Due to continued transistor scaling, work function tuning of metal gates has become important for advanced CMOS applications. Specifically, this research has been undertaken to discover the tuning of the MoxSiyNz gate work function through the incorporation of nitrogen. Metal Oxide Semiconductor (MOS) capacitors were fabricated using thermal SiO2 as gate oxide on lightly doped p-type Si wafer. A molybdenum silicide (MoSi2) target was reactively sputtered at 10mTorr in presence of N2 and Ar. The gas flow ratio, RN = N2/ (N2+Ar), was adjusted to vary the nitrogen concentration in MoSiN films. The gate work function (Фm) was extracted from capacitance-voltage (CV) measurements using the VFB-tox method. Interfacial barrier heights were measured using internal photoemission (IPE) as an independent confirmation of the MoSiN gate work function. The work function was found to decrease linearly (from ~4.7eV to ~4.4eV) for increasing gas flow ratios (from 10% to 40%). Secondary ion mass spectrometry (SIMS) depth profiles suggested that the nitrogen concentration was relatively uniform throughout the film. X-Ray Photoelectron Spectroscopy (XPS) surface analysis showed a steady increase in the total nitrogen concentration (from ~20% to 32%) in these films as gas flow ratio was increased. These data suggests that the increase in nitrogen concentration in MoSiN films corresponds directly with the lowering of MoSiN work function. These results clearly demonstrate that the work function of MoxSiyNz can be varied ~0.3 eV by adjusting the nitrogen concentration. / October 2008

The strategic importance of microelectronics is reflected in its ubiquity in the global production network and in our daily lives. Above all, the microelectronics revolution has been enabled and driven by the scalability of the silicon transistor and the computational efficiency of its CMOS architecture. While the semiconductor industry has been incredibly adept at pushing the boundaries of scaling in the last few decades, many factors suggest that silicon technology is running into scientific and practical limitations to further scaling. Thus, the push for a beyond-silicon computing platform is imperative. Akin to the transition from bipolar to MOSFET technology or from NMOS to CMOS architecture, the industry is once again looking for the next disruptive technology to continue the exponential growth of computing power. In 2004, two research groups, one from the University of Manchester and the other from Georgia Tech, reported on the electrical properties of ultrathin graphite. Their findings demonstrated the stability of graphene, an atomic layer of graphite, as well as its superb carrier mobility, spurring the semiconductor industry to invest in the material as a candidate for a beyond-silicon computing platform. Within this framework, this thesis explores the promise of graphene as a material and technological platform for electronic devices. The objectives of the thesis are (i) to elucidate opportunities and challenges in the design and fabrication of graphene field-effect devices, and (ii) to advance a new device platform based on graphene p-n junctions.

Indisponible

Indisponible

REALISATION DE MICROCAPTEURS DU TYPE MOS A GRILLE DE PALLADIUM DESTINES A LA DETECTION D'HYDROGENE. ORIGINE DES FORCES RESPONSABLES DE PHENOMENES D'ADSORPTION A L'INTERFACE SOLIDE-GAZ, TAUX D'OCCUPATION DES SITES, PRESSION DES GAZ PRESENTS A LA SURFACE DU SOLIDE, ENERGIE D'ACTIVATION. ETUDE DES MODIFICATIONS DES CARACTERISTIQUES ELECTRIQUES DES STRUCTURES MOS SUSCEPTIBLES D'ETRE PROVOQUEES PAR L'ADSORPTION DES GAZ. DESCRIPTION DES BANCS DE MESURE ET DU PROCESSUS TECHNOLOGIQUE UTILISE POUR LA REALISATION DE STRUCTURES MOS. RESULTATS EXPERIMENTAUX PORTANT SUR LA REPONSE DES DISPOSITIFS A L'HYDROGENE: EN PRESENCE D'OXYGENE A LA PRESSION ATMOSPHERIQUE ET SOUS PRESSION REDUITE EN ABSENCE D'OXYGENE DANS UNE ENCEINTE A VIDE.

ETUDE PORTANT SUR LES MOYENS DE CONTROLE DE LA DUREE DE VIE DES PORTEURS DANS LE SILICIUM, LES METHODES ELECTRIQUES DE MESURE DE CE PARAMETRE PHYSIQUE ET L'EVALUATION DE L'IMPACT DE LA DUREE DE VIE DES PORTEURS SUR LES PERFORMANCES ELECTRIQUES DES REDRESSEURS P I N DE PUISSANCE. DANS LE 1ER CHAPITRE ON CONSIDERE LES DIFFERENTES IMPURETES METALLIQUES ET DEFAUTS QUI SONT UTILISES POUR LE CONTROLE DE LA DUREE DE VIE DES PORTEURS DANS LES DISPOSITIFS DE PUISSANCE AU SILICIUM. DANS LE 2EME CHAPITRE ON EFFECTUE UNE ANALYSE COMPARATIVE DES DIFFERENTES METHODES ELECTRIQUES DE MESURE DE LA DUREE DE VIE SUR LES DIODES P I N DE PUISSANCE. DANS LE 3EME CHAPITRE ON ETUDIE L'INFLUENCE DE LA DUREE DE VIE DES PORTEURS SUR LES PERFORMANCES ELECTRIQUES DES REDRESSEURS P I N.

Cette thèse, effectuée dans le cadre du projet Européen MEDEA+, PICS, porte sur la conception d'imageurs CMOS destinés aux applications de sécurité automobile et de surveillance. Le travail s'est focalisé sur l'amélioration de la dynamique de fonctionnement des imageurs CMOS tout en conservant des valeurs de bruit spatial fixe, une consommation et une surface de pixel minimales. Plusieurs solutions ont été explorées, les pixels à compresseur logarithmique, les pixels à temps d'intégration et les pixels intégrant une adaptation aux conditions lumineuses. Ces études ont abouties à la conception et la fabrication de quatre imageurs CMOS. Ces capteurs ont été testés et ont permis de valider les approches choisies.

ETUDE DU BRUIT DE FOND DE TRANSISTORS BIPOLAIRES COMPORTANT 4 PARTIES: ETUDE THEORIQUE DE LA ZONE ACTIVE DU COMPOSANT EN PRENANT EN COMPTE LES EFFETS DE LA DEFOCALISATION DES LIGNES DE COURANT EMETTEUR, PRISE EN COMPTE DES ZONES PASSIVES ET DES ELEMENTS PARASITES, DESCRIPTION DES TECHNIQUES D'IDENTIFICATION DES PARAMETRES DU MODELE ET DES METHODES DE MESURE DU FACTEUR DE BRUIT, CONFRONTATION DES RESULTATS THEORIQUES ET EXPERIMENTAUX.

Indisponible

Pas de résumé