6 research outputs found
LIFECYCLE MANAGEMENT, MONITORING AND ASSESSMENT FOR SAFE LARGE-SCALE INFRASTRUCTURES: CHALLENGES AND NEEDS
Many European infrastructures dating back to â50 and â60 of the last century like bridges and viaducts are approaching the end of their design lifetime. In most European countries costs related to maintenance of infrastructures reach a quite high percentage of the construction budget and additional costs in terms of traffic delay are due to downtime related to the inspection and maintenance interventions. In the last 30 years, the rate of deterioration of these infrastructures has increased due to increased traffic loads, climate change related events and man-made hazards. A sustainable approach to infrastructures management over their lifecycle plays a key role in reducing the impact of mobility on safety (over 50â000 fatalities in EU per year) and the impact of greenhouse gases emission related to fossil fuels. The events related to the recent collapse of the Morandi bridge in Italy tragically highlighted the sheer need to improve resilience of aging transport infrastructures, in order to increase the safety for people and goods and to reduce losses of functionality and the related consequences. In this focus Structural Health Monitoring (SHM) is one of the key strategies with a great potential to provide a new approach to performance assessment and maintenance over the life cycle for an efficient, safe, resilient and sustainable management of the infrastructures. In this paper research efforts, needs and challenges in terms of performance monitoring, assessment and standardization are described and discussed.The networking support of COST Action TU1402 on âQuantifying the Value of Structural Health Monitoringâ and of COST Action TU1406 on âQuality specifications for roadway bridges, standardization at a European level (BridgeSpec)
Experimental validation of the âFLoating Islandâ concept: realization of low on-resistance FLYMOSâą transistors
The present 14Â volts automotive electrical system will
soon become 42Â volts. For these future automotive applications, development
of 80Â volts power MOSFETs exhibiting low on-resistance is desired. The
âFLoating Islandâ MOSFET (FLIMOSFET) is one of the new candidates to break
the silicon limit, which is the âspecific on-resistance/breakdown
voltageâ trade-off limit of conventional power MOSFETs. In this paper, the
âFLoating Islandâ concept has been implemented on silicon: new vertical
N-channel FLIMOSFETs (FLYMOSâą) dedicated to automotive
applications (below 100Â volts) have been fabricated for the first time,
using two steps epitaxy process. Experimental results show that the
FLYMOSâą transistor exhibit a breakdown voltage of 73Â volts
but also an improved specific on-resistance compared to conventional
VDMOSFETs (33% reduction of the specific on-resistance for the same
breakdown voltage). In other words, in terms of âspecific on-resistance/breakdown voltageâ trade-off, the FLYMOSâą transistor is one
of the best MOS devices in low voltage applications. These measurements
validate the âFLoating Islandâ concept and the efficiency of the original
edge cell that is used in the FLYMOSâą technology
Experimental validation of the âFLoating Islandsâ concept: 95âV breakdown voltage vertical FLIDiode
International audienceIn this paper, the âFLoating Islandâ concept has been implemented on silicon: a FLIDiode has been built for thefirst time. Experimental results confirm the predictive 2D simulations: this new diode exhibits an importantbreakdown voltage (about 95 Volts) with a N- epitaxial layer doping concentration (1.1 x 1016 cm-3) usuallydedicated to 50 Volts devices. These measurements validate the âFLoating Islandâ concept and the efficiency ofthe original edge cell that will be used in the FLIMOS technology: it can be expected that the specific on-resistance of the FLIMOSFET will be drastically reduced compared to the conventional VDMOSFE
Contribution to Silicon-Carbide-MESFET ESD robustness analysis
International audienceIn this work, ElectroStatic Discharge (ESD) tests are performed on SiC MESFETs in order to understand their physical behavior and failure mechanisms during such stresses. The purpose is to point out advantages and drawbacks of this technology, paying special attention to aspects related to its possible commercialization and reliability. Three MESFETs designed to be integrated as a driver in monlithic SiC systems, featuring some ESD internal protection are investigated. Different configurations on ohmic and Schottky contacts are analyzed. Lock-in thermography is carried out for the physical failure location. With TCAD Sentaurus simulation, it allows to determine the nature of the defects on the damaged areas. Hypothesis on the failure mechanism as SiO 2 breakdown or SiC sublimation are presented. Solutions to increase the ESD robustness such as a Zener diode integration or the use of Al2O3 dielectric for passivation are therefore proposed in this article
Robustesse de MESFET SiC face aux décharges électrostatiques
National audienceL'Ă©mergence des composants de puissance commercial en carbure de silicium (SiC) dans notre sociĂ©tĂ© s'accentue d'annĂ©es en annĂ©es mais certaines de leurs faiblesses perdurent. Dans ce travail nous Ă©tudierons l'impact de dĂ©charges Ă©lectrosta-tiques (ESD) sur diffĂ©rents MESFET et nous montrerons que la faiblesse principale est intrinsĂšquement liĂ©e aux propriĂ©tĂ©s de son diĂ©lectrique de passivation le plus commun, le SiO2. Une analyse de ce composant vouĂ© Ă fonctionner en conditions sĂ©vĂšres dĂ©finira les limites actuelles de cette technologie en terme de robustesse aux ESD. Mots-clĂ©s â SiC, MESFET, stress ESD, fiabilitĂ©, oxyde de passiva-tion, Lock'in thermographie, thermographi infrarouge active, robus-tess
Performances dynamiques des transistors FLYMOSTM 65 Volts Ă canal N
National audienceDans ce papier, un transistor FLYMOSâą 65V est caractĂ©risĂ© en commutation pour la premiĂšre fois dans le but d'ĂȘtre comparĂ© Ă un transistor VDMOS conventionnel. Il s'avĂšre que les mesures de capacitĂ©s inter-Ă©lectrodes et de gate charge des deux composants sont comparables. Une Ă©tude comparative, Ă l'aide de simulations 2D, de deux structures de mĂȘme tenue en tension nous a permis de conforter ces rĂ©sultats, confirmant l'hypothĂšse que l'insertion d'Ăźlot flottants n'entraĂźnait pas de phĂ©nomĂšne parasite ou nouveau, dans le cas d'Ăźlots faiblement dopĂ©s