de sobreaquecimento ou outro tipo de fenómenos dispersivos mais complexos presentes em algumas tecnologias. Desta forma, será possível caracterizar estes transístores para um estado pré determinado não só de temperatura, mas de todos os fenómenos presentes. Ao longo do trabalho vai ser demostrado o projeto e a construção deste sistema, incluindo a parte de potência que será o principal foco do trabalho. Foi assim possível efetuar medidas pulsadas DC-IV e de parâmetros S (do inglês, Scattering) pulsados para vários pontos de polarização. Estas últimas foram conseguidas á custa da realização de um kit de calibração TRL. O interface gráfico com o sistema foi feito em Matlab, o que torna o sistema mais fácil de operar. Com as medidas resultantes pôde ser obtida uma primeira análise acerca da eficiência, ganho e potência máxima entregue pelo dispositivo. Mais tarde, com as mesmas medidas pôde ser obtido um modelo não linear completo do dispositivo, facilitando assim o projeto de amplificadores.
Lately, the wireless networks should feature higher data rates than ever. With this rise, although very powerful codification schemes are used, the bandwidth of the transmitted signals is rising, as well as the frequency. Not only caused by this rise in frequency, but also by the growing need for more efficient systems, major advances have been made in terms of Radio Frequency (RF) Transistors that are used in Power Amplifiers (PAs), which are dominant components in terms of the total efficiency of base stations (BSS). With this evolution, new technologies of transistors are being developed, such as the Gallium Nitride High Electron Mobility Transistor (GaN HEMT). In order to predict and correct some dispersive effects that affect these new technologies and obtain the best possible amplifier for each different transistor, the designers are relying more than ever in the models of the devices. During this work, one system capable of performing very precise pulsed measurements on RF transistors was developed, so that they are not affected, during the measurements, by self-heating or other dispersive phenomena that are present in some technologies. Using these measurements it was possible to characterize these transistors for a pre-determined state of the temperature and all the other phenomena. In this document, the design and assembly of the complete system will be analysed, with special attention to the higher power component. It will be possible to measure pulsed Direct Current Current-Voltage (DC-IV) behaviour and pulsed Scattering (S) parameters of the device for many different bias points. These latter ones were possible due to the development of one TRL calibration kit. The interface with the system is made using a graphical interface designed in Matlab, which makes it easier to use. With the resulting measurements, as a first step analysis, the maximum efficiency, gain and maximum delivered power of the device can be estimated. Later, with the same measurements, the complete non-linear model of the device can be obtained, allowing the designers to produce state-of-art RF PAs.
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Behmenburg, Hannes [Verfasser]. "Comprehensive study on MOVPE of InAlN/GaN HEMT structures and GaN nanowires / Hannes Behmenburg." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1036302067/34.
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Fontserè, Recuenco Abel. "Advanced AlGaN/GaN HEMT technology, design, fabrication and characterization." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/129098.
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Nowadays, the microelectronics technology is based on the mature and very well established silicon (Si) technology. However, Si exhibits some important limitations regarding its voltage blocking capability, operation temperature and switching frequency. In this sense, Gallium Nitride (GaN)-based high electron mobility transistors (HEMTs) devices have the potential to make this change possible. The unique combination of the high-breakdown field, the high-channel electron mobility of the two dimensional electron gas (2DEG), and high-temperature of operation has attracted enormous interest from social, academia and industry and in this context this PhD dissertation has been made. This thesis has focused on improving the device performance through the advanced design, fabrication and characterization of AlGaN/GaN HEMTs, primarily grown on Si templates.
The first milestone of this PhD dissertation has been the establishment of a know-how on GaN HEMT technology from several points of view: the device design, the device modeling, the process fabrication and the advanced characterization primarily using devices fabricated at Centre de Recherche sur l'Hétéro-Epitaxie (CRHEA-CNRS) (France) in the framework of a collaborative project. In this project, the main workhorse of this dissertation was the explorative analysis performed on the AlGaN/GaN HEMTs by innovative electrical and physical characterization methods. A relevant objective of this thesis was also to merge the nanotechnology approach with the conventional characterization techniques at the device scale to understand the device performance.
A number of physical characterization techniques have been imaginatively used during this PhD determine the main physical parameters of our devices such as the morphology, the composition, the threading dislocations density, the nanoscale conductive pattern and others. The conductive atomic force microscopy (CAFM) tool have been widely described and used to understand the conduction mechanisms through the AlGaN/GaN Ohmic contact by performing simultaneously topography and electrical conductivity measurements. As it occurs with the most of the electronic switches, the gate stack is maybe the critical part of the device in terms of performance and longtime reliability. For this reason, how the AlGaN/GaN HEMT gate contact affects the overall HEMT behaviour by means of advanced characterization and modeling has been intensively investigated.
It is worth mentioning that the high-temperature characterization is also a cornerstone of this PhD. It has been reported the elevated temperature impact on the forward and the reverse leakage currents for analogous Schottky gate HEMTs grown on different substrates: Si, sapphire and free-standing GaN (FS-GaN). The HEMT' forward-current temperature coefficients (T^a) as well as the thermal activation energies have been determined in the range of 25-300 ºC. Besides, the impact of the elevated temperature on the Ohmic and gate contacts has also been investigated.
The main results of the gold-free AlGaN/GaN HEMTs high-voltage devices fabricated with a 4 inch Si CMOS compatible technology at the clean room of the CNM in the framework of the industrial contract with ON semiconductor were presented. We have shown that the fabricated devices are in the state-of-the-art (gold-free Ohmic and Schottky contacts) taking into account their power device figure-of-merit ((VB^2)/Ron) of 4.05×10^8 W/cm^2. Basically, two different families of AlGaN/GaN-on-Si MIS-HEMTs devices were fabricated on commercial 4 inch wafers: (i) using a thin ALD HfO2 (deposited on the CNM clean room) and (ii) thin in-situ grown Si3N4, as a gate insulator (grown by the vendor). The scientific impact of this PhD in terms of science indicators is of 17 journal papers (8 as first author) and 10 contributions at international conferences.
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Saini, Kanika. "Linearity Enhancement of High Power GaN HEMT Amplifier Circuits." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/94361.
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Gallium Nitride (GaN) technology is capable of very high power levels but suffers from high non-linearity. With the advent of 5G technologies, high linearity is in greater demand due to complex modulation schemes and crowded RF (Radio Frequency) spectrum. Because of the non-linearity issue, GaN power amplifiers have to be operated at back-off input power levels. Operating at back-off reduces the efficiency of the power amplifier along-with the output power. This research presents a technique to linearize GaN amplifiers. The linearity can be improved by splitting a large device into multiple smaller devices and biasing them individually. This leads to the cancellation of the IMD3 (Third-order Intermodulation Distortion) components at the output of the FETs and hence higher linearity performance.
This technique has been demonstrated in Silicon technology but has not been previously implemented in GaN. This research work presents for the first time the implementation of this technique in GaN Technology.
By the application of this technique, improvement in IMD3 of 4 dBc has been shown for a 0.8-1.0 GHz PA (Power Amplifier), and 9.5 dBm in OIP3 (Third-order Intercept Point) for an S-Band GaN LNA, with linearity FOM (IP3/DC power) reaching up to 20.
Large-signal simulation and analysis have been done to demonstrate linearity improvement for two parallel and four parallel FETs. A simulation methodology has been discussed in
detail using commercial CAD software. A power sampler element is used to compute the IMD3 currents coming out of various FETs due to various bias currents. Simulation results show by biasing one device in Class AB and others in deep Class AB, IMD3 components of parallel FETs can be made out of phase of each other, leading to cancellation and improvement in linearity. Improvement up to 20 dBc in IMD3 has been reported through large-signal simulation when four parallel FETs with optimum bias were used.
This technique has also been demonstrated in simulation for an X-Band MMIC PA from 8-10 GHz in GaN technology. Improvements up to 25-30 dBc were shown using the technique of biasing one device with Class AB and other with deep class AB/class B. The proposed amplifier achieves broadband linearization over the entire frequency compared to state-of-the-art PA's. The linearization technique demonstrated is simple, straight forward, and low cost to implement. No additional circuitry is needed. This technique finds its application in high dynamic range RF amplifier circuits for communications and sensing applications.Doctor of Philosophy
Power amplifiers (PAs) and Low Noise Amplifiers (LNAs) form the front end of the Radio Frequency (RF) transceiver systems. With the advent of complex modulation schemes, it is becoming imperative to improve their linearity. Through this dissertation, we propose a technique for improving the linearity of amplifier circuits used for communication systems. Meanwhile, Gallium Nitride (GaN) is becoming a technology of choice for high-power amplifier circuits due to its higher power handling capability and higher breakdown voltage compared with Gallium Arsenide (GaAs), Silicon Germanium (SiGe) and Complementary Metal-Oxide-Semiconductor (CMOS) technologies. A circuit design technique of using multiple parallel GaN FETs is presented. In this technique, the multiple parallel FETs have independently controllable gate voltages. Compared to a large single FET, using multiple FETs and biasing them individually helps to improve the linearity through the cancellation of nonlinear distortion components. Experimental results show the highest linearity improvement compared with the other state-of-the-art linearization schemes. The technique demonstrated is the first time implementation in GaN technology. The technique is a simple and cost-effective solution for improving the linearity of the amplifier circuits. Applications include base station amplifiers, mobile handsets, radars, satellite communication, etc.
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Liu, Zhengyang. "Characterization and Failure Mode Analysis of Cascode GaN HEMT." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/49580.
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Recent emerging gallium nitride (GaN) high electron mobility transistor (HEMT) is expected to be a promising candidate for high frequency power conversion techniques. Due to the advantages of the material, the GaN HEMT has a better figure of merit (FOM) compared to the state-of-the-art silicon (Si) power metal oxide silicon field effect transistor (MOSFET), which allows the GaN HEMT to switch with faster transition and lower switching loss. By applying the GaN HEMT in a circuit design, it is possible to achieve high frequency, high efficiency, and high density power conversion at the same time.
To characterize the switching performance of the GaN HEMT, an accurate behavior-level simulation model is developed in this thesis. The packaging related parasitic inductance, including both self-inductance and mutual-inductance, are extracted based on finite element analysis (FEA) methods. Then the accuracy of the simulation model is verified by a double-pulse tester, and the simulation results match well with experiment in terms of both device switching waveform and switching energy.
Based on the simulation model, detailed loss breakdown and loss mechanism analysis are made. The cascode GaN HEMT has high turn-on loss due to the body diode reverse recovery of the low voltage Si MOSFET and the common source inductance (CSI) of the package; while the turn-off loss is extremely small attributing to the cascode structure.
With this unique feature, the critical conduction mode (CRM) soft switching technique are applied to reduce the dominant turn on loss and increase converter efficiency significantly. The switching frequency is successfully pushed to 5MHz while maintaining high efficiency and good thermal performance.
Traditional packaging method is becoming a bottle neck to fully utilize the advantages of GaN HEMT. So an investigation of the package influence on the cascode GaN HEMT is also conducted. Several critical parasitic inductors are identified, which cause high turn on loss and high parasitic ringing which may lead to device failure. To solve the issue, the stack-die package is proposed to eliminate all critical parasitic inductors, and as a result, reducing turn on loss by half and avoiding potential failure mode of the cascode GaN device effectively.
Utilizing the proposed stack-die package and ZVS soft switching, the GaN HEMT high frequency, high efficiency, and high density power conversion capability can be further extended to a higher level.Master of Science
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Danesin, Francesca. "Stress, Overstress and Strain on AlGaN/GaN HEMT Devices." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425693.
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Defence radar and wireless communication systems have a drastic need for increased rf performance for high power, high efficiency, high linearity and low-cost monolithic amplifiers operating in the 1-40 GHz frequency range. Semiconductor devices based on Silicon (Si) or Gallium Arsenide (GaAs) are currently used for the fabrication of communication systems but they are not able to deal with the continuous increase in demand for microwave power performances: those devices are very close to their limit, working with a poor efficiency and requiring large cooling systems. Therefore Gallium nitride-based devices are becoming extremely attractive for a wide range of applications, from optoelectronics to power electronics. In particular, High Electron Mobility Transistors (HEMT) are emerging as a key technology for rf and microwave amplifiers, but their stability and reliability is still one of the main issue that has to be solved in order to achieve production level quality devices.I sistemi di comunicazione di ultima generazione, basati su amplificatori che operano a frequenze tra gli 1 ed i 40 GHz, necessitano di prestazioni rf sempre più spinte per quel che riguarda la potenza, l’efficienza, la linearità ed il basso costo. I semiconduttori basati sul Silicio (Si) o sull’ Arseniuro di Gallio (GaAs) che sono abitualmente utilizzati per la costruzione di sistemi di comunicazione non sono in grado di soddisfare la domanda continua e crescente di prestazioni di potenza alle microonde. Questo tipo di dispositivi sono vicini al limite delle proprie prestazioni, lavorano con bassa efficienza e richiedono sistemi di raffreddamento di grandi dimensioni. I dispositivi basati su Nitruro di Gallio stanno quindi diventando interessanti per un gran numero di applicazioni: dalla optoelettronica all’ elettronica di potenza. In particolare i transistor ad alta mobilità elettronica (HEMT) si sono rivelati promettenti per gli amplificatori a microonde ma la loro stabilità e affidabilità sono ancora uno dei problemi da risolvere per ottenere un prodotto commercializzabile e pronto per il mercato.
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Cibie, Anthony. "Substrats innovants pour des composants de puissance à base de GaN." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI014/document.
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A l’heure actuelle, le marché de l’électronique de puissance est dominé par les composants silicium. Néanmoins, de nouveaux matériaux comme le nitrure de gallium ont émergé dans ce domaine grâce à leurs propriétés intéressantes. Ces nouveaux composants sont principalement réalisés sur des substrats silicium ce qui induit certaines problématiques lors de leur fabrication ou au niveau de leurs performances. Nous nous sommes intéressés dans cette thèse à des approches d’un point de vue du substrat dans l’objectif de résoudre ces problématiques. Ce travail a permis notamment de mettre en place une succession de procédés technologiques afin de remplacer le substrat silicium de fabrication par d’autres matériaux pour améliorer les performances de ces composants. Cette approche a notamment permis de transférer des composants fonctionnels sur un substrat cuivre. L’impact électrique et thermique du remplacement du substrat initial par un nouveau matériau a été étudié. Ce travail ouvre ainsi la voie du report de composants en nitrure de gallium réalisés sur des substrats silicium de diamètre 200 mm ou plusNew materials such as gallium nitride (GaN) emerge as promising candidates for power electronics. The current trend is to fabricate the AlGaN/GaN power devices directly on (111) silicon substrates. It makes the expitaxy of the GaN challenging and affects the device performances. In this work, we focus on substrate approaches to solve these problems. A transfer process was developed to replace the silicon substrate by another material to enhance electrical performances of the devices. Especially, GaN devices were transferred on copper substrates without electrical degradation. Electrical and thermal characterizations were performed to study the impact of the transfer. This work offers a first approach on the transfer of GaN devices from 8 or even 12 inches silicon substrates
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APPASWAMY, ARAVIND C. "SIMULATION OF SHORT CHANNEL AlGaN/GaN HEMTs." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109277211.
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Jogi, Sreeram. "Modelling of GaN Power Switches." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1431717800.
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Neuburger, Martin. "Entwurf und Technologie von GaN-Heterostruktur FETs für hohe Leistung." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-57224.
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Kuhn, Bertram. "AlGaN-GaN-Heterostrukturen Epitaxie und elektrische Eigenschaften /." [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9755220.
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Someswaran, Preethi. "Large Signal Modelling of AlGaN/GaN HEMT for Linearity Prediction." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440392889.
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Nie, Hanqing. "Analysis and Optimization of Parallel Gan Hemt for LLC Converters." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1627311347738337.
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Embar, Ramanujam Srinidhi. "Intermodulation distortion modelling and measurement techniques for GaN HEMT characterization." Kassel Kassel Univ. Press, 2008. http://d-nb.info/992643643/04.
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Ehteshamuddin, Mohammed. "Design of a High Temperature GaN-Based Variable Gain Amplifier for Downhole Communications." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/74958.
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The decline of easily accessible reserves pushes the oil and gas industry to explore deeper wells, where the ambient temperature often exceeds 210 °C. The need for high temperature operation, combined with the need for real-time data logging has created a growing demand for robust, high temperature RF electronics. This thesis presents the design of an intermediate frequency (IF) variable gain amplifier (VGA) for downhole communications, which can operate up to an ambient temperature of 230 °C. The proposed VGA is designed using 0.25 μm GaN on SiC high electron mobility transistor (HEMT) technology. Measured results at 230 °C show that the VGA has a peak gain of 27dB at center frequency of 97.5 MHz, and a gain control range of 29.4 dB. At maximum gain, the input P1dB is -11.57 dBm at 230 °C (-3.63 dBm at 25 °C). Input return loss is below 19 dB, and output return loss is below 12 dB across the entire gain control range from 25 °C to 230 °C. The variation with temperature (25 °C to 230 °C) is 1 dB for maximum gain, and 4.7 dB for gain control range. The total power dissipation is 176 mW for maximum gain at 230 °C.Master of Science
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Meiners, Joseph R. "Simulation and design of a submicron gate-length AIHaN/GaN HEMT." Cincinnati, Ohio University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?ucin1177520581.
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MEINERS, JOSEPH R. "SIMULATION AND DESIGN OF A SUBMICRON GATE-LENGTH AIGaN/GaN HEMT." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1177520581.
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Langley, Derrick. "AlGaN/GaN HEMT Topology Investigation Using Measured Data and Device Modeling." Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1177728294.
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Taher, Mohammad Iktiham Bin. "New HEMT Type Sensors for In-situ Bio‐Geochemical Analysis." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0229.
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Une nouvelle classe de capteurs de gaz innovants basée sur des transistors à haute mobilité électronique (HEMT) AlGaN/GaN a été développée pour les applications géologiques. Elle est conçue dans le but d'étudier le transfert de masse des gaz (H2, CO2, CH4, O2, H2S, SO2 et He) entre le sous-sol et l'atmosphère sur de grandes étendues géographiques. Pour cela, elle intègre les caractéristiques clé suivantes : la miniaturisation, la robustesse, l'insensibilité aux environnements difficiles associées à un coût contenu. Les étapes technologiques comme la conception des capteurs, les technologies de micro-fabrication et l'optimisation des performances électriques des HEMT ont été continuellement étudiées et améliorées tout au long du travail. Ainsi, des densités de courant supérieures à 400 mA/mm, un courant de pincement = ~1×10-5 A et une transconductance = ~0,03 S/mm ont été atteints dans certaines conditions de polarisation. Les capteurs HEMT AlGaN/GaN traités avec différentes couches fonctionnelles (Pt, ITO et IZO) ont aussi été fabriqués et caractérisés pour différents gaz (H2, CO2, CH4 et He) en laboratoire et en environnement souterrain (Forage de 51 m) dans différentes conditions environnementales (température= 25 à 450°C, humidité= 0 à 100%). Grace à ces mesures, les enthalpies d'adsorption d'hydrogène ont été mesurées sur divers matériaux de détection tels que Pt, ITO et IZO et sont de -30.3 kJ mol^(-1), -32.5 kJ 〖mol〗^(-1) et -34 kJ 〖mol〗^(-1), respectivement. Ces valeurs indiquent que ITO et IZO sont complémentaires de Pt pour le développement d'un capteur d'hydrogène gazeux. Les HEMTs Pt/AlGaN/GaN ont été également été étudiés pour optimiser les performances des capteurs d'hydrogène dans l'air atmosphérique pur et dans le diazote afin de simuler les conditions souterraines, où la concentration d'O2 change avec la profondeur du sol. L'analyse thermodynamique montre que pour le Pt, l'affinité de H2 est environ 2000 fois supérieure à celle de l'O2. Cela rend le capteur adapté à la détection d'O2 dans l'air ou de divers mélanges d'O2 et de H2 en fonction des différentes profondeurs souterraines impliquées. Un lot de capteurs de gaz spécifique a été fabriqué avec des composants de capteur passivés (càd, non-actifs) comme référence pour la détection de gaz (capteur actif). Le capteur actif Pt/AlGaN/GaN fournit un changement de courant indiquant la présence de H2, tandis que le capteur non-actif n'indique aucun changement de courant en relation avec le gaz. Le capteur non-actif permet de suivre et d'éliminer les changements causés par les paramètres environnementaux externes comme la température. Cette thèse présente également de nouvelles techniques de mesure utilisant la polarisation par impulsions pour la détection des gaz souterrains avec les HEMT Pt-AlGaN/GaN. Au lieu d'imposer une polarisation d'entrée continue (toujours dans état ON) sur une longue période, le capteur est activé plusieurs fois successivement avec des impulsions sur de courtes périodes (état ON/OFF). Les capteurs ont ainsi montré une réponse rapide au gaz sous la forme d'une variation de courant significative jusqu'à des concentrations de 25 ppm. Toutes les expériences menées dans le cadre de cette étude ont démontré que les capteurs peuvent fonctionner dans divers scénarios de mesure susceptibles de se produire dans la situation réelle de détection de gaz en contexte géologique souterrainAn innovative gas sensor generation based on AlGaN/GaN High Electron Mobility Transistor (HEMT) has been developed for complex geological environments. It is designed to study the mass transfer of gases (H2, CO2, CH4, O2, H2S, SO2, and He) from the underground to the Earth's atmosphere. It incorporates the key features for subsurface gas sensor development such as miniaturization, robustness, insensitivity to harsh environments, and low cost.Technological steps, design of the sensor layouts, micro-fabrication techniques, and optimization of the electrical performance of the HEMTs have been continuously investigated and improved. Current densities above 400 mA/mm and pinch-off current= (~1×10-5 A), and transconductance (gm)= ~0.03 S/mm have been achieved for certain bias conditions. At the same time, the processed AlGaN/GaN HEMT sensors with different functional layers (Pt, ITO, and IZO) are fabricated and characterized for different gases (H2, CO2, CH4, and He) in the laboratory, and real subsurface conditions (Borehole: 51 m) under different environmental conditions (temperature= 25 to 450°C, humidity= 0 to 100%). The measured adsorption enthalpies of hydrogen onto various sensing materials like Pt, ITO, and IZO are calculated -30.3 kJ mol^(-1), -32.5 kJ 〖mol〗^(-1), and -34 kJ 〖mol〗^(-1), respectively, indicating that ITO and IZO are complementary to Pt for the development of a hydrogen gas sensor.Pt/AlGaN/GaN-based HEMT devices have been studied to evaluate the performance of hydrogen sensors in pure atmospheric air and a fully N2-based atmosphere to simulate subsurface conditions where the O2 concentration changes over the depth of the soil. From the thermodynamic analysis, the affinity of hydrogen for Pt was found nearly 2000 times greater than the affinity of oxygen for platinum. This makes the sensor suitable for detecting hydrogen in the air or various mixtures of O2 and H2 at different underground depths imply.A dedicated gas sensor batch has been fabricated with passivated (i.e., non-active) sensor components as a reference for gas detection (active sensor). The active sensor Pt/AlGaN/GaN provided a change in current indicating a response to the hydrogen exposure, while the non-active (Passivated-Pt/AlGaN/GaN) provides no changes in current. But non-active sensor (reference) tracks and eliminates the changes caused by external environmental parameters.This thesis also presents new measurement techniques using pulse polarization for subsurface gas detection with a Pt-AlGaN/GaN HEMT sensor. Instead of imposing a continuous input bias (which always maintains the ON state) over a long period of the experiment, the sensor is activated several times with pulsed polarization for a short period of time (ON/OFF state). The sensors showed a sufficiently fast response to the target gas by changing the drain current in pulsed bias mode with a linear increase in output current even at very low concentrations such as 25 ppm. All the experiments conducted in the study demonstrated that the sensors could work in various measurement scenarios that may occur in the real situation of subsurface gas detection
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Lehmann, Jonathan. "Caractérisation électrique d’hétérostructures AlGaN/GaN pour des applications de puissance." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT081/document.
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Cette thèse s'inscrit dans le cadre du développement de transistors de puissance HEMT à base de nitrure de gallium au CEA. Les HEMT AlGaN/GaN sont des composants très prometteurs pour les applications d'électronique de puissance. Le but de cette thèse est d'étudier en détail le matériau AlGaN/GaN en amont de la fabrication de transistors. Cette thèse est organisée en quatre chapitres. Le premier chapitre introduit les concepts théoriques nécessaires à la compréhension du fonctionnement des HEMT AlGaN/GaN. Les trois chapitres restant sont consacrés à l'étude des propriétés électriques de l'empilement AlGaN/GaN: résistance de couche, résistance des contacts, mobilité et densité de porteurs. Dans le chapitre deux, à travers des mesures de la résistance de couche, il est démontré que des phénomènes de piégeage interviennent dans le matériau et que l'utilisation d'une source lumineuse permet une stabilisation de la mesure. Ensuite, à travers des structures avec des longueurs de contacts différentes, une étude détaillée des résistances de contact a été effectuée. Pour cela, le modèle TLM a été utilisé. Les résultats obtenus montre que dû à la variation non linéaire des caractéristiques de nos contacts en fonction de leur longueur, un tel modèle n'est pas adapté à l'étude des contacts fabriqués au CEA. Dans le chapitre trois, une méthode de mesure de la résistance de couche d'un empilement AlGaN/GaN sans fabrication de contacts a été mise au point. Cette méthode repose sur les travaux de Van Der Pauw concernant la mesure colinéaire et permet la caractérisation précise et rapide de plaques entières en sortie d'épitaxie. Enfin dans le dernier chapitre, une étude comparative des propriétés électriques de l'empilement AlGaN/GaN sous la grille et en dehors de la grille a été effectuée. Premièrement, on a procédé à une étude statistique de la résistance de couche, de la mobilité et de la densité de porteurs. Il est démontré que la gravure du Si3N4 préalable au dépôt de la grille injecte des ions fluor dans l'empilement, causant des dégradations des propriétés électriques. Ensuite, les phénomènes de diffusion de la mobilité ont été caractérisés à travers une étude détaillée de la mobilité en fonction de la densité de porteurs. Enfin, pour compléter cette étude, une analyse en température des mesures de capacité et de la mobilité a été effectuéeThis PhD is part of the development of HEMT power transistor based on galliumnitride at the CEA. Due to their high electron mobility, high breakdown _eld and goodthermal conductivity, AlGaN/GaN HEMT are very promising devices for power electronic applications.The goal of this PhD is, using electrical characterization, to increase the knowledge ofthe AlGaN/GaN material prior to the fabrication of transistors. First, through measurements ofthe resistance of the electron gas located at the AlGaN/GaN interface, a trapping phenomenonwas evidenced in the material. Then, in order to set a production follow-through of AlGaN/GaNon Si wafers , a method of measuring the sheet resistance of a AlGaN/GaN stack without thefabrication of contacts was developed and patented. Finally, on HEMT transistors fabricatedusing di_erent epitaxies, a detailed study of the sheet resistance, the mobility and the sheetcarrier density in and out of the gated area was carried out
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Jarndal, Anwar Hasan. "Large-signal modeling of GaN device for high power amplifier design." Kassel Kassel Univ. Press, 2006. http://www.upress.uni-kassel.de/publi/abstract.php?978-3-89958-258-1.
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Callet, Guillaume. "Caractérisation et modélisation de transistors HEMT AlGaN/GaN et InAlN/GaN pour l’amplification de puissance en radio-fréquences." Limoges, 2011. https://aurore.unilim.fr/theses/nxfile/default/3c0fde17-3720-49cd-9824-bd071826245e/blobholder:0/2011LIMO4033.pdf.
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Ce document traite de la caractérisation de composants HEMT à base de GaN en vue de leur modélisation. Une caractérisation exhaustive des transistors à base d’InalN/GaN et AlGaN/GaN est réalisée. Une importance particulière est donnée aux méthodes de caractérisation thermique, avec l’utilisation de la méthode 3ω pour la mesure de l’impédance thermique. Une étude des facteur d’échelle du modèle linéaire est également abordée. Le modèle non-linéaire présenté est développé afin d’élargir son champ d’application à l’amplification de puissance et à la commutation. Enfin, il est utilisé pour la réalisation du premier amplificateur de puissance utilisant la technologie InAlN en bande KaThis report deals with the characterization of GaN HEMTs devices in order to create their model. An exhaustive characterization has been realized for AlInN/GaN and AlGaN/GAN based HEMTs. A special care has been given to the different thermal characterization methods, with the use of the 3ω method for the measurement of the thermal impedance. A study of scaling rules for small-signal model is presented. The non-linear model presented is developed in order to extend his application domain to the power amplification and power switches. Finally it is used in the design of the first poser amplifier base on AlInN technology in Ka-band
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Spisser, Hélène. "Développement de capteurs THz utilisant l'hétérostructure AlGaN/GaN." Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10290.
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Le domaine du spectre électromagnétique correspondant aux fréquences térahertz est encore peu exploité, pourtant, les applications nécessitant la génération, l’amplification ou la détection d’un signal térahertz sont nombreuses et intéressantes. Dans ce travail, nous nous intéressons tout particulièrement au détecteurs plasmoniques, qui constituent une alternative prometteuse à la montée en fréquence des capteurs électroniques et à l’utilisation de capteurs thermiques pour les photons de faible énergie.
Les capteurs plasmoniques fonctionnent grâce au couplage entre le photon térahertz et un plasmon au sein d’un gaz d’électrons bidimensionnel (2DEG). Le plasmon-polariton est ensuite transformé en un signal continu et détectable. Nous utilisons pour cela le 2DEG présent dans l’hétérostructure AlGaN/GaN. Le couplage entre le photon et le plasmon-polariton est réalisé par un réseau métallique déposé sur la structure semi-conductrice.
Tout d’abord, l’étude du couplage photon/plasmon par des simulations électromagnétiques nous a permis de connaître les fréquences de résonance des plasmons-polaritons en fonction des dimensions du réseau. Le motif de réseau composé de deux bandes de métal de largeurs différentes a été plus particulièrement étudié. Ce motif permettant aux détecteurs d’atteindre une très haute sensibilité [Coquillat et al., 2010] et n’avait pas encore été étudié du point de vue de son efficacité de couplage.
Des détecteurs, dimensionnés pour notre montage de test à 0,65 THz, ont ensuite été fabriqués puis mesurés avec un réseau non-polarisé, à température ambiante et refroidis à l’azote. La correspondance entre la variation de la sensibilité en fonction de la fréquence et les spectres d’absorption mesurés au spectromètre infrarouge à transformée de Fourier (FTIR) montre l’importance de l’étape de couplage dans le processus de détection.
Contrôler la densité électronique dans le 2DEG permet de modifier la fréquence de résonance des plasmons-polaritons et d’augmenter la sensibilité des détecteurs. Nous avons mené des développements technologiques de manière à pouvoir contrôler la densité électronique du 2DEG en appliquant une tension sur le réseau. Cette étape constitue un défi technologique compte tenu de la surface très étendue des réseaux (plusieurs mm²). Nous avons finalement fabriqué des détecteurs pour lesquels la fréquence de résonance de couplage peut être contrôlée grâce à la tension appliquée sur le réseau.Abstract: The objectives of this thesis were the fabrication, the measurement and the study of gallium nitride THz detectors. These detectors are working as follows : first the incident THz photon is coupled to a plasmon in the quantum well at the interface AlGaN/GaN. This plasmon is then turned into a continuous measurable current. One of the key-components in this type of detectors is the grating coupling the incident photon and the plasmon. Electromagnetic simulations have been made to determine the dimensions of the grating depending on the detection frequency. Detectors were then fabricated using the precendently calculated grating patterns. Their working frequency depending on their dimensions were measured with a good agreement with the previously led simulations. The grating is not used only as coupling element, but can be used to monitor the electron density in the quatum well as well, what should allow an exaltation of the rectification phenomenon and a frequency tunability. A technological development was needed to achieve grating actually monitoring the electron density over a wide range. It was a real challenge to fabricate such wide grating (36 mm²) with such small periods (about one micrometer) using epitaxies developped for devices with a much smaller area.
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Malela-Massamba, Ephrem. "Développement et caractérisation de modules Technologiques sur semiconducteur GaN : application à la réalisation de cathodes froides et de transistor HEMT AlGaN/GAN." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1078.
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Les travaux présentés dans ce manuscrit sont axés sur le développement et la caractérisation de modules technologiques sur semiconducteurs à large bande interdite à base de nitrure de gallium (GaN), pour la réalisation de transistors et de cathodes froides. Ils ont été réalisés au sein du laboratoire III-V lab, commun aux entités : Alcatel - Thales - CEA Leti. Notre projet de recherche a bénéficié d'un soutien financier assuré par Thales Electron Devices (TED) et l'Agence Nationale de la Recherche ( ANR ). Concernant les transistors HEMT III-N, nos investigations se sont focalisées sur le développement des parties actives des transistors, incluant principalement la structuration des électrodes de grilles, l'étude de la passivation des grilles métalliques, ainsi que l'étude de diélectriques de grille pour la réalisation de structures MIS-HEMT.Les transistors MOS-HEMT « Normally-off » réalisés présentent des performances comparables à l'état de l'art, avec une densité de courant de drain maximum comprise entre 270 mA et 400 mA / mm, un ratio ION / IOFF > 1100, et des tensions de claquage > 200V. Les tensions de seuil sont comprises entre + 1,8 V et + 4 V. Nos contributions au développement des cathodes froides ont permis de démontrer une première émission dans le vide à partir de cathodes GaN, avec une densité de courant maximale de 300 µA / cm2 pour une tension de polarisation de 40 VThe results presented in this manuscript relate to technological developments and device processing on wide bandgap III-N semiconductor materials. They have been focused on III-N HEMT transistors and GaN cold cathodes. They have been realised within the III-V lab, which is a common entity between: Alcatel - Thales - CEA Leti. They have been financially supported by Thales Electron Devices company (TED) and the French National Research Agency ( ANR ). Regarding III-N HEMTs, our investigations have been focused on the development of device gate processing, which includes : the structuration of gate electrodes, the study of device passivation, and the realization of Metal-Insulator-Semiconductor High Mobility Electron Transistors ( MIS-HEMTs ). The “ Normally-off ” MOS-HEMT structures we have realized exhibit performances comparable to the state of the art, with a maximum drain current density between 270 and 400 mA / mm, a ION / IOFF ratio > 1.100, and a breakdown voltage > 200V. The threshold voltage values range between + 1,8 V and + 4V. We have also been able to demonstrate prototype GaN cold cathodes providing a maximum current density of 300 µA / cm2, emitted in vacuum for a bias voltage around 40 V
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Saha, Sumit. "RF Front-End Design for X Band using 0.15µm GaN HEMT Technology." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34622.
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The primary reason for the wireless technology evolution is towards building capacity and obtaining higher data rates. Enclosed locations, densely populated campus, indoor offices, and device-to-device communication will require radios that need to operate at data rates up to 10 Gbps. In the next few years, a new generation of communication systems would emerge to better handle the ever-increasing demand for much wider bandwidth requirements. Simultaneously, key factors such as size, cost, and energy consumption play a distinctive role towards shaping the success of future wireless technologies. In the perspective of 3GPP 5G next generation wireless communication systems, the X band was explicitly targeted with a vast range of applications in point to point radio, point to multi point radio, test equipment, sensors and future wireless communication.
An X-band RF front-end circuit for next generation wireless network applications is presented in this work. It details the design of a low noise amplifier and a power amplifier for X band operation. The designed amplifiers were integrated with a wideband single-pole-double-throw switch to achieve an overall front-end structure for 10 GHz. The design was carried out and sent for fabrication using a GaN 0.15µm process provided by NRC, a novel design kit. Due to higher breakdown voltage, high power density, high efficiency, high linearity and better noise performance, GaN HEMTs are a suitable choice for future wireless communication. Thus, the assumption is to further explore capabilities of this process in front-end design for future wireless communications.
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Aroulanda, Sébastien. "Co-intégration de HEMT GaN hyperfréquence normally-off avec des normally-on." Thesis, Lille, 2020. http://www.theses.fr/2020LILUI083.
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Dans le cadre de la fabrication de dispositifs hyperfréquences, la fonctionnalité normally-off présente deux avantages : elle permet d’une part de s’affranchir de la source de tension négative pour les circuits intégrés monolithiques hyperfréquences (Monolithic Microwave Integrated Circuit – MMIC) et, d’autre part, la co-intégration de transistors normally-on et normally-off permettrait de réaliser des circuits logiques.Ce manuscrit présente les travaux réalisés dans l’objectif de développer un procédé de fabrication de HEMT normally-off compatible avec la fabrication de normally-on, permettant ainsi leur co-intégration au sein de la même puce. Pour cela, deux technologies ont été étudiées : l’une basée sur la combinaison d’un recess de grille, d’une implantation de fluor sous la grille et d’un dépôt d’oxyde de grille et l’autre basée sur la nanostructuration de l’espace source-drain afin des réaliser des FinFET GaN. La première technologie nous as permis d’obtenir des transistors normally-off présentant une tension de seuil d’environ 1,4 V associée à une densité de courant maximale de 1 A/mm. Ces composants, bien que présentant des résultats satisfaisants, souffrent toutefois d’effets de pièges importants qui sont probablement dus à l’oxyde de grille et qui doivent absolument être réduits. La technologie FinFET était quant à elle une première au laboratoire et nécessite encore de nombreuses optimisations. Les transistors ainsi fabriqués présentent cependant des résultats prometteurs avec des topologies entrainant un décalage de la tension de seuil de + 3 V par rapport aux transistors de références et d’autres permettant de quasiment doubler la densité de courant de drainIn the context of high frequency devices fabrication, normally-off transistors offer two benefits: they eliminate the need of a negative voltage supply in the case of Monolithic Microwave Integrated Circuit (MMIC) and would allow the fabrication of logic circuits if integrated with normally-on HEMT.This manuscript exposes the work performed to develop a normally-off HEMT fabrication process compatible with the fabrication of normally-on transistors. To achieve this, we studied two technologies: one based on the combination of a gate recess, fluorine implantation under the gate and gate-oxide deposition while the other is based on the nanostructuration of the source-drain region in order to make GaN FinFET. The first process gave us normally-off transistors with threshold voltage of 1,4 V associated with current density of about 1 A/mm. However, these devices suffer from significant trap effects that are probably due to the gate oxide. The FinFET technology we have developed, as a first trial, still needs a lot of optimization but showed promising results. While a topology lead to an increase of the threshold voltage of about + 3 V compared to the reference, an other one lead to a doubling of the current density
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Li, Xiao. "Short Circuit Capability and Degradation Mechanism Analysis of E-mode GaN HEMT." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492643687305536.
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Mengistu, Endalkachew Shewarega. "Large-signal modeling of GaN HEMTs for linear power amplifier design /." Kassel : Kassel Univ. Press, 2008. http://d-nb.info/987878476/04.
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Endruschat, Achim [Verfasser], Robert [Akademischer Betreuer] Weigel, Martin [Akademischer Betreuer] März, and Martin [Gutachter] März. "Simulationsmodell für einen GaN-HEMT mit Schottky p-GaN-Gate / Achim Endruschat ; Gutachter: Martin März ; Robert Weigel, Martin März." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2021. http://d-nb.info/1239898479/34.
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Arehart, Aaron R. "Investigation of electrically active defects in GaN, AlGaN, and AlGaN/GaN high electron mobility transistors." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253626881.
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Spisser, Hélène. "Développement de capteurs THz utilisant l'hétérostructure AIGaN/GaN." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS040/document.
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Le domaine du spectre électromagnétique correspondant aux fréquences térahertz est encore peu exploité, pourtant, les applications nécessitant la génération, l’amplification ou la détection d’un signal térahertz sont nombreuses et intéressantes. Dans ce travail, nous nous intéressons tout particulièrement aux détecteurs plasmoniques, qui constituent une alternative prometteuse à la montée en fréquence des capteurs électroniques et l’utilisation de capteurs thermiques pour les photons de faible énergie. Les capteurs plasmoniques fonctionnent grâce au couplage entre le photon térahertz et un plasmon au sein d’un gaz d’électrons bidimensionnel (2DEG). Le plasmon-polariton est ensuite transformé en un signal continu et détectable. Nous utilisons pour cela le 2DEG présent dans l’hétérostructure AlGaN/GaN. Le couplage entre le photon et le plasmon est réalisé par un réseau métallique déposé sur la structure semi-conductrice. Tout d’abord, l’étude du couplage photon/plasmon-polariton par des simulations électromagnétiques nous a permis de connaître les fréquences de résonance des plasmons-polaritons en fonction des dimensions du réseau. Le motif de réseau composé de deux bandes de métal de largeurs différentes a été plus particulièrement étudié. Ce motif permettant aux détecteurs d’atteindre une très haute sensibilité [Coquillat et al., 2010] et n’avait pas encore été étudié du point de vue de son efficacité de couplage. Des détecteurs, dimensionnés pour notre montage de test à 0,65 THz, ont ensuite été fabriqués puis mesurés avec un réseau non-polarisé, à température ambiante et refroidis à l’azote. La correspondance entre la variation de la sensibilité en fonction de la fréquence et les spectres d’absorption mesurés au spectromètre infrarouge à transformée de Fourier (FTIR) montre l’importance de l’étape de couplage dans le processus de détection. Contrôler la densité électronique dans le 2DEG permet de modifier la fréquence de résonance des plasmons-polaritons et d’augmenter la sensibilité des détecteurs. Nous avons mené des développements technologiques de manière à pouvoir contrôler la densité électronique du 2DEG en appliquant une tension sur le réseau. Cette étape constitue un défi technologique compte tenu de la surface très étendue des réseaux (plusieurs mm²). Nous avons finalement fabriqué des détecteurs pour lesquels la fréquence de résonance de couplage peut être contrôlée grâce à la tension appliquée sur le réseauThe THz-domain of the electromagnetic spectrum is not frequently used, even if the generation, amplification and detection of THz-waves would open a wide range of interesting applications. In this work, we focus on plasmonic detectors as a promising alternative to the frequency-raising of high-frequency electronic detectors and to the use of thermic detectors for low-energy photons. The coupling between a THz-photon and a plasmon in a 2D electron gas (2DEG) gives birth to a plasmon-polariton, which is then turned into a continuous, measurable signal and explains the operation of the plasmonic detector. In this work, we use the 2DEG in the semiconductive heterostructure AlGaN/GaN. A metallic grating deposited on-top of the semiconductor realises the coupling between photon and plasmon. First, we used electromagnetic simulations to study the coupling between photon and plasmon and calculate the resonant coupling frequency with respect to the grating dimensions. We studied specifically a grating pattern made of two metal stripes of different widths. This pattern gives the highest sensitivity to the detectors [Coquillat et al., 2010] and had not been studied before in term of coupling efficiency. In a second time, we fabricated detectors designed to match our 0.65 THz experimental setup. These detectors have been measured at 77 K and at room-temperature. No voltage has been applied on the grating. We saw that the sensitivity variations with respect to the incident frequency correspond to the absorption spectra measured by Fourier Transform spectrometer (FTIR), what show the importance of the coupling for the detection. Monitoring the electronic density in the 2DEG is a way to monitor the plasmon-polariton resonant frequency and the detector sensitivity. We led technological development to monitor the electronic density in the 2DEG by applying a voltage on the grating. This has been a technological challenge because of the wide grating area (a few mm²). Finally, we fabricated detectors for which it was possible to monitor the resonant absorption frequency using the grating voltage
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"Analysis of Heat Dissipation in AlGaN/GaN HEMT with GaN Micropits at GaN-SiC Interface." Master's thesis, 2016. http://hdl.handle.net/2286/R.I.41224.
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abstract: Gallium Nitride (GaN) based microelectronics technology is a fast growing and most exciting semiconductor technology in the fields of high power and high frequency electronics. Excellent electrical properties of GaN such as high carrier concentration and high carrier motility makes GaN based high electron mobility transistors (HEMTs) a preferred choice for RF applications. However, a very high temperature in the active region of the GaN HEMT leads to a significant degradation of the device performance by effecting carrier mobility and concentration. Thus, thermal management in GaN HEMT in an effective manner is key to this technology to reach its full potential.
In this thesis, an electro-thermal model of an AlGaN/GaN HEMT on a SiC substrate is simulated using Silvaco (Atlas) TCAD tools. Output characteristics, current density and heat flow at the GaN-SiC interface are key areas of analysis in this work. The electrical characteristics show a sharp drop in drain currents for higher drain voltages. Temperature profile across the device is observed. At the interface of GaN-SiC, there is a sharp drop in temperature indicating a thermal resistance at this interface. Adding to the existing heat in the device, this difference heat is reflected back into the device, further increasing the temperatures in the active region. Structural changes such as GaN micropits, were introduced at the GaN-SiC interface along the length of the device, to make the heat flow smooth rather than discontinuous. With changing dimensions of these micropits, various combinations were tried to reduce the temperature and enhance the device performance. These GaN micropits gave effective results by reducing heat in active region, by spreading out the heat on to the sides of the device rather than just concentrating right below the hot spot. It also helped by allowing a smooth flow of heat at the GaN-SiC interface. There was an increased peak current density in the active region of the device contributing to improved electrical characteristics. In the end, importance of thermal management in these high temperature devices is discussed along with future prospects and a conclusion of this thesis.Dissertation/Thesis
Masters Thesis Electrical Engineering 2016
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Liu, Cheng-Chih, and 劉政志. "The Fabrication and Analysis of High Frequency AlGaN/GaN HEMT and AlInN/GaN HEMT." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/64732834284178885341.
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碩士國立清華大學
電子工程研究所
101
In this thesis, we compare the DC and RF characteristics of AlGaN/GaN and AlInN/GaN HEMTs and their equivalent small signal signal circuit model are constructed and compared. For the DC characteristics the saturated current density(Idss) and the transconductance(Gm) of the AlInN/GaN HEMT is 1271mA/mm and 231mS/mm respectively which are higher than the AlGaN/GaN’s value 900mA/mm and 187mS/mm because of the higher 2DEG concentration in AlInN/GaN. But the leakage current of the AlInN/GaN HEMT is also higher than that of AlGaN/GaN HEMT. For high frequency characteristics, the AlInN/GaN HEMT shows an ft=82GHz and an fmax=70GHz, which is also higher than the AlGaN/GaN’s numbers because of the higher transconductance of AlInN/GaN HEMT. But for RF power characteristics the AlInN/GaN HEMT is poor than AlGaN/GaN HEMT due to the higher leakage current of AlInN/GaN HEMT. Finally we extract small signal parameters, contstruct equivalent circuit models, and compare their intrinsic values. From the extracted values, It is found that the intrinsic gm of AlInN/GaN HEMT is higher than the AlGaN/GaN which is also attributed to the higher carrier density on the AlInN/GaN wafer.
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李奕辰. "Novel Light Emitting AlGaN/GaN HEMT." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/7efx9a.
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Huang, Wei-Hsun, and 黃瑋珣. "GaN HEMT Modeling and Passive Mixer Design." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/81543692717494340013.
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碩士國立清華大學
電子工程研究所
100
本論文可分成兩部分討論，第一部分是氮化鎵高電子移導率電晶體模型的建立，包含小訊號及大訊號模型，第二部分提出了兩種不同的被動混頻器架構，包含基頻混頻器與次諧波混頻器。 在第一部分首先我們利用cold-FET量測來萃取出外部寄生的電阻和電感值，再利用Y參數將外部寄生的參數扣除掉之後，可以計算出內部等校電路的元件值。在本論文中採用Angelov的模型做為我們的電流模型，此模型中的各個參數可利用擬合的方式獲取，另外將內部元件值隨電壓變化的關係也用方程式擬合，最後在ADS中建立出完整的電晶體等效模型，並比較量測與模擬的直流特性與S參數。 在第5章中，我們提出一種寬頻高線性度的被動混頻器，此混頻器是利用第2和3章建立出的電晶體模型來設計，我們所採用的元件大小是2×100 μm，IF頻率固定在1 GHz，可得到頻率操作在11-18 GHz，轉換損耗最小為7.9 dB的被動混頻器，此混頻器的P1dB和IIP3為13和22 dBm。 在第六章中，我們提出另一種被動混頻器架構，此混頻器是利用穩懋半導體提供的0.15 μm pHEMT 元件設計並製作，此混頻器操作在11-21 GHz，擁有轉換損耗8.8-11.8 dB，其P1dB和IIP3為3和6 dBm。
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May, Kae Dyi, and 麥凱迪. "The Investigation of Enhancement/Depletion-mode p-GaN Gate AlGaN/GaN HEMT." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/06583780731061211519.
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Peng, Po-Chin, and 彭柏瑾. "Simulation and Design of P-GaN MOS-HEMT." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/ssw69e.
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碩士國立清華大學
電子工程研究所
102
In this thesis, we used TCAD for fitting AlGaN/GaN heterojunction Transmission Line Model (TLM) I-V characteristics. A physics-based model of self-heating is included in TCAD simulations to investigate the internal device behavior. A dual metal Schottky Barrier Diode (SBD) is also simulated with the constructed models. The fitting errors of less than ±10% for DC I-V characteristics in both cases have been achieved. Another topic of this thesis is to design a normally-off p-GaN MOS-HEMT. A p-GaN MOS-HEMT with Al2O3 as the gate dielectric can significantly reduce the gate leakage current and achieve normally-off operation. To build the best performing device we optimized the channel length and doping concentration of the p-GaN. A p-GaN MOS-HEMT performance can also be improved by adding an i-GaN layer as the channel layer. Compared with a p-GaN MOS-HEMT, the i-GaN layer design reduced the threshold voltage and increased the saturation current. The i-GaN channel MOS-HEMT with a channel length of 0.4µm and a gate-drain length of 10µm shows a specific on-resistance as low as 3.7mΩ•cm2. The channel region resistance is 0.41mΩ•cm2 which contributes about 11% of the total resistance. The largest part of the total resistance is 1.75mΩ•cm2 from the gate-drain distance and it contributes about 47%.
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Wu, Chih-Chiang, and 吳至強. "Gate Driver Design and Implement for GaN HEMT." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/66827681276620623097.
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碩士國立交通大學
機械工程學系
100
GaN materials have some unique properties, including high electron mobility, high breakdown voltage, high electron saturation velocity, and high current density, which make them very suitable for high-speed and high temperature operating environment. However, the lack of high frequency and no readily available drivers for both zero turn-on voltage and negative turn-off voltage are the factors preventing their application to power converters. This study provides the design and implementation of a new gate driver circuit that is suitable for driving normally-on GaN-HEMT device, which is founded by using opto-coupler to float the driver side. This operation let upper-bridge gate to source voltage of the half bridge circuit won’t be affected by the output voltage swing to drive the upper-bridge power switch successfully. For the safety of the operation, normally-off GaN HEMT device is also fabricated in the future, so normally-off gate driver is also needed. The parameter of the gate driver can be known by measuring transistor electricity, including breakdown voltage, I-V curve, threshold voltage, gate to source forward leakage, gate charge test, and resistive switching test. After all, the drive of the BLDC motor is realized by using these electrical information.
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李奇穎. "Thermal Analysis of Packaged AlGaN/GaN Power HEMT." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/55969076439903598105.
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碩士國立交通大學
機械工程學系
101
AlGaN/GaN High electron mobility transistor(AlGaN/GaN HEMT) has many attractive material properties, such as wide bandgap(about 3.4 eV), high breakdown voltage, high critical breakdown field and high saturation electric drift velocity, high peak electron velocity, high electron saturation velocity and good thermal conductivity, which make it suitable for power electronics and Radio frequency (RF) communication applications. This study describes AlGaN/GaN HEMT for power electronic application. Therefore, the thermal analysis technology plays an important role in the high power and high power density packaging. First, use thermal resistance calculation and ANSYS ICEPAK simulation to analysis different packaging processes. Then, calculate the power loss and measure the temperature distribution of packaged AlGaN/GaN HEMT under the DC test by using three temperature measurement such as IR thermography microscope, Micro-Raman spectroscopy and IV-Curve electrical measurement. Finally, the simulation result is verified by compare it with experimental observations. Thermal simulation is used when designing a new device, in the design of the placement of the dissipating elements on the chip and for an efficient thermal management.
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Huang, Chao-Hua, and 黃昭華. "MOSFET and GaN HEMT Pulse Test and Analysis." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ywa7u7.
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Wang, Chieh-An, and 王婕安. "Electro-Thermal Simulation and Heat Dissipation Analysis of Packaged GaN Power-HEMT Devices." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/80245632143150963673.
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碩士國立交通大學
機械工程系所
103
AlGaN/GaN high electron mobility transistors（HEMTs）are one of the prospective candidates for high switching frequency power electronics applications thanks to its wide band gap（3.4eV）, high breakdown voltage, large critical electric field, high carrier mobility, and the inherent high speed characteristics. With the high power densities that AlGaN/GaN HEMTs are capable of reaching, heat dissipation is a crucial issue. This research presents an in depth thermal study of packaged GaN on Si power devices. The device is attached in a V-groove copper base, to enhance Si substrate thermal dissipation. The effects of structure design and fabrication processes on the device performance were studied. To improve the reliability and the performance of GaN power-HEMT devices, thermal management is one of the most critical aspects. Micro-Raman spectroscopy and Infrared（IR）thermography were used to identify temperature profiles and the hot spots of the devices. For the purpose of more precise temperature measurements, temperature vs. Raman shift curve fitting of experimental data of our device is illustrated. The measurements of longitudinal temperature have been acquired, so that the position of the hottest layer（2DEG）is realized. Then, Raman area temperature map measured over the lateral hottest layer depicted in this study. The comparison between Raman/IR experiment results and finite-element electro and thermal simulation has been shown.
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Khalil, Ibrahim [Verfasser]. "Intermodulation distortion in GaN HEMT / vorgelegt von Ibrahim Khalil." 2009. http://d-nb.info/999709720/34.
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Wei, Yi-Chiang, and 危以強. "High Power AlGaN/GaN HEMT Device Fabrication by Stepper." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/17991927981814293434.
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碩士國立交通大學
工學院半導體材料與製程設備學程
103
The AlGaN/GaN high electron mobility transistors have many superior electronic characteristics such as high operation frequency, low switching loss, and low on-resistance. For this reason, AlGaN/GaN HEMTs were very suitable for high power device applications. In this study, we focus on the improvements of breakdown voltage and output current of depletion mode AlGaN/GaN HEMTs. The methods include passivation adjustment, gate metal optimization, and large dimension (80mm) device with its series connection circuit. Concerning the passivation, we deposited AlN/Al2O3 by atomic layer deposition (ALD) and silicon nitride (SiN) by plasma enhanced chemical vapor deposition (PECVD) to reduce surface leakage current and increase breakdown voltage. In addition, we compared tungsten nitride with nickel gold as the gate metal materials and the T-shaped gate was included to obtain better breakdown voltage. In order to increase output current, we also manufactured series circuits. For 4-inch wafer fabrication, the lithography process was carried out by I-line stepper to achieve high yield device production.
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Lai, Ting-Hao, and 賴定豪. "Improved Passivation of GaN MIS-HEMT for Power Application." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/92067836930023890467.
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碩士國立交通大學
工學院半導體材料與製程設備學程
103
There are many researches demonstrated that the high-K passivation can significantly improve the AlGaN/GaN MIS-HEMT performance and reduce gate leakage and current collapse. In this thesis we focus on SiN as the gate insulation on GaN device. We present a systematic study on AlGaN surface treatment by CF4/NH3/N2O/N2 prior to SiN deposition to enhance the reliability of the AlGaN/GaN MIS-HEMT. We chose N2 treatment be this experiments treatment gas. Owing to N2 treatment can get smallest leakage current and biggest Drain current, among these treatment gases, We summarize this experiment and easy to get significantly MIS-HEMT performance improvement by N2 treatment process and SiN passivation layer deposition.
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Wang, An-Cheng, and 王安城. "Analysis of the characteristics of Vertical AlGaN/GaN HEMT." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/69811610490387063979.
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碩士國立高雄應用科技大學
電子工程系碩士班
101
In this thesis, a two-dimensional vertical HEMT (VHEMT) structure is studied by using the APSYS package. The theoretical model includes the Coulomb interaction and the drift-diffusion transport. The self-consistent algorithm is applied to calculate the current-voltage characteristics of VHEM. In this study, a new structure with a body contact to the p-GaN blocking layer is proposed. The body contact plays the role as another control gate to modulate the drain current according to the aperture modulation effect. In addition, the influences of channel-layer thickness, barrier-layer thickness, aperture size, and mole fraction of aluminum in AlxGa1-xN on the drain current are also studied. The increase of channel-layer thickness increases the drain current according to increasing the current cross-section. The increase of barrier thickness decreases the control-gate efficiency due to the reduction of gate capacitance. However, the reduction of the aperture size decreases the output resistance of VHEMT according to the aperture modulation. The increase of the mole fraction of aluminum in AlxGa1-xN barrier layer slightly increases the drain current because the increase of x increases the degree of lattice mismatch and, thus, increases the polarization charge at the interface of AlxGa1-xN/GaN.