Дисертації з теми "Canaux à haute mobilité"
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Shchepetov, Andrey. "Étude et fabrication de dispositifs nanométriques pour applications THz." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10069/document.
The emergent applications in the Terahertz (THz) frequencies range stimulate the development of active and passive rapid devices as much as of emitters and detectors working in this domain. Actually existent devices do not respond to all industry needs because of too high consumption, size and cost, and other inconvenient. A solution for realisation of emitters and detectors could come from plasma-wave transistor that we studied. These devices are based on 1I1-V HEMT and utilised a particular behaviour of electronic transport. Measurements have shown the possibility of emission and detection of radiation at about 1 THz. From the other hand it is necessary to realize electronic active devices (transistors) able to operate near the THz range. This is necessary for realisation of rapid integrated circuits such as amplifiers, mixers and so on. To do this we have chosen to study two kinds of double-gate transistors. Measurements have shown the increasing of static and dynamic performances (maximum drain current and drain current saturation, efficiency of charge control, transconductance, output conductance, operation frequencies). Besides, the same performances can be obtained at lower consumption. Simulations show that performances could be improved even more
Hutin, Louis. "Etude des transistors MOSFET à barrière Schottky, à canal Silicium et Germanium sur couches minces." Grenoble INPG, 2010. http://www.theses.fr/2010INPG0159.
Until the early 2000’s Dennard’s scaling rules at the transistor level have enabled to achieve a performance gain while still preserving the basic structure of the MOSFET building block from one generation to the next. However, this conservative approach has already reached its limits as shown by the introduction of channel stressors for the sub-130 nm technological nodes, and later high-k/metal gate stacks for the sub-65 nm nodes. Despite the introduction of high-k gate dielectrics, constraints in terms of gate leakage and reliability have been delaying the diminution of the equivalent oxide thickness (EOT). Concurrently, lowering the supply voltage (VDD) has become a critical necessity to reduce both the active and passive power density in integrated circuits. Hence the challenge: how to keep decreasing both gate length and supply voltage faster than the EOT without losing in terms of ON-state/OFF-state performance trade-off? Several solutions can be proposed aiming at solving this conundrum for nanoscale transistors, with architectures in rupture with the plain old Silicon-based MOSFET with doped Source and Drain invented in 1960. One approach consists in achieving an ION increase while keeping IOFF (and Vth) mostly unchanged. Specifically, two options are considered in detail in this manuscript through a review of their respective historical motivations, state-of-the-art results as well as remaining fundamental (and technological) challenges: i/ the reduction of the extrinsic parasitic resistance through the implementation of metallic Source and Drain (Schottky Barrier FET architecture); ii/ the reduction of the intrinsic channel resistance through the implementation of Germanium-based mobility boosters (Ge CMOS, compressively-strained SiGe channels, n-sSi/p-sSiGe Dual Channel co-integration). In particular, we study the case of thin films on insulator (SOI, SiGeOI, GeOI substrates), a choice justified by: the preservation of the electrostatic integrity for the targeted sub-22nm nodes; the limitation of ambipolar leakage in SBFETs; the limitation of junction leakage in (low-bandgap) Ge-based FETs. Finally, we show why, and under which conditions the association of the SBFET architecture with a Ge-based channel could be potentially advantageous with respect to conventional Si CMOS
Zimmermann, Katrin. "Contacts ponctuels quantiques dans le graphène de haute mobilité." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY008/document.
In the quantum Hall regime, the charge carriers are conducted within one-dimensional channels propagating at the edge of a two-dimensional electron gas (2DEG). A quantum point contact (QPC) – a narrow constriction confining spatially electron transport – can control the transmission of these quantum Hall edge channels. In conventional 2DEG systems, a negative voltage applied on the electrostatic split gates depletes locally the electrons underneath them forcing the electrons to pass through the constriction. In contrast, due to the absence of a band gap in graphene, a negative gate voltage induces a continuous shift of the doping from electrons to holes. In the quantum Hall regime, electron and hole edge channels propagate along the pn-interface in the same direction while inelastic scattering induces charge transfer and mixing between them.In this PhD thesis, we have fabricated ballistic graphene devices made by van der Waals stacking of hBN/Gr/hBN heterostructures, and equipped with split gates forming a quantum point contact (QPC) constriction. We have studied the effect of the QPC on the propagation of integer and fractional quantum Hall edge channels and the mixing among them. In the quantum Hall regime, we demonstrate that the integer and fractional quantum Hall edge channels can be controlled and selectively transmitted by the QPC. Due to the high mobility of our devices and the resultant full lifting of the degeneracies of the Landau levels in strong magnetic field, equilibration at the pn-interface is restricted to sublevels of identical spins of the N=0 Landau level.A QPC in the quantum Hall regime offers also an ideal system to study the tunnelling of charge carriers between counter-propagating fractional edge channels of highly correlated, one-dimensional fermions described by the theory of Tomonaga-Luttinger. We study the tunnelling between fractional quantum Hall edge channels in our QPC device in graphene and focus on the 7/3-fractional state to explore the temperature dependence of tunnelling characteristics
Lesic-Arsic, Biljana. "Mobilité de l'îlot de haute pathogénicité de Yersinia pseudotuberculosis." Paris 6, 2004. http://www.theses.fr/2004PA066204.
Sallé, Damien. "Conception optimale d'instruments robotisés à haute mobilité pour la chirurgie mini-invasive." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00762265.
Weber, Olivier. "Etude, fabrication et propriétés de transport de transistors CMOS associant un diélectrique haute permittivité et un canal de conduction haute mobilité." Lyon, INSA, 2005. http://theses.insa-lyon.fr/publication/2005ISAL0127/these.pdf.
CMOS scaling allows an improvement of the performance, the integration density and the price of electronic circuits. Several breakthroughs, concerning the MOSFET architecture and materials must be added to push the transistor at his atomic scale limit. The replacement of the gate silicon oxide by a high-k dielectric is promising to improve the oxide thickness/gate leakage current trade-off. A high mobility channel provides a carrier velocity improvement and thus, an increase of the speed/active power ratio in the circuits. This work concerns the study, the fabrication and the transport properties of CMOS transistors with both of these new technological options. It includes several different transistors with a TiN/HfO2 gate stack: strained Si channel nMOSFETs, strained SiGe(:C) or Ge pMOSFETs and a new pMOS architecture with a (111) surface oriented channel. High mobility enhancements compared to the HfO2/Si reference, up to +800% for the hole mobility in strained Ge, are reported in addition to the high-k dielectric characteristic: a 4 decades gate leakage reduction compared to the silicon oxide. Our in-depth electrical characterization demonstrates that the dielectric/channel interface optimization is crucial to obtain high mobility gains. Transistors characteristics are presented and discussed down to 50nm gate length. Finally, the mobility degradation with a TiN/HfO2 gate stack, which constitutes a serious issue for the high-k/metal gate stack emergence, is analysed and the mobility scattering mechanisms are determined experimentally
Mouis, Mireille. "Étude théorique du fonctionnement des dispositifs à effet de champ haute mobilité à hétérojonction." Paris 11, 1988. http://www.theses.fr/1988PA112053.
Sabatini, Giulio. "Étude Monte Carlo de matériaux et composants électroniques à haute mobilité pour les applications TeraHertz." Montpellier 2, 2009. http://www.theses.fr/2009MON20170.
TeraHertz radiation belongs to a part of the electromagnetic spectrum which is not mastered at present. Nevertheless, it is characterized by physical properties which are of interest for different domains: spectroscopy, wireless telecommunications, imaging, security, etc. To understand the behavior of the devices working in this frequency range, a thorough knowledge of the transport properties of the materials which constitute them is necessary. The Monte Carlo method was employed in this thesis to study the physical phenomena present in InGaAs and InAs, which can be exploited for the development of new THz sources or detectors. We thus undertook a detailed study of the static and dynamic transport of electrons and holes in bulk InGaAs, possible component of the HEMT channel (High Electron Mobility Transistor), and in bulk InAs, considering its even better transport properties. We have also directed our research on their high frequency behavior and on various parameters associated with fluctuations. Then, we have analyzed the properties of electronic transport of InAs nanometric diodes, which can be related to the collector zone of a QHET (Quantum Hot Electron Transistor). The objective of part work is to characterize the various modes of transport, their dependences as functions of doping and the type of injection, before studying the ballistic effects present in this type of structures
Besseron, Guillaume. "Contrôle de la stabilité des systèmes locomoteurs à haute mobilité évoluant sur des terrains accidentés." Paris 6, 2008. http://www.theses.fr/2008PA066545.
The research presented in this report deals with the improvement of the autonomous mobile robots locomotion capacities on natural terrains. In this work, an adaptive locomotion system with a redundant wheel-legged hybrid kinematic structure was designed and realized. Indeed, this kind of mechanism has the capacities to adapt itself to uneven grounds. The autonomy of the robot is linked to both its kinematics capacities of adaptation and to its energetic dependence. When the vehicle reconfigurates itself, while moving on an uneven field, a big amount of energy is needed by its internal mobilities. That is why, a posture control aiming at minimizing the number of reconfigurations of the robot has been developed. The goal is to modify the posture of th erobot only when its integrity, i. E. Its stability is jeopardized. The use of a posture control command law based on the potential fields allow to obtain the wanted behaviour of the robot. The command of the movements of the robot relies on the inverse of the differential kinematic model. In this model, the different terms are split, ensuring so both the trajectory and the change of the posture of th erobot. The robot reconfigurates itself when its stability reached a pre-determined value. The principle of this control is validated through numeric simulations representing the dynamic behavoiur of the robot moving on a natural terrain
Najjar, Atallah Leïla. "Estimation haute résolution des directions d'arrivée et des retards temporels de propagation dans un contexte de radio communications." Paris 11, 2002. http://www.theses.fr/2002PA112095.
In this PhD, array processing is used for the estimation of propagation parameters in radio communication channels. A high resolution approach based on a subspace formulation is adopted for the estimation of Directions Of Arrival (DOA) and time delays corresponding to the co-channel users. The estimated parameterized channel is expected to enhance the performances at the reception. These parameters also serve to localize the users which can be exploited in a spatial diversity multiple access scheme. An adaptive approach is firstly used for the source subspace tracking and the algorithm PASTd is adapted through two new versions to handle coherent arrivals that frequently occur in multipath scenario. After this, a supervised approach using known signals is considered for the DOA or delays and DOA estimation. A new method called PADEC is proposed to estimate and to associate DOA to users. It consists of a parallel processing per tap delay in the impulse response of each user channel. In the spatio-temporal frame, two supervised algorithms are proposed. They sequentially process delays then DOA of each user paths. In the supervised approach, unstructured estimates of the impulse response of SIMO channels are firstly recovered by matched filtering or via the optimization of an MMSE criterion. The use of known signals is shown to relax the constraint on the antenna size, through processing only a subset of paths at a time. Also, an important reduction in the computational load is obtained. The estimation performance is enhanced in comparison to blind approach and the parameters and users are naturally gathered
Hamady, Saleem. "Nouveaux concepts de transistors de puissance à haute mobilité électronique (HEMT) en nitrure de gallium (GaN)." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2635/.
AlGaN/GaN HEMTs are very promising candidates for high frequency applications with high power and low noise. While switching applications strongly demand normally-off operation, conventional HEMTs attain a channel populated with electrons at zero gate voltage making them normally-on. For the sake of achieving normally-off HEMTs, several structures have been proposed such as recessed gate structures, fluorine ion treatment, pn junction gate structures, thin AlGaN barrier and Gate Injection transistor. The effectiveness of the agent used to obtain normally-off, whether it is recessing the gate, introducing a cap layer or implanting fluorine, increases as the agent comes closer to the AlGaN/GaN interface. Unfortunately, when introducing a cap layer or recessing the gate, coming closer to the interface means decreasing the barrier thickness, which strongly affects the density of the 2DEG. In the case of fluorine implantation, getting closer will increase the probability of fluorine ions getting into the channel and hence degrade the mobility of the 2DEG. In this work we propose two new concepts to achieve normally-off operation. We suggest the introduction of negative fluorine ions on one hand or a p-GaN region on the other hand, below the channel, under the AlGaN/GaN interface and away from high current density regions. After calibrating the simulator using experimental results from a normally-on HEMT device, we have shown that our proposed structures are more effective: the concentration required to achieve normally-off operation is lower than in the other existing solutions and the confinement of the two dimensional electron gas below the gate is better. The proposed ideas were also applied to Metal Insulator Semiconductor HEMT (MIS-HEMT) and Gate Injection Transistor (GIT), giving rise to a normally-off HEMT with high controllable threshold voltage
Juery, Lucie. "Communication térahertz sans fil à haut débit avec un transistor à haute mobilité électronique comme détecteur." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20115/document.
One of the major objectives of communication systems is the ability to transmit data at the highest possible rates. The ever-growing user demand for wireless communication already exceeds capacities of present networks.In order to solve this problem, we introduce communication systems based on terahertz (THz) high-frequency carriers, whose frequencies are high enough to support data-rates higher than a hundred of gigahertz. In particular, we are interested in the development and the integration of a high data-rate detector intended for THz wireless communication.We use a GaAs High-electron-mobility transistor (HEMT) as detector. Unlike existing detectors such as Schottky diodes, the transistor studied in this thesis offers advantages in terms of cost, compactness and performances. In particular, the output impedance is more suitable for high data-rate integrated circuits whose input impedance is 50 Ohm. We present the characterization of the detector in terms of sensitivity and modulation bandwidth, demonstrating for the first time its ability to be used for high data-rate communications. The transistor's integration, essential for real communications, is detailed.A wireless THz communication is demonstrated around 0.200 THz and 0.309 THz. For the first time, an error-free transmission at data-rates up to 8.2 Gbps is demonstrated, using a GaAs plasma wave HEMT and a 0.309 THz carrier frequency. Finally, we present new transistors with integrated antenna, allowing communications at higher data-rates and with a longer range, thanks to a better sensitivity
Kunc, Jan. "Gaz électronique bidimensionnel de haute mobilité dans des puits quantiques de CdTe : études en champ magnétique intense." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00586639.
Billaud, Mathilde. "Intégration de semi-conducteurs III-V sur substrat Silicium pour les transistors n-MOSFET à haute mobilité." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT010/document.
The replacement of the silicon channel by III-V materials is investigated to increase the electron mobility in the channel and reduce the power consumption. In order to decrease the cost and to take advantage of the microelectronic silicon platform, III-V transistors must be built on Silicon substrates. However, the lattice parameter mismatch between Silicon and the III-V layers leads to a high defects density in the channel and reduces the carrier mobility. This thesis aims to realize III-V transistors on silicon substrate in the CEA-Leti microelectronic clean room. In the frame of this PhD, two integration process are elaborated to realize In0,53Ga0,47As tri-gate transistors on silicon: the molecular bonding of an InGaAs layer grown on a InP substrate, and the direct epitaxy of InGaAs on a silicon substrate. The fabrication steps for InGaAs transistors were developed, taking into account the clean room contamination restriction. InGaAs surface treatment and high-permittivity dielectric deposition by ALD are studied in order to reduce the density of interface states (Dit) and to optimize the EOT. XPS analysis and C(V) measurement are performed at the scale of a 300mm Silicon substrate
Sars, Vincent de. "Conception et commande d' une micro-structure active à haute mobilité : application à la chirurgie mini-invasive." Paris 6, 2005. http://www.theses.fr/2005PA066249.
Aupetit-Berthelemot, Christelle. "Etude des effets parasites du transistor à haute mobilité électronique (HEMT) sur InP pour applications micro-optoélectroniques." Limoges, 1998. http://www.theses.fr/1998LIMO0042.
Joblot, Sylvain. "Croissance d'hétérostructures à bases GaN sur substrat de silicium orienté (001) : application aux transistors à haute mobilité d'électrons." Nice, 2007. http://www.theses.fr/2007NICE4102.
GaN based devices are usually grown on silicon carbide (SiC), sapphire (Al2O3), and silicon substrates. Silicon substrate presents a thermal conductivity close to GaN one and advantages in terms of availability, size and cost. The (111) orientation with a 6-fold symmetry is preferred for the GaN-based heterostructures on silicon substrate. Nevertheless, in the aim of integrating GaN based devices into MOS (Metal-Oxyde-Semiconductor) based technology, the use of (001) and (110) orientations, with a square and quadratic surface symmetry, respectively, is preferred. This is why, in this thesis, we have developed the growth process of (Al,Ga)N structures on the (001) orientation. We have shown that the use of misoriented substrates towards the [110] direction with specific surface treatment and growth process have permitted to obtain a single orientation wurtzite GaN layers. They were grown by molecular beam epitaxy (MBE) and metal organic vapour phase epitaxy (MOVPE). We have also achieved, by the insertion of optimized AlN/GaN stack layers, crack-free AlGaN/GaN HEMT structures and devices with properties close to those obtained on the (111) orientation
Ouro, Bodi Dissadama. "Etude des effets parasites du transistor à haute mobilité électronique : corrélation avec les aspects technologiques et la fiabilité." Bordeaux 1, 1992. http://www.theses.fr/1992BOR10643.
Bouallegue, Kaïs. "Contribution à la radio intelligente à forte mobilité : adaptation spectrale et allocation dynamique des ressources." Thesis, Valenciennes, 2017. http://www.theses.fr/2017VALE0023.
The main objectives of railway operators are to increase safety, reduce operating and maintenance costs, increase attractiveness and profit by offering new services to customers. These objectives will be achieved through a huge increase of data fluxes between existing infrastructure and the technologies currently used on the train. Spectral efficiency, optimization of radio resources, interoperability and reliability of communications are major elements for railway applications. These constraints and the sporadic use of available frequency bands have gave rise to cognitive radio. Cognitive radio is an emerging technology that improves the performance of existing radio systems by integrating artificial intelligence with software radio. A cognitive radio system is defined by its ability to be aware of its radio environment. Indeed, to optimize as much as possible the available spectral opportunities, the cognitive radio device must be able to transmit on free bands while performing a spectrum sensing to not interfere with users having priority on the band and to detect other vacant frequencies. As part of this thesis, we propose to focus on the problem of spectrum detection in a highly mobile environment. Some constraints should be considered, such as speed. Added to this, there are regulatory constraints on detection criteria, such as the IEEE 802.22 WRAN standard, which stipulates that detection of a priority user must be performed at -21 dB within a period of 2 seconds. The objective is therefore to design an intelligent radio terminal in the physical and regulatory conditions of transmission in a railway environment
Joblot, Sylvain, and S. Joblot. "Croissance d'hétérostructures à base de GaN sur substrat de silicium orienté (001): applications aux transistors à haute mobilité d'électrons." Phd thesis, Université de Nice Sophia-Antipolis, 2007. http://tel.archives-ouvertes.fr/tel-00396384.
DESGREZ, Simon. "Conception de diviseurs de fréquence analogiques réalisés en technologie monolithique à base de transistors pseudomorphiques à haute mobilité électronique." Phd thesis, Université Paul Sabatier - Toulouse III, 1997. http://tel.archives-ouvertes.fr/tel-00010077.
Belhadj, Abdenabi. "Etude des effets parasites et des mécanismes de dégradation du transistor à effet de champ à haute mobilité électronique." Limoges, 1990. http://www.theses.fr/1990LIMO0092.
Desgrez, Simon. "Conception de diviseurs de fréquence analogiques réalisés en technologie monomithique à base de transistors pseudomorphiques à haute mobilité électronique." Toulouse 3, 1997. http://www.theses.fr/1997TOU30138.
Combal, Cécile. "Mobilité, adaptation, reconversion : trajectoires croisées de territoires désindustrialisés, basse Romanche, moyenne Maurienne, haute Durance (Fin XIXe siècle - XXIe siècle)." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALH001.
This PhD dissertation seeks to understand the impact of de-industrialisation in alpine aluminium territories through changes in demographic and land-use on the long-term. More specifically we seek to understand how successive processes of industrialisation/de-industrialisation followed by tourism reconversion, were experienced ; constructed ; implemented ; and what their impacts on local communities were. First we review the key features of industrial development in the Moyenne Maurienne, the Basse romanche and the Haute Durance. We explore the arrival of external actors and the implementation of corporate social policies. Next we lay the framework to understand how the process of de-industrialisation is constructed. To that end we go back and forth between the Maurienne factories (Saint-Jean, la Saussaz, la Praz), the decision-making authorities and the relevant negotiating bodies. This allows us to focus on two case-studies : the closing of l’Argentière in exchange for social and economic benefits, and the closing of Rioupéroux without compensation. Finally, following the end of industrial activity, we seek to analyse the implementation of tourism reconversion policies. In each territory, they appear to be of varying intensity, to operate within different time frames and to differ in content. The dissertation concludes by comparing the lived experiences of the above communities in relation to these processes extending throughout the 20th century and beyond. It seeks to question the relation between these territoires and the trope of modernity. We find that in each case, the communities are compelled to abide by recurrent schemes of outdated development models imposed by the maket, scientific communities and public authorities
Curutchet, Arnaud. "Etude du bruit aux basses fréquences dans les transistors à haute mobilité électronique à base de Nitrure de Gallium." Bordeaux 1, 2005. http://www.theses.fr/2005BOR13025.
Lazar, Oana. "Analyse et modélisation des mécanismes de dégradation de grille des transistors à haute mobilité électronique (HEMT) de type AlGaN/GaN." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30349.
The recent introduction of wide bandgap materials revolutionizes the RF field of power modules. Due to the high-power levels for telecommunication frequency bands, GaN technologies represent nowadays a major integrated alternative which is believed to gradually replace III-V GaAs technologies (SSPA amplifiers), and even to compete with wave tubes technologies (TWTA amplifiers). Development of GaN material in the last decade is proved by the market release of several GaN versions, such as GH50 and GH25 from UMS. These batches are issued from technological versions that feature delicate mastering of the various degradation mechanisms induced by thermal, electrical or RF stress: IDQ tests, HTRB, HTOL, etc. The complexity of the involved processes (thermal, piezoelectric, ...) often makes difficult the analysis of mechanisms that caused the identified damage, and it is necessary to establish a rigorous multi-physics study in order to identify the sensitive electrical and technological parameters. The analysis associated with this work are based on cross non-invasive measurements, in transient and spectral domains. This purely metrological approach reaches its limits insofar as the crossing between non-destructive and destructive data cannot be applied to the same components, nor before/after application of a stress. Therefore, the objective of this thesis consists in giving some key indicators which can be useful when converging from these industrial and under development technologies to more robust and more efficient processes. In this way, we will be able to improve also our knowledge concerning the multitude and poorly controlled degradation kinetics. The identified technologies for technological support are the qualified or under development dies, issued from UMS: GH50 and GH25. On each of these versions, we can identify limiting mechanisms both at instant t0, and during evolution under stress. From technology maturation point of view, we can identify sensitive areas that limit operational security zones of the devices, and enable technologists to improve the technological processes. In addition, this dual input technology will allow us to implement the working methods that we have developed in this thesis. Transient techniques (non-invasive), such as I-V-T DC and pulsed measurements, will be analyzed and correlated with low frequency noise measurements (in frequency domain), on witness (virgin) components. By the means of electrical measurements, gate lag and lag drain phenomena can be identified, which are the main limiting factors for power applications and pulsed radar applications. Low frequency noise characterizations are recognized as reliable indicators for the analysis of defects in different areas (active or not) of the devices under test. The analysis and the location of these noise sources is fundamental for the next step. Then, these associated measurements and modeling techniques are used to study stressed (aged) components. On one hand, the evolution of electric linearity characteristics allows the comprehension of the stress consequences on the operational behavior of the device. On the other hand, the evolution of noise spectra allows the access to a corpuscular view of the defect that initiates the lowering of the transistor performances. These evolutions constitute a reliable database, which can be used in order to better understand the immediate and slow changes in reversible and irreversible degradation process of the devices under test: modification of the Schottky diode, presence of acceptors traps, mobile and fixed charges, slow and fast traps phenomena
Ekogo, Thierry-Blanchard. "Préparation des lasers performants pour la spectroscopie haute résolution de l'ion calcium et du refroidissement sympathique de molécules ioniques." Aix-Marseille 1, 2006. http://www.theses.fr/2006AIX11035.
Favier, Elsa. "Énarques et femmes : le genre dans la haute fonction publique." Thesis, Paris, EHESS, 2020. http://www.theses.fr/2020EHES0153.
Between 2001 and 2017 the share of women in the senior civil service increased from 12% to 40%. The feminization of the administrative elites, and more broadly of places of power, has been a major social change of the past decades. While the mechanisms of women's exclusion are now well understood, feminization has been under-investigated. This is the topic of this dissertation, which is based on an ethnographic investigation and a statistical analysis on women who graduated from the ENA. How did it become possible for women to reach positions of power within the state that were historically monopolized by men? Who are the women who can access these professional positions at the top of the social hierarchy? How do they appropriate prestigious masculine roles? To address these questions, the dissertation uses two main analytical frameworks: an intersectional approach that articulates both class and gender relationships; and a sociology of family, school and professional socialization. The thesis sheds new light on the sociology of administrative elites, the sociology of the upper classes, and gender dynamics in places of power
Henry, Guillaume. "Dimensionnement et étude expérimentale d’un vaporiseur à milli-canaux." Thesis, Université de Lorraine, 2020. http://www.theses.fr/2020LORR0130.
The ever-growing awareness of the impact of human activities on the environment makes industries find environmentally friendly alternatives. In the automotive sector, the development of less polluting cars using hydrogen as fuel is an example. To successfully promote this type of vehicles to people, the providing network of hydrogen has to be set up. To tackle the challenge of this deployment, Air Liquide, through the FAIR project (Additive manufacturing for the intensification of reactors), aims to intensify the Steam Methane Reforming process in order to develop small mobile hydrogen production unit. Inside this process, a particular step, the water vaporisation, has to be intensified. To study this intensification, an experimental test bench and a vaporisation module are sized, assembled and instrumented in the Reactions and Chemical Engineering Laboratory (LRGP) in Nancy. The test bench uses a hot oil convection to vaporise the water. The vaporisation module, designed as a milli-structured plate heat-exchanger, has a window enabling the visualisation and the recording of the boiling water hydrodynamics with a high-speed camera. Four milli-structured plates are tested: two of them have 10 semi-circular straight channels either mechanically engraved of made by additive manufacturing, the third plate has various shapes of engraved channels and finally the fourth plate has 7 engraved straight channels with triangular cavities. An innovative method for the post-treatment of high-speed videos is developed in order to produce Spatio-Temporal Diagrams (DST) showing the spatial evolution of liquid-vapor interfaces by the time inside a channel. The exploitation of this new tool enables the determination and the description of boiling phenomena (spontaneous bubble nucleation, liquid oscillations), the understanding of the boiling events chronology and the characterisation of flow regimes (bubbly, slug, churn, annular flow and dry out of the channel). Moreover, a quantitative exploitation of the DST is possible such as the local vapor quality needed for the drawing of flow regime map. Thanks to the measurement of various operating data on the test bench, the characterisation of the heat losses is done in order to assess the vapor quality of the water flow outgoing the vaporiser by a heat balance. The two-phase heat-transfer coefficients are also assessed. Finally, a methodology of milli-structured vaporiser made by additive manufacturing pre-sizing is put forward. It is based on two case-study on the intensification of water vaporisation in a small mobile hydrogen production unit and in a standard SMR process
Baron, Nicolas. "Optimisation de l'épitaxie sous jets moléculaires d'hétérostructures à base de GaN : application aux transistors à haute mobilité d'électrons sur substrat silicium." Phd thesis, Université de Nice Sophia-Antipolis, 2009. http://tel.archives-ouvertes.fr/tel-00451937.
Cerba, Tiphaine. "Intégration de matériaux III-V à base d’arséniures et d’antimoniures pour la réalisation de transistors TriGate et NW à haute mobilité." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT082/document.
The transistors’s miniaturization evolved through technological nodes with the successive introduction of new materials (high k) and new architectures (FinFET, NWFET). For the advanced technological nodes, a new break in material is considered to replace the silicon of the conduction channel with high mobility materials (2D, III-V). III-V materials are good candidates to address a solution to this problem thanks to their n-type (InGaAs, InAs, InSb)or p-type (GaSb) high mobility. During this PhD, a particular interest has been given to the InAs/GaSb pair of materials, which offers an additional advantage by its lattice parameter agreement making it possible to access n-type and p-type high mobility layers in the same structure.Nowadays, the growth of III-V materials directly on (001) -Si 300mm substrates is a challenge of major interest to develop industrial platforms compatible processes. These growths remain complex because of defects formation: antiphase boundaries, dislocations, cracks; generated respectively by the difference in polarity, lattice mismatch and difference in thermal expansion coefficient, between the silicon and III-V materials. In this PhD, we present a first demonstration of GaSb growth by MOVPE directly on nominal (001) -Si 300mm substrate compatible with industrial platforms. The GaSb layers have a sub-1nm surface roughness, and an equal to MBE state of the art crystalline quality. The growth of a InAs layer then allowed the realization of an InAs FinFET multi-channel demonstrator. The latter was developed via a high resolution alternative lithographic technique based on the use of block copolymer. This simple method for producing conduction channels makes it possible to access a high density of wires, of small dimensions, and in only five manufacturingsteps
Belache, Areski. "Etude des propriétés physiques et performances potentielles en basses températures du transistor à effet de champ à haute mobilité électronique AlGaAs/GaAs." Lille 1, 1989. http://www.theses.fr/1989LIL10037.
Drouot, Virginie. "Elaboration par épitaxie par jets moléculaires et caractérisation d'hétérostructures pseudomorphiques Ga1-xInxAs/AlInAs sur InP pour transistors à haute mobilité d'électron (HEMT)." Ecully, Ecole centrale de Lyon, 1993. http://www.theses.fr/1993ECDL0035.
Le, Coustre Gwenael. "Contribution au développement d’une filière de transistor de forte puissance à base de technologie HEMT GaN pour applications télécoms et radar." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10118/document.
The use of wide-gap materials is a solution for the generation of power at microwaves frequencies, and HEMTs processed on Gallium Nitride currently present the best world performances in this domain. However, the designers need to know their electrical limitations. More precisely, they need to know their electric characteristics in their areas of operation, and also to have at their disposal mathematical model for CAD tools. In a first part, electrical characterizations were carried out in order to determine the impact of the physical limitations on the generation of power: breakdown voltage, gate-lag and drain-lag related trapping effects, thermal resistance of interface in the epitaxy…In the second part of this thesis, the design and the realization of first demonstrators were carried out in band S (3 GHz). These demonstrators allow a first characterization of the power devices with several millimeters of gate development processed in the laboratory. These characterizations are not to be done on wafer, for thermal reasons as well as electrical connections issues. They allow determining the optimum impedances for power and/or PAE very close to the DUT terminals, i.e. with a good precision. These impedances will be used for the design of the amplifiers, presented in the first part. First, an analysis of the impact of the input and output loads on the reachable bandwidth has been done. Secondly, a presentation of the design and the characterization of 25W and 100W class HPA is presented. The measurements of these latter amplifiers have shown output power higher than 120W, with a power added efficiency and an associated power gain respectively of 40% and 22 dB. These results, in terms of power, PAE and temperature, make us very confident for the future design of GaN HEMTs based amplifiers in S-band for radar applications
Malbert, Nathalie. "Développement d'une méthodologie et des techniques d'analyse associées permettant l'évaluation de la qualité et de la fiabilité des transistors à haute mobilité électronique." Bordeaux 1, 1996. http://www.theses.fr/1996BOR10506.
Braga, A. Judson. "Sondage de Canal SIMO à l'intérieur des bâtiments et formation de faisceaux numérique utilisant des techniques de traitement de signal à haute résolution et corrélateurs cinq-ports." Phd thesis, Télécom ParisTech, 2006. http://pastel.archives-ouvertes.fr/pastel-00002667.
Souillard, Chloé. "Impact de la microstructure chimique sur la mobilité moléculaire des élastomères en régime linéaire." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0058/document.
This work deals with the study of the molecular mobility in rubbers used for pneumatic applications, namely, polybutadiene (PB) and styrene butadiene rubber (SBR). They exhibit relaxation processes, which are in fact responsible for their main behaviors (adhesion, energy consumption, etc.). From mechanical and dielectric spectroscopy data, we tried to understand the molecular origins of these elastomers relaxation, but, also the role of their chemical microstructure on molecular mobility. We studied materials with different chemicals microstructures, i.e., with different butadiene 1,2 vinyl, butadiene 1,4 cis and 1,4 trans and styrene (for SBR only) ratio. The impact of microstructure modification was also studied with addition of diluents, which modifies the molecular mobility. Experimental temperature range was between 90 and 350K, so all relaxations present in polymer can be studied: the β relaxation at low temperature, the α relaxation for temperature near Tg, the chain-end relaxation at higher temperature and free chain reptation phenomenon at Tg+90K. Mechanical (10-4 Hz to 1 Hz) and dielectric spectroscopy (0,1 Hz to 106 Hz) allow obtaining large frequency range. Besides that, mechanical and dielectric induced stresses are different so both methods are complementary. The β relaxation exhibits two main contributions, so-called here high and low temperature contributions. The use of modeling permits to show that movements responsible for the high temperature contribution are those of butadiene 1,2 vinyl, whereas butadiene 1,4 cis and trans are responsible from low temperature contribution. Perez model used for studying the α relaxation shows that 1,2 vinyl also impact it. High temperature contribution of the β relaxation disappears after dilution by polar oil. Decreasing the crosslinking density in polymers results in the increase of average chain-end length. These chain-ends relax, and it has been found that their relaxation processes follow the chain-end retraction model developed by Curro from Pearson and Helfand works. On the contrary, free chains motions, when introduced in the already cross-linked polymer network follow De Gennes-Doi-Edwards reptation theory
Berry, Olivier. "Contribution à l'Etude d'un Onduleur Haute Température à base de JFET en carbure de silicium." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0125/document.
The aircraft must become more electric in order to be greener. But in this transition to the more electric aircraft, some actuators and their associated electronics are facing a technological barrier related to the high temperature (200°C). In this context, this thesis presents works that contributes to raising the technological barrier. We showed that the power electronic converter, called inverter, was designed to meet our needs with the more reliable and mature component, the silicon carbide (or SiC) JFET with two-channel manufactured by SICED INFINEON. To better understand the way to work of the SiC JFET with two channels and subsequently validate its model, we performed electrical characterization of its static and dynamic behavior on a wide temperature range from -40°C to +180°C. We showed and described precisely, especially at 27°C, the phases of JFET switching; we highlighted the important role of capacitive coupling (Cgd, Cds et Cgs). A model representing its static and dynamic behavior was presented and validated at 27°C. We then minimized the effects of the Drain-to-Gate Interaction DGI due to Cgd concerning the JFET operating in freewheeling mode (punch-through phenomenon at turn-on and a risk of a leg short-circuit at turn-off have to be considered). To do this, we studied and compared three specific gate circuits, and we showed the role of the gate impedance (RG, lG) to minimize the DGI and optimize the specific gate circuits. Finally, we presented the issue related to the stability of the DC bus at high temperature (200°C) and high voltage (540V). A simple and effectiveness solution of stabilizing the DC bus was presented
Herbecq, Nicolas. "Conception et réalisation de composants GaN innovants pour les applications de conversion de puissance au-delà du kilovolt." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10152.
GaN-based High Electron Mobility Transistors (HEMTs) on Silicon substrate (GaN-on-Si) are promising candidates for future generations of power converters. Today, technical limitations need to be overcome in order to allow the industrial commercialization of this technology, particularly for high-voltage applications (≥ 600 V). In this frame, this work constitutes a contribution to the development of innovative GaN-on-Si devices operating above 1kV. We mainly focused on the improvement of the blocking voltage of the transistors with the realization of a local substrate removal process with the aim of suppressing the parasitic conduction phenomena between the buffer layer and the substrate. Owing to an improved technological process and innovative epitaxial structures, we observed a drastic improvement of the electrical performances of the transistor under high voltages. In particular, we have been able to demonstrate for the first time a blocking voltage above 3kV for this emerging technology. These results, well beyond the state of the art, pave the way for higher voltage operation GaN-on-Si power devices
San, Juan Maria Luisa. "Etude par frottement intérieur de la mobilité des dislocations aux températures supérieures à 0,3 Tf dans l'aluminium de haute pureté : relation avec la microstructure." Lyon 1, 1985. http://www.theses.fr/1985LYO10010.
Constals, Audrey. "Etude de la régulation glutamate dépendante de la mobilité des récepteurs AMPA et de son rôle physiologique." Thesis, Bordeaux 2, 2013. http://www.theses.fr/2013BOR22058.
AMPA receptors (AMPAR) are ionotropic glutamate receptors which are responsible for the vast majority of fast excitatory synaptic currents in fast transmission. Upon release of glutamate, AMPAR undergo three main conformational states: pore closed/agonist unbound, pore open/agonist bound and pore closed/agonist bound. Controlling the number of AMPAR and their organization in the synapse, through a combination of lateral diffusion and endo/exocytosis, is essential to regulate the intensity of synaptic transmission. The interactions between proteins of the post-synaptic density and accessory receptor proteins regulate the distribution of receptors, controlling their number and organization in the post-synapse. During my PhD, I studied the impact of AMPAR activation on their mobility and organization in the post-synapse. Indeed, the binding of glutamate to AMPAR and their following desensitization lead to major structural changes on the receptor which impacts on their interactions with scaffolding proteins and accessory proteins. The impact of such modifications on the lateral diffusion and sub-synaptic organization of AMPAR was not known yet. My findings show a mobilization of synaptic AMPAR following their activation by glutamate. At the molecular level, I suggest that the transition from the activated state to the desensitized state of AMPAR leads to a change in affinity of the receptor for their partner protein: Stargazin. This glutamate dependent regulation of AMPAR diffusion participates in maintaining the fidelity of fast synaptic transmission
Medjdoub-El, Amraoui Mokhtaria. "Dépôts de nitrure de silicium assistés par plasma à couplage inductif ICP-PECVD : application à la passivation du transistor à haute mobilité électronique GaInAs/InP." Paris 7, 2001. http://www.theses.fr/2001PA077100.
Shi, Xiangjun. "Etude par simulations de dynamique des dislocations des effets d'irradiation sur la ferrite à haute température." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066500/document.
This study is a contribution to the multi-scale modeling of hardening and embrittlement of the vessel steel in Pressurized Water Reactors (PWR) under irradiation conditions. Dislocation Dynamics simulations (DD) were conducted to describe the plasticity of irradiated iron at grain scale. Quantitative information about the pinning strength of radiation-induced loops was extracted and can be transferred at crystal plasticity scale. Elementary interactions between an edge dislocation and different types of loops were first analyzed. A new model of DD was identified and validated, both qualitatively in terms of interaction mechanisms and quantitatively in terms of critical stress, using Molecular Dynamics results available in the literature. The influence of the size of the loops and of the strain rate was particularly studied. Elementary simulations involving a screw dislocation and the same radiation-induced defects were conducted and carefully compared to available MD results, extending the range of validity of our model. Finally, a set of massive simulations involving an edge dislocation and a large number of loops was performed and allowed a first estimation of the obstacle strength for this type of defects (α≈0.26). This value is in a good agreement with previous experimental and numerical studies, and gives us confidence in future work based on this new DD model
Guillermin, Nicolas. "Implémentation matérielle de coprocesseurs haute performance pour la cryptographie asymétrique." Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00674975.
Roucher, Vincent. "Etude de HEMT's AlInAs/GaInAs à désertion et à enrichissement pour applications haute fréquence." Lille 1, 2005. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2005/50376-2005-188.pdf.
Cutivet, Adrien. "Caractérisation et modélisation de dispositifs GaN pour la conception de circuits de puissance hyperfréquence." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10194/document.
Amongst the emerging and developing technologies of the 21st century, wireless transmission is a fundamental aspect for mobile networks, aeronautics, spatial applications and global positioning systems. In that sense, the use of higher frequency bandwidths and increase of transmission channels are aimed by various current research works. Investigated technologies are based upon integrated systems to meet the criteria of devices costs and size. As the cornerstone of such devices, the transistor largely accounts for the final system performance in terms of working frequency, reliability and consumption. To respond to the challenges of today and tomorrow challenges, alternatives to the dominant current silicon process are clearly considered. To date, gallium nitride based technology is found to be the most promising for hyperfrequency power amplification for Ka and W bands given the associated physical and electrical characteristics, prototypes performance and first commercial “off-the-shelf” products. Exploitation of this technology to its full potential requires controlling and mastering the involved fabrication, characterization and modeling steps related to the transistor. This work aims at establishing a methodology enabling a semi-physical modeling of experimental transistors which exhibit state-of-the-art performance. A significant part of this work will also focus on thermal characterization of devices under test and on modeling of passive elements suited for the design of hyperfrequency power circuits
Ahmed, Sajjad. "Système de mesures temporelles 4-canaux à échantillonnage entrelacé ultra haute fréquence basé sur des amplificateurs « Track & Hold » pour la caractérisation impulsionnelle d’amplificateurs de puissance non linéaires." Limoges, 2012. https://aurore.unilim.fr/theses/nxfile/default/de58888d-e1d7-46b1-88e9-0612c10e1eaa/blobholder:0/2012LIMO4022.pdf.
Les communications de forte puissance, telles que celles des applications radar, sont fondées surdes modulations impulsionnelles de signaux RF. La mesure précise de ces signaux RF impulsionels est très complexe parce que leur bande passante est infinie. Pour obtenir les informations instantanées de phase et d’amplitude, il est nécessaire de les mesurer dans le domaine temporel. Ces mesures temporelles ont aussi des limitations en termes de bande passante et de résolution. Ce travail propose une nouvelle technique de mesure temporelle fondée sur l’utilisation d’amplificateurs « Track and Hold » qui permettent de simplifier les circuits analogiques des instruments. Un système de mesure 4 canaux entièrement calibré a été créé pour caractériser des amplificateurs de puissance non linaires excités par des signaux continus ou pulsés. L’outil de caractérisation permet l’extraction des enveloppes des signaux ainsi que la visualisation de leurs transitoires. Les résultats de mesure ont été analysés et validés par comparaison avec des instruments mesures commerciaux. Le système de mesure réalisé à base de THA est associé à une procédure de traitement temporel cohérent des données entrelacées. Des fréquences d’échantillonnage 100 fois supérieures a la fréquence porteuse pour les signaux continus et 10 fois supérieures pour les signaux impulsionnels ont été obtenus et utilisés pour extraire les variations des réponses transitoires pour différentes conditions de charges
Gardès, Cyrille. "Composants nanométriques balistiques de la filière InGaAs/InAlAs/InP pour applications hautes fréquences." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10003/document.
The increase of speed in conventional electronic devices, such as in HEMT, with down-scale rules, is reaching limitations. That is why it is interesting to develop devices with a new design such as ballistic devices which have dimensions around the electron me an free path at room temperature. The aim of this study is the technological optimisation and the electrical characterisation of InGaAs/lnAIAs pseudomorphic InP-based ballistic devices. Nonlinear properties of three-terminal ballistic junctions (TBJ) fabricated using an optimised heterostructure have been studied in DC mode. TBJ, which are operating as rectifiers and frequency multipliers, have been characterised in high frequency. A rectifying sensitivity of O.022mV/µW at 94GHz, without a DC bias, has been obtained on devices with two junctions integrated in parallel. Frequency doubling in the nonlinear domain has been shown with an applied sinusoidal signal of 4GHz. voltage measured in the output branch corresponding essentially to the second harmonie at 8GHz. Finally, TBJ with a Schottky gate have been tàbricated and their property of current inversion has been characterised up to 400kHz. Their transistor behaviour has been measured in microwaves. A current gain eut-off frequency fT of 30GHz has been obtained for a device with a branch width under the gate of 200nm
Lancry, Ophélie. "Étude par microspectrométrie Raman de matériaux et de composants microélectroniques à base de semi-conducteurs III-V grand gap." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10128/document.
GaN based semi-conductors present numerous advantages linked essentially to their large band gap as compared to traditional Si systems. In addition, it is possible to form hetero-junction III-V HEMTs (High electron Mobility Transistor) like AlGaN/GaN which makes it possible to obtain both a large density of carriers confined at the heterojunction and a high electronic mobility. At the moment these systems are the most promising for high-power hyperfrequency applications. However heating occurs during operation which results in abnormal impacts on the performance of the microelectronic components. Micro-Raman characterization of these components makes it possible to understand the influence of the behaviour of the semi-conductor materials on the performance of the HEMTs in hyperfrequency mode. Micro-Raman spectroscopy being non-destructive and possessing a submicronic spatial resolution is well adapted to such studies. The use of various UV and visible excitation wavelengths (266 and 632.8 nm) makes it possible to probe the heterostructures at different penetration depths. We present results of micro Raman studies for analysis of the heterostructure composition, the stresses between layers, the thermal boundary resistance, the crystalline quality of each layer and the doping and thermal behaviour of each layer. In addition, recent time-resolved UV micro-Raman studies have made it possible to analyse the transient thermal behaviour of AlGaN/GaN HEMTs under voltage and in the active area of the component
El, Makoudi Ikram. "Étude et fabrication de transistors à enrichissement de la filière InAlAs/InGaAs pour applications millimétriques faible bruit." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10069/document.
The increasing needs of high frequency electronic systems combined with constant efforts in miniaturization require low noise and high frequency Field Effect Transistor with high operation voltage. For digital applications, enhancement mode HEMT is needed. The enhancement-mode metamorphic AlInAs/GaInAs HEMT on GaAs substrate developed in OMMIC in 2007 meet these requirements and it represents the starting point of our study. The aim of our work is to provide AlInAs/InGaAs E-HEMTs for low noise applications, on InP substrate in order to take advantage of its high electronic mobility, while maintaining high static and dynamic performances. We first optimized the structure, then we realized and characterized E-HEMTs which reach high cutoff frequencies, such as 204 GHz for FT and 327 GHz for FMAX, combined with a low noise figure of 0.96 dB and an associated gain of 13.2 dB at 30 GHz. These structures also show high static performances such as a 30 mV threshold voltage, a gate-to-drain breakdown voltage of –7 V, and a high transconductance of 1040 mS/mm. These results make this pseudomorphic E-HEMT on InP substrate at the state of the art of the enhancement mode HEMTs, and it even competes with the best low noise applications depletion mode HEMTs