The market introduction of high temperature wide bandgap power semiconductor devices with junction temperature exceeding 200°C significantly accelerates the trend towards high power density and severe ambient temperature electronics applications. Such evolution may have a great impact in aeronautics applications, especially with the development of More Electric Aircraft (MEA), since it can allow to reduce the mass and volume of power electronics systems. As a consequence, the aircraft operating cost can decrease. However, for electronics used under such harsh conditions, the package reliability and the heat evacuation are very critical issues. The goal of this project is to design and fabricate high performance double sided cooled power electronics modules with optimized thermomechanical properties. The assembly is based on copper joints and a copper heat sink and integrates several technological breakthroughs. Three main technological bricks will be deeply addressed in order to reach the target: 1) Synthesis of nanoporous copper films, either freestanding or directly deposited on metallized substrates with controlled microstructure: In order to limit the risks, three independent strategies will be investigated during the project: the synthesis of nanoporous copper free standing films using melt-spinning and chemical dealloying techniques, the direct on-substrate electroforming of copper-alloy followed by anodic dealloying, and the direct growth of nanoporous structures without any additional treatment by tuning electrolyte formulation and plating parameters. 2) Thermocompression of the nanoporous copper films for die attach: Conventional heating will be achieved at low pressure and in inert/reductive atmosphere. An alternative method based on laser induced fast heating will also be evaluated to thermocompress the nanoporous copper in air. Both solutions allow to limit the oxidation copper issues. The underlying physical mechanisms taking place during the thermocompression of the various morphologies and microstructures of nanoporous copper films will be in-depth investigated. The joint stability under electro-thermo-mechanical aging conditions will be evaluated. 3) Deposition of thick copper layers for substrate/heatsink assembly using electroforming process: A thick dense metal layer will be deposited on a designed sacrificial polymer preform allowing to create a wide range of complex shapes directly on the metallized substrate with low residual stresses. This technology combined to virtual prototyping will allow us to fabricate high performance heat sink patterns (liquid forced convection without phase change) in terms of high local heat transfer coefficient and low pressure drop. The thermal-hydraulic performances of the heat sinks will be analyzed with an experimental setup. The robustness of the assembly (substrate/heat-sink) under repetitive temperature variations will be also evaluated. Silicon Carbide (SiC) devices based power modules (inverter phase leg) using the aforementioned technological bricks will be realized and evaluated in the project. Electrical, thermal and robustness tests are planned to estimate the module performances. The COPPERPACK project will contribute to validate and push our concept from Technology Readiness Level (TRL) 2 up to a TRL 3-4 with a functional technological demonstrator.

Pressures on ecosystems have reached such an unprecedented rate that many ecosystems have been irreversibly damaged and that many animal populations have declined since the 1950s. Although human pressures on ecosystems have been identified, the mechanisms of biodiversity decline (i.e. relative importance of each pressure in the decline, temporality of events…) are poorly known. One reason is the lack of long-term data on population monitoring to study the impact of human pressures from past to present on animal populations and communities. REPAST proposes to use a retrospective multidisciplinary approach to study the impact of environmental pressures on the decline of bats through the study of guano cores collected in bat roosts. In caves or buildings, bat droppings (guano) fall to the ground and accumulate chronologically until reaching substantial thickness over time, and constitute historical archives containing temporally situated information about bat populations, environmental context, and human pressures. REPAST will test the general hypothesis that one or several stressors (habitat and climate changes, exposure to pollutants) will be associated to temporal variations of biological responses (pathogen prevalence, shift in diet, genetic diversity, bat richness). On 10 cores already sampled in bat colonies located in Burgundy Franche-Comté region, a robust chronology based on proxies used for paleoecological studies (14C, 137Cs, 210Pb concentrations) will be performed. The feasibility study done within the last 2 years shows that the cores date back from at least the 1950s, one being much older. Temporal variations of some anthropogenic pressures will also be reconstructed. Pollens will be studied on the cores to reconstruct the foraging areas (habitat) characteristics. The concentrations of some pollutants (~20 metals, 17 persistent organic pollutants including DDT and PCBs, and neonicotinoids) will be measured along the cores. Climate changes will be studied using meteorological data from 76 stations active since the 1940s across the region. Guano cores will also provide biological descriptors of bat colonies, which will be related to human pressures indices. The richness and composition of bat colonies, their diet using a metabarcoding approach, their exposure to eukaryotic pathogens, and their genetic diversity (using guano and Museum specimens already collected) will be reconstructed over time. Finally, historical archives and current counts from NGOs working in bat conservation will allow reconstructing the pattern of demographic trends and extinction risk of bat species since the 1940s. As the various anthropogenic pressures may act directly or indirectly on the biological responses, the complex set of variables measured in REPAST will be analysed using the structural equation modelling (SEM) framework. SEM’s causal diagrams will be constructed, based on explicit causal assumptions/hypotheses related to the mechanisms supposed to be involved between one or several pressures to one or several biological responses. The nature and the pattern of associations (what stressor(s) is(are) linked to what response(s) and how (from long and continuous associations to sudden shifts)) will improve our understanding of the mechanism(s) of bat decline. NGOs and stakeholders of bat roosts will be fully involved in the project and have already took part in the sampling process and share their data (e.g. bat counts). Apart from the classical scientific exploitation of the results (international meetings and articles), the large public will also be informed and invited to participate (e.g. in indicating colonies with guano accumulation unknown from NGOs) through a specific website and conferences. REPAST will allow gaining insights in the understanding of the mechanisms underlying the decline and the temporality of bat decline (and resilience) and, as some of the stressors still occur, may allow to predict and prevent new declines.

This proposal addresses the two major roadblocks in the development of graphene for high-performance nano-optoelectronics, namely how to efficiently and reliably integrate them in pristine conditions in electronic devices, and how harness the exceptional properties of graphene. Specifically, proof of principle of ultra-thin body tunnel field effect transistors (UB-TFET) are proposed consisting of two-dimensional (2D) all epitaxial graphene/boron nitride heterostructures with a viable large scale integration scheme. Tunnel transistors are an efficient alternative to standard field effect transistors designs that are inefficient for graphene because of the lack of a bandgap. Importantly UB-TFET should overcome the thermal limitation of thermioic sub-threshold swing in common transistors. The TFET will be based on epitaxial graphene on SiC (epigraphene, or EG)/BN structures; the most advanced implementation will utilize the recently discovered exceptional conductance properties of epigraphene nano-ribbons that are quantized single channel ballistic conductors at room temperature. But having excellent graphene is far from having a device and the active component has to be integrated. This project is based on the fundamental realization that only (hetero)-epitaxial growth can provide the required atomic control for reliable devices. Epitaxial growth insures clean interfaces and precise orientation of the stacked layers, avoiding trapped molecules and the randomness inherent to layer transfer. However, despite this absolute requirement, very little progress has been made up to now to grow large 2D dielectric on graphene; most dielectric deposition needs chemical modification of the graphene surface for adhesion, which invariably compromises the graphene electronic performance. Hexagonal boron nitride (h-BN) layers is considered the best substrate for graphene, but only micron size BN flakes are available, making the integration tedious, unreliable and impossible at large scale. In this proposal we will grow h-BN epitaxialy on epigraphene by metalorganic vapor phase epitaxy (MOVPE). As demonstrated in preliminary work by this three-team partnership, this technique provides exceptional unmatched graphene/h-BN epitaxial interfaces as required for high performance electronics, and immediate upscaling capabilities. The SiC/EG/h-BN heterostructure will give access to graphene properties in an exceptionally reproducible and clean environment, not otherwise available. Growth conditions will be investigated to produce ultra thin h-BN on epigraphene, which have not been achieved yet. This proposal will then follow two tracks to build UB-TFETs, demonstrating proof of principle of vertical and lateral BN/EG-based FETs. Our ultimate goal is to combine ballistic epigraphene nanoribbons in tunneling devices to enable a new generation of electronic devices. This is an extremely promising alternative to the standard FET paradigm that can enable ultra-high frequency operation as well as low power operation. This project is a tight well-focused partnership between three teams with a history of highly successful collaboration and perfect complementarity: CNRS-Institut Néel (Grenoble), CNRS/ONERA-Laboratoire d’Etude des Matériaux (Châtillon), and CNRS/Georgia Institute of Technology -UMI 2958 (Metz, in collaboration with GT Atlanta). We will build up on the important milestone of epitaxial h-BN growth on EG, towards critical development including ultra-thin BN and fabrication of tunnel transistors devices. IN will be in charge of providing epigraphene, will design and realized transistor devices and perform transport measurements; the UMI team will produce the BN epitaxial film and provide basic structural study for rapid optimization of the growth process; LEM will perform advanced structural and optical studies, in particular HR-TEM studies, critical to the layer characterization of ultra thin 2D films.

Glioblastoma (GBM) remains the most aggressive of all primary brain tumors and no effective treatment is available so far. The recent success of immune checkpoint inhibitors in several cancers paved the way for the rehabilitation of anticancer vaccines. However, critical factors challenge the efficacy of cancer vaccines in clinic, such as the nature of tumor antigens, vaccine design and delivery system as well as tumor-associated immune resistance mechanisms. Our ambition is to develop new vaccine strategies in GBMs by combining multiple approaches to overcome these limitations. First, we will take advantage of the tumor antigen Telomerase reverse transcriptase (TERT), which is a promising antigen target given its high overexpression in many cancers, and especially in GBMs. Second, we will assess 2 recently developed vaccine technologies for TERT delivery: i) messenger RNA-based vaccines, which have gained considerable interest in the field of anticancer vaccine, ii) melanin-based vaccine, which represents a novel generation of vaccine delivery platform. Third, we will evaluate the combination of TERT-based vaccines with therapies targeting GBM-associated immune escape mechanisms such as immune checkpoints and immunosuppressive cells on an orthotopic tumor model. By the end of this project, we will define a new vaccine formulation /protocol, aiming to be translated into a clinical trial in GBM patients. Furthermore, the results obtained in this particular tumor model with these 2 different technologies will be of major interest for further vaccine developments, which go far beyond the glioblastoma field, as it has a transfer potential to many more indications (various cancers, viral diseases, infectious diseases…).

The ETHICS project aims to develop new generations of piezoelectric transducers and MEMS based on the microfabrication of lead-free piezoelectric composites. This project addresses technological developments to make an ecological transition towards robust sensors and frequency sources for applications in health, non-destructive testing or extreme temperature conditions. ETHICS is a single-team multidisciplinary project for the integration of lead-free piezoelectrics, the validation of mirofabrication processes and test phases, finally the development of robust models for the integration of piezoelectric composites in their environment. ETHICS will make it possible to constitute a technological hub and a team of excellence to carry out academic and industrial research.