Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

See all positions [+]

5G mmW integrated BiDirectional TRX for hybrid and digital beamforming system

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Architectures Intégrées Radiofréquences

01-10-2020

SL-DRT-20-0478

baudouin.martineau@cea.fr

Communication networks, IOT, radiofrequencies and antennas (.pdf)

This thesis addresses the topic of compact, low-cost millimeter wave transceiver in the context of the new coming 5G FR2. Indeed, a considerable number of chips and an area-efficient design will be necessary for hybrid and digital MIMO beamforming. However, conventional transceiver designs use switch-based bidirectional approach with one Tx and one Rx working alternatively in time duplex. For this reason, bi-directional transceiver completely sharing amplifiers and matching networks between the transmitter and the receiver is proposed. Additionally, bidirectional phase shifter, quadrature mixer and baseband amplifier will be studied and design offering a complete solution for hybrid and digital beamforming architecture. The thesis study will cover the architecture, the design and the measurement of such blocs in standalone and the full transceiver. The awaited innovation will encompass several aspect: bidirectional front-end compatible with hybrid configuration, mmW digital beamforming compatible, LO multiplication and local quadrature generation, CMOS SOI process. This phd research will give the opportunity to work in cross-scientific disciplinary from millimeter wave to baseband design and transceiver system architecture offering a very large panel of experiences and competencies. The thesis will take place in the CEA Leti institute under the supervision of Mr Martineau Dr and Mr Belot Hab. The publication in journals and international conferences will be encouraged and facilitated.

Download the offer (.zip)

Study of Vertical GaN Device Architectures

Département Composants Silicium (LETI)

Laboratoire Composants Electroniques pour l'Energie

01-10-2020

SL-DRT-20-0481

julien.buckley@cea.fr

Emerging materials and processes for nanotechnologies and microelectronics (.pdf)

LETI is currently transferring an AlGaN/GaN epitaxy-based power device technology on 200mm Silicon wafers to a well-established industrial partner in the field of power devices (Silicon, SiC,?) Current GaN transistor technologies that are available on the market have a lateral architecture. They allow to render electric power conversion circuits up to the several 10 kilowatt range. The implementation of a vertical architecture will allow to address power ranges above the megawatt. The work proposed in this PhD will involve a study aiming to evaluate the performance and physical properties at the basis of the operation of vertical devices using GaN substrates. The tasks will involve as well the management of the device fabrication (epitaxy, deposition, lithography, implantation) and electrical measurements. Finite element simulations (TCAD using Synopsys tools) will be performed in order to tune the dimensions of structures that will be included in a mask set and subsequently be used to test physical hypotheses to interpret the electrical results.

Download the offer (.zip)

Aluminum/ Silicon carbide nanocomposites obtained by laser powder bed fusion additive manufacturing process.

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire de Formulation des Matériaux

01-11-2020

SL-DRT-20-0483

mathieu.soulier@cea.fr

Emerging materials and processes for nanotechnologies and microelectronics (.pdf)

Metal matrix composite composed of an aluminum metal matrix embedding silicon carbide inclusions is widely used in various industries from automotive to aerospace or defense. Such composites allow the reduction of the parts weight thanks to an increase of the Young modulus/density ratio drastically higher compared to steels or titanium alloys. The study aims at developing aluminum composites reinforced by nanosized silicon carbide particles to improve the material stiffness without compromising on the elongation to fracture criterion. In addition, shaping by an additive manufacturing process based on a laser powder bed fusion process (L-PBF) should allow further improvements in terms of weight reduction, thus fully complying with the strategical objectives of material savings and environmental impact. The first objective of the thesis is to develop the powder mixing process to obtain homogeneous and stable nanocomposite powder, using either a blade mixing to coat aluminum particles by the nano SiC, or a milling process to include the reinforcements inside the aluminum particles. For the case of blade mixing, the challenge is to identify process conditions that allow an homogeneous repartition of the nano-Sic within the solidified material. The second objective of the thesis is to test the potential of tailored specific nano-SiC reinforcements. To this end, the idea is to use the laser pyrolysis process that allows a modification of the surface chemistry to improve the SiC wettability and also limit its decomposition in the aluminum matrix.

Download the offer (.zip)

Piezoelectric MEMS actuator hydraulically amplified

Département Composants Silicium (LETI)

Labo Composants Micro-actuateurs

01-09-2020

SL-DRT-20-0488

laurent.mollard@cea.fr

Cyber physical systems - sensors and actuators (.pdf)

The main objective of micro-actuators research is an architecture that can generate large displacements and forces over a wide frequency range, while not consuming a significant amount of electrical power. To date, no solution meets all these criteria. Indeed hydraulic actuators do not meet the criterion of compactness and frequency but allow significant force and displacement. Similarly, electromagnetic actuators have a good frequency range with excellent force and stroke output, but they are generally heavy and require significant electrical current. Piezoelectrics are also known for their excellent operating bandwidth and can generate large forces in a compact size, but traditionally they have very small displacements. The technological breakthrough of the thesis will consist to develop a hydraulic amplification mechanism, by applying small displacements on a large surface, sa as to move a liquid, and to generate, by conservation of the volume, important displacements on a weaker moving surface. Therefore, the thesis will consist to develop and integrate into a MEMS (Micro Electro-Mechanical System) system, this hydraulically amplified piezoelectric actuator (called HDAM system for "Hydraulic Displacement Amplification Mechanism") and optimize it

Download the offer (.zip)

ultra low temperature solid phase recrystallization assited by nanosecond laser annealing

Département des Plateformes Technologiques (LETI)

Laboratoire

01-09-2020

SL-DRT-20-0514

Pablo.ACOSTAALBA@cea.fr

Emerging materials and processes for nanotechnologies and microelectronics (.pdf)

During last years, great progress has been made in reducing the thermal budget required for the manufacture of microelectronics devices. Moreover, nanosecond laser annealing represents a very promising alternative for the integration of microelectronic devices whose thermal budget must be limited. Since very few years, CEA/LETI has started a very ambitious program on advanced thermal treatments for microelectronics. In this context, a nanosecond laser annealing equipment has been installed in the LETI clean room. This innovative process makes it possible to reach very high temperatures for extremely short durations (a few tens of ns). This implies that the thermal budget applied to the irradiated structures is very low. It has recently been demonstrated that nanosecond laser annealing can be used to obtain solid phase recrystallization of partially amorphized silicon layers. This method can be used to optimize different steps of the manufacturing processes, as for exemple dopant activation on source and drain. It is therefore fundamental to understand the physical mechanisms and to explore the impact of different parameters on the recrystallization kinetics in order to manage this process in basic materials such as Si and SiGe. This thesis aims evaluating the contribution of nanosecond laser annealing on the structural and electrical properties of different semiconductor stacks

Download the offer (.zip)

Lensless imaging and artificial intelligence for rapid diagnosis of infections

Département Microtechnologies pour la Biologie et la Santé (LETI)

Laboratoire Systèmes d'Imagerie pour le Vivant

01-10-2020

SL-DRT-20-0518

caroline.paulus@cea.fr

Artificial intelligence & Data intelligence (.pdf)

The objective of the thesis is to develop a portable technology for pathogen identification. Indeed, in a context of spread of medical deserts and resurgence of antibiotic-resistant infections, it is urgent to develop innovative techniques for rapid diagnosis of infections in isolated regions. Among optical techniques for pathogen identification, lens free imaging methods draws attention because they are the only ones currently able to offer simultaneous characterization of a large number of colonies, all with low-cost, portable and energy-efficient technology. The objective of the thesis is to explore the potential of lensless imaging combined with artificial intelligence algorithms to identify bacterial colonies present in a biological fluid. The thesis will aim to optimize the sizing of the imaging system (sources, sensors) and to study image processing and machine learning algorithms necessary for colony identification. Two cases of clinical applications will be studied.

Download the offer (.zip)

172 Results found (Page 4 of 29)
first   previous  2 - 3 - 4 - 5 - 6  next   last

See all positions