Scientific direction Development of key enabling technologies
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Inductors for quantum reflectometry

Département Composants Silicium (LETI)

Laboratoire Composants Radiofréquences

01-04-2020

PsD-DRT-20-0039

jean-philippe.michel@cea.fr

Quantum computing is nowadays a strong field of research at CEA-LETI and in numerous institutes and companies around the world. Reflectometry is one of the major avenues envisaged for Qubits reading. Reflectometry and frequency multiplexing techniques requires many small resonators that must be positioned as close to the quantum chip as possible. First demonstrations performed with discrete inductors showed limitations in terms of size and coupling. Large-scale passives component integration technologies mastered at CEA-LETI can meet these dimensional constraints. Especially, CEA-LETI is positioned at the highest level of the state of the art in magnetic inductors on silicon, with record inductance densities (> 3 000 nH/mm²). First measurements have already validated the operation of the technology at very low temperature. We now have to demonstrate the feasibility of an inductive interposer dedicated to Qubits reading by leveraging high inductance densities. The student will perform the accurate RF characterization of our magnetic inductors at cryogenic temperature. He will analyze the obtained results to describe the electrical and magnetic behaviour of the components. The bibliographic analysis and the studies already carried out will enable him to define a new technological stack combining the advantages of magnetic materials and superconductors. He will propose suitable designs to realize high quality factor inductors and an inductive interposer for Quantum reflectometry.

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Modeling of trapping and vertical leakage effects in GaN epitaxial substrates on Si

Département Composants Silicium (LETI)

Laboratoire de Simulation et Modélisation

PsD-DRT-20-0043

marie-anne.jaud@cea.fr

State of the art: Understanding and modeling vertical leakage currents and trapping effects in GaN substrates on Si are among the crucial subjects of studies aimed at improving the properties of GaN power components : current collapse and Vth instabilities reductions, reduction of the leakage current in the OFF state. Many universities [Longobardi et al. ISPSD 2017 / Uren et al. IEEE TED 2018 / Lu et al. IEEE TED 2018] and industrials [Moens et al. ISPSD 2017] are trying to model vertical leakages but until now, no clear mechanism has emerged from this work to model them correctly over the entire range of voltage and temperatures targeted. In addition, modeling the effects of traps in the epitaxy is necessary for the establishment of a a robust and predictive TCAD model of device. For LETI, the strategic interest of such a work is twofold: 1) Understanding and reducing the effects of traps in the epitaxy impacting the functioning of GaN devices on Si (current collapse, Vth instabilities?) 2) Reaching the leakage specifications @ 650V necessary for industrial applications. The candidate will have to take charge in parallel of the electrical characterizations and the development of TCAD models: A) Advanced electrical characterizations (I (V), I (t), substrate ramping, C (V)) as a function of temperature and illumination on epitaxial substrates or directly on finite components (HEMT, Diodes, TLM ) B) Establishment of a robust TCAD model integrating the different layers of the epitaxy in order to understand the effects of device instabilities (dynamic Vth, dynamic Ron, BTI) C) Modeling of vertical conduction in epitaxy with the aim of reducing leakage currents at 650V Finally, the candidate must be proactive in improving the different parts of the substrate

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Low temperature process modules for 3d coolcube integration : through the end of roadmap

Département Composants Silicium (LETI)

Laboratoire d'Intégration des Composants pour la Logique

01-03-2019

PsD-DRT-19-0048

claire.fenouillet-beranger@cea.fr

3D sequential integration is envisaged as a possible solution until the end of CMOS roadmap. Different process modules have been developped @ 500°C for planar FDSOI technology in a gate first process. However, regarding bottom transistor level stability in CoolcubeTM integration, and yield consideration, the need to reduce further the top transistor temperature down to 450°C should be explored. The post-doc will have in charge the development of specific technological modules at low temperature both 500°C and 450°C for FDSOI planar devices to acquire a solid knowledge in low temperature CMOS process integration. The specific low temperature gate module will be addressed on planar devices. The threshold voltage modulation will also be studied. The work will be performed in collaboration with the technological platform process of LETI for the low temperature modules development. The electrical characterization in collaboration with the characterization laboratory and the TCAD simulations team of LETI.

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Polymer synthesis and characterizations of solid-state electrolyte for lithium-ion batteries

Département de l'Electricité et de l'Hydrogène pour les Transports (LITEN)

Laboratoire Matériaux

01-02-2020

PsD-DRT-20-0052

laurent.bernard3@cea.fr

LITEN is one of the highest European research centers in the field of the new energy technologies. LITEN research activities focus on the renewable energy, on the energy efficiency and on the high performance materials for energy. Our department is focused on the development of lithium-ion batteries to enhance both simultaneously their energy density and their safety. Standard liquid electrolytes used in actual battery are intended to be replaced by solid-state electrolyte to reach these objectives. The selected candidate will work on patented and exclusive organic materials designed to fulfill all the requirements of solid-state electrolytes. He/she will be in charge of synthesizing new organic and polymer structures. Some steps of the synthesis/process will be carried out under anhydrous conditions (i.e. Glove box or anhydrous room). The post-doc will be in charge of characterizing these materials in terms of structure (NMR, FT-IR, HPLC-MS..), nanostructure (SAXS, POM, XRD, GI-SAXS), physical properties (DSC , TGA, rheology) and electrochemical properties (EIS, cycling, electrochemical stability window measurements). He/she will be in contact with various experts in batteries and large-scale instruments. The project is part of an ANR project with several partners, dedicated to the fundamental understanding of ion diffusion/transport in soft electrolytes by means of multi-scale multi-techniques methodology. Strong and good communication skills (reporting) are expected.

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Numerical Meta-modelization based study of the propagation of ultrasonic waves in piping system with corroded area

Département Imagerie Simulation pour le Contrôle (LIST)

Laboratoire Simulation et Modélisation en Acoustique

01-05-2020

PsD-DRT-20-0055

vahan.baronian@cea.fr

The aim of the ANR project PYRAMID (http://www.agence-nationale-recherche.fr/Projet-ANR-17-CE08-0046) is to develop some technics of detection and quantification of the wall thinning due to flow accelerated corrosion in piping system. In the framework of this project involving French and Japanese laboratories, CEA LIST develops new numerical tools based on finite elements dedicated to the modelling of an ultrasonic guided wave diffracted by the corrosion in an elbow pipe. These solutions support the design of an inspection process based on electromagnetic-acoustic transduction (EMAT). To this end, the ability of CEA LIST to adapt meta-modeling tools of its physical models will be the key asset to allow intensive use of the simulation.

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Measurement of active cell nematics by lensless microscopy

Département Microtechnologies pour la Biologie et la Santé (LETI)

Laboratoire Systèmes d'Imagerie pour le Vivant

01-03-2020

PsD-DRT-20-0059

cedric.allier@cea.fr

At CEA-Leti we have validated a video-lens-free microscopy platform by performing thousands of hours of real-time imaging observing varied cell types and culture conditions (e.g.: primary cells, human stem cells, fibroblasts, endothelial cells, epithelial cells, 2D/3D cell culture, etc.). And we have developed different algorithms to study major cell functions, i.e. cell adhesion and spreading, cell division, cell division orientation, and cell death. The research project of the post-doc is to extend the analysis of the datasets produced by lens-free video microscopy. The post-doc will assist our partner in conducting the experimentations and will develop the necessary algorithms to reconstruct the images of the cell culture in different conditions. In particular, we will challenge the holographic reconstruction algorithms with the possibility to quantify the optical path difference (i.e. the refractive index multiplied by the thickness). Existing algorithms allow to quantify isolated cells. They will be further developed and assessed to quantify the formation of cell stacking in all three dimensions. These algorithms will have no Z-sectioning ability as e.g. confocal microscopy, only the optical path thickness will be measured. We are looking people who have completed a PhD in image processing and/or deep learning with skills in the field of microscopy applied to biology.

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