Literatura académica sobre el tema "Nitrure d'aluminium gallium"
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Tesis sobre el tema "Nitrure d'aluminium gallium"
Gloux, Florence. "Comportement des semiconducteurs de structure wurtzite à base d'azote sous implantation d'ions terres rares de moyenne énergie". Caen, 2008. http://www.theses.fr/2008CAEN2047.
Texto completoThis PhD dissertation has been devoted to the investigation of the structural damage formed by medium energy rare earth heavy ions implanted in wurtite GaN and AlN semiconductors. Indeed, contradictory results about the nature of the damage formed in GaN at room temperature had reported discrepancies with the conventional behaviour. The aim of this present work was to contribute to understand the damage formation mechanism in GaN during such ion implantations. To this end, the evolution of the nature and distribution of defects versus rare earth ion fluence was analyzed by transmission electron microscopy. The behaviour of AlN was studied for comparison. From a threshold fluence, a nanocristalline layer appeared from the GaN surface while in AlN, amorphization took place from the bulk. These behaviours were correlated to the different distributions of basal and prismatic stacking faults distributions that were generated in the two materials during the ion implantation. Subsequently, this research has also dealt with procedures which may be used to avoiding the formation of the nanocristalline GaN surface layer which rapidly decomposed at attempts to annealing, even at low temperatures (~500°C). Implantation at high temperature led to a decrease of the stacking faults density but erosion from the surface took place. Implanting through a thin AlN cap epitaxially grown on GaN surface allowed to increase the nanocristallization threshold fluence by an order of magnitude. The AlN cap was shown to protect the GaN surface from decomposition with the aim of carrying out high temperature annealing (≥1300°C) required for rare earth activation and luminescent devices fabrication
Rossner, Ulrike. "Epitaxie des nitrures de gallium et d'aluminium sur silicium par jets moléculaires : caractérisation structurale et optique". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10181.
Texto completoLe, Louarn Arnaud. "Première étape de la croissance de GaN sur Si(111) : la nucléation d'AIN". Nice, 2006. http://www.theses.fr/2006NICE4016.
Texto completoThis work deals with the study of AlN nucleation on Si(111), the needed first stage for the growth of GaN on this substrate. Indeed, details of the realization of this stage, in particular the exposure sequence of Si(111) to Al and NH3, play a key role on final properties of GaN epitaxial layers. Based on an experimental setup coupling under ultra-high vacuum a scanning tunnelling microscope (STM) and a molecular beam epitaxy chamber, the purpose of this thesis was to identify and understand the mechanisms at work in AlN nucleation on Si(111). At first, we studied in details the different phases resulting of Al adsorption on Si(111) and we established a phase diagram of Al on Si(111). Subsequently, we identified the different types of surfaces which can result from Si(111) nitridation by NH3. Finally, it is demonstrated that NH3 exposure on an “Al on Si(111)” type surface leads to amorphous AlN formation while Al exposure on a Si(111) nitrided surface leads to epitaxial AlN formation by a reduction mechanism of the nitrided surface by Al
Vermaut, Philippe. "Structure de couches de composes semi-conducteurs iii-v a large bande interdite, nitrure de gallium ou d'aluminium, epitaxiees sur carbure de silicum, par microscopie electronique en transmission". Caen, 1997. http://www.theses.fr/1997CAEN2019.
Texto completoBassaler, Julien. "Propriétés de transport électronique et performances de HEMT à canal AlGaN pour l'électronique de puissance". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALY002.
Texto completoThe increasing demand for energy requires the development of new and suitable infrastructure, and the advancement of power electronics plays a pivotal role in addressing this need. Utilizing wide-bandgap semiconductors, due to their superior physical properties compared to silicon, emerges as the most promising avenue for designing high-performance components. While high electron mobility transistors (HEMT) based on GaN on silicon are already commercialized, their operating voltage is limited to 650 V, and they exhibit substantial performance degradation at elevated temperatures. HEMTs with AlGaN channels on silicon offer the potential to overcome these limitations while also offering lower production costs compared to SiC devices.Initially, an AlGaN/GaN/AlN heterostructure with an ultrathin channel was investigated. The objective was to enhance the breakdown voltage of the structure by minimizing the impact of the GaN channel. An analysis of the transport properties in this heterostructure using Hall effect measurements revealed relatively low electron mobility, coupled with anisotropy depending on the crystal orientation. This finding was substantiated by a structural analysis of the layer stack and the detection of electrically active defects, further supporting the conclusions drawn from the Hall effect measurements. Furthermore, charge carrier diffusion models indicated that interface roughness constituted the primary limiting mechanism for electron mobility.Subsequently, a detailed analysis of AlGaN channel heterostructures on silicon was conducted. Deep-level transient spectroscopy (DLTS) was used to study defects in the AlN layer epitaxially grown on the Si (111) substrate, which influences the overall quality of the heterostructure. Based on physical models, a study of the transport properties in these AlGaN channel heterostructures was then performed to determine the optimal Al compositions in the AlGaN layers. The impact of the aluminum fraction in the AlGaN channel on electronic mobility has been studied experimentally by Hall effect measurements. These experimental results were compared to charge carrier diffusion models and simulations to identify mobility-limiting factors. While alloy disorder was identified as the primary limiting mechanism in these structures, its impact was less pronounced than expected. Observations also indicated a less severe degradation of transport properties compared to GaN channel heterostructures, demonstrating superior thermal stability.Finally, the degradation of transistor performance with temperature was assessed based on the aluminum fraction in the AlGaN channel, substrate choice (Si and AlN), and gate structure. Increasing the aluminum fraction in the channel not only led to a reduction in on-state current but also reduced off-state leakage current, resulting in improved thermal stability of performance. The mechanisms responsible for gate leakage currents were identified by comparing models with experimental results, revealing that increasing the aluminum fraction effectively reduces the intensity of these mechanisms.In conclusion, AlGaN channel HEMTs exhibit superior thermal stability of on-state performance and a significant enhancement of off-state blocking characteristics. These devices thus hold excellent potential for high-voltage and high-temperature applications
Lecourt, François. "Hétérostructures AlGaN/GaN et InAlN/GaN pour la réalisation de HEMTs de puissance hyperfréquence en bande Ka". Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10123/document.
Texto completoGaN based High Electron Mobility Transistors (HEMTs) represent the most promising devices for microwave and millimeter-wave power applications. One key advantage of GaN is the superior physical properties such as a wide band gap (3.4eV) leading to high breakdown fields (>106 V/cm) and a high saturation electron drift velocity (>107 cm/s).In practice, physical limitations appear and avoid reaching expected performances in terms of frequency and microwave power. Short channel effects appear with the decrease of the transistor gate length. In large signal conditions, traps related to surface states of the semiconductor lead to drain current drops. In this work, we have studied short channel effects for transistors fabricated on AlGaN/GaN and InAlN/GaN heterostructures. Devices with 75nm-T-shaped-gates exhibit a current gain cut-off frequency and a power gain cutoff frequency of 113GHz and 200GHz respectively. To the author knowledge, these cut-off frequencies are the highest reported values for InAlN/GaN HEMTs grown on sapphire substrate. For AlGaN/GaN HEMTs, traps related to surface states were neutralized thanks to optimized passivation steps, permitting to mitigate DC to RF dispersion. It consists of a N2O pretreatment followed by a SiN/SiO2 bilayer deposition. From an appropriate transistor topology, microwave power measurements were performed at 40GHz. An output power density of 1.5W/mm, very closed to the state of the art, was measured for AlGaN/GaN HEMTs grown on Si(111) substrate. For InAlN/GaN HEMTs grown on sapphire substrate, state of the art output power density of 2W/mm was achieved with an associated power added efficiency of 13%
Zeng, Yijia. "Circuits photoniques III-nitrure avec des cristaux photoniques et des microdisques". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS070.
Texto completoNitride semiconductors are extremely interesting for integrated photonics on silicon. They have a large transparent window and dispose of non zero nonlinear susceptibilities which enable second and third order nonlinear experiments. In this context, this thesis has been devoted to integrated photonic circuits with microresonators such as photonic crystals and microdisks. The microcavity design and the fabrication process have been optimized in order to obtain a near infrared resonant mode with a quality factor up to 34000 for photonic crystals and 80000 for microdisks. I carried out harmonic conversion experiments such as second harmonic generation (SHG) and third harmonic generation (THG). With THG, by combining simply an optical objective and a CCD camera, I carried out near infrared photonic crystal modes imaging with a subwavelength spatial resolution (300 nm). I also did SHG imaging on microdisks with an optical excitation in resonance with the gallery mode for the pump laser. The last part of the work is dedicated to the demonstration of phase-matched SHG in microdisk photonic circuits between the TM-0-0-X and TM-0-2-2X modes by varying the microdisk diameter with a very small step (8 nm). These experiments have been done for resonant modes with quality factors around 10000.These demonstrations show the potential of III-nitride semiconductors for the realization of two dimensional optical circuits on silicon
Douvry, Yannick. "Étude de HEMTs AlGaN/GaN à grand développement pour la puissance hyperfréquence : conception et fabrication, caractérisation et fiabilité". Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10131/document.
Texto completoThis thesis describes the work performed within iemn laboratory. The design, fabrication and improvement of AlGaN/GaN HEMTs on Si(111) substrate is the main goal of this work, as these transistors are aimed to be integrated in devices for microwave power applications. In the first chapter, this manuscript shows the worthwhile physical, electrical and mechanical properties of the used materials. HEMT working principle is also exposed in this part. Next, every step of the HEMT manufacturing process are described in the second chapter, including several optimization studies. Particular attention will be paid to bottlenecks encountered during the device making. The third chapter presents the whole studies done on these electronic components. Each study relies on electrical characterization in DC, pulsed and microwave modes. The final chapter regards reliability studies of AlGaN/GaN HEMT on SiC substrate having the same topology. Defects induced during more than 3000h ageing in high operating temperature will be highlighted
Agboton, Alain. "Études théorique et expérimentale de dispositifs à hétérojonction AL(Ga, In)N/GaN pour des applications de puissances en bande Q (40.5 - 43.5GHz)". Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10047/document.
Texto completoThis PhD work consisted in a theoretical and experimental study of Al(In, Ga)N/GaN HEMTs (High Electron Mobility Transistor). It was carried out in Microwave Power Devices group at IEMN (Institut d’électronique de Microélectronique et de Nanotechnologie). The manuscript is shared in four chapters: The first chapter deals with the main physical properties of nitride materials. It presents the main specificities of Al(In,Ga)N/GaN HEMTs and exposes through the state of art, their performance in terms of microwave power. The second part describes Schottky and Ohmic contacts analysis based in particular to cryogenic temperatures measurement in order to identify the different conduction modes occurring within. In the third chapters, we studied static and microwave characteristics of Al(In,Ga)N/GaN HEMTs manufactured for the purposes of this thesis. They are used to examine the frequency performance of these transistors through an original study based on transit time. And finally, the last chapter explains the effects of traps interfaces that constitute one of the fundamental limitations inherent to this type of components. They are characterized and quantified by several defects spectroscopy methods such as subthreshold slope method, conductance method, high frequency - low frequency method
Ben, ammar Hichem. "Investigation of ternary ΑlΙnΝ and quaternary ΑlGaΙnΝ alloys for high electron mobility transistors by transmission electron microscopy". Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC241/document.
Texto completoGroup III-Nitrides and their alloys exhibit outstanding properties and are being extensively investigated since the 90’s. In comparison to other III-V semiconductors, III-nitrides (AlGaN, InGaN, and AlInN) cover from deep ultraviolet (UV) to near infrared (IR) across the visible range of wavelengths. Thus, they are suitable for numerous applications both in civilian and military fields showing higher performances. Moreover, the quaternary alloy AlGaInN shows versatile properties as it can grow either lattice or polarization or bandgap matched to GaN. Alongside to AlInN, these two alloys are expected to replace conventional AlGaN/GaN High Electron Mobility Transistors (HEMT) barriers as higher performances have been theoretically demonstrated.In this work, we have studied AlInN and AlGaInN grown by metal organic vapor phase epitaxy (MOVPE) using mainly TEM. The aim was to characterize defects and the MOVPE growth alloying process. In this instance, the gallium incorporation in the barrier due to the geometry of the growth chamber leading to a quaternary alloy was studied. The control of the gallium content is achieved by a cleaning process between runs or by the growth condition. Defects were then differentiated as extrinsic and intrinsic. In this way, dislocations and inversion domains from the GaN buffer layer generate extrinsic defects, while, pinhole not connected to dislocations and individual hillocks responsible of surface roughening are termed as intrinsic. The origins of the latter defects depend strongly on the physical mismatches of the end-binary compound. These systematic degradations happen also with optimized growth conditions as soon as the nominal composition is changed and/or the thickness is increased.Our work proposes different mechanisms to explain defects generation processes which constitutes a forward step for higher quality HEMTs