Evaluation technologique de structures 3D dans le silicium pour la réalisation de composants de puissance

La verticalisation des composants de puissance, nécessaire pour acheminer des fortes densités de courant, est bien connue. Il n empêche que la circulation des courants perpendiculairement à la surface dans les composants de puissance limite aujourd hui leur intégration. Dans cette problématique, une rupture technologique, associée à un concept nouveau de l électronique, les structures 3D, voit le jour avec ce travail de thèse. Il s agit de concevoir, dans un premier temps, des structures électroniques connues, dans lesquelles la circulation du courant est parallèle à la surface de la plaquette en utilisant toute l épaisseur de celle-ci. L intérêt de ce travail tient en premier lieu dans le gain important en densité d intégration des composants de puissance qu autorise l approche 3D. De plus, ce concept s inscrit en rupture au niveau des technologies du silicium, ouvrant ainsi la voie à de nouveaux développements dépassant largement le cadre de l électronique de puissance. La première partie de ce document introduit et formalise le concept 3D. Elle propose de plus une analyse de la faisabilité technologique des éléments de base de l intégration 3D. Le développement des étapes technologiques de base (gravure, photolithographie, dépôt et dopage) adaptées à des structures 3D y est donc décrit. La seconde partie de ce travail présente la conception et la fabrication d'un prototype de composant de puissance 3D, un transistor MOSFET, permettant d'évaluer l'application de l'ensemble des technologies 3D développées. Finalement, cette étude permet de statuer sur la maturité technologique requise pour que le concept 3D offre les gains théoriques espérés.Vertical through-wafer current conduction is a well know configuration used to conduct high current in power devices. However, the perpendicular current conduction to the power devices surface limits its integration factor. In this context, a technological breakthrough associated with a new electronic concept, the 3D structures, appear in this thesis work. Firstly, it consists in conceiving standard electronics structures, in which the current flow is parallel to the wafer surface, in the whole wafer thickness. This work was conducted to show the potential high integration capability of power devices with this 3D approach. Moreover, this concept dealing with a tremendous modification in silicon technologies, paves the way to new developments going beyond the power electronics domain. The first part of this document introduces and formalizes the 3D concept. It proposes a capability analysis of basic technological steps of 3D integration. The main technological developments (etching, photolithography, deposition and doping) adapted to 3D structures are described. The second part of this work presents the design and fabrication of a 3D power device prototype, a 3D MOSFET, which allows an evaluation of the technology developments implementation. Finally, this study defines the technological maturity required to observe someday the level of integration expected from this 3D concept.TOURS-BU Sciences Pharmacie (372612104) / SudocSudocFranceF

Climate Change Mitigation: The Contribution of Carbon Capture and Utilisation (CCU)

editorial reviewedCarbon Capture and Utilisation (CCU) is a broad term that covers processes that capture CO2 from flue and process gases or directly from the air and convert it into a variety of products such as renewable electricity-based fuels, chemicals, and materials. No precise estimate of the potential mitigation role of CCU technologies exists to date, because of uncertainties in renewable electricity cost scenarios and the low granularity of models that simulate different CCU options. However, CCU technologies have the potential to play a significant role in the mitigation of climate change as described, in the latest report of the Working Group 3 of the Intergovernmental Panel on Climate Change1. Many of the technologies are already mature enough to be deployed and have the potential to reduce net CO2 emissions in gigatons equivalence CO2 emissions. Unlike other options, CCU technologies provide drop-in fuel solutions which can be introduced in existing markets without significant modifications to powertrain production, distribution and infrastructures. CCU technologies have potential to provide solutions to hard-to-abate sectors and to generate revenues through the producion of marketable products. Moreover, CCU can help achieve an energy sovereignty and a reduced depedency on fossil fuels-based energy. Nevertheless, the slow deployment of CCU results from the low availability of renewable energy, the lack of market incentives and the absence of a favourable regulatory framework. The present work discusses the climate mitigation potential of CCU, including opportunities and limitations of CCU technologies from CO2 mineralisation to power-to-X applications

Carbon capture and utilization: More than hiding CO2 for some time

peer reviewedThe recently published third working group of the sixth assessment report of the Intergovernmental Panel on Climate Change mentions for the first time Carbon Capture and Utilisation (CCU) as a solution to decrease net CO2 emissions, as well as a potential technology to move away from fossil carbon by using CO2 as an alternative feedstock for the production of renewable chemicals and fuels. This paper clarifies some of the myths related to CO2 utilisation and highlights some important facts around CCU technologies with a focus on hydrocarbon e-fuels which refers to synthesizing fuels from renewable energy, water and CO2. The argument sometimes heard that CCU would be just a delay of CO2 emissions is wrongly but still frequently used by critics of the technology. CCU, even when using CO2 from fossil point sources, may make sense and can reduce up to 50% of the CO2 emissions if renewable energy is used. However, lock-in effects in which fossil assets are continued to operate to provide CO2 should be avoided. The utilisation of CO2 from biomass, air or water can allow to reach a carbon circular economy and support the efforts towards carbon neutrality. Air sourced CO2 for CCU makes the design possible of an autothermally operated process for the production of molecules based on CO2 and water from the ambient air. Full Life Cycle Assessments, going beyond just carbon footprinting as well as social perception and acceptance evaluations should be standard practice for all new CCU projects